The quality evaluation of wine grape and its respond to weather condition

Wine grape was sampled from six provinces and autonomous regions in China between 2004-2005.We applied the analytical hierarchy process(AHP) method to evaluate main influences of weather factors on the quality of wine grape in each sites.Main quality factors included in this study were total sugar,the ratio of sugar and acidity,pH,and tannin.The results showed that the quality of wine grape were higher in Yuma,Yuquanying,the Third of Guangxia and Hedong vineyard in east foot of Helan mountain,Gaotai county,Wuwei city in Hexi corridor,and Shihezi city in Xinjiang than that in Yantai,Penlai and Changli in Bohai gulf.The mainly climatic factors impacting the quality of wine grape were precipitation and water-heat coefficient during July August when wine grape was in veraison,but precipitation played a more important role in affecting the quality of wine grape than water-heat coefficient.The diurnal range of temperature during veraison and mean air humidity during growing season regulated the quality of wine grape as well.In addition,mean minimum temperature was not significant compared with other climatic factors.Sunshine and heat in the six sampling sites were suitable for high quality of wine grape.