Genetic Diversity as Revealed by SSR Markers and Combining Abilily among Yellow Maize Inbred Lines

摘要

Knowledge about genetic diversity and combining ability of maize germplasm has important applications in maize breeding. This study was undertaken to (a) assess the genetic diversity of 11 yellow maize inbred lines using SSR markers, (b) determine their combining ability, and (c) compare the efficiency of factorial and diallel mating designs in identifying promising crosses. Cluster analysis based on data from 39 SSR markers grouped the inbred lines into three distinct clusters. The lines were crossed in a diallel study and the crosses evaluated. Of the top 14 high-yielding single crosses, 9 came from crossing inbred lines belonging to different groups while 5 came from lines belonging to the same group. The efficiency of finding promising hybrids using clustering of lines followed by factorial mating (26%) is comparable to that of the conventional diallel mating (25%); although overall, factorial mating has the advantage of involving less number of crosses. Significant differences in crosses were mainly due to specific combining ability effects contributing 78% for yield, 55%-kernel number per ear, 81%-plant height, 69%-silking date, and 78%- moisture content, indicating the prevalence of non- additive effects conditioning the expression of these traits. Three crosses could be considered as potential single cross hybrids for commercial production in the Philippines. The results show that the use of SSR markers can help reduce the number of crosses, resulting in time and cost savings.