Use of pesticides,herbicides and fertilizers is among the techniques to control insect pests and fungal pathogens.However,the technique is the major contributor to severe environmental implications in terms of air,wat...Use of pesticides,herbicides and fertilizers is among the techniques to control insect pests and fungal pathogens.However,the technique is the major contributor to severe environmental implications in terms of air,water and soil pollution.Besides,variable inconsistency becomes an important issue in the implementation of inclined bed dryers,leading to significant rice grain loss.Cold plasma technology has been widely proposed as a potential alternative for rice grain postharvest treatment management due to the presence of generated ionised gas that eventually produces reactive oxygen species or reactive nitrogen species.These species are used to decontaminate foodborne pathogens,mycotoxins and bacterial diseases.This review explores the current literature regarding cold plasma treatment technology,focusing on its efficiency as the microbial decontamination medium and insect pest mortality medium,and on the enhancement functional,nutritional and cooking properties,especially in rice grains.Previous studies have successfully demonstrated the ability of cold plasma treatment to significantly reduce the microbial count of foodborne pathogens,detoxify mycotoxins,and control seedborne rice seedling bacterial diseases.Previous studies have also proved that the implementation of cold plasma technology in postharvest management should be seriously considered for improving rice grain quantity and quality in Malaysia.展开更多
To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate...To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30oC were germinated in the dark at 30oC for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.展开更多
Annual ryegrass(Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little i...Annual ryegrass(Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year(2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass(RG) as a winter cover crop and winter fallow(WF) without weed. Subplots were three N treatments for each rice season: 0(N_0), 100(N_(100)) and 200 kg N ha–1(N_(200)). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice(0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake) and double rice(0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_(100) and N_(200) plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.展开更多
Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natura...Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.展开更多
This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-...This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations, that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), and abscisic acid (ABA), the ethylene evolution rate, activities of sucrose synthase (SuSase) and starch synthase (StSase) in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z + ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z + ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and grain weight. The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight. Spraying ethephon (ethylene-releasing agent) at the early grain filling stage increased the evolution rate of ethylene, reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight. The results were reversed when cobatous nitrate (an inhibitor of ethylene synthesis) was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z + ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents.展开更多
Objective:To determine distribution of arthropods in rice grains obtained from different sources.Methods: Rice samples were randomly collected from public in urban areas,farmers in rice field areas,aborigines in undev...Objective:To determine distribution of arthropods in rice grains obtained from different sources.Methods: Rice samples were randomly collected from public in urban areas,farmers in rice field areas,aborigines in undeveloped areas and retailers in commercial premises.Random samples of rice were taken out from each sample for isolation of arthropods using a modified Berlese Tullgren Funnel Method.Mites were mounted prior to identification; weevils were directly identified.Results:Samples of rice from retailers in commercial premises had the highest infestation by arthropods followed by samples from urbanites,aborigines and rice farmers.Two species of weevils,Sitophilus oryzae(S.oryzae) and Sitophilus granarius(S.granarius),were found.Samples from commercial premises had the least percentage of weevils compared to those collected from domestic premises. Depending on the source of samples,densities of S.granarius and S.oryzae ranges from 11-103 weevils/ kg and 7- 80 weevils/kg,respectively.Important species of mites in stored rice identified were mainly members of the families Cheyletidae,Echimyopodidae,Pyroglyphidae,Saproglyphidae and Tenuipalpidae.Among the species of mites identified were Austroglycyphagus malaysiensis,Cheyletus fortis,Cheyletus malaccensis,Dermatophagoides pteronyssinus,Grammolichus malukuensis and Suidasia pontifica.Average density of most of the mites was less than 40 mites/kg of rice grains.In this study,the highest number of mites in rice samples was recovered from commercial premises,followed by samples from urbanites.Samples from farmers and aborigines contained lesser mites.Conclusion:This study demonstrated the presence of 3 allergenic mite species in rice, i.e A.malaysiensis,D.pteronyssinus and S.pontifica.Weevils,S.oryzae and S.granarius that are known to be allergenic,were also found.展开更多
