Molecular genetic distances and hybrid performances among maize inbreds and their hybrids

Genetic variations and genetic distances of the maize inbred breeding lines were analyzed using SSR (simple sequence repeats) and AFLP (amplified fragment length polymorphisms) techniques in order to assess the agronomic performances in their hybrids. The 25 inbred lines utilized consisted of mainly two groups of Lancaster Sure Crops in BSSS and Reid Yellow Dents except one line. The genetic distances, GDs, between groups were higher than the GDs within groups. The AFLP-based GDs were higher than the SSR-based GDs in all inbreds. While the clustering patterns derived from SSR polymorphisms showed low correlations with the pedigree information, AFLP-based clustering pattern generally matched with the pedigree grouping. In the analysis of correlation of GDs with agronomic performance in the hybrids, the AFLP-GDs showed high correlations with the plant height, ear diameter, hundred seed weight, and grain yield. However, there was a low correlations between the SSR-GDs and the above traits. The possible reasons of this low correlation and ambiguity in clustering pattern using SSR analysis were sought in the discussion. The trait of ear length showed low correlation with GDs from either technique. Therefore, the AFLP analysis might provide an efficient and practical utility in predicting hybrid performance in the yield components except ear length.