Relationship among Heterosis, Combining Ability and SSR Based Genetic Distance in Single Cross Hybrids of Maize (Zea Mays L)
*Corresponding author: Bhusal TN, Department of Genetics and Plant Breeding, Sam Higginbottom Institute of Agriculture Technology and Sciences, Deemed-to-be-University, Allahabad-211007, Uttar PradeshIndia, Tel: 0532 268 4281; E-mail: email@example.com
Combining ability and heterosis for different morphological and quality traits were studied under three environments using 10 inbred lines, 45 single cross hybrids and three commercial hybrids as checks at SHIATS, Allahabad, India during monsoon, 2014. Ten simple sequence markers (SSR) were used to quantify genetic distance, which was further used to analyse relationship with combining ability and heterosis in single cross hybrids. Pearson's correlation and linear regression were analysed to identify the important factors determining heterosis and per se performance of hybrids. Variances due to general combining ability (GCA) and specific combining ability (SCA) were found to be significant for all but their interaction with environments were significant only for morphological traits. SSR marker bnlg 1523 was found as a potential marker for discriminating maize inbred lines at molecular level as it has high PIC (0.71) and gene diversity (0.74). Significant positive association were recorded for per se performance with mid parent heterosis (MPH) and best parent heterosis (BPH) along with high coefficient of determination for days to 50% tasseling, days to 50% silking, days to 50% maturity, seed fill duration, number of grain rows/cob, number of grains/row, 100 seed weight, grain yield/plant, starch, protein and oil content. Moreover, F1's grain yield showed significant positive relationship with varying degree to MPH, BPH and SCA of hybrids in all environments. Correlation of SSR based genetic distance with heterosis and combining ability was significant positive for oil content but non-significant positive or negative for other traits indicating the significant role of SSR based genetic distance for determining heterosis and combining ability of oil content. Besides, SCA was found as a key determinant for heterosis and mean performance of all morphological and quality traits.
MPH, BPH, GCA, SCA, Genetic distance, Pearson's correlation.