The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quali...The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 (indica) and Yangjing 9538 (japonica),were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content (SSC) exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content (CPC) of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content (GWC) of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.展开更多
Cadmium(Cd) contamination in rice has been a hot topic of research because of its potential risk to human health. In this study, a double haploid(DH) population derived from Zhongjiazao 17(YK17)(an early-season indica...Cadmium(Cd) contamination in rice has been a hot topic of research because of its potential risk to human health. In this study, a double haploid(DH) population derived from Zhongjiazao 17(YK17)(an early-season indica cultivar)×D50(a tropical japonica cultivar) was used to identify quantitative trait loci(QTLs) associated with Cd concentration in brown rice(CCBR) and Cd concentration in milled rice(CCMR). Continuous and wide variation for CCBR and CCMR were observed among the DH population. Correlation analysis revealed a positive and highly significant correlation between the two traits. A total of 18 QTLs for CCBR and 14 QTLs for CCMR were identified in five different pot and field trials. Two pairs of QTLs for CCBR(qCCBR2-1 and qCCBR2-2, qCCBR9-1 and qCCBR9-2) and one pair of QTLs for CCMR(qCCMR5-1 and qCCMR5-2) were detected in multiple trials. The alleles increasing CCBR at the qC CBR2-1/qC CBR2-2 and qC CBR9-1/qC CBR9-2 QTLs were contributed by YK17 and D50, respectively, whereas the D50 allele at the qCCMR5-1/qCCMR5-2 QTLs increased CCMR. Eight pairs of QTLs for CCBR and CCMR, qCCBR2-2 and qCCMR2-2, qCCBR3 and qCCMR3, qCCBR4-2 and qCCMR4-1, qCCBR4-3 and qCCMR4-2, qCCBR4-4 and qCCMR4-3, qCCBR5 and qCCMR5-2, qCCBR7 and qCCMR7, and qCCBR11-1 and qCCMR11-2, co-localized on chromosomes 2, 3, 4, 5, 7, and 11, respectively. For all of these QTL pairs, except qCCBR5/qCCMR5-2, the additive effects came from YK17. In addition, four CCMR QTLs showing significant additive×environment interaction and two pairs of CCMR QTLs with bi-allelic epistatic interactions were identified. The results of this study could facilitate marker-assisted selection of breeding rice varieties with low Cd accumulation in grain.展开更多
The main objective of this research was to identify quantitative trait loci associated with rice qualities to provide reliable information for marker-assisted selection and development of new varieties. In total, 120 ...The main objective of this research was to identify quantitative trait loci associated with rice qualities to provide reliable information for marker-assisted selection and development of new varieties. In total, 120 doubled haploid (DH) lines developed by another culture from the F1 hybrid of a cross between “Cheongcheong”, a Tongil variety, and “Nagdong”, a japonica variety, were used. A microsatellite linkage map of 222 markers spanned 2082.4 centimorgans (cM) and covered 12 rice chromosomes with an average interval of 9.4cM between markers. Eight quantitative trait loci (QTLs) were associated with rice quality, consisting of two QTLs on chromosomes 1 and 9 for amylose content;three QTLs on chromosomes 8, 9, and 10 for protein content;and three QTLs on chromosomes 2, 3, and 6 for lipid content. PCR expression levels measured using the SSR markers RM23914 for proteins and RM6266 for lipids, and RM586 showed a higher degree of amplification. The present study should be useful for improving the nutritional quality of rice by means of marker-assisted selection.展开更多
Rice grain shape is one of the important factors affecting grain quality and yield,but it is liable to be influenced by genetic backgrounds and environments.The chromosome single segment substitution lines(SSSLs) in r...Rice grain shape is one of the important factors affecting grain quality and yield,but it is liable to be influenced by genetic backgrounds and environments.The chromosome single segment substitution lines(SSSLs) in rice have been considered as ideal populations to identify the quantitative trait loci(QTLs).In this study,22 QTLs affecting rice grain shape were detected to be distributed on eight chromosomes except chromosomes 6,9,11 and 12 by using SSSLs.Among them,seven QTLs conditioned grain length,six conditioned grain width,five affected grain length-width ratio and four controlled grain thickness.展开更多
