粒用高粱种质中后期抗旱性鉴定筛选与分类指标评价

【目的】高粱为世界第五大禾谷类作物,具有多种使用价值。与其他作物相比,高粱具有较强的抗旱能力,但是伴随全球干旱的加剧,干旱成为限制高粱尤其是粒用高粱生产的主要因素之一,同时,不同品种间抗旱能力差异显著。通过对粒用高粱材料进行抗旱性鉴定评价,为高粱抗旱性分子机理以及抗旱育种研究奠定基础。【方法】 以165份粒用高粱为材料,通过干旱（DS）和正常灌溉（NI）2种处理方式,在山西省和海南省两地开展抗旱试验。采用大田自然鉴定法,调查株高、穗长、茎粗、叶片持绿性、倒伏率、千粒重、籽粒大小和产量8个主要形态指标。采用综合抗旱系数（CDTC）、抗旱指数（DI）和隶属函数（D）进行聚类分析,结合3种方法对材料进行分类,并对抗旱指标进行评价。【结果】 在干旱胁迫下,粒用高粱8个形态指标均出现下降。除叶片持绿性与株高和籽粒大小不相关,抗倒伏性与穗长和籽粒大小不相关外,其余指标均存在一定程度上的相关性。根据3种综合抗旱评价方法筛选出高抗材料5份（L013、SX44B、SX18-25、SX18-87和L405）,敏感材料4份（SX18-46、SX18-82、SX18-96和SX18-73）;根据形态指标的相对值和变异系数,两地试验都显示叶片的持绿性、产量、籽粒大小和抗倒伏性,4个指标对干旱较为敏感,且存在信息交叉。主成分分析结果显示,决定第一主成分的主要是产量、株高和籽粒大小,贡献率31.841%;决定第二主成分的主要是叶片持绿性和千粒重,贡献率20.441%;决定第三主成分的主要是茎粗,贡献率13.557%;决定第四主成分的主要是抗倒伏性,贡献率11.428%;决定第五主成分的为穗长,贡献率9.461%。【结论】 粒用高粱中后期干旱胁迫对其主要形态指标均有显著影响。不同高粱材料间抗旱性差异显著,结合3种抗旱性综合评价方法,可以较为准确地评价高粱材料的抗旱性。叶片的持绿性和产量可以作为评价高粱花后抗旱性的主要形态指标。

Evaluation of Identification and Classification Index for Drought Resistance at Middle and Late Growth Stage in Grain Sorghum Germplasms

【Objective】 Sorghum is the fifth largest cereal crop in the world, which has a variety of usages. Compared with other crops, sorghum has a strong drought resistance, drought has become one of the main restricting factors in sorghum (especially grain sorghum) production, with the intensification of the global drought. Through drought resistance identification and classification index evaluation of grain sorghum materials were carried out in order to lay foundations for future studies on molecular mechanism of and breeding for drought resistance in sorghum. 【Method】 With 165 grain sorghum accessions as the experimental materials, drought resistance experiments with two treatments, drought (DS) and normal irrigation (NI), were carried out in the fields in Shanxi and Hainan provinces. Eight morphological traits, including plant height, panicle length, stem diameter, leaf greenness, lodging rate, 1000-grain weight, grain size and yield, were investigated. Cluster analysis was carried out by using three methods: Comprehensive Drought Tolerance Coefficient (CDTC), Drought Resistance Index(DI) and membership function(D).【Result】 Under drought stress, all 8 morphological indexes of grain sorghum decreased. Except that leaf greenness was not correlated with plant height and grain size, and lodging resistance was not correlated with panicle length and grain size, all the other indicators were correlated to some extent. Five high-resistant accessions (L013, SX44B, sx18-25, sx18-87 and L405) and 4 sensitive accessions (sx18-46, sx18-82, sx18-96 and sx18-73) were selected according to the three comprehensive drought resistance evaluation methods; According to the relative value and variation coefficient of morphological indicators, the experiments in both places showed that the stay-green, yield, grain size and lodging resistance were sensitive to drought, and there was overlapped information among the four indicators. According to the principal component analysis, yield, plant height and grain size were the main factors determining the first principal component, and the contribution rate was 31.841%; The greenness of the leaves and thousand-grain weight were the main factors determining the second principal component, and the contribution rate was 20.441%; Stem thickness were the main factors determining the third principal component, the contribution rate was 13.557%; the main factors determining the lodging resistance of the fourth principal component, the contribution rate was 11.428% ; The fifth principal component was spike length, the contribution rate was 9.461%. 【Conclusion】 It was found that drought stress at the middle and late growth stages had significant effects on the main morphological indicators of grain sorghum. There existed significant difference among accessions in drought resistance. Combined with three comprehensive evaluation methods of drought resistance, the drought resistance of sorghum accessions could be evaluated more accurately. Two traits stay green and yield could can be used as main morphological indicators to evaluate drought resistance of sorghum after flowering.