The authors evaluated 57 parental inbred lines of maize hybrids disseminated in Southwest China for drought tolerance under drought-stressed and well-watered conditions. Multiple regression analyses between drought to...The authors evaluated 57 parental inbred lines of maize hybrids disseminated in Southwest China for drought tolerance under drought-stressed and well-watered conditions. Multiple regression analyses between drought tolerant coefficients of the grain yield per plant and 15 morphological and physiological traits measured from a subset of 12 selected lines, identified traits 1 and 5, which were important for drought tolerance, at the seedling and reproductive stages respectively. Gene effects, combining abilities, and heritabilities of these traits were estimated using generation mean and diallel cross methods. Dominance effect was more important than additive effect for the plant height, anthesis-silking interval （ASI）, root weight, and the grain yield per plant, whereas, they were about equal for the leaf emergence rate. The variances of special combining ability （SCA） were about double that of the general combining ability （GCA） for plant height, ASI and grain yield per plant, although they were about equal for leaf emergence rate and root weight. Narrow sense heritabilities of the five traits for the reproductive stage were not high （12.8-29.6%）, although broad sense heritabilities for plant height, ASI, and grain yield were as high as 70-85%. A segregating population consisting of 183 F2 plants from the cross N87-1 （drought tolerant） × 9526 （susceptible）, was genotyped at 103 SSR loci and the F2：4 families were evaluated under two water regimes. Twelve quantitative trait loci （QTLs） （two for plant height, five for ASI, four for root biomass, and one for grain yield） were identified, most of which had overdominant gene action. Some chromosomal regions, such as those linked to markers umcl051 （bin 4.08）, umc2881 （bin 4.03）, and phi034 （bin 7.02）, had overlapping QTLs.展开更多
The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by ...The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by additive effect of multiple genes was the basis of continuous variation. Its precondition was for effective genes to have equal effect, to show merodominance and binomial distribution and to inherit independently. In fact, quantitative characters were determined by many genes with different property, effect and behavior. So it was difficult to solve all problems of continuous variation by the aid of polygenic hypothesis. The researchers should seek new ways. With Mendelian group as research object and by means of Lyapunov central limit theorem it was proved that both genotypic value G and the environmental effect in a niche E were subordinated to the normal distribution and respectively. According to additivity of the normal distribution the phenotype P = G + E also obeyed the normal distribution P = G + E ~ and quantitative characters showed continuous variation, whether or not the linkage was presented, whether or not every gene effect was equal, whether or not there were dominance and what kind of dominance between alleles. Moreover it was discussed that the quantitative characters in self-fertilized organism and clone were submitted to the normal distribution and presented continuous variation too.展开更多
基金supported by the Asian Development Bank(RETA 6055,Asian Maize Biotechnology Network),the Rockefeller Foundation(2004 FS 047)the National Natural Science Foundation of China(30571172)the Program for Changjiang Scholars and Innovative Research Team in Universities,China(IRT0453).
文摘The authors evaluated 57 parental inbred lines of maize hybrids disseminated in Southwest China for drought tolerance under drought-stressed and well-watered conditions. Multiple regression analyses between drought tolerant coefficients of the grain yield per plant and 15 morphological and physiological traits measured from a subset of 12 selected lines, identified traits 1 and 5, which were important for drought tolerance, at the seedling and reproductive stages respectively. Gene effects, combining abilities, and heritabilities of these traits were estimated using generation mean and diallel cross methods. Dominance effect was more important than additive effect for the plant height, anthesis-silking interval （ASI）, root weight, and the grain yield per plant, whereas, they were about equal for the leaf emergence rate. The variances of special combining ability （SCA） were about double that of the general combining ability （GCA） for plant height, ASI and grain yield per plant, although they were about equal for leaf emergence rate and root weight. Narrow sense heritabilities of the five traits for the reproductive stage were not high （12.8-29.6%）, although broad sense heritabilities for plant height, ASI, and grain yield were as high as 70-85%. A segregating population consisting of 183 F2 plants from the cross N87-1 （drought tolerant） × 9526 （susceptible）, was genotyped at 103 SSR loci and the F2：4 families were evaluated under two water regimes. Twelve quantitative trait loci （QTLs） （two for plant height, five for ASI, four for root biomass, and one for grain yield） were identified, most of which had overdominant gene action. Some chromosomal regions, such as those linked to markers umcl051 （bin 4.08）, umc2881 （bin 4.03）, and phi034 （bin 7.02）, had overlapping QTLs.
文摘The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by additive effect of multiple genes was the basis of continuous variation. Its precondition was for effective genes to have equal effect, to show merodominance and binomial distribution and to inherit independently. In fact, quantitative characters were determined by many genes with different property, effect and behavior. So it was difficult to solve all problems of continuous variation by the aid of polygenic hypothesis. The researchers should seek new ways. With Mendelian group as research object and by means of Lyapunov central limit theorem it was proved that both genotypic value G and the environmental effect in a niche E were subordinated to the normal distribution and respectively. According to additivity of the normal distribution the phenotype P = G + E also obeyed the normal distribution P = G + E ~ and quantitative characters showed continuous variation, whether or not the linkage was presented, whether or not every gene effect was equal, whether or not there were dominance and what kind of dominance between alleles. Moreover it was discussed that the quantitative characters in self-fertilized organism and clone were submitted to the normal distribution and presented continuous variation too.
