Cold Hardiness Evaluation Of Grape Varieties Based On Temperature-injury Relation And Its Affecting Factors

A system for Differential Thermal Analysis (DTA) was applied for Low Temperature Exotherms (LTE) Analysis of canes、buds and roots of wine grape varieties, then established buds injury grape temperature(LT-I) of all cultivars, and LT-I of canes and roots were established by three-point method; A comprehensive evaluation on LTs of different varieties was analyzed by subordinate function value analysis; We determined the relative water content and examined the root cross-sectional anatomy and firmness and roughness in12varieties with different cold hardiness gradients and performed correlation analysis of cold hardiness. And buds cold hardiness in different over-wintering stage was compared.1. The injury degrees of phloem and cane from LT-I analysis were significantly related to the browning rates and electrolytic conductivity from traditional low temperature freezing analysis, and the correlation coefficient was0.996and0.983. As temperature decreased, the observed browning rates of140Ru and Vidal increased remarkably, which were consistent with expected damage by LT-I, which indicated that the LT-I analysis method could be used to distinguish cold hardiness of grapevine canes and buds.2. Analysis of cold hardiness of seven wine grape canes indicated that phloem and xylem had different levels of hardiness. The slope of phloem LT-I was different among the seven cultivars when the temperature decreased. The order was Italian Riesling<Syrah<Cabernet Sauvignon<Merlot<Chardonnay<Cabernet Gernischt<White Xiongyue. The order of phloem lethal temperature was Merlot> Cabernet Gernisch>Chardonnayt>Ltalian Riesling>Syrah> Cabernet Sauvignon> White Xiongyue. The order of slope of xylem was different from phloem. The order was Syrah<White Xiongyue<Chardonnay<Cabernet Gernischt<Merlot<Cabernet Sauvignon<Italian Riesling. The xylem lethal temperature of different cultivars was in the order of Syrah>Chardonnay> Cabernet Gernischt>Merlot>Cabernet Sauvignon>Italian Riesling>White Xiongyue. The LTE integrated assessment index indicated that White Xiongyue and Italian Riesling had better cold resistance, Cabernet Sauvignon was the moderate one, and Syrah, Merlot, Chardonnay and Cabernet Gernischt were the worse.3. Buds cold hardiness identification analysis of grapes indicated that the order of Qlt of buds was Chancellor<5BB<Frontenac<Beichun<SO4<Vidal<101-14Mgt<Beta<3309C<140Ru<Moldova<Cabernet Sauvignon<110R<1103P; The buds50%lethal temperature of different cultivars was in the order of Cabernet Sauvignon> Moldova> Vidal> Chancellor>110R>1103P>3309C>140Ru> Beichun>101-14Mgt> Frontenac> Beta>5BB> SO4. A comprehensive evaluation on LT20to LTgo of different varieties were analyzed by subordinate function value analysis. The result indicated that the buds of Cabernet Sauvignon had the worst cold hardiness, followed by Moldova, Vidal, Chancellor,110R,3309C,140Ru, Beichun,1103Pand101-14M, while Frontenac, Beta,5BB and SO4had the best cold hardiness.4. Roots cold hardiness identification analysis of grapes indicated that the sequence of varieties with complete phloem freezing temperatures resulting in death (P100; from high to low) was Tannat> Dorn felder> Carmenere> Syrah> Riesling> Merlot noir>110R> Vidal> Summer Black>1103P>140Ru> Beck memento> Chambourcin>5BB>3309C> Golden Queen> Dogridge>101-14M> S04> Frontenac> Beta; the sequence of varieties with complete xylem freezing temperatures resulting in death (X100) from high to low was Dorn felder> Tannat> Summer Black> Vidal> Syrah> Merlot noir>110R>1103P>101-14M>3309C>5BB> Golden Queen>140Ru> Riesling> Carmenere> SO4> Dogridge> Chambourcin> Beck memento> Frontenac> Beta.The data show that the sequence of Qlt of phloem is Carmenere<Tannat<Merlot noir<Dorn felder<Syrah<Summer Black<Riesling<Vidal<3309C<110R<5BB<Beck memento<140Ru<Golden Queen<1103P<Chambourcin<Dogridge<101-14M<SO4<Beta<Frontenac. Qltx data show that the sequence of Qlt of xylem is Summer Black<SO4<101-14M<Golden Queen<3309C<5BB<Tannat<Merlot noir<Vidal<1103P<11OR<140Ru<Dorn felder<Dogridge<Frontenac<Syrah<Riesling<Beck memento<Chambourcin<Beta<Carmenere. The LTE integrated assessment index indicated that Beta had the best cold hardiness in all rootstocks, followed by SO4、Dogridge、3309C,5BB、101-14M and140Ru,1103P and110R were the worse; for cultivars, Frontenac had the best cold hardiness, followed by Golden Queers Chambourcin and Beck memento, with Summer Black、Merlot noir、Vidal and Riesling being moderate, and Syrah、Carmenere、Dorn felder Tannat the least hardy.5. We examined the root cross-sectional anatomy and determined the relative water content in12varieties with different cold hardiness gradients and performed correlation analysis of the subordinate function values. We found that in grape root tissue, low water content and free water content and high bound water and bound water/free water content resulted in small subordinate function values for LTE, which indicates good cold hardiness. Grape varieties with thick root exodermis layers, thin phloem and a high proportion of xylem had better cold resistance than the other varieties. Grape root hardness was determined by Texture Analyzer. The correlation of root hardness and cold hardiness was also analyzed. Root cold hardiness had a significantly positive correlation with all the hardness indexes.6. Buds in deep dormancy had a better cold hardiness， characterized by the buds cold hardiness in January were better than in November. Within a certain roughness (0.2-0.6cm), the cold hardiness of Italian Riesling roots didn’t change along with the change of roughness; There was no difference at the cold hardiness of Cabernet Sauvignon buds in Taian and Penglai.