Influence Of Differernt Training Systems On Photosynthetic Characteristics,growth And Development Of Cabernet Sauvignon

Training systems and canopy exert an important impact on grape berry quality which is the foundation of making excellent wine.This study was performed in Manas winery of Citic Guoan Wine CO.,LTD.Photo synthetic characteristics of Cabernet Sauvignon trained with modified vertically shoot positioned(M-VSP),fan training system with two trunks(Fan-TT)and fan training system with multiple trunks(Fan-MT),was studied using LI-6400 portable photosynthesis system during berry enlargement,veraison and mature period.Grape berry quality was also comparatively analyzed to comprehensively evaluate the effect of of different training systems on grape berry and come up with a theory basis for making wine of high quality in Xinjiang vinegrowing region.The main coclusions are as follows:(1)Response curve of net photosynthetic rate(Pn)of Cabernet Sauvignon leaves at different node positions presented a unimodal type change trend in M-VSP,Fan-TT and Fan-MT during berry enlargement,veraison and mature period;Pn of leaves at different node positions varied significantly among different training systems,the Pn value of vines trained with Fan-TT was lower than M-VSP,and Pn with Fan-MT was the lowest.(2)Maximum peak of the diurnal variation of photosynthetic parameters of Cabernet Sauvignon in the three training systems,decreased in the order:M-VSP>Fan-TT>Fan-MT;in M-VSP,the photosynthesis of Cabernet Sauvignon had a midday depression phenomenon during berry enlargement,veraison periods;in Fan-TT,the midday depression phenomenon only occurred in berry enlargement,periods,while in Fan-MT,the photosynthesis of Cabernet Sauvignon had no midday depression phenomenon.(3)M-VSP system may effectively enhance the grape leaves’ability of utilizing poor light.Among the three training systems,leaves of Cabernet Sauvignon trained with M-VSP had the largest photosynthetic affecting radioation(PAR)range,the lowest light compensation point(LCP),and the biggest apparent quantum yield(AQY).(4)M-VSP system was beneficial to the accumulation of sugar,phenolic compounds and anthocyanins in grape berry.These grape berries from M-VSP had the highest content of soluble solid(23.8°Brix),total phenolics(40.7 mg/g dry weight)and total anthocyanins(6.3 mg/g dry weight),following by Fan-TT and Fan-MT.Compared comprehensively,vines trained with M-VSP had the highest net photosynthetic rate and eco-physiological factors,and best fruit quality among these vines trained with M-VSP,Fan-TT and Fan-MT.