Genetic diversity assay of maize (Zea mays L.) inbreds based on morphometric traits and SSR markers

Twenty maize genotypes (19 inbred lines and a commercial hybrid) were studied assessing the extent of genetic diversity for 21 qualitative and quantitative morpho-metric traits and 18 expressed sequence tags-simple sequence repeats (EST-SSR) markers. A wide range of variation was observed among the 20 maize genotypes for quantitative traits predominantly for plant height, ear height, days to tasseling, days to silking, and kernel yield per plant. Among the qualitative traits, green-glume base, green inter-node, conico-cylindrical, flint grain texture, and white stone type were found predominant. The 18 primer pairs produced 92 different markers with polymorphism information content (PIC) value ranging from 0 to 0.87. Three different dendrograms based upon the dis/similarity coefficients were constructed. Poor and no correlations were observed among the sets of dendrograms patterns depicted from qualitative and quantitative traits and molecular markers. However, wide variation among genotypes of different clusters and within clusters was observed for different methods of clustering. It was concluded that the selection of suitable clustering system of genotypes should be determined by the purpose of clustering. Key words: Genetic diversity, maize, morphometric traits, simple sequence repeats (SSR) markers, cluster analysis.