Achieving Multiple Pest Tolerance Through Manipulation of Morphological Features in Cotton
Dec 24, 2018

WCRC WCRC2 Breeding

ABSTRACT
Breeding for tolerance to sucking pests and bollworm in cotton is treated as mutually exclusive events. Selection for resistance to sucking pests with more hairy leaves brought increased susceptibility to bollworms. An effort was made to select genotypes with high density hair on the lower leaf surface and low density hair on the upper surface. The number of hairs on both the upper and lower surfaces of the leaf blade and midribs and glands on the calyx were recorded. The yield was also assessed. The material used represented collections from India, the USA, China and the Central Asian Republics. Generally lower numbers of hairs on the midribs and leaf blade with more glands on the calyx and less bracteole teeth were recorded on bollworm tolerant genotypes. The bollworm tolerant lines exhibited higher yields than susceptible lines under unprotected conditions. Few of these lines showed differences in hair density on the upper and lower leaf surfaces. When the lower leaf surface had 70% more hair than the upper surface, the line had a jassid grade II. Only indigenous lines exhibited bollworm tolerance. Use of multiple tolerant genotypes in transgenic cotton studies opens new dimensions in pest tolerance breeding in cotton



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