Inheritance and Variability of (+) Gossypol in Ecologically Different Cotton Hybrids

The selected American accessions #18 BC3S1-47-8-1-17 and #19 BC3S1-1-6-3-15 have a high level of (+)-gossypol in flower petals (average 98.3% and 98.8%, respectively).  Research showed that the levels of (+)‑gossypol in petals in F1 hybrids were mainly inherited as an intermediate type with parameters of hp from -0.2 up to +0.3. Only in F1 hybrid C-6530 x #19BC3S1-1-6-3-15 was it dominant. The average level of (+)-gossypol of F1 hybrids were between 85.6%-98.1%.  The highest level of (+)-gossypol (more than 98%) was found in F1 hybrid C-6530 x BC3S1-1-6-3-15, and the lowest (87%) in F1 hybrids L-10/04 x BC3S1-47-8-1-17 and L-10/04 x BC3S1-1-6-3-15.  We found that the level of (+)‑gossypol in flower petals of the F1 hybrids developed from crosses with gland free (i.e., gossypol free) lines L-10/04 and L-16/04 was 2-3% less than in hybrids developed with other varieties.  F2 hybrids segregated transgressively providing (+)-gossypol levels of 52.0-55.9% and 96.0-99.9%.  We also investigated the level of (+)-gossypol in backcross hybrids F1BC1 and determined that the average dates of this trait exceeded pair hybrids on 6-10%.  The exception was F1BC1 (C-6524 X BC3S1-47-8-1-17) X BC3S1-47-8-1-17) in which the level of (+)‑gossypol appeared on a level of pair hybrids (i.e. 91%).