A half diallcl cross between lo inbred lines of maize (Zea mays L.) was evaluated under two different sowing dates for ten quantitative characters. Sowing date, genotypes, parents and hybrids mean squares were significant for all traits under study. Significant genotypes x sowing date mean squares were obtained for all traits except ear height, car husk and no. of rows/ear. Significant interaction between hybrids and sowing dates mean squares were obtained for all traits except car height, car husk and no. of rows? car. General and specific combing ability mean squares were significant for all traits. The magnitudes of the ratios of GCAISCA revealed that the additive and additive x additive types of gene action were the most important expressions for ear husk, maturity date, no. of rows/ear, tasseling date and silking date. Plant height, ear height, no. of grain/row, 100-kernel weight and grain yield/plant showed GCAISCA ratios less than unity. The mean squares of interaction between sowing dates and both types of combining ability were significant for tasseling date, silking date, plant height, no. of grains/row and grain yield/plant. The ratio for GCA x D/GCA was higher than ratio of SCA x D/SCA for tasseling date, plant height, no. of grains/row, and grain yield/ plant. The parental inbred line no. 4 seemed to be good combiner for; plant height, car height, no. of grains/row, 100-kernel weight and grain yield/plant. The parental inbred line no, 10 appeared to be one of the good combiner for; ear husk, no. of rows? ear, no. of grains/row and grain yield/plant. The cross P1xP8 had the highest values for both SCA and heterotic effects followed by crosses PIXP)O, P4xP5, P6xP5 and P6xP,0 for grain yield. The five RAPD primers generated 143 scorablc bands across 10 inbred lines. These primers produced a total of 32 reproducible fragments, from which 26 (73.06) were polymorphic. The mean of polymorphic bands per pruner was 5.2. The lowest genetic similarity (0.333) was obtained between the two inbred lines P2 and P,, while, the highest genetic similarity (0.81) was scored between the two inbred lines P10 and P,. The estimated value for correlation coefficient between genetic diversity (GD), and each of performance and hetcrosis relative to both checks vanetes and SCA for grain yield? plant were significant (r 0.3 15, 0.332, 0.334, 0.401), respectively. The corrclaiion coefficient between sub clusterl (inbred lines P1 and P2) and main cluster 2 (inbred lines P,, P8, P,and P,0) was higher (r 0.56). In the same time the highest values of grain yield and heterosis were obtained from the crossing between inbred line P, (sub cluster I) and inbred line P8 (main cluster 2). |
