Genetic Diversity Revealed by SSR Markers in Tropical Maize Population Pob32 after 5 Cycles of Biparental Mass Selection for Adaptation
Biparental mass selection was conducted to improve the tropical maize population Pob32 for 5 cycles in order to reduce photoperiod sensitivity in the Chinese maize belt. Evaluation trials indicated that flowering times were significantly improved after 5 cycles of mass selection. The coefficients of phenotypic variation for most traits under study, such as barren tip, ear weight, kernels per row, cob diameter, kernel depth, plot yield, ear diameter, and cob weight, were decreased by selection. Significant genetic diversity was revealed by 40 SSR markers. About 88.5％ of the genetic diversity was estimated as intra-population and 11.5％ was inter-pop-ulation. The inter-population genetic diversity was much lower than the intra-population, and the genetic diversity index within populations was decreased by mass selection. Both the numbers and proportions of polymorphic loci were decreased in each cycle by selection. The number of alleles in C0 was 418, and the frequency distribution was dispersive. The numbers of alleles in C4 and C5 were lower and the frequency distributions were convergent. It is possible that the decline in genetic variation resulting from continuous artificial selection in the early silking stage can be reduced by genetic drift or by smaller population sizes.
Maize Mass selection SSR markers Genetic diversity
Xin Wei Guangtang Pan
Maize Research Institute, Sichuan Agricultural University, Yaan, Sichuan 625014, P.R. China
国际会议
第九届亚洲玉米大会(the Ninth Asian Regional Maize Workshop)
北京
英文
95-100
2005-09-05（万方平台首次上网日期，不代表论文的发表时间）