The Effects Of Shed And Potassium Fertilizer On The Germination And High-quality Berry Formation Of Grape Under Rain-sheltered Cultivation

‘Early Summer Seedless’（Vitis vinifera L.×V.labruscana L.,ESS）grape is an extremely early ripening bud mutation of the triploid seedless‘Summer Black’grape（V.vinifera L.×V.labruscana L.）,which is the hybrid of Europe and America grape type.The skin of ESS grape is purple-black and this cultivar is high in soluble solids.The yielding property,growth vigor,and disease resistance of ESS are similar to those of‘Summer Black’grape,but the mature time is approximately 10-15 days earlier than‘Summer Black’grape,conferring the obvious market advantage.In this study,ESS grape planting in Sichuan area（high temperature,high humidity and little sunshine area）was used as experimental material to investigate the changes in various ecological factors and the mechanism of grape germination,analyzed the effects of different shed treatments on leaf antioxidant system and sugar metabolism,and compared the effects of different types of potassium fertilizers and application rates on fruit quality formation of grape.The main results are as follows:（1）Sheded at January 1st to January 20th,irrigated 8-10 t/667 m² immediately,and irrigated 3 t/667 m² again after 10 d and 20d of the shed,respectively,which could stabilize the temperature in the feasible shed at 8.0-11.2℃and 9.4-15.1℃,respectively,and stabilize the humidity at 64.2%-81.7%and 79.1%-90.6%,respectively.The shed treatment significantly reduced the light intensity in the shed,and the service life of the converted celestial membrane increased.The annual light intensity decreased by 4.9-9.1%.The gradual decrease of the luminous intensity in the shed for 1-3 years reached 498-3034 lx,but the difference in maturity was only about1 d,and there was no significant difference in yield,quality and control.（2）The winter bud shed treatment significantly increased the contents of IAA GA₃ and ZT in the bud germination process of grapes,which gradually increased from 0.31,0.58 and 0.14μg/g during the dormancy period to 0.71-0.74μg/g,1.57-1.61μg/g and 0.38-0.40μg/g,respectivelt,during the germination,which increased by 0.09-0.12μg/g,0.25-0.29μg/g and 0.06-0.08μg/g,respectively,compared with the control.During this process,the ABA content showed a gradual downward trend,from 1.62μg/g to 0.48-0.50μg/g,which reduced by 0.23-0.25μg/g compared with the control.Therefore,the shed technology significantly advanced the germination time,the grape germination period was 10-35 d earlier than the control,the flowering period was 6-29 d earlier,and the maturity period was 3-25 d earlier.However,the shed was too early（December 20）,the early temperature was too low,the germination was not regular,the fruit ripening period was not concentrated and the yield was reduced by 47-65 kg/667 m²;the shed was too late（January 20）,the difference of phenology was not significant compared with the control.Both conflict with the centralized supply period of the market,and the economic benefit was not significantly improved.The maturity period of the shed was 16-18 d ahead of January1-10,and it matured in the middle and late June.It was in the gap period of grape market demand,and the benefit increased by 10324-10814 yuan/667 m².（3）The activities of antioxidant enzymes such as SOD,POD,CAT of grape leaves in the shed and unshed grapes showed a trend of increasing first and then decreasing and then increasing from May 20 to June 24,reaching the maximum values in early June,and the trend of MDA content change is the opposite.The antioxidant enzyme activities of the young leaves,functional leaves and old leaves treated by the shed increased to a different degree than the control,and affected the young leaves>functional leaves>old leaves.（4）The sugar metabolic enzyme activity of the grape leaves in the shed treatment and the unshed grapes showed a trend of increasing first and then decreasing from May 20 to June 24.The shed treatment was raised to the highest value about a week earlier than the less shed control.In the same period,the activities of sugar metabolic enzymes in leaves under shed treatment were significantly higher than the control before the beginning of June,and were lower than the control in different degrees afterwards,which affected January 1 shed>January 20 shed>the control.Before January 1st,the acidities of invertase,neutral invertase,sucrose synthase,and sucrose phosphate synthase were significantly increased by 55.25%-58.85%,38.26%-91.04%,26.91%-74.29%,and 5.56%-8.01%,respectively,compared with the control,and then significantly reduced by 4.80%-17.27%,10.83%-20.91%,17.77%-42.19%,and10.96%-17.22%,respectively,compared with the control.（5）According to the principle of potassium ion equivalence,the application of compound fertilizer（nitrogen:phosphorus:potassium,10:10:40）,potassium nitrate and potassium sulphate one month before the ripening period of ESS grape was compared.The application of potassium sulfate significantly improved the color uniformity of fruit and inner quality.The effects of different potassium sulfate application rates on fruit quality were compared,and it was found that with the increase of potassium sulfate application rate,the fruit firmness,soluble solid content,vitamin C content,total sugar content,sugar-acid ratio,malva pigment content（peel）,delphinium pigment content（peel）,ellagic acid content,quercetin content,folic acid content,vitamin b1 content,acid invertase activity,neutral invertase activity and polyphenol oxidase activity of grape fruit showed a significant increase,but no more significant increase was found after applying more than 55 kg/667 m² potassium sulfate.The peony pigment content（peel）,morning glory pigment content（peel）,cyanidin content（peel）,malva pigment content（fruit pulp）,succinic acid content,tartaric acid content,citric acid content,vitamin b1 content and sucrose synthesis enzyme activity of grape fruit increased with the increasing application rate of potassium sulfate,but no more significant increase was found after applying more than 60 kg/666.7 m² potassium sulfate.The titratable acid content,cyanidin content（fruit pulp）,rutin content and gallic acid content of grape fruit significantly decreased with the increase of potassium sulfate,but no more significant decrease was found after applying more than 55 kg/666.7 m² potassium sulfate.The peony pigment content（pulp）,catechin content and malic acid content of grape fruit significantly decreased with the increase of potassium sulfate concentration,but no more significant reduction was found after the application of potassium sulfate over 60kg/667 m².In summary,from January 1 to 10,the shed was immediately irrigated with 8-10t/667 m²,and a total of 55 kg/667 m² of potassium sulfate was applied 40 days,30days,and 20 days before the fruit matured,which was the fastest for the grape shed.The best production measures,the results of this study have theoretical significance and practical value for the high-quality development of grapes in Sichuan Province.