Estimation of Some Gnetic Parameters for Yiled and its Components Traits in Intra and Inter Specific Hybrids of Cotton (Gossypum spp. L.)

(Maha Lutfi Hadid )

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Abstract

Combining ability analysis was carried out for eight trails in an eight-parent (p1 - C6040, p2- Line5, p3-Aleppo118, p4- Aleppo90, p5-Aleppo40, p6- Aleppo33, p7-Dirzor22, p8-Raqua5) Half diallel cross using Griffing65533;s method-2, model-I. The first and second parents belonged to G-barbadense while the remained parents belonged to G-hirsutism. The plants were grown and tested in the research farm of Damascus University during 2007-2008 and 2008-2009 seasons. Genitic analysis was performed to indicate the mode of inheritance for yield and its components to determine the best combination for yield improvement. Combining ability variance for GCA of parent and SCA variance of crosses were highly significant for all traits, suggesting the importance of additive and non-additive type of gene action for traits. Combining ability analysis revealed that specific combining ability variance was greater in magnitude and more important for the characters number of bolls per plant , seed index, and lint index indicating the involvement of non-additive type of gene action for the expression of these parameters. While seed cotton yield per plant, boll weight, flowering earliness, reproductive branches number, and plant height were controlled by additive type of gene action. Genotype p1-C6040 and p3-Aleppo118 proved to be the best general combiner to be exploited in hybridization programs to improve yield in cotton. SCA effects were considerably high by some hybrids for number of bolls per plant, and plant high in the cross p1xp2 ,for seed index, and lint index in the cross p7xp8, and for seed cotton yield per plant in the cross p3xp4 .Hence, while breeding varieties for high yield these crosses should be considered. Key Words: Additive, Cotton, General combining ability, Half diallel cross, Specific combining ability, Yield.
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