商洛主栽玉米苗期耐热性鉴定与评价

Identification and Evaluation of Heat Tolerance in Seedling Stage of Major Cultivated Maize in Shangluo

摘要: 选育耐热品种是应对全球气候变暖、减轻高温热害对玉米生产影响的最根本措施。为筛选适宜商洛地区种植的耐热玉米品种，本研究以商洛14种常栽玉米品种为研究对象，播种后19 d后进行5 d的高温处理，测定株高、茎粗、根长、叶面积、地上部鲜重、地下部鲜重、地上部干重、地下部干重、叶绿素含量、总干重和根冠比11个性状的耐热系数，采用主成份分析与聚类分析相结合的方法，综合分析鉴定和评价了不同品种的抗热性。利用主成份分析方法，将11项指标分解为4个单独的综合指标，占总资料79.83%的信息。结果表明，利用隶属函数法和耐热综合评定D值，将14个玉米品种分为高耐热、中耐热、弱耐热、热敏感4大类，分别选出了SD22、SK9两个高耐热品种，两个热敏型品种DH11和QA23。本研究筛选出了适宜于商洛本地栽植的耐热品种，也为研究玉米耐热性基因资源发掘和耐热性品种培育奠定了理论依据。

Abstract: Developing heat-tolerant maize cultivars represents a fundamental approach to addressing the challenges posed by global climate warming and mitigating the detrimental effects of heat stress on maize production. This study aimed to identify maize varieties with superior heat tolerance suitable for cultivation in the Shangluo region. Fourteen commonly cultivated maize varieties were subjected to a five-day high-temperature treatment beginning 19 days after sowing. Eleven agronomic and physiological traits were evaluated, including plant height, stem diameter, root length, leaf area, aboveground fresh weight, belowground fresh weight, aboveground dry weight, belowground dry weight, chlorophyll content, total dry weight, and root-to-shoot ratio. Heat tolerance coefficients were calculated for each trait. Comprehensive evaluation of heat tolerance was conducted using a combination of Principal Component Analysis (PCA) and cluster analysis. PCA extracted four principal components explaining 79.83% of the total variance from the measured traits. Based on membership function analysis and the comprehensive heat tolerance index (D value), the fourteen maize varieties were classified into four categories: highly heat tolerant, moderately heat tolerant, weakly heat tolerant, and heat sensitive. Two varieties, SD22 and SK9, were identified as highly heat-tolerant, while DH11 and QA23 were classified as heat sensitive. The findings provide a theoretical foundation for the selection of heat-tolerant maize cultivars adapted to the Shangluo region and contribute to the exploration of heat tolerance gene resources and the breeding of heat-resilient maize varieties.