高寒区不同燕麦品种(系)表型性状和茎秆力学特征与抗倒伏性的关系研究

A study of the relationship between phenotypic traits, stem mechanical traits and lodging resistance of oat varieties for alpine regions

为明确不同燕麦品种(系)间抗倒伏能力差异及其原因,在青藏高原高寒地区对选育的I-D品系及父本(青海甜燕麦)、母本(青海444),以抗倒伏较强的林纳和抗倒伏较弱的青引1号燕麦为对照,在开花期和乳熟期开展了表型性状、器官鲜重和茎秆力学特征等指标与抗倒伏性间的相关关系研究,找出影响燕麦倒伏的主要性状,探明燕麦抗倒伏评价的主要指标,为今后抗倒伏型燕麦品种选育及相关研究提供理论依据。结果表明,5个燕麦品种(系)乳熟期抗倒性强弱依次为林纳>I-D品系>青海甜燕麦>青海444>青引1号。相关分析表明,倒伏指数、表观倒伏率与穗长、穗位高、株高、重心高度、各器官鲜重、节间长呈正相关,与茎粗、秆壁厚间呈显著或极显著负相关,与茎秆力学特性间呈显著或极显著负相关关系。燕麦第二茎节对抗倒伏性的影响大于第三茎节。茎粗、秆壁厚、穿刺强度、茎秆折断力、折断弯矩、弯曲力矩和弯曲性能可作为燕麦抗倒性评价指标。株高对燕麦品种倒伏性的影响大于穗部特征,秆壁厚和茎粗对燕麦的抗倒性影响最大,穿刺强度最能反映燕麦品种抗倒伏能力,提高茎秆厚度和折断性能是提高燕麦抗倒伏能力的重要途径。选育的I-D品系燕麦株高适中,茎粗、秆壁厚、节间长及茎秆力学特性等方面优于亲本,其抗倒性显著优于亲本。

This research studied factors contributing to differences between oat varieties for lodging resistance, in order to identify major traits contributing to, and to further breeding for lodging resistance. Five lines or cultivars were selected for study: a recently bred hybrid(I-D line), its two parents [male Avena sativa cv. Qinghai(Q), female A. sativa cv. Qinghai 444(Q444)], and 2 reference cultivars more and less susceptible to lodging,[Qinyin No. 1(QY1), and LENA(L)], used as controls. Plants were examined during flowering and milky-grain growth phases, and fresh weight and a range of stem physical traits potentially contributing to lodging resistance were assessed. The ranking of the 5 studied varieties for lodging resistance was: L>I-D line>Q>Q444>QY1. Correlation analysis indicated that lodging index and phenotypic lodging score were positively correlated with ear length, ear position, plant height, height of the head centre of gravity, head fresh weight, and stem internode lengths;and where significantly or highly significantly negatively correlated with stem diameter and thickness, and stem mechanical strength traits. The second internode contributed more to lodging resistance more than the third one. It is suggested that stem diameter and thickness, stem wall penetration resistance, breaking resistance, bending moment and other physical bending parameters be used for evaluating oat lodging resistance. Plant height influenced lodging resistance more than ear characters. The stem diameter and thickness had the largest impact on lodging resistance, while the stem wall penetration resistance was the best indicator of lodging resistance in oats. The results indicate that it is important to enhance the stem thickness and the breaking resistance in order to increase lodging resistance in oats. Compared to their parents, the newly bred I-D lines had better plant height, stem diameter and thickness, internode length, and stem mechanical traits, resulting in better lodging resistance.