Genetic analysis of the antioxidant enzymes, methane dicarboxylic aldehyde (MDA) and chlorophyll content in leaves of the short season cotton (Gossypium hirsutum L.)

Premature senescence is an important limited factor for the short season cotton (SSC), which decreases yield and declines fiber quality. The activity of antioxidant enzyme, methane dicarboxylic aldehyde (MDA) content and chlorophyll content is related with premature senescence. The present study is aimed to investigate the heredity and relationship of the antioxidant enzymes catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), MDA content and chlorophyll content for breeding high yield and good quality of the SSC varieties. Six parents from two types of senescence varieties (type A, which matures early and displays premature senescence; type B, which matures early but does not display premature senescence) and their F₁, F₂progenies in a diallel crossing scheme were planted in the experiment field. Phenotypic data on the traits were analyzed according to the Additive–Dominance–Epistasis and Additive–Dominance–Maternal–Paternal effects genetic model. CAT activity of dominant genetic effects were significant and large from 9 to 85 days after planting, the variance components were 34.69, 8.41, 31.93, 19.57 and 27.96 % at 9, 36, 50, 66 and 85 days, respectively. Additive-by-additive epistatic effects on CAT activity were significant and important from 9 to 85 days after planting. POD activity of additive genetic effects was significant and stable. There was not interaction by environment during 24 to 50 days after planting, the variance components were 9.82, 18.86 and 7.87 % at 24, 36 and 50 days, respectively. SOD activity of additive genetic effects was significant and stable. There was not interaction by environment during 66 to 100 days after planting, the variance components were 11.56, 11.80 and 13.84 % at 66, 85 and 100 days, respectively. MDA content of additive genetic effects was significant and stable. There was not interaction by environment during 50 to 100 days after planting, the variance components were 24.81, 13.81, 14.38 and 4.77 % at 50, 66, 85 and 100 days, respectively. Chlorophyll content was mainly controlled by significant dominance effects and main genetic effect from 9 to 66 days after planting, the dominant variance components were over 30 %. Maternal and paternal genetic effects on CAT and chlorophyll content were significant among 36–85 days after planting. Based on these results, it is suggested to selection of POD, SOD and MDA should be undertaken at early generation (F₂, F₃) and selection of chlorophyll and CAT should be undertaken at late generation (F₄, F₅) in SSC breeding programs.