新疆自然高温环境下玉米自交系开花期耐热性鉴定与评价

在新疆夏季自然高温环境下,以田间玉米空秆率、果穗结实率、相对结实率为主要评价指标,综合籽粒产量与穗部性状,对26份国内外玉米骨干自交系连续2年进行耐热性鉴定与评价,结合新疆当地高温干燥的气候特点,建立一套适宜玉米种质资源大田耐热性的鉴定、评价体系,为中国玉米耐热种质资源的遗传改良和新品种选育提供参考。结果表明:(1)不同基因型玉米自交系空秆率、果穗结穗率、相对结实率和耐热性差异较大,其中GW5F、GW4F、GW7F和PH6WC耐热性最强,在高温胁迫下空秆率最低,果穗结实率与相对结实率最高;其次为PHBA6、新自351等8份自交系,在高温胁迫下籽粒产量及综合表现较好;其余自交系对高温均表现敏感。(2)高温胁迫导致玉米穗部性状严重衰退,其中的穗重、穗行数和行粒数所受影响最大。(3)在年份或材料之间,玉米自交系籽粒产量与其主要农艺性状相关性差异较大,并以果穗重与籽粒产量相关性最高。(4)以相对结实率为主要指标通过层次聚类可将参试材料分为两大群,耐热性最强的GW5F、PH6WC、GW4M聚为第Ⅰ群,其余自交系聚为第Ⅱ群;第Ⅱ群中‘吉63’、Mo17等6份自交系可聚为第1亚群,PHBA6、LH82等6份自交系聚为第2亚群,郑58、新农育6390M等11份自交系聚为第3亚群。综合分析来看,该研究中表现极耐高温的4份自交系均为国外优异种质,可用于玉米耐高温基础研究和遗传改良;表现较强耐热性的8份品系多来自于新疆本地选育的材料,其遗传基础较为广泛,适应当地的高温环境,也是优异的耐热育种资源。

Identification and Evaluation of Heat Tolerance of Maize Inbred Lines during Flowering under Natural High Temperature in Xinjiang

Under the natural high temperature environment in summer of Xinjiang, taking the barren stalk, ear seed setting rate and relative seed setting rate as the main evaluation indexes, we coupled with the yield and main agronomic traits, to identify and evaluate the heat tolerance of 26 maize inbred lines for 2 consecutive years. Combined with the local high temperature and dry climate characteristics, we established a set of heat tolerance identification and evaluation system, which is helpful for heat tolerance improvement and breeding new varieties of maize in China. The results showed that: (1) there were great differences in the empty stem rate, ear setting rate, relative seed setting rate and heat tolerance of different maize genotypes. Among them, GW5F, GW4F, GW7F and PH6WC had the strongest heat tolerance. Under high temperature stress, the empty stem rate was the lowest, and the ear seed setting rate and relative seed setting rate were the highest; Secondly, 8 inbred lines such as PHBA6 and Xinzi 351 had better yield and comprehensive performance under high temperature stress. Other inbred lines were sensitive to high temperature. (2) High temperature stress led to a serious decline in maize ear traits. Ear weight, rows per ear and grains per row were most seriously affected. (3) The correlation between yield and main agronomic traits was quite different between years or materials, and the correlation between ear weight and yield was the highest. (4) Taking the relative seed setting rate as the main assessment criteria, the tested materials can be divided into two categories by hierarchical clustering. GW5F, PH6WC and GW4M were clustered into the first group. The second group contains three subgroups; Six inbred lines such as Ji 63 and Mo17 were clustered into the first subgroup; 6 inbred lines such as PHBA6 and LH82 were clustered into the second subgroup; 11 inbred lines such as Zheng 58 and Xinnongyu 6390M were clustered into the third subgroup. In summary, four inbred lines with extremely high temperature tolerance were identified, which can be used for basic research and genetic improvement of maize heat tolerance. 8 inbred lines with strong heat tolerance were mostly local inbred lines in Xinjiang, which have a wide genetic basis, adapt to the local high temperature, and were excellent heat resistant breeding materials.