Research Progress of Short-season Cotton in China

Short-season cotton varieties were cultivated to increase cropping index, and they also were introduced to the short frost-free areas for expanding the cotton planting area in China. The report described 1) the selection basis of early maturity traits of cotton varieties, 2) genetic characteristics of early maturity traits in cotton varieties, 3) early maturity related gene cloning and 4) early maturity cotton breeding. In terms of selection of early maturity traits, seedling period, boll period, node of first fruiting branch, plant height and yield percentage before frost were mainly controlled by genetic inheritance, which could be used as an indicator of early maturity. In the aspects of early maturity genetic traits, the heritability of flowering stage was controlled by both additive and dominant genes. The genetic analysis of the Upland cotton showed that there were significant additive effects at flowering period and boll opening period. Node of first fruiting branch, plant height and mature period showed additive and dominant effects significantly, but dominated by the dominant effect. The genetic map was constructed using early maturity cotton varieties, which mainly focused on seedling period, bud period, flowering period, flower and boll period, growth period, yield percentage before frost, the first fruit branch node, node of first fruiting branch, boll opening period. At the same time, cotton flowering related genes such as FPF1 (FLOWERING PROMOTING FACTOR 1), SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CO 1), CO (CONSTANS), LFY (LEAFY) and AP1 (APETALA1) were cloned and their function needs to be further verified. Hybridization breeding was mainly applied in early maturity cotton breeding. The parents should be complementary, one of the parents is an extremely early mature type or the two parents are more mature materials which often appear of the super-separation in the maturity. The selection of parents should have high general combining abilities. The application of short-season cotton was summarized in China's Yellow River cotton area, the Yangtze River cotton area and the northwest inland cotton area, and the main problems and countermeasures were overviewed briefly,, which provided a reference for short-season cotton breeding in research and utilization.