Effects Of Delayed Grape Cultivation On Growth Production And Quality Under Water Deficit

The experiment was conducted in Zhangye Water Irrigation Test Center during May to December in 2014, which was about the quality facilities of delayed planting grapes at different growth stages under the water deficit environment, the growth stages are germination period, vining stage, blossom period, enlargement period and coloring maturity, and each growth stage set up three irrigation levels(sufficient water supply,mild water deficit and moderate water defic it). This paper mainly discussed the changes of soil moisture, water consumption characteristics and the growth characteristics namely, grape stem diameter particle dynamic changes of delayed cultivation grapes in different irrigation under water stress, a nd analyzed the response of grape leaf protection system to water deficit,the relation between the water and the grape yield as well the nutritional quality index also were studied,which was in order to determine some reasonable irrigation systems with smaller effects on grape growing to improve the yield and quality,and then providing a theoretical basis for quality and high yield development of delayed cultivation grape.(1)Water stress on soil 20cm-40 cm soil layer has the maximum influences, it will increase the thickness of the dry soil in top soil,though increase the stability of 60cm-80 cm of soil moisture at deep soil, this would keep water retention for deep soil, grapes germination and colored need less water,during this 2 stages, regulated deficit irrigation can saving much water, but in the flowering and enlargement stages, due to strongest water consumption, the regulated deficit irrigation can make the grape root soil moisture decrease quickly, then affecting grapes’ normal growth and development(2)Water deficit will inhibit the growth of grapes’ stem diameter and particle size, as for the stem diameter, it mainly presents the water deficit in germination period,vining stage, and the blossom period, water stress germination of stem diameter increment offset smaller, but it can recover quickly after rehydration,the stem diameter growth are 0.374 and 0.395 cm,which is significantly higher than the rest of the processing, there is no big difference for particle size of grape in vining stage compared with the control(P<0.05), and water deficit make the grape stem diameter growth decrease rapidly in this stage, the stem diameter growth are only 0.121,and 0.16 cm,after rehydration, it still recovers poor, total growth is minimum among each treatment, water stress during the blossom stage due to the accumulation of the first two stages, the total growth of stem diameter of grapes has no great difference compared with CK control; grapes changes in particle size show a trend of fast to slow then to fast, before the enlargement of the two grape stage namely vining stage and blossom stage, water deficit in the pre-enlargement show strong rehydration, which makes a larger enlargement rate of grapes’ particle size, during enlargement stage,water deficit will make the overall rate of the grape partical size decline obviously, the mild water deficit will make the grapes fruit is more outstanding,but its fruit shape index is poor.(3)Water stress will reduce the enzymatic activity of SOD and POD in grapes. The lower degree of water stress reduces 50 percent of it, and the middle degree of water stress reduces 70 percent of it. The recovery of the enzymatic activity in germination period and vining period is obvious when the water is supplied again. The enzymatic activity will rapidly increase 10 percent, which is very helpful for improving grapes’ drought tolerance. The recovery of the enzymatic activity is limit in enlargement period and coloring maturity period, and PO D is not as sensitive as SOD for moisture. Water stress will obviously increase the content of MDA and ABA of the leafs(over 50 percent). The recovery in the first three periods is obvious, and the enzymatic activity will reduce 10 percent rapidly, which is very helpful for improving grapes’ drought tolerance. The moisture recovery in enlargement period and coloring maturity period is very limit, and variation of the content of MDA and ABA will be relatively delayed. The changes will be only obtained in 15 days. Water stress in the first three periods is good to improve grapes’ drought tolerance, but it doesn’t work in the last two periods.(4)The regulated deficit irrigation can help to improve the production of grapes, especially under the circumstances of the middle degree of water stress in germination period and the lower degree of water stress in vining period. The production in these two periods respectively increase 19.86 percent and 7.2 percent. As for the quality of grapes, water stress can obviously reduce titratable acid in the different periods of grapes’ growth except in enlargement period. The water stress of soluble solids in blossom period and the middle degree of water stress of soluble in coloring maturity period are relatively higher. The water stress of anthocyanins in germination period and coloring maturity period is relatively higher. The reasonable water stress can help to improve grapes’ sugar content, and the sugar contents in coloring period is highest than other four periods.Considering grapes growth characteristics, resistance index, yield and quality, the mild water deficit in coloring maturity, namely lightly regulated deficit irrigation lower limit of 60% to 65% of field capacity, is the optimal combination in different growth stages under water stress,there will be higher yield, better quality, and stronger resistance under this treatment.