自然干旱胁迫条件下48个甘蔗品种(系)耐旱性综合评价OA

48 sugarcane varieties(strains)were used as experimental materials in this study to screen sugarcane germplasm with excellent drought tolerance at early growth stage and identify key evaluation indicators for drought tolerance.After 90 days of natural drought stress,a series of drought resistance-related indices at seedling stage of ra-toon crop were measured.A comprehensive evaluation of the germplasm drought tolerance was carried out using prin-cipal component analysis,cluster analysis and regression analysis.The coefficients of variation of the 12 evaluation indices ranged from 2.62%to 61.53%.Principal component analysis reduced the 12 indices to four comprehensive in-dicators,with a cumulative contribution rate of 81.53%.Based on the comprehensive evaluation value(D-value)calcu-lated by the membership function method and cluster analysis,the 48 sugarcane lines were classified into four drought tolerance grades,10 highly drought-tolerant lines,21 drought-tolerant lines,14 moderately drought-tolerant lines and 3 drought-sensitive lines.A prediction model for drought tolerance evaluation at seedling stage of sugarcane was estab-lished by stepwise regression analysis,D=-1.576+0.078X1+0.014X2+0.008X3+0.003X4+0.003X5+0.003X6+0.001X7+0.001X8(R2=0.923,P<0.01).Eight indices,including soluble protein content,leaf water content,chlorophyll content,shooting rate,leaf area,catalase activity,tillering rate and proline content,were screened as the key indicators for the seedling drought tolerance identification in sugarcane.This study established a comprehensive evaluation system suitable for sugarcane drought tolerance assessment at seedling stage,providing a method reference and basic materials for research of the drought tolerance mechanisms and breeding of new drought-tolerant sugarcane germplasm.