TYPES OF GENE ACTION AND HYBRID VIGOUR FOR YIELD AND QUALITY TRAITS OF MELON (CUCUMIS MELO, L.).

Abstract

This study was carried out in two successive summer seasons (2012 and 2013), at the Experimental Farm of Research Station, Qanater El-Khairya, El- Kalupia Governorate, Agriculture Research Center. The main objectives of this investigation were to estimate of magnitude of additive and non-additive gene effects for some traits in an attempt to stablish some inbred lines. The study also aimed to estimate heterosis degree, relative to mid, better parents and the standard cultivar to determine the hybrid vigour for some important characters. Phenotypic correlation coefficients between all possible pairs of the different studied traits were estimated. The following traits were assessed: early and total yield as fruit number and weight, average fruit weight, shape index, skin and flesh colour, flesh thickness, β carotene, vitamin C and sugars contents. The obtained results showed that both additive and non-additive gene effects were involved, the additive gene effects appeared to be playing the main role in the inheritance of all studied traits, since the estimated GCA: SCA ratio values ranged from 4.4 to 57.8. None of the parents found to be good combiner for all characters. Generally the two parents Magyar Kincs and Muszkotaly were the best combiner for breeding to most characters. It is noticed that the bestcombinations were resulted from crossing between these two parents or between one of them and other parent. Hybrid vigour was detected for early and total yield, as well as, most fruit characters. In some crosses, high better parent heterosis and potence ratio values were given for these traits supporting the over dominance hypothesis. Other degrees of dominance were observed by many crosses concerning some traits. High estimated standard heterosis were reflected by three crosses i.e., Shahd El-Dokki X Muszkotaly, Shahd El-Dokki X Magyar Kincs and Magyar Kincs X Muszkotaly for yield and most important traits. Hence, it could be suggested that these crosses may be recommended as new promising hybrids for commercial production of melon after further evaluation. Desirable correlations were detected between many pairs of character. In many cases phenotypic correlations used to help breeders in selecting and improving quantitative of difficulty measured characters through the selection for simply and correlated ones.