GENETIC DISPARITY AND RELATIONSHIP AMONG QUANTITATIVELY INHERITED YIELD RELATED TRAITS IN DIALLEL CROSSES OF UPLAND COTTON

In quantitative genetics, development of high yielding genotypes from parental cultivars of same ancestry is some what confusing as compared to genetically diverse parents. However, sufficient recombinations through allelic variations in mating of closely-related populations result in superior agronomic performance. Development of improved cotton genotypes is one of the prime objectives of any cotton breeding programmes. Genetic divergence and yield potential of parental cotton genotypes versus their diallel hybrids, relationship of yield with various morpho-yield traits and their heritability were studied in 8 x 8 F-1 diallel hybrids and their parental cultivars in Gossypium hirsutum L. during 2008-09 at Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan. Highly significant (p <= 0.01) differences were observed among parental genotypes and F-1 populations for all the traits. Results revealed that F-1 hybrids i.e., CIM-506 x CIM-554, CIM-473 x CIM-554, CIM-446 x CIM-496 and CIM-446 x CIM-554 produced significantly higher number of sympodia, bolls per plant and seed cotton yield. Some F-1 populations showed incredible performance for plant height, locules per boll and seeds per locule. Seed cotton yield manifested positive association with morpho-yield traits which also accounted for greater genetic variations to yield being dependent trait. Heritabilities (broad sense) were moderate to high in magnitude for all traits. Results revealed that F-1 populations with larger genetic potential, positive relationship between yield and yield contributing traits and moderate to high heritability can guide intensive selection and improvement per se in segregating populations.