EVALUATION OF DROUGHT-RESISTANCE TRAITS OF CITRUS ROOTSTOCK SEEDLINGS BY MULTIPLE STATISTICS ANALYSIS

The objective of this study is to evaluate drought resistance of citrus rootstocks and select drought resistant resources. This experiment was done with seedlings of local citrus rootstock resources of Jiangxi province in China, named ‘Sanhuhongju’, ‘Choupigan’, ‘Sanhuhuahong’, ‘Chongyiyeju’ and the common rootstocks, ‘Swingle’ citrumelo, ‘Trifoliate’ orange, ‘Goutoucheng’, ‘Carrizo’ citrangeand ‘Sour’ pummelo. The rate and index of drought injury was determined by field observations and principal component and subordinate function analysis was applied to analysis physiological parameters such as relative water content (RWC), the activity of superoxide dismutase (SOD), catalase (CAT), peroxydase (POD) and the content of malonaldehyde (MDA), proline (Pro) and soluble sugars (SSC). The results showed that ‘Sanhuhongju’ and ‘Goutoucheng’ had stronger drought resistance having latest time, lowest rates and indexes on drought injury. ‘Sour’ pummelo and ‘Sanhuhuahong’ had the lowest drought resistance. The order of drought resistance from the comprehensive subordinate function values was: ‘Sanhuhongju’ > ‘Goutoucheng’ > ‘Carrizo’ citrange > ‘Choupigan’ > ‘Trifoliate’ orange > ‘Swingle’ citrumelo > ‘Chongyiyeju’ > ‘Sanhuhuahong’ > ‘Sour’ pummelo. This study suggests that ‘Sanhuhongju’, a local citrus cultivar of Jiangxi province, had stronger drought resistance and thus has the potential to be exploited as drought-resistant rootstock.