Identification Of Waterlogging Tolerance Of 11 Table Grapes And The Effects On Summer Black Fruit Quality

In recent years,with global warming,extreme weather events occur frequently,and flood disasters have become one of the important disasters in agricultural production.Grape is one of the important fruit trees in China,and its cultivation range is wide.In some parts of China,the groundwater level is high,the drainage and irrigation system is not being dispaired,and the frequent occurrence of natural disasters such as floods and rainstorms has caused inestimable losses to grape cultivation and production.Therefore,it is of great significance to screen waterlogging-tolerant germplasm and study the impact of waterlogging disasters on the production of table grapes for the selection and the breeding of waterlogging-tolerant varieties in the southern waterlogging-prone grape production areas.In this study,the seedlings of 11 grape cultivarieswere used as test materials.By simulating the form of waterlogging stress,different varieties were studied under the continuous waterlogging stress of 0 d,3 d,6 d,9 d,12 d and 15 d.The different changes of the waterlogging damage index,photosynthesis,chlorophyll fluorescence response and other waterlogging tolerance indicators were analyzed,and the membership function method was used to convert the waterlogging tolerance indicators of each variety into membership function values for comprehensive evaluation.Use the 5-year-old Summer Black grape tree as the test material,and the artificial simulated waterlooging stress test method was used.The growth of shoots,root vigor,relative chlorophyll content of mature leaves,photosynthetic indicators,chlorophyll fluorescence parameters and fruit quality were measured and analyzed.The research results are as follows:（1）With the waterlooging stress continued,the waterlogging damage index of all tested varieties showed an increasing trend.The Zaoxiameigui was the highest,reaching 100%after 9 days of flooding,and the lowest in Summer Black,only 40%after 15 days of flooding;The relative chlorophyll content,net photosynthetic rate,transpiration rate,stomatal conductance,and maximum photochemical efficiency showed a gradual downward trend,which decreased from 15.76%to 82.42%,59.2%-119.5%,62.1%-94.6%,67.3%.After 15 days of waterlogging decreased from 15.76%to 82.42%,59.2%-119.5%,62.1%-94.6%,67.3%-98.7%,4.09%-74.16%;the intercellular CO₂concentration showed a gradual upward trend,and the 15-day flooding increased by 24.2%-122.6%respectively;the water utilization rate showed a trend of first increasing and then decreasing,and different to the end of flooding Varieties decreased by 29.8%-86.7%;（2）Further,the membership function method comprehensively analyzed the waterlogging tolerance of 11 grape varieties in descending order:Summer Black（0.530）,Shine Muscat（0.438）,Scarlotta Seedless（0.432）,Crimson Seedless（0.423）,Zitianwuhe（0.412）,Hutai 8hao（0.393）,Jumeigui（0.390）,Manicure Finger（0.375）,Zuijinxiang（0.374）,Muscat Hamburg（0.336）and Zaoxiameigui（0.294）.The waterlogging-tolerant varieties Summer Black and Shine Muscat have higher waterlogging tolerance,and the indicators can be stabilized at a lower level in the later period of flooding.Zaoxiameigui and Muscat Hamburg belong to waterlogging-prone varieties.Under continuous waterlogging stress,they cannot alleviate hypoxia damage and maintain normal photosynthetic capacity,causing plant growth to be inhibited until plant death.（3）Waterlogging stress reduced the root activity and shoot growth of Summer Black grapes by 51.22%and 82.06%,respectively,after 30 days of flooding.The degree and maximum photochemical efficiency decreased by 9.67%,31.49%,30.90%,25.79%and 1.50%,respectively,which increased the intercellular CO₂concentration.At the same time,waterlogging stress reduced the soluble solid content and soluble sugar content of the fruit,had no significant impact on berry size and weight,but increases the berry firmness,reduces the tensile strength of the stalk,and has a certain adverse effect on the quality and storage performance of the fruit.