Assessing genetic diversity, population structure, and linkage disequilibrium is important in identifying potential parental lines for breeding programs. In this study, we assessed the genetic and phenotypic variation of 174 normal maize (Zea mays) inbred lines and made association analyses with respect to nine agronomical traits, using 150 simple sequence repeats (SSR). From population structure analysis, the lines were divided into three groups. Association analysis was done with a mixed linear model and a general linear model. Twenty one marker-trait associations involving 19 SSR markers were observed using the mixed model, with a significance level of P<0.01. All of these associations, as well as 120 additional marker-trait associations involving 77 SSR markers, were observed with the general model. Two significant marker-trait associations (SMTAs) were detected at P ≤ 0.0001. In the mixed linear model, one locus was associated with water content, two loci were associated with 100-kernel weight, setted ear length, ear thickness and stem thickness; three loci were associated with ear height, four loci were associated with total kernel weight and five loci were associated with plant height. These results should prove useful to breeders in the selection of parental lines and markers.

For understanding the genetic diversity and genetic relationship between cultivated and weedy types, we evaluated genetic variation of 80 accessions of rice (O. Sativa). This included 42 cultivated accessions and 38 weedy accessions with the help of AFLP and CACTA-TD. A total of 542 loci were analyzed (255 for AFLP and 287 for CACTA-TD) of which AFLP markers exhibited 75% of polymorphism and transposon based CACTA-TD markers exhibited 93% of polymorphism. The average genetic diversity value for all 80 accessions, using AFLP markers was 0.226 (Cultivated – 0.210; Weedy 0.241) and based on CACTA-TD markers was 0.281 (Cultivated – 0.294; Weedy 0.269). A UPGMA phylogenetic tree revealed three major groups for both the marker system. The average polymorphic content value obtained with AFLP and CACTA-TD markers were 0.21 and 0.232, Effective multiplex ratio (AFLP – 47.50; CACTA-TD – 66.75), Marker Index (AFLP – 9.94; CACTA-TD – 21.13) and Resolving power (AFLP – 19.53; CACTA-TD – 34.62) indicated that the CACTA-TD markers were relatively efficient than AFLP markers.