GENE ACTION OF EARLINESS AND SOME MORPHOLOGICAL TRAITS IN COTTON UNDER DIFFERENT ENVIRONMENTAL CONDITIONS | ||||
| Journal of Plant Production | ||||
| Article 11, Volume 25, Issue 11, November 2000, Page 6753-6765 PDF (866.93 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2000.260084 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| M. M. Abd El-Maksoud,1; A. M. El-Adl1; Z. M. El-Diasty1; M. A. El-Yazied2 | ||||
| 1Dept. of Genetics, Faculty of Agric., Mansoura Univ., Egypt. | ||||
| 2Cotton Research Institute, Agriculture Research Center, Egypt. | ||||
| Abstract | ||||
| This study aimed to investigate the type of gene action and the relative amount of genetic variance components as well as their interaction by locations using eight Egyptian cotton varieties. These varieties were: Ashmouni (Giza-19), Giza-70, Giza-45, Giza-85, Giza-86 , Giza- 89 (P6), American-Egyptian; Pima-S6 and Creamy type of [Bahteem 105 x Giza-67] x [Giza-72 x Delsero]. These varieties and their 15 F1 hybrids, which produced using 3 x 5 factorial mating designed were evaluated at two different locations for some earliness and morphological characters. The obtained results could be summarized in the following: The mean squares of genotypes were highly significant for all studied earliness and vegetative traits which included first fruiting node, days to first flower, days to first opening boll, earliness index, number of fruiting branches per plant and plant height. Also, the locations and genotypes by location interaction mean square were highly significant for these traits. These results indicated the presence of real differences between these genotypes for these traits and gave also different performances at the different environmental conditions. The results showed that the means of F1 hybrids were decreased towards earliness over their mid-parents with respect to first fruiting node, days to first flower and days to first opining boll. Thus, negative heterosis values over mid-parents were observed for these traits. The results revealed that additive effects play a major role in the expression of studied traits, while dominance effects had a minor role. Genetic parameters by location interactions also revealed that the magnitude of non-additive by locations interaction (s2DL) were positive and larger in magnitude than their corresponding values of additive by locations interaction (s2AL) for all studied earliness and vegetative traits except for first fruiting node. These results suggested that additive effects were more stable over the environments than non-additive effects with respect to most of studied earliness and vegetative traits. The importance of additive genetic variance (s2A) over the dominance genetic variance (s2D) was verified once again by the dominance degree ratio, which was less than one for first fruiting node, number of fruiting branches per plant and plant height or equal zero for days to first flower, days to first opening boll and earliness index. It could be concluded that the investigated traits are mainly controlled by additive genetic variance, while non-additive and its interactions with epigenetic factors play a minor role in the inheritance of these traits. Thus, the selection program could be a proper tool to produce earlier genotypes. | ||||
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