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STUDY OF FIBER QUALITY TRAITS IN UPLAND COTTON USING ADDITIVE-DOMINANCE MODEL

NAQIB ULLAH KHAN¹, KHAN BAHADAR MARWAT², GUL HASSAN², MOULA BUX KUMBHAR³, FARHATULLAH¹, ZAHOOR AHMAD SOOMRO³, NAEEM KHAN², AISHA PARVEEN¹ AND UMM-E-AIMAN¹

Abstract: Diallel analysis was studied in F₁ and F₂ hybrids by crossing six upland cotton cultivars (CIM-109, CIM-240, CIM-1100, FH-682, BH-36 and CRIS-9) following Hayman’s diallel approach using Mather’s concept of D, H components of variation for additive and dominance genetic variances, respectively. The objectives were to study the additive-dominance model, nature of gene action, heritability and genetic gain in F₁ and F₂ hybrids and mean performance of the selections (made in F₂ population) in advanced segregating generations (F₃, F₄ and F₅) in upland cotton. Genotypes mean values differed significantly for all the fiber quality traits. Additive-dominance model was adequate for fiber length, fiber fineness, and uniformity ratio, while showed partially adequate for fiber strength in F₁ generation. In F₂s, fiber fineness showed the adequate data, while other three traits manifested partial adequacy. Additive component (D) was found significant for all the traits in F₁ and F₂ generations. Dominance components (H₁, H₂) were also significant for all the traits in F₁s except the fiber fineness, while were insignificant for all the traits in F₂ generation. In F₁s the additive gene action was somewhat partial, while in F₂s all the traits were controlled by additive gene action as confirmed by average degree of dominance (ÖH₁/D<unity). Heritabilities (broad & narrow sense) were moderate to high with appreciable genetic advance. On the basis of transgressive segregation, heritability with appreciable genetic gain, selections made in F₂ population of cv. CIM-1100 surpassed the standard cultivar (CIM-446) for fiber quality traits in segregating generations.

¹Department of Plant Breeding and Genetics, NWFP Agricultural University Peshawar, Pakistan

²Department of Weed Science, NWFP Agricultural University Peshawar, Pakistan

³Department of Plant Breeding and Genetics, Sindh Agriculture University Tandojam, Pakistan.