With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase(ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in the grains during gra...With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase(ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in the grains during grain filling, and theirrelationships with the filling rate, gel consistency (GC), alkali spreading value (ASV) and amylose content (AC) werestudied. The results showed that changes in activities of ADPGPase, SSase and Q-enzyme exhibited a single peak duringgrain filling, and the time of the activity peaks for the former two enzymes was earlier than that of the maximum grain-fillingrate (Tmax), and the time reaching the peak for Q-enzyme was synchronous with Tmax. The activities at early grain fillingstage, and the mean and maximum activities of each enzyme during grain filling period were positively and significantly orvery significantly correlated with the mean and maximum grain filling rate and starch content (mg grain-1) in the grains.Activities of ADPGPase at all grain filling stages and those of Q-enzyme at the early and mid filling stages were notsignificantly correlated the cooking quality (GC, ASV and AC). SSase activities at the early filling stage were significantlyand negatively correlated with GC and ASV, and positively correlated with AC. Activities of SSase at mid and late grainfilling stages and Q-enzyme at the late filling stage were significantly and positively correlated with GC and ASV, andnegatively correlated with AC. Spraying zeatin or abscisic acid at early grain filling stage could obviously regulate theactivities of ADPGPase, SSase and Q-enzyme in the grains.展开更多
Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to decli...Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grain-filling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6-34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.展开更多
Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for tw...Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment (location) interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb con-centrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concen-tration.展开更多
Studies were conducted with rice varieties developed in recent years in Liaoning Province of China as test materials.Results showed that the varieties tested could be divided into three types: (1) the high-yielding (H...Studies were conducted with rice varieties developed in recent years in Liaoning Province of China as test materials.Results showed that the varieties tested could be divided into three types: (1) the high-yielding (HYV), (2) the medium-yielding (MYV), and (3) the low-yielding (LYV). The panicle population was in the order of HYV< MYV < LYV, while thegrain number per panicle and seed-setting rate were just opposite. There was no significant difference in the 1 000-grainweight. Biomass was higher in HYV than in MYV and LYV, while the harvest index was higher in HYV and MYV than inLYV. Yield was inversely correlated with panicle population, but positively correlated with the grain number per panicle,seed-setting rate, the number of primary and secondary branch grains, seed density and harvest index. Yield was mostclosely linked with the grain number per panicle which was determined chiefly by the number of secondary branch grainsand to a lesser degree by seed density and the number of primary branch grains. The seed-setting rate of the secondarybranches was positively correlated with that of the whole panicle and yield. The peak value of primary branches for HYV,MYV and LYV was 12-14, 10-13 and 8-12, respectively. LYV had fewer secondary branch grains, while MYV and HYV hadmore. Such grains distributed mainly in the middle and lower parts of panicle axis for LYV and in the middle and upper partsfor MYV and HYV.展开更多
Zeolite(Z)can hold soil water and nutrient to obtain a higher yield on introduction into moist soil.However,the effects of Z and nitrogen(N)managements on rice grain quality is unclear.Therefore,the effects of differe...Zeolite(Z)can hold soil water and nutrient to obtain a higher yield on introduction into moist soil.However,the effects of Z and nitrogen(N)managements on rice grain quality is unclear.Therefore,the effects of different amounts of Z(Z0:0 t/hm^(2);Z0.9 and Z0.22:10 t/hm^(2)in different particle sizes of 0.45-0.9 mm and 0.17-0.22 mm in diameter)and N(N0,N52.5,N105,N157.5:0 kg/hm^(2),52.5 kg/hm^(2),105 kg/hm^(2),157.5 kg/hm^(2)),and Z(Z0,Z10:0 t/hm^(2),10 t/hm^(2))and application frequencies of N on rice yield and grain quality were investigated in 2014 and 2015 in Northeast coastal region of China where Z10 was extended to use in large areas.Results showed that both N and Z applications significantly increased the yields of rough rice(RRY),brown rice,milled rice and head rice.However,there was no significant difference between Z0.9 and Z0.22.The chalkiness area,length-width ratio and head rice rate were not influenced by Z and N applications.However,Z application significantly decreased the chalk rate and slightly increased amylose content(AC)but mattered little to taste value(TV)of rice and rice cooking quality.N could significantly increase rice protein content(PC)but lessen the TV and breakdown value;the order of influence degree on rice yield increasing was as follows:CRF2(third-split fertilization with Z10),CRF1(basal fertilization one time with Z10),U2(urea:third-split fertilization without Z)and U1(basal fertilization one time without Z).Both CRF1 and CRF2 greatly enhanced the RRY.However,CRF1 was recommended for clear decrease in labor and fuel for growers.Compared with treatments of U1 and CRF1,CRF2 and U2 significantly decreased the AC.PC exhibited significant negative relation to TV and greatly determined the rice eating quality and cooking quality.展开更多
