Effects of different rootstocks on the growth and fruit quality of ‘Italian Riesling’ in Hexi Corridor

Abstract:【Objective】The objective of this study was to evaluate the influence of different rootstocks onthe growth, biomass, yield and fruit quality of Italian Riesling grape. Proper rootstocks may enhance theadaptability and resistance of grape cultivars. It may also improve their growth, berry masses and quality.However, the effects of rootstocks on grapes varied with scion varieties, site conditions and cultivationmeasures. This study was conducted to find the most suitable rootstocks for growth and development of‘Italian Riesling’grape in Gansu Hexi Corridor.【Methods】‘Italian Riesling’grape was grafted onto 12 different rootstocks, including‘101-14’‘520a’‘3309C’‘SO4’‘420’‘1103P’‘St George’‘110R’‘Flourilush’‘Beta’‘5C’and‘5BB’, self-root seedlings were used as the control. The effects of rootstocks on branch growth, average cluster masses, berry masses, soluble solids, titratable acids, reducingsugars, phenols and tannins were evaluated. The experiment was carried out in the experimental station ofthe Institute of Fruit and Floriculture Research, Gansu Academy of Agricultural Sciences in Gaotai, whereit has an annual rainfall of 103 mm, an annual evaporation of 2 000 mm, and deep and loose sandy loamsoils. The seedlings of the twelve rootstocks and the self-rooted Italian Riesling seedlings were planted inSpring, 2011. The grafting was made on green shoots in May to June, 2012. Shoot lengths, shoot diameters, average cluster mass, average berry mass and yield were collected, and the contents of soluble solids,reducing sugars, titratable acids, phenols and tannins in the peel were measured.【Results】The resultsshowed that Italian Riesling grafted on‘101-14’‘3309C’‘SO4’‘St George’‘110R’and‘5BB’root⁃stocks had obviously higher lengths of the forth internode.‘5C’‘520a’‘110R’and‘Beta’significantlydecreased the pith diameter of the forth internode, sign of increased shoot maturity, by 20.72%, 20.17%,19.06% and 11.88%, respectively.‘Flourilush’and‘Beta’significantly increased the cluster massesand yield of Italian Riesling grape compared to the control.‘Flourilush’obtained the highest yield, whichwas 10.47% higher than the control.‘110R’produced the highest cluster mass, however, there was no sig⁃nificant difference in berry yield. Meanwhile, the cluster masses, berry masses and yield in plants on‘520a’‘420’and‘5C’were significantly lower than in the self-root seedlings. Different rootstocks haddifferent effects on reducing sugar content.‘SO4’‘420’and‘5BB’had 15.78%, 11.66% and 10.61%higher reducing sugars than the control, respectively. However,‘Flourilush’was 10.04% lower than thecontrol.‘5BB’‘420’‘1103P’‘520a’‘St Georges’and‘3309C’significantly increased sugar to acidratio in the fruit by a range of 7.97% to 42.15% compared with the control.‘5BB’significantly reducedthe acid content in fruit, and the total acid content of‘5C’was much higher than that of the control. Therootstocks had little effect on fruit pH. Most of these rootstocks could improve tannin content in fruit, and‘101-14’‘420’‘110R’‘Beta’and‘5C’rootstocks were most effective.‘420’‘3309C’‘101-14’and‘Flourilush’increased the soluble solids in ice-wine raw materials during harvest period (from Oct. 2to Oct. 26). The soluble solid in‘101-14’rootstocks increased from 29.63% to 40.30%. In seedlingsgrafted on‘110R’rootstock, soluble solid increase was very slow, from 24.77% to 28.27%, which was significantly lower than that of the control.【Conclusion】‘3309C’‘110R’‘SO4’‘101-14’‘5BB’and‘StGeorges’contributed to increased growth of branches, however, they had no effect on shoot thickening.‘5C’‘520a’‘110R’and‘Beta’promoted shoot maturation.‘Flourilush’and‘Beta’significantly im⁃proved the cluster masses and yield.‘SO4’‘420’and‘5BB’increased reducing sugar content in fruit,while‘Flourilush’reduced it.‘420’‘5BB’‘1103P’520a’‘St Georges’and‘3309C’rootstocks increased reducing sugar content and sugar to acid ratio.‘5BB’significantly decreased the acid content andimproved fruit quality.‘101-14’‘420’‘110R’and‘Beta’obtained the best result in increasing totalphenols and tannins in fruits. According to the above results, depend on the production purpose, the suit⁃able rootstock can be selected to improve the wine quality of Italian Riesling grape in Hexi Corridor area.