Effects of rootstocks on growth and development of‘Cabernet Sauvignon'grape

Abstract:【Objective】The first objective of the study was to elucidate the influence of rootstocks on biomass, fruit development, and berry pigmentation in‘Cabernet Sauvignon'grape. Proper use of rootstocks can enhance the adaptability and resistance of grape cultivars and also improve their growth, fruit set and quality. The second objective was to select the most suitable rootstocks for‘Cabernet Sauvignon'grape cultivated in Turpan.【Methods】‘Cabernet Sauvignon'grape was grafted on‘SO4'‘5BB'‘3309C'and‘101-14M'rootstocks. The effects of rootstocks on branch growth, berry mass, soluble solids, titratable acids, reducing sugars and peel color were evaluated. The experiment was conducted in Research Institute of Grape and Melons of Xinjiang Uygur Autonomous Region. The experimental plots were at an altitude of419 m, with an annual rainfall of 25.3 mm, annual evaporation capacity of 2 751 mm, and sandy loam soil.Rootstocks to be tested were all three years old, and planted on May 5th, 2011. Strain 685 of‘Cabernet Sauvignon'was grafted onto the selected rootstocks, using current season green budwoods and cleft grafting that was carried out on May 15 th, 2014. The self-rooted‘Cabernet Sauvignons' seedlings at the same age were used as the control, and related indexes were measured from April, 2015. Branch lengths, branch diameters, leaf net photosynthetic rates, 100-berry mass, soluble solids, reducing sugars, titratable acids,relative content of anthocyanins in the peel and color indexes were measured for different treatments. The color parameters included L-value, a-value, b-value, h-value, and c-value. L-value means luminosity,abblue, h-value or hue angle is a comprehensive color index, and c-value means color saturation, which is the chroma of color.【Results】All rootstocks, especially‘3309'could improve branch growth and berry mass of‘Cabernet Sauvignon'grape(aliased as CS/3309 C, likewise for other grafting combinations).From seed to pruning in summer, branch length was the order of CS/3309C>CS/5BB>CS/SO4>CS/101-14M>control. At fruit ripening stage, the branch diameters of CS/3309 C, CS/SO4, CS/5BB and CS/101-14 M were 138.42%, 132.76%, 123.39%, and 120.88% of control, respectively. Berry mass followed the order of CS/3309C>CS/101-14M>CS/5BB>CS/SO4, being 122.15%, 117.16%, 115.73%, and 109.02%of control, respectively. Diurnal variation of net photosynthetic rate in each treatment followed a doublepeak curve. All rootstocks could improve leaf net photosynthetic rate and changed the time of the peaks.With fruit development and coloring, soluble solids and reducing sugars increased. Soluble solids and reducing sugars in CS/3309 C, CS/5BB, CS/101-14 M and control ranged in the same level, they were all significantly higher compared with those in CS/SO4. Fruit maturation in CS/SO4 was delayed by about 20 days. During fruit ripening, titratable acids in CS/SO4, control, CS/5BB, CS/3309 C and CS/101-14 M were0.59%, 0.55%, 0.52%, 0.49% and 0.42%, respectively, and titratable acid content in CS/SO4 was the highest. Anthocyanin content in CS/SO4 rose gradually and showed significant difference, so SO4 rootstock could delay the coloration of‘Cabernet Sauvignon'grape. The trend of coloring indexes(L-value,a-value, b-value, h-value and c-value) of CS/3309 C, CS/5BB, CS/SO4, CS/101-14 M and control were similar, but h-value in CS/SO4 was much higher than the others.【Conclusion】‘3309C'rootstock could help to improve the growth vigor and berry mass in‘Cabernet Sauvignon'grape. All rootstocks could increase the peak values of diurnal leaf net photosynthetic rate.‘SO4'rootstock could delay fruit maturation by about 20 days. It could also delay fruit coloration and anthocyanin accumulation.