Effect Of Waterlogging During Grain Filling Stage On Yield And Quality Of Waxy Maize

In recent years,extreme changes in global climate have led to major changes in the temporal and spatial distribution,circulation and ecosystem of water resources,resulting in an increase in extreme rainfall,which is a serious threat to maize production.The overlap of the grain filing period of waxy maize sown in spring and the plum rain season in southern China,coupled with the possible extreme rainfall,have a serious impact on the growth and development of maize.In order to explore the effect of waterlogging at grain filling stage on the yield and quality of spring waxy maize,Suyunuo 5(SYN5)and Jingkenuo 2000(JKN2000)were used as materials to study the effects of waterlogging and waterlogging duration at different stages on the yield and quality of waxy maize at fresh and mature stage in 2021-2022,which could provide theoretical basis for high yield,high quality and stress resistance cultivation for waxy maize production.The main results are as follows:1.Effects of waterlogging stress at different grain filling stages on yield and quality of fresh waxy maizeWaterlogging stress at grain filling stage significantly affected the ear yield and its components of fresh waxy maize.Compared with CK,the average fresh ear yield of SYN5 decreased by 12.43%,13.35%and 24.90%,respectively,under Wl-10,W11-20 and W1-20 treatments.The fresh grain yield of JKN2000 decreased by 12.98%,18.10%and 29.67%,respectively.Waterlogging significantly decreased the number of grains per ear,and the decrease was the largest in W1-20 treatment.Compared with the two varieties,the effect of waterlogging stress on yield of JKN2000 was greater than that of SYN5.Waterlogging stress reduced the yield of waxy maize by reducing the grain numbers and grain weight,and the decrease was the largest under W1-20 treatment.The contents of starch,soluble sugar and protein in waxy maize grains decreased under waterlogging stress.The starch content and soluble sugar content of SYN5 and JKN2000 were the lowest under W1-20 treatment,followed by W1-10 treatment,and the protein content was the lowest under W11-20 treatment.The peak viscosity of waxy maize flour in the fresh period decreased under waterlogging stress,the decrease of SYN5 was the largest in W1-20 treatment and that of JKN2000 was the largest in W11-20 treatment.The gelatinization enthalpy decreased under waterlogging stress,the decrease of SYN5 was the largest in W1-10 treatment,and that of JKN2000 was the largest in W1-20 treatment.The retrogradation enthalpy of both varieties increased,and the increase of retrogradation enthalpy was the highest under W1-20 treatment.The retrogradation percentage increased under waterlogging stress,SYN5 was the highest under W11-20 treatment,and JKN2000 was the largest under W1-20 treatment.2.Effects of waterlogging stress at different grain filling stages on grain yield and quality of waxy maize at maturityWaterlogging stress at different grain filling stages had significant effects on grain yield and quality at maturity.Under W1-10,W11-20 and W21-30 treatments,the average grain yield of SYN5 decreased by 15.96%,8.16%and 6.74%,respectively.The average grain yield of JKN2000 decreased by 17.45%,15.47%and 11.36%,respectively.Waterlogging at the grain filling stage significantly reduced the dry matter accumulation of waxy maize after flowering,and the decrease was the largest in W1-10 treatment,followed by W11-20.Overall,the effect of waterlogging at different grain filling stages on the yield of waxy maize at maturity was greater in the early of the grain filling stage than that in the middle and late stage.Waterlogging stress at different stages decreased the contents of starch,soluble sugar and protein in waxy maize grains at maturity.In 2021-2022,the starch and soluble sugar contents of SYN5 and JKN2000 were the lowest under W1-10 treatment,and the protein content was the lowest under W1-10 treatment.The peak viscosity of waxy flour at mature stage decreased under waterlogging stress,and the decrease was the largest in W1-10 treatment.The gelatinization enthalpy of flour decreased,and the gelatinization enthalpy of SYN5 was the lowest under W11-20 treatment,and that of JKN2000 was the lowest in W1-10 treatment.Under different stages of waterlogging stress,the average starch granule size was increase,the peak viscosity of waxy maize starch decreased,and the peak viscosity of waxy maize starch decreased the most in W1-10 treatment,and the decrease of starch enthalpy was the largest in W1-10 treatment and JKN2000 treatment in W21-30 treatment.Starch retrogradation percentage increased,and increased most under W1-10 treatment;starch crystal structure did not change significantly under different stages of waterlogging stress,but crystallinity decreased significantly.At maturity,starch F1/F2 ratio decreased and average chain length distribution decreased under different stages of waterlogging stress,and the decrease was the largest in W1-10 treatment,and the proportion of short chain in amylopectin increased.3.Effect of waterlogging duration at grain filling stage on grain yield and quality of waxy maize at maturityWaterlogging stress at different duration at grain filling stage had significant effects on the yield and quality of waxy maize at maturity.Compared with CK,the average grain yield of SYN5 decreased by 15.95%,29.29%and 35.34%under W1-10,W1-20 and W1-30 treatments,respectively.The average grain yield of JKN2000 decreased by 17.45%,28.80%and 38.21%,respectively.Under waterlogging treatment,the dry matter accumulation of waxy maize decreased after flowering,and the decrease exacerbated with the prolongation of waterlogging stress duration.The contents of starch,soluble sugar and protein in waxy maize grains decreased under different duration of waterlogging stress,and the decrease was the largest in W1-30 treatment.The peak viscosity,trough viscosity and breakdown viscosity of flour decreased in varying degrees,and the effect of W1-30 treatment was the greatest.The gelatinization enthalpy of waxy maize flour decreased,while the retrogradation enthalpy and retrogradation percentage increased,and the range of change was proportional to the duration of waterlogging.Under different duration of waterlogging stress,the average starch granule size was increased,the Peak viscosity and gelatinization temperature of waxy maize starch decreased,while the retrogradation enthalpy and retrogradation percentage increased,which were proportional to the duration of waterlogging stress.Under different duration of waterlogging stress,the crystal structure of starch had no significant change,but the crystallinity decreased,and the decrease was proportional to the duration of waterlogging.At maturity,the ratio of starch F1/F2 decreased and the decrease exacerbated with the prolongation of waterlogging stress,and the average chain length distribution of starch decreased.W1-30 treatment had the greatest effect,the proportion of DP6-12 in amylopectin increased,and the ratio of short chain to long chain increased.On the whole,the change range of quality index of the two waxy maize varieties was proportional to the duration of waterlogging stress,and showed W1-30>W1-20>W1-10.