Diallel analysis of yield and some agronomic traits in Egyptian cotton [electronic resource].

Includes references.

This study was carried out during two successive seasons 2002 and 2003. In the first season, all possible crosses and their reciprocals were made between the Zgyptian cotton cultivars: Giza 70 (P1, Giza 89 (P2), Giza 90 (P3, Giza 85 (P4 and Giza 88(p5, to obtain F1 hybrid seeds. In the second season, the parental varieties and FI hybrids (25 entries) were studied. In respect of crosses, all studied traits had significant mean squares except number of fruiting branches/plant and seed index (S/). The earliest hybrids were P3X P2and P4x P.3 for three earliness traits and the hybrid P4.x P3 had the highest value for lint index (Ll) and lint percentage (L. %). The best hybrid for seed cotton yield per plant (S. C Y./PL) was P4.x P5 while the best hybrid for lint cotton yield per plant ( LC Y/PL) was P3XP2 and the hybrid P5X PI Was the best hybrid for seed index (8.l) and fiber strength (RS.). No specific cross was superior for all studied fiber quality traits. For parents Giza-90 was the best for earliness traits, seed cotton yield (S.C Y./PL), seed index ( S.I) and lint index (Ll), Giza-89 had the highest value for vegetative traits, and Giza-85 was the Best for lint cotton yield (LC Y/PL) and lint percentage ( L %). For fiber quality the best parent for Micronaire reading (Mic.) and fiber strength ( R8.) was Giza-70. The best parent for fiber length at 2.5% span length was Giza-88 and l5est parent for uniformity ratio (U.R %) was Giza-85. The estimated value~ of the additive variance was greater than the non additive variance for days from first opening boll to picking, plant height, seed index, lint index, lint percentage, fiber length at 2.5% SL .,fiber strength and uniformity ratio, revealing that additive effects were more important than dominance in the inheritance of these traits. On the other hand, non-additive type of gene action was of greater value than the additive for the other traits. Estimates of narrow sense heritability (Hz n %) in the FI varied from 24.7'HJ for seed cotton yield/plant to 93.00% for fiber length at 2.5%SL However,estim.ates of broad sense heritability (H2b %) varied from 64.4 % for lint index to 94. 0"% for fiber length at 2.5%SL

Summary in Arabic.

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