Heterosis in Yellow Maize (Report‪)‬

Introduction Heterosis is the phenomenon in which the cross of two checks produces hybrid that is superior in growth, size yield, or vigor of the F1 over the better parent. The term is a contraction of stimulus of heterozygosis vigor yield and most characters of economic importance in corn are quantitative in nature and controlled by large number of genes the true heterosis differed from pseudoheterosis.In case of heterosis, there is an increase in general vigor, yield and adaptation .In case of pseudoheterosis, the F1hybrid exhibits increase in vegetative growth. It refers to the superiority of F1 over the standard commercial check variety. So, it is also called economic heterosis or superiority over checks. However, the commercial usefulness of a hybrid would primarily depend on its performance in comparison to the best commercial variety of the concerned crop species. The top crosses test with abroad and narrow base testers is the most common procedure for the evaluating process. Jenkins (1935) and Sprague (1939) suggested the method of early testing which greatly is affected by nature and number of tester needed for efficient evaluation of inbred lines of maize. Rawling and Thompson (1962) and Hallauer (1975) stated that appropriate tester should include simplicity in use, provide information that correctly classifies the relative importance of lines and maximize genetic gain. The choice of suitable tester is important to information for evaluating inbred lines. Uhr and Goodman (1995) used a public U S single cross to compare the performance of test crosses with 190 lines derived from seven tropical commercial hybrids. They found that 17 out of all the crosses yielded more than the tester. Many of the lines would combine well to produce hybrids adapted with the temperature climate.