GENETIC ANALYSIS OF TRICHOME DENSITY IN RELATION TO JASSID RESISTANCE IN COTTON
Loading...
Date
2013-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Agricultural Sciences, Dharwad
Abstract
The insect pests are the major yield limiting factors in cotton. Bt toxin expressed by Bt-cotton is toxic against bollworms but not against sucking pests especially jassids has become major pests among Bt cotton in India. Pubescence is important and easily recognizable morphological traits which will reduce the leafhopper damage. In the present study genetic variability and interrelationship between pubescence related traits with jassid resistance traits were assessed in germplasm and advanced breeding.
High variation and genetic advance was observed for pubescence, trichome length, jassid resistance traits both in germplasm and advanced breeding lines. Correlation Coefficient was found to be highly significant among all the pubescence related traits recorded based on trichome density and pubescence rating in germplasm and advanced breeding lines whereas a strong negative association was observed between pubescence traits and trichome length traits with jassid nymphal count and jassid injury grade. Detailed analysis of germplasm and advanced breeding lines resulted in identification of superior genotypes, BM-1and IGMH-12 with moderately high yield, good GOT, boll weight, lint index and jassid tolerance whereas genotypes TCHH-35102 , NISC-39 R-55 and R-18 were moderately tolerant but with high yield, boll weight and lint index. F2 population exhibited normal distribution for pubescence and trichome length traits indicating quantitative nature of inheritance.
The two genotypes of inter-specific F2 mapping population (NISC-37: Pilose X GB-68-Br2: Glabarous) were screened with 29 marker loci reported to be linked with pubescence traits. Twenty two markers were used for construction of genetic maps of LG1 and LG2. Altogether, a total of 11 significant QTLs (LOD more than 3) were identified, which included one QTL each for LWSP, BRHL, BMHL and STHL, two QTLs each for EPSP, ALHL and LMHL, Four QTLs each for ALFP, LFMP, BRTP and BRMP and five QTLS each for ALFPC, LFVP, ALHLC and LVHL.
Description
Keywords
null