Quantitative studies on heterosis and inbreeding depression in maize (Zea mays l.)

Abstract

The present investigation was carried out for studying heterosis and inbreeding depression of twenty eight hybrids (F1 ? s) and their F2 ? s made by crossing of eight maize inbreds in all possible cross combinations excluding reciprocal. Observations were recorded on ten quantitative traits viz., plant height (cm), ear length (cm), ear girth (cm), number of kernel rows per ear, number of kernels per row, 100 kernels weight (g) yield per plant (g), days to 50 % tassel emergence, days to 50% silk emergence and days to 50% maturity. Variable magnitude of heterosis was observed for different cross combinations for all the traits. Based on higher mean performance (94.33 to 118.67 g/plant) and higher heterotic response (11.95 to 30.48%) eleven crosses were selected. Response of inbreeding depression was significant in positive direction for most of the traits. Among these eleven crosses five crosses CM 300 x CML 142, CM 300 x CML 144, CM 300 x CML 150, CM 300 x CML 176 and CML 150 x CML 144 were selected having high heterotic value (12.31 to 30.48%) and lower inbreeding depression (less than 15%) for their utilization in maize improvement programme for the development of superior inbred lines.