estimate of heterosis and combining ability in ranian melon using diallel crosses analysis

in order to estimate heritability, heterosis, general and specific combining ability and relationships between them in traits of fruit number per plant, days to the first fruit harvest, yield per plant, average fruit weight and rind thickness, seven local populations of iranian melon (‘tashkandi’, ‘khatouni’, ‘garmak’, ‘aran1’, ‘mirpanji’, ‘suski-e-sabz’ and ‘golpaygan’) were crossed using a complete diallel crosses design, griffing’s method 1, model i. parents and all possible hybrids were evaluated in a randomized complete block design with three replications. analysis of variance revealed high significant differences among f1 hybrids and their parentes for all studied traits. therefore analysis of combining abilities showed that specific combining ability (sca) for yield per plant was greater than general combining ability (gca), indicating the importance of non-additive genes controlling this character. general combining ability effects were significant for most parents in all the studied traits. high estimation of narrow sense heritability (h2ns) for the traits of fruit number per plant, fruit weight, days to the first fruit harvest and rind thickness (0.83, 0.82, 0.79 and 0.74, respectively) indicated low effects of environment on the expression of those traits and very important role of additive gene effects. high estimate of h2ns (0.83) was found for fruit number per plant. high heterosis effect over the better parent was found for yield per plant (15.78 percent), therefore, it is suggested to apply both additive and non-additive genetic effects to develop superior hybrids in melons.