Genetic effects of high fibre strength breeding lines in crosses with transgenic Bt cotton cultivars (Gossypium hirsutum L.)

Evaluation of genetic effects in cotton (Gossypium hirsutum L.) high fibre strength lines is necessary for the genetic improvement of fibre properties. Six breeding lines with high fibre strength and five transgenic Bt cultivars were diallely crossed. Fibre properties and agronomic traits of 11 parents and resultant 30 F1 hybrids were analyzed by an additive-dominant model with genotype by environment interaction effects. Lint percentage, seed index, fibre length, strength and micronaire were primarily controlled by additive effects. Lint yield was mainly governed by dominance effects. Boll size was equally influenced by additive and dominance effects. A9-1 was a desirable general combiner for lint percentage, micronaire and fibre length. Yumian1 and Jinxing2 were good general combiners for fibre strength. Gk22 was a desirable general combiner for lint yield and boll size but poor for fibre length and strength. Some F1 hybrids were identified with favourable heterozygous dominant effects for lint yield and various fibre properties. This study revealed that current transgenic Bt cotton cultivars can be improved in fibre quality and lint yield by using some of the lines with high fibre strength in crosses with them.