Effects Of Flooding And Waterlogging Stress On Growth And Development Characteristics Of Potted Cotton During Square-boll Stage

Waterlogging stress is one of important natural disasters that we are confronted with in cotton production in Yangtze river valley of China where more rainy weather happen frequently during cotton squaring period and flower and boll-setting period.The trials were conducted to explore cotton plant growth, physical index, biomass accumulation, yield and fiber quality response to waterlogging stress. Hua mian 3109 was selected as experimental material in three pot-trials. The first potted trials was performed to study the effect of waterlogging time(T1,7d; T2,14d) on cotton growth and development. The other one was set as quantitative experiment of waterlogging(T’,7.5L) during flower and boll setting period compared to control group(CK’,2.5L) with three replicates. Results were indicated as below.(1)The same trend that concluded CK>T1>T2 was observed in cotton SPAD value, plant height, green leaves, functional leaf area, numbers of squares, flowers, bolls, fruiting branches and fruiting positions. After flower and boll setting, plant height, numbers of squares, flowers, bolls and fruiting branches and fruiting positions assumed an rapidly compensatory increase. In addition, other agronomic indicators decreased as waterlogging time proceed, such as cotyledon height, first fruiting branch height, length of fruiting internode and main internode.(2)There was an obvious decreasing tendency in such indicators as plant leaf area, leaf fresh weight, leaf dry weight, ratio of fruiting leaves area to plant leaves area, rates of fruiting branches and leaves distributed from total plant, reproductive organ biomass, aboveground biomass, underground biomass, total plant biomass, V/R(Vegetative and reproductive organs biomass ratio), BIWUE(Biomass irrigation water use efficiency) during square period when waterlogging time continued. The difference among treatments ranked T2<T1, CK.(3)As waterlogging time carried on, cotton abscission rate rose in squaring and boll retention rate dropped, which had direct influence on cotton yield. Waterlogging stress were attributed to the decrease in these indicators, including plant boll numbers, plant seed cotton yield, plant lint yield, seed index, Upper half mean fiber length, length uniformity, specific strength, fiber elongation.(4)The effect of sustain waterlogging stress on cotton indicators showed: value of SPAD with different leaf position in treatment group was less than that in control group; no significant difference among treatment group and control group was observed in plant height, green leaves numbers and stem diameter during stressing period, whereas treatment group started to be less than control group according to plant height, green leaves numbers and stem diameter in final stress time. In terms of the whole process, multiply continuous waterlogging stress have no remarkable effect on cotton growth. Moreover, decline in first fruiting branch nodes, first fruiting branches height, length of fruiting branch internode and main stem internode was achieved from continuous waterlogging stress, which was opposite to cotyledon height.(5)Cotton abscission rate was significantly affected by continuous waterlogging stress both in vertical and horizontal parts. In terms of temporal distribution of cotton bolls, waterlogging showed a greater influence in autumn boll, which was reflected that control group was higher than treatment group. Meanwhile, multiply continuous waterlogging decreased plant seed yield, boll numbers, boll weight, lint yield, seed index, lint percentage, upper half mean fiber length, length uniformity, specific strength, fiber elongation, and yield components with different parts. A higher irrigation use efficiency was obtain from control group than treatment group.In conclusion, significant difference in cotton growth and development affected by waterlogging stress could provide a complementally theoretical basis for assessment of cotton waterlogging disaster and establishment of farm drainage theory. However, boundedness existing in pot-trial should be required to be verified further for cotton field production.