A pot culture experiment was carried out to investigate the accumulation properties of mercury(Hg) in rice grain and cabbage grown in seven soil types(Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambos...A pot culture experiment was carried out to investigate the accumulation properties of mercury(Hg) in rice grain and cabbage grown in seven soil types(Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols) spiked with different concentrations of Hg(CK, 0.25, 0.50, 1.00, 2.00, and 4.00 mg/kg). The results of this study showed that Hg accumulation of plants was significantly affected by soil types. Hg concentration in both rice grain and cabbage increased with soil Hg concentrations, but this increase differed among the seven soils. The stepwise multiple regression analysis showed that pH, Mn(II), particle size distribution, and cation exchange capacity have a close relationship with Hg accumulation in plants, which suggested that physicochemical characteristics of soils can affect the Hg accumulation in rice grain and cabbage. Critical Hg concentrations in seven soils were identified for rice grain and cabbage based on the maximum safe level for daily intake of Hg, dietary habits of the population, and Hg accumulation in plants grown in different soil types. Soil Hg limits for rice grain in Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols were 1.10, 2.00, 2.60, 2.78, 1.53, 0.63, and 2.17 mg/kg, respectively, and critical soil Hg levels for cabbage are 0.27, 1.35, 1.80, 1.70, 0.69, 1.68, and 2.60 mg/kg, respectively.展开更多
With the advancement of agricultural mechanization and the development of combine harvesters, cleaning devices play a very important role in the grain harvesting process. In this study, the DFPF-25 type material float...With the advancement of agricultural mechanization and the development of combine harvesters, cleaning devices play a very important role in the grain harvesting process. In this study, the DFPF-25 type material floating velocity measuring device was used to measure the suspension velocity of each component of the grain material. Secondly, the DFQX-3 cleaning device was used to conduct the airflow field test, then the fluid simulation of the cleaning shoe was carried out. The results showed that the simulation and experimental results were in a good agreement under the conditions of single fan and double fan. The high-speed flow velocity formed by the double fan system at the tail of the cleaning shoe was 4.76 m/s (simulation) and 4.03 m/s (experiment), which had outstanding cleaning effects on unfilled grains, long stems, and short stems. To sum up, the installation of the cross-flow fan at the rear of the cleaning shoe has a positive effect on the cleaning effect of the combine harvester, and the double-fan cleaning structure composed of the cross-flow fan and the centrifugal fan can significantly improve the cleaning effect.展开更多
The performance of rice quality affects the market competitiveness of rice to a certain extent,and grain shape is an important factor for yield traits and appearance quality.The mapping and cloning of major rice grain...The performance of rice quality affects the market competitiveness of rice to a certain extent,and grain shape is an important factor for yield traits and appearance quality.The mapping and cloning of major rice grain type genes were briefly reviewed,and the utilization of related genes in breeding was prospected.展开更多
文摘Use of pesticides,herbicides and fertilizers is among the techniques to control insect pests and fungal pathogens.However,the technique is the major contributor to severe environmental implications in terms of air,water and soil pollution.Besides,variable inconsistency becomes an important issue in the implementation of inclined bed dryers,leading to significant rice grain loss.Cold plasma technology has been widely proposed as a potential alternative for rice grain postharvest treatment management due to the presence of generated ionised gas that eventually produces reactive oxygen species or reactive nitrogen species.These species are used to decontaminate foodborne pathogens,mycotoxins and bacterial diseases.This review explores the current literature regarding cold plasma treatment technology,focusing on its efficiency as the microbial decontamination medium and insect pest mortality medium,and on the enhancement functional,nutritional and cooking properties,especially in rice grains.Previous studies have successfully demonstrated the ability of cold plasma treatment to significantly reduce the microbial count of foodborne pathogens,detoxify mycotoxins,and control seedborne rice seedling bacterial diseases.Previous studies have also proved that the implementation of cold plasma technology in postharvest management should be seriously considered for improving rice grain quantity and quality in Malaysia.
