A microsatellite marker based study of chromosomal regions and gene effects on yield and yield components in maize

The genetic basis of different traits and the effect of chromosomal regions on the expression of such traits is the primary interest of this study. In the present investigation, the effect of chromosomal regions on yield and its two primary components was studied, and two genetic parameters, additive effect and degree of dominance, were estimated based on a single-locus model using markers with significant effects on the traits (informative markers). Eight inbred lines from diverse geographical regions of India were crossed in all possible pairs, and F1S were evaluated for the yield and yield components in a replicated trial in two environments. Sequential path analysis was employed to find those yield components showing significant direct effects on yield with negligible multicollinearity. The parental lines were profiled using 56 polymorphic SSR (Simple Sequence Repeat) markers covering 10 chromosomes of maize. Stepwise multiple regression analysis was used to determine the informative markers on yield and its primary components detected through path analysis. Fourteen markers were found to have association with chromosomal regions showing significant effects on the total grain yield, 100-grain weight and total number of kernels per ear. Chromosome 1 with four informative markers revealed the highest genic effects on yield and its components. Markers bnlg594 and bnlg1360 on chromosome 10, and bnlg147 on chromosome 1 revealed the highest additive effects on the total grain yield, 100-grain weight and total number of kernels per ear, respectively. For the analyzed traits, overdominance occurred in all the loci and d/a values, varying from 8.60 for 100-grain weight to 1.40 for total grain yield.