小麦茎秆实心度对茎秆强度的影响及相关性状QTL分析

摘要

Improving stem strength is an important way to increase lodging resistance of wheat. Solid stem traits, including thick-ness-diameter ratio of culm, stem diameter, culm wall thickness and pith diameter, are the main targets for improvement of stem strength in wheat. In the present study, an F2 population and F2:3 families derived from the cross N18 × WYSG were used to study the influence of stem solidness on stem strength and to identify QTLs for solidness related traits. The thickness-diameter ratio of culm, stem diameter, culm wall thickness and pith diameter were significantly correlated with stem strength. By using composite interval mapping (CIM), a total of 23 QTLs for the five traits were detected on chromosomes 1B, 3B, 4A, 4B, and 5A. Phenotypic variations explained by individual QTL ranged from 3.5% to 44.0%. Pleiotropic QTLs were found on chromosomes 3B (gwm547–gwm247), 4A (wmc718–wmc468), and 5A (gwm156–gwm443), all contributing very high phenotypic variations. The reliability of the markergwm247 was confirmed using 24 F7 lines derived from the N13 (hollow stem) × WYSG (solid stem) cross. The markers linked to major QTLs could be valuable in wheat breeding for lodging resistance with marker assisted selection technology.%在 QTL 水平上研究茎秆实心度与强度的遗传关系及实心度对茎秆强度的影响,为小麦抗倒伏育种提供依据。利用普通小麦宁麦18与实秆小麦种质“武云实秆”的F2群体和F2：3家系,对小麦茎秆强度、实心度及影响实心度的相关性状包括厚径比、壁厚、茎粗和髓腔直径进行了相关分析,并对茎秆强度相关性状QTL进行分子标记定位及遗传效应分析。结果表明小麦茎秆强度与厚径比、壁厚均呈极显著正相关,与髓腔直径呈极显著负相关。基于复合区间作图法进行QTL定位,检测到与茎秆强度、厚径比、壁厚、茎粗和髓腔直径相关QTL共23个,分布在1B、3B、4A、4B、5A上,表型贡献率3.5%~44.0%。在染色体3B、4A和5A上的标记区间gwm547–gwm247、wmc718–wmc468和 gwm156–gwm443均检测到贡献率很高的茎秆实心度相关 QTL,说明在这3条染色体上可能存在控制茎秆强度的主效QTL。用普通小麦宁麦13(N13)×武云实秆的24个F7家系检验分子标记gwm247的可靠性表明利用标记gwm247选育茎秆实心度优于宁麦13的概率较大。研究结果为进一步精细定位相关主效 QTL以及分子标记辅助改良小麦茎秆强度奠定了基础。