文摘To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30oC were germinated in the dark at 30oC for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.
基金supported by the National Natural Science Foundation of China(31501274,31171509,30671222,31270488)the Special Fund for Agro-scientific Research in the Public Interest,China(201103001)the National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD16B15)
文摘Annual ryegrass(Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year(2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass(RG) as a winter cover crop and winter fallow(WF) without weed. Subplots were three N treatments for each rice season: 0(N_0), 100(N_(100)) and 200 kg N ha–1(N_(200)). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice(0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake) and double rice(0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_(100) and N_(200) plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.
文摘Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.
基金This study was supported by the National Natural Science Foundation of China （30671225）the Natural Science Foundation of Jiangsu Province, China （BK2006069, BK2007071）the National Key Technologies R＆D Program, China （2006BAD02A13-3-2）.
文摘This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations, that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), and abscisic acid (ABA), the ethylene evolution rate, activities of sucrose synthase (SuSase) and starch synthase (StSase) in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z + ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z + ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and grain weight. The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight. Spraying ethephon (ethylene-releasing agent) at the early grain filling stage increased the evolution rate of ethylene, reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight. The results were reversed when cobatous nitrate (an inhibitor of ethylene synthesis) was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z + ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents.
基金funded by a grant from the Malaysia Toray Science Foundation.
文摘Objective:To determine distribution of arthropods in rice grains obtained from different sources.Methods: Rice samples were randomly collected from public in urban areas,farmers in rice field areas,aborigines in undeveloped areas and retailers in commercial premises.Random samples of rice were taken out from each sample for isolation of arthropods using a modified Berlese Tullgren Funnel Method.Mites were mounted prior to identification; weevils were directly identified.Results:Samples of rice from retailers in commercial premises had the highest infestation by arthropods followed by samples from urbanites,aborigines and rice farmers.Two species of weevils,Sitophilus oryzae(S.oryzae) and Sitophilus granarius(S.granarius),were found.Samples from commercial premises had the least percentage of weevils compared to those collected from domestic premises. Depending on the source of samples,densities of S.granarius and S.oryzae ranges from 11-103 weevils/ kg and 7- 80 weevils/kg,respectively.Important species of mites in stored rice identified were mainly members of the families Cheyletidae,Echimyopodidae,Pyroglyphidae,Saproglyphidae and Tenuipalpidae.Among the species of mites identified were Austroglycyphagus malaysiensis,Cheyletus fortis,Cheyletus malaccensis,Dermatophagoides pteronyssinus,Grammolichus malukuensis and Suidasia pontifica.Average density of most of the mites was less than 40 mites/kg of rice grains.In this study,the highest number of mites in rice samples was recovered from commercial premises,followed by samples from urbanites.Samples from farmers and aborigines contained lesser mites.Conclusion:This study demonstrated the presence of 3 allergenic mite species in rice, i.e A.malaysiensis,D.pteronyssinus and S.pontifica.Weevils,S.oryzae and S.granarius that are known to be allergenic,were also found.
基金supported by the National Natural Science Foundation of China(Grant Nos.30400276 and 30871480)the National Natural Science Foundation of Major International Cooperation Project(Grant No.31061140457)+1 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK2009005)the Scientific Research Foundation for the Talents of Jiangsu Province,China
文摘The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 (indica) and Yangjing 9538 (japonica),were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content (SSC) exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content (CPC) of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content (GWC) of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.
