Estimation of genetic effects controlling different plant traits in cotton (Gossypium hirsutum L.) under CLCuV epidemic condition

Abstract

Nine cotton genotypes, comprised of four non Bt males (CIM-1100, CIM-506, FH-942 and FH-900), five Bt female genotypes (FH-113, FH-114, MNH- 886, AA-703 and IR-3701) and their 20 crosses were screened in order to evaluate their response to Cotton leaf curl virus symptoms through epidemiology in the field and greenhouse. The 20 crosses among their nine parents were sown in two replications under randomized complete block design, during 2013 and 2014. The mean squares were significant for all traits indicating that both additive and non-additive genes control the characters, but non-additive genes were more important because, variance of dominant genes were higher than additive genes. In our test, FH-900 showed the best performance against CLCuV, number of lobes per boll and seed yield. The CIM- 1100 genotype performed well in boll weight, fiber strength and fiber fineness, whereas CIM-506 was good for plant height, number of sympodial branches and ginning. Maximum boll number, seed index and fiber length were shown by FH-942. Among lines, MNH886, FH-113, IR-3701 and FH-114 exhibited the best general combination for many traits. Hence, parents were preferred for hybridization program to improve the majority of characters. Hybrids FH-113 × FH-942, MNH-886 × CIM-1100, MNH-886 × FH-942, IR-3701 × CIM-506, AA-703 × CIM-1100, FH-114 × FH-942, FH-114 × CIM-1100 and MNH-886 × FH- 900 was best in specific combinations for different traits, especially against CLCuV. The results indicated that to increase resistance against CLCuV, hybrids should be exploited to develop CLCuV resistance.