| In order to explore the effects of different drip irrigation amounts on corn growth,dry matter accumulation and yield,and determine the appropriate amount of drip irrigation for maize in Ningxia irrigation area,"Yinyu 439","Xianyu 1225" and "Lanshan 861" were selected as materials in 2021 and "Xianyu 1225" as experimental factors in 2022.Five drip irrigation levels were set with drip irrigation amount as experimental factor.Were W1(960m3·hm-2),W2(2160m3·hm-2),W3(3360m3·hm-2),W4(4560m3·hm-2)and W5(5760m3·hm-2),respectively.The results showed that:1.Reasonable drip irrigation is beneficial to the growth and development of maize,and can improve plant height uniformity,stem diameter,leaf area index and dry matter accumulation of maize.In summary,W3 has the best growth and development,while W1 has the worst performance and is significantly lower than other treatments.The average plant height,stem diameter and dry matter accumulation of W3 were 25.25cm,2.28mm and 5.81t·hm-2 higher than those of W1 at the maturity stage of 2-year Xianyu 1225.The increase of drip irrigation in 2022 significantly increased the leaf area index at maturity,and W5 was 179.45%,132.87%,81.88%and 16.62%higher than W1,W2,W3 and W4,respectively.2.Reasonable drip irrigation can improve the chlorophyll content in the middle and late growth of maize functional leaves and prolong the functional duration of maize leaves;In 2021,high drip irrigation(W3,W4,W5)increased Fv/Fo,Fv/Fm,ABS/RC and PI parameters in the whole growth period of maize,and all the parameters at maturity stage W3 were the highest values between treatments.It was 0%～44.44%,3.71%～166.91%,17.91%～393.75%and 49.38%～1353.73%higher than the other treatments,respectively.In 2022,low or high drip irrigation in the early growth stage would decrease the fluorescence parameter value,and W3 would maintain a high value in the whole growth period.In 2022,there was no significant difference between Pn and Tr at the later growth stage of W3 treatment and the highest value W5,which were 44.93%,44.44%and 63.13%and 32.92%higher than those of W1 and W2,respectively.3.Reasonable drip irrigation can increase starch content and enzyme activities of ADPGppase,UDPGppase,SSS and GBSS at early and late filling stage,and W5 activity is the highest at late filling stage.Compared with W1--W4,they are 0.92%～57.14%,8.33%～30%,3.70%～14.28%and 1.97%～6.52%higher,respectively.Transcriptome sequencing was performed on corn grains at filling stage,and RNA-sep technology was used to screen out starch-related differential genes.In 2022,W3_vs_W1 group had the largest number of differential genes with 1170,among which 501 were up-regulated and 669 were down-regulated.Seven up-regulated and down-regulated genes were found in the metabolic pathway map of starch and sucrose,and differential genes were involved in the formation of sucrose and sucrose in the glucose formation process,including UDPglucose and ADP-glucose.Each gene regulates the expression of enzyme activity in each pathway,thus affecting the formation of maize starch.4.Between two years of treatment,the yield increased with the increase of drip irrigation amount,but there was no significant difference between W3 and W4 and W5 treatments.The highest water utilization rate was 46.3%in W3,and W3 significantly increased the yield compared with W1 and W2.W3 could not only increase the yield but also save some irrigation water,so 3360m3·hm-2(W3)was the appropriate irrigation amount.In conclusion,the optimal drip irrigation can meet the growth and development requirements of maize,enhance photosynthetic performance,increase dry matter accumulation,and improve yield and water use efficiency. |
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