基金financially supported by the National Natural Science Foundation of China (31501285)the Zhejiang Science and Technology Projects, China (2015C32045)+1 种基金the National Key Research and Development Program of China (2016YFD0101801)the National S&T Major Project, China (2016ZX08001006)
文摘Cadmium(Cd) contamination in rice has been a hot topic of research because of its potential risk to human health. In this study, a double haploid(DH) population derived from Zhongjiazao 17(YK17)(an early-season indica cultivar)×D50(a tropical japonica cultivar) was used to identify quantitative trait loci(QTLs) associated with Cd concentration in brown rice(CCBR) and Cd concentration in milled rice(CCMR). Continuous and wide variation for CCBR and CCMR were observed among the DH population. Correlation analysis revealed a positive and highly significant correlation between the two traits. A total of 18 QTLs for CCBR and 14 QTLs for CCMR were identified in five different pot and field trials. Two pairs of QTLs for CCBR(qCCBR2-1 and qCCBR2-2, qCCBR9-1 and qCCBR9-2) and one pair of QTLs for CCMR(qCCMR5-1 and qCCMR5-2) were detected in multiple trials. The alleles increasing CCBR at the qC CBR2-1/qC CBR2-2 and qC CBR9-1/qC CBR9-2 QTLs were contributed by YK17 and D50, respectively, whereas the D50 allele at the qCCMR5-1/qCCMR5-2 QTLs increased CCMR. Eight pairs of QTLs for CCBR and CCMR, qCCBR2-2 and qCCMR2-2, qCCBR3 and qCCMR3, qCCBR4-2 and qCCMR4-1, qCCBR4-3 and qCCMR4-2, qCCBR4-4 and qCCMR4-3, qCCBR5 and qCCMR5-2, qCCBR7 and qCCMR7, and qCCBR11-1 and qCCMR11-2, co-localized on chromosomes 2, 3, 4, 5, 7, and 11, respectively. For all of these QTL pairs, except qCCBR5/qCCMR5-2, the additive effects came from YK17. In addition, four CCMR QTLs showing significant additive×environment interaction and two pairs of CCMR QTLs with bi-allelic epistatic interactions were identified. The results of this study could facilitate marker-assisted selection of breeding rice varieties with low Cd accumulation in grain.
文摘The main objective of this research was to identify quantitative trait loci associated with rice qualities to provide reliable information for marker-assisted selection and development of new varieties. In total, 120 doubled haploid (DH) lines developed by another culture from the F1 hybrid of a cross between “Cheongcheong”, a Tongil variety, and “Nagdong”, a japonica variety, were used. A microsatellite linkage map of 222 markers spanned 2082.4 centimorgans (cM) and covered 12 rice chromosomes with an average interval of 9.4cM between markers. Eight quantitative trait loci (QTLs) were associated with rice quality, consisting of two QTLs on chromosomes 1 and 9 for amylose content;three QTLs on chromosomes 8, 9, and 10 for protein content;and three QTLs on chromosomes 2, 3, and 6 for lipid content. PCR expression levels measured using the SSR markers RM23914 for proteins and RM6266 for lipids, and RM586 showed a higher degree of amplification. The present study should be useful for improving the nutritional quality of rice by means of marker-assisted selection.
基金supported by the National Basic Research Program of China(Grant No.2005CB120807)
文摘Rice grain shape is one of the important factors affecting grain quality and yield,but it is liable to be influenced by genetic backgrounds and environments.The chromosome single segment substitution lines(SSSLs) in rice have been considered as ideal populations to identify the quantitative trait loci(QTLs).In this study,22 QTLs affecting rice grain shape were detected to be distributed on eight chromosomes except chromosomes 6,9,11 and 12 by using SSSLs.Among them,seven QTLs conditioned grain length,six conditioned grain width,five affected grain length-width ratio and four controlled grain thickness.
