Effects Of Rain-Shelter Cultivation On Growth And Quality Of ‘Cabernet Sauvignon’ In Northern China

In recent years,rain-shelter cultivation was widely applie cultivation mode which could effectively reduce the risk of grape diseases and insect pests.In this experiment,‘Cabernet Sauvignon’ was used as the experimental material to study the effects of rain-shelter cultivation on wine grapes,including photosynthetic characteristics of grape leaves,the risk of disease,the grape fruits shape and soluble solids content,total acid content,total sugar content,phenol content and other fruit quality.The main findings were as follows:1.Photosynthetic characteristics of grape leavesThe rain-shelter cultivation significantly reduced light intensity and different degrees of reduced leaf photosynthesis in different parts.The light intensity under the shelter film was lower than that of the open cultivation.The diurnal variation of Pn in the upper leaves appeared to be a single peak curves,and there were not phenomenon of ‘noon break’ in the upper leaves,the chlorophyll content increased,the chlorophyll a/b decreases,and the daily average Pn decreased by 13.90%.That of Pn in the middle and lower leaves did a double peak curves in rain-shelter mode and obvious ‘noon break’ in the middle and lower leaves,but short duration,and the daily average Pn decreased by 10.03% and 23.80%.Rain-shelter reduces the transpiration rate of plant leaves.The average daily of intercellular CO2 concentration of the leaves in different parts in rain-shelter mode was higher and that of the stomatal conductance was lower in the open cultivation.The rain-shelter cultivation improves the adaptability of upper and lower leaves to weak light,and has little effect on the middle leaves.The leaves growed bigger in the upper,the chlorophyll content increased,the chlorophyll a/b significantly decreases(p<0.05);The leaf area,chlorophyll content,and chlorophyll a/b of the middle leaves did not differ statistically(p>0.05);The leaf area of the lower leaves did not differ statistically(p>0.05),but the chlorophyll content and chlorophyll a/b significantly decreased(p<0.05).2.Plant diseases:The risk of disease in the leaves and cluster was reduced in rain-shelter cultivation.In the harvest period,the incidence rate of sooty blotch disease decreased by 9.33% and 6.84% in leaves and grape cluster and the disease index decreased by 8.33% and 4.17%,respectively.3.Fruit shape traits and fruit quality traits:The rain-shelter cultivation did not significant effect on the shape of the fruit,which reduces the adverse effects of rainfall on the accumulation rate of soluble solids and the rate of totel acid decomposition,and effectively improves the quality traits.In the harvesting period,the weight and size of cluster,average weight and length,diameter of berry were not significantly different(p>0.05).The rain-shelter cultivation significantly increased total sugar content and reducing sugar(p<0.05).The sugar acid ratio and soluble solids increased slightly,the total acid content decreased slightly,p H did not differ statistically(p>0.05).The contents of total phenols and flavonoids in peel and tannins in seeds decreased significantly of rain-shelter cultivation(p<0.05),respectively.The contents of tannin,flavanol,proanthocyanidins and anthocyanins in peel and total phenols,flavonoids,flavanols and proanthocyanidins in seeds decreased of rain-shelter cultivation,respectively,without significant difference(p>0.05).