Inheritance, disease resistance of cotton hybrids with different level of gossypol in seeds
Аннотация
The presence of gossypol in glands of cotton protects the plant from pests. However, there is limited information on how the level of (+)- and (-)-gossypol enantiomers affect resistance to insect and pathogens. We have evaluated the resistance of plants that exhibit the high (+)-gossypol seed trait to diseases (thielaviopsis basicola, rizactonia solani and xanthomonas malvacearum); effects of total seed gossypol on resistance to this insect and these pathogens was also evaluated. Field and greenhouse tests indicated that it should be possible to breed lines that exhibit the high (+)-gossypol seed trait and retain acceptable levels of insect and disease resistance together with acceptable levels of agronomic properties. The best lines in this study were crosses between the U.S. line Backcross-3 and the Uzbek variety Bukhara; this cross gave good acceptable resistance to all pathogens in both spring and autumn. We are continuing our studies to develop cotton lines that have a high percentage of (+)-gossypol in the seed. We have determined the total and percentage of (+) - and (-)-gossypol in U.S. accessions and Uzbek varieties, and in F1-F3 hybrids developed in crosses between these varieties. We found an intermediate type inheritance for (+)-gossypol in petals and seeds of F1, and negative transgressive segregation for (+)-gossypol in seeds with 53.0% in F2; however, there appeared to be recombinants with (+)-gossypol of 96.0% (at F2 Bukhara-8 x Backcross-3).