Triallel analysis for yield and some fiber quality characters in Egyptian cotton [electronic resource].

Includes references.

This study was carried out during three successive growing seasons (2006, 2007 and 2008).Thirty triallel crosses were developed among five cotton parental cultivars belong to Gossypium barbadense L., three of them are long staple ,viz.,. Gha-89 (P2), Giza¬90 (P3) and Giza-85 (P4) while, the other two cultivar are extra long staple, Le. Gha-70 (P 1) and Giza-88 (P5 ). The triallel crosses were evaluated at the Experimental Station, Faculty of Agriculture, Cairo University, Giza, Egypt to estimate general and specific combining abilities for yield, yield components and some fiber quality traits. The nature of gene action that control the inheritance of the studied characters was also estimated. The results revealed that partitioning mean squares due to the three-way crosses into their components predicated the significant contribution of additive, dominance and epistatic variances in the genetic expression of studied tralts.Giza-70 (P1) was the best general combiner among this group of cultivars for all studied traits, except for seed index (S I), lint percentage (L %), lint index (L I), pressely index (P 1) and uniformity ratio (U R. %) and cultivar Giza-89 (P 2J was the best for lint cotton yield per plant (L C Y /P), cultivar Giza-90 (PJJ was the best for boll weight B Wand the cultivar Giza-88 (Ps) was the best for fiber length (F L),. they were good combiners when used as the third parent in the three-way crosses. The crosses P1XP4xP5,P2xP3XP5, P12xP3XP5, P2XP4xP5s and P2,xP5xP4 appeared to be the most promising three-way crosses for breeding toward improving most studied yield and fiber traits. The results also showed that the magnitude of additive genetic variance (óA 2) was positive and larger than that of dominance genetic variance ((óD 2), with respect to all the studied traits. The results indicated that the additive by dominance ( (óAD 2) type of epistasis variance played the secondary role in controlling the inheritance of studied characters of the triallel crosses. Estimates of narrow sense heritability (h2n %) varied from 3.59 % for U R% to 45.11% for S I and estimates of broad sense heritability (h2b %) varied from 93.38% for L% to 99.11% for F L. Results concluded that yield and its components and some fiber properties under study were mainly controlled by additive variance in addition to additive by dominance epistatic variance, suggesting that the selection practiced in the advanced generations of superior three-way crosses may be effective for improving these traits.

Summary in Arabic.

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