基金supported by the National Natural Science Foundation of China(30370828)the Natural Science Foundation of Jiangsu Province,China(BK2003041)
文摘With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase(ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in the grains during grain filling, and theirrelationships with the filling rate, gel consistency (GC), alkali spreading value (ASV) and amylose content (AC) werestudied. The results showed that changes in activities of ADPGPase, SSase and Q-enzyme exhibited a single peak duringgrain filling, and the time of the activity peaks for the former two enzymes was earlier than that of the maximum grain-fillingrate (Tmax), and the time reaching the peak for Q-enzyme was synchronous with Tmax. The activities at early grain fillingstage, and the mean and maximum activities of each enzyme during grain filling period were positively and significantly orvery significantly correlated with the mean and maximum grain filling rate and starch content (mg grain-1) in the grains.Activities of ADPGPase at all grain filling stages and those of Q-enzyme at the early and mid filling stages were notsignificantly correlated the cooking quality (GC, ASV and AC). SSase activities at the early filling stage were significantlyand negatively correlated with GC and ASV, and positively correlated with AC. Activities of SSase at mid and late grainfilling stages and Q-enzyme at the late filling stage were significantly and positively correlated with GC and ASV, andnegatively correlated with AC. Spraying zeatin or abscisic acid at early grain filling stage could obviously regulate theactivities of ADPGPase, SSase and Q-enzyme in the grains.
基金supported by the National Basic Research Program of China (2010CB951302-2)the National Natural Science Foundation of China (51109214 and 31101074)
文摘Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grain-filling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6-34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.
基金Project supported by the Postdoctoral Science Foundation of China(No. 2005037824), the Natural Science Foundation of ZhejiangProvince (No. Z304104), China, the Science and Technology De-partment of Zhejiang Province (No. 2005C32007), China, and theScience and Technology Bureau of Jiaxing, Zhejiang Province (No.2005AZ3003), China
文摘Genotypic and environmental variation in Cd, Cr, As, Ni and Pb concentrations of grains, and the relationships between these heavy metals and Fe, Zn were investigated using 9 rice genotypes grown in 6 locations for two successive years. Significant genotypic variation was detected in the five heavy metal concentrations in grains, indicating the possibility to reduce the concentration of these heavy metals in grains through breeding approach. The environmental effect varied with metal, with Pb and Ni having greater variation than the other three metals. There was significant genotype-environment (location) interaction of the concentrations of all five heavy metals in grains, suggesting the importance of cultivar choice in producing rice with low heavy metal concentrations in grains for a given location. Correlation analysis showed that Cd and As, Cr and Ni, and As and Pb con-centrations in rice grains were closely associated, and that Ni concentration in grains was negatively correlated with Zn concen-tration.
基金This work was supported by the National Natural Science Foundation of China （30370866）the National 863 Program of China.
文摘Studies were conducted with rice varieties developed in recent years in Liaoning Province of China as test materials.Results showed that the varieties tested could be divided into three types: (1) the high-yielding (HYV), (2) the medium-yielding (MYV), and (3) the low-yielding (LYV). The panicle population was in the order of HYV< MYV < LYV, while thegrain number per panicle and seed-setting rate were just opposite. There was no significant difference in the 1 000-grainweight. Biomass was higher in HYV than in MYV and LYV, while the harvest index was higher in HYV and MYV than inLYV. Yield was inversely correlated with panicle population, but positively correlated with the grain number per panicle,seed-setting rate, the number of primary and secondary branch grains, seed density and harvest index. Yield was mostclosely linked with the grain number per panicle which was determined chiefly by the number of secondary branch grainsand to a lesser degree by seed density and the number of primary branch grains. The seed-setting rate of the secondarybranches was positively correlated with that of the whole panicle and yield. The peak value of primary branches for HYV,MYV and LYV was 12-14, 10-13 and 8-12, respectively. LYV had fewer secondary branch grains, while MYV and HYV hadmore. Such grains distributed mainly in the middle and lower parts of panicle axis for LYV and in the middle and upper partsfor MYV and HYV.
基金the Doctoral Program of Higher Education from the Ministry of Education,China(20112103110007)Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(201303125).
