Muhammad, Iqbal (2002) INHERITANCE AND COMBINING ABILITY STUDIES FOR EARLINESS, YIELD AND YIELD COMPONENTS IN 6X6 INTRA-SPECIFIC HYBRIDS OF Gossypium hirsutum L. PhD thesis, Sindh Agriculture University, Tando Jam.
The node above white flower (NAWF) technique was used to monitor the growth, development and maturity of ten cotton varieties viz. Reshmi CRIS-9, MNH-93, MNH- f 329, MNH-395, MNH-439, 8-12, 8-14, CM-ll00 and NIAB- 78 during the years 1996, 1997 and 1998. The NAWF counts were made at weekly intervals. By regressing NAWF means over time, the number of days to reach NAWF of 5.0 (NAWF-5) was determined. Days to NAWF-5 were highly correlated with percent first pick of seed cotton yield. It was observed that NIAB- 78 and CRIS-9 achieved NAWF-5 earlier-by 109.86 and 109.09 days (average of three years). Days to NAWF-5 provided a focal, point all management decisions. Therefore, it became evident that NAWF technique could be used for monitoring cotton plant after flowering, earliness determination of variety/strain and detecting fruiting problems during growth season. Six upland cotton (G. hirsutum L.) varieties were crossed in all possible .combinations. The parents and F) were sown in a replicated experiment. Hayman's diallel cross analysis was employed to investigate the nature of gene action involved in the " inl1eritance of node of first fruiting branch, number of monopodial branches per plant, number of sympodial branches per plant, days taken to first flower, days taken to open first boll, number of flowers per plant, number of bolls per plant, boll weight, yield, percent of seed cotton yield in first pick (percent first pick), ginning out turn %, staple length, fiber fineness and fiber strength. Griffing's technique was used to estimate the general and specific combining ability of parents and also genetic components of variances for above-mentioned traits. The dialleI analysis revealed that all the characters were polygeneically inherited and exhibited partial dominance with additive gene action. Significant estimates of general combining ability (GCA) were determined for all traits under study. Estimates of specific combining ability were significant for the node of first fruiting branch, number of monopodial branches per plant, number of sympodial branches per plant, days taken to first flower, number of bolls per plant, seed cotton yield, ginning out turn, staple length and fiber fineness. Specific combining ability estimates further indicated that hybrids DPL-54 x MNH-93, Reshmi x DPL-54 and Reshmi x MNH-93 for seed cotton yield, Reshmi x NIAB-78 for earliness (node of first fruiting branch, days taken to first flower, days taken to open first boll and percent first pick) and Reshmi x S-14 for ginning out turn may be preferred for these traits. The cross Reshmi x MNH-93 is valuable cross for i seed cotton yield and fiber quality which can yield segregates for fiber quality to meet r international standard. The proportion of variance due to GCA was higher than SCA for all the traits which suggested that these traits were controlled by additive genes. Genotypes having good general combining ability (GCA) estimates for earliness related traits exhibited negative GCA estimates for the most fiber quality traits. The genotypes having good GCA estimates for fiber quality exhibited negative GCA for most basic seed cotton yield components. Among these genotypes, three way crosses, modified back cross, or recurrent selection procedure would be required to be exercised for increased seed cotton yield with improved fiber quality and earliness. The F2 and back crosses were grown in a Randomized Complete Block Design with three replications to estimate the heritability in broad and narrow sense, interrelationships among the above mentioned traits and their direct and indirect effects on seed cotton yield. Heritability in broad and narrow sense for all the traits under study was moderate to high with reasonable genetic variation. This suggested that major part of the total phenotypic variance was additive. Narrow and broad sense heritability values indicted that pedigree method would be employed to achieve genetic progress for these traits. It is concluded that mass selection should be effective for improving boll weight and reducing days required to open first boll among varieties in this material and some what less effective for improving other traits. Alternatives, such as pedigrees, sib tests, and progeny test must be considered to achieve genetic progress for node of first fruiting branch, days taken to first flower, GOT% and staple length in this material. The reciprocal recurrent selection will provide improvement in sympodial branches per plant, number of bolls per plant, seed cotton yield, percent first pick, fiber fineness and fiber strength. Path coefficient analysis showed that number of boll per plant, boll weight and number of sympodial branches were the morphological traits that contributed directly towards seed cotton yield. The genotypic correlation among all the traits showed that node of first fruiting -branch, days taken to first flower, days taken to open first boll and number of monopodial branches were significantly correlated with percent first pick. Therefore, these traits could be considered as reliable and practical indicators for earliness in breeding programmes due to their significant correlation and high heritability estimates. To study inheritance of CLCuV, nine selected varieties / lines (four resistant five susceptible) of up land cotton (G. hirsutum L.) were used for five F1 combinations. The F1 was sown for raising F2 and back crossing purpose. Subsequently P1, P2 F1, F2, BC, BC2 population were established and to ensure the inoculation of CLCuV no pesticide was used to control insect population. The results analysed through chi square test indicated that duplicate dominant epistasis was involved in control of resistance of CLCuV. Virus resistance was controlled by two dominant duplicate genes as F2 ratio was modified to 15:1 from 9:4:4: 1 and the test cross ratio was modified to 3: 1 instead of 1: 1.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Gossypium hirsutum L, Earliness, Heritability, Cotton Leaf Curl Virus, Boll weight, Seed cotton yield, Ginning out turn %, Staple length, Fibre fineness, Fibre strength, Node above white flower (NAWF), Reshmi, CRIS-9, MNH-93, MNH-329, MNH-395, MNH-439, S-12, S-14, CM-1100, NIAB-78, Gene action, General combining ability (GCA), DPL-54,|
|Subjects:||Agriculture & Veterinary Sciences(a) > Agriculture(a1)|
|Deposited By:||Mr Ghulam Murtaza|
|Deposited On:||21 Jun 2006|
|Last Modified:||04 Oct 2007 21:00|
Repository Staff Only: item control page