耐低氮棉花种质的筛选及评价OA

The low-nitrogen tolerance of 51 cotton germplasm accessions was systematically evaluated under two nitrogen levels[low nitrogen(N0)and normal nitrogen(N345)]using analysis of variance(ANOVA),correlation analysis,principal component analysis,fuzzy membership function analysis,and stepwise regression analysis.The results showed significant differences among the 51 cotton germ-plasm accessions at both nitrogen concentration levels.Under the N0 treatment,most traits,inclu-ding plant height,fruiting branch number,boll numbers,decreased,whereas nitrogen use efficiency and lint percentage increased.Principal component analysis extracted five principal components,with contribution rates of 31.054%,17.783%,12.875%,11.926%,and 7.295%,respectively,and a cu-mulative contribution rate of 80.933%.Based on the fuzzy membership function method,the compre-hensive evaluation value(D value)for low-nitrogen tolerance of each cotton germplasm accession was calculated.Among them,'Lumian 319''Lumian 303''Xinluzhong 74''Xinluzhong 80''Xinluzao 74'and'Xinluzao 63'exhibited relatively high D values(0.560-0.609),indicating strong low-nitro-gen stress tolerance and were therefore classified as low-nitrogen tolerant varieties.In contrast,'Xin-luzao 58''Xinluzhong 71''Zhong 7700''Wanmian LHM9''Xinluzhong 77'and'Xinluzao 62'showed weak tolerance to low-nitrogen stress and were classified as low-nitrogen-sensitive varieties.The analysis identified total dry matter mass,micronaire,boll number,root nitrogen accumulation,and plant height as key indicators for evaluating low-nitrogen tolerance in cotton.The low-nitrogen tolerant germplasm accessions identified in this study provide an important theoretical basis and mate-rials basis for reduced-nitrogen cultivation and breeding of low-nitrogen tolerant cotton varieties.