文摘Zeolite(Z)can hold soil water and nutrient to obtain a higher yield on introduction into moist soil.However,the effects of Z and nitrogen(N)managements on rice grain quality is unclear.Therefore,the effects of different amounts of Z(Z0:0 t/hm^(2);Z0.9 and Z0.22:10 t/hm^(2)in different particle sizes of 0.45-0.9 mm and 0.17-0.22 mm in diameter)and N(N0,N52.5,N105,N157.5:0 kg/hm^(2),52.5 kg/hm^(2),105 kg/hm^(2),157.5 kg/hm^(2)),and Z(Z0,Z10:0 t/hm^(2),10 t/hm^(2))and application frequencies of N on rice yield and grain quality were investigated in 2014 and 2015 in Northeast coastal region of China where Z10 was extended to use in large areas.Results showed that both N and Z applications significantly increased the yields of rough rice(RRY),brown rice,milled rice and head rice.However,there was no significant difference between Z0.9 and Z0.22.The chalkiness area,length-width ratio and head rice rate were not influenced by Z and N applications.However,Z application significantly decreased the chalk rate and slightly increased amylose content(AC)but mattered little to taste value(TV)of rice and rice cooking quality.N could significantly increase rice protein content(PC)but lessen the TV and breakdown value;the order of influence degree on rice yield increasing was as follows:CRF2(third-split fertilization with Z10),CRF1(basal fertilization one time with Z10),U2(urea:third-split fertilization without Z)and U1(basal fertilization one time without Z).Both CRF1 and CRF2 greatly enhanced the RRY.However,CRF1 was recommended for clear decrease in labor and fuel for growers.Compared with treatments of U1 and CRF1,CRF2 and U2 significantly decreased the AC.PC exhibited significant negative relation to TV and greatly determined the rice eating quality and cooking quality.
基金supported by the Ministry of Environmental Protection of China(No.2011467057)the Fundamental Research Funds for the Central Universities of China
文摘A pot culture experiment was carried out to investigate the accumulation properties of mercury(Hg) in rice grain and cabbage grown in seven soil types(Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols) spiked with different concentrations of Hg(CK, 0.25, 0.50, 1.00, 2.00, and 4.00 mg/kg). The results of this study showed that Hg accumulation of plants was significantly affected by soil types. Hg concentration in both rice grain and cabbage increased with soil Hg concentrations, but this increase differed among the seven soils. The stepwise multiple regression analysis showed that pH, Mn(II), particle size distribution, and cation exchange capacity have a close relationship with Hg accumulation in plants, which suggested that physicochemical characteristics of soils can affect the Hg accumulation in rice grain and cabbage. Critical Hg concentrations in seven soils were identified for rice grain and cabbage based on the maximum safe level for daily intake of Hg, dietary habits of the population, and Hg accumulation in plants grown in different soil types. Soil Hg limits for rice grain in Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols were 1.10, 2.00, 2.60, 2.78, 1.53, 0.63, and 2.17 mg/kg, respectively, and critical soil Hg levels for cabbage are 0.27, 1.35, 1.80, 1.70, 0.69, 1.68, and 2.60 mg/kg, respectively.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.52175235)the Key Laboratory of Modern Agricultural Equipment and Technology(Jiangsu University),the Ministry of Education(MAET202109)+2 种基金the Key Laboratory of Crop Harvesting Equipment Technology of Zhejiang Province(Grant No.2021KY02)the Jiangsu Province“Six Talents Peak”High-level Talent Project(GDZB-085)The data used to support the findings of this study are available from the corresponding author upon request.
文摘With the advancement of agricultural mechanization and the development of combine harvesters, cleaning devices play a very important role in the grain harvesting process. In this study, the DFPF-25 type material floating velocity measuring device was used to measure the suspension velocity of each component of the grain material. Secondly, the DFQX-3 cleaning device was used to conduct the airflow field test, then the fluid simulation of the cleaning shoe was carried out. The results showed that the simulation and experimental results were in a good agreement under the conditions of single fan and double fan. The high-speed flow velocity formed by the double fan system at the tail of the cleaning shoe was 4.76 m/s (simulation) and 4.03 m/s (experiment), which had outstanding cleaning effects on unfilled grains, long stems, and short stems. To sum up, the installation of the cross-flow fan at the rear of the cleaning shoe has a positive effect on the cleaning effect of the combine harvester, and the double-fan cleaning structure composed of the cross-flow fan and the centrifugal fan can significantly improve the cleaning effect.
文摘The performance of rice quality affects the market competitiveness of rice to a certain extent,and grain shape is an important factor for yield traits and appearance quality.The mapping and cloning of major rice grain type genes were briefly reviewed,and the utilization of related genes in breeding was prospected.
