甘蓝型油菜微核心种质耐旱鉴定与评价指标筛选

摘要

Drought poses great threat to rapeseed (Brassica napus L.) production.It is important to establish a reliable evaluation method for drought tolerance.To select resistant germplasm,mini-core collection including seedlings of 107 rapeseed accessions was employed to establish a reliable method.Drought tolerance was evaluated after the procedure of'dehydration-rehydration-dehydration-rehydration'.The variations of drought tolerance were evaluated and ideal indicators of drought tolerance were selected.The evaluation included measuring several drought-tolerance-related indicators.Results showed that drought severely inhibited plant growth.Eight indicators were all significantly different.The distribution frequency of 107 accessions was normal.It indicated that shoot fresh weight stress index,plant fresh weight stress index,and drought resistant index were remarkably correlated with each other,thus the indicators could be used as major evaluation indicators for drought tolerance of B.napus seedlings.Among these indicators,shoot fresh weight stress index was the simplest,most accurate and effective one.By integrating the 3 indices,drought tolerance of 107 accessions were verified,and highly-tolerant accessions were selected among the mini-core collection.%干旱是威胁油菜生产的主要非生物逆境,建立有效的耐旱鉴定方法,筛选鉴定耐旱油菜种质资源,对培育油菜耐旱新品种、提高油菜稳产性具有重要意义.本文以107份甘蓝型油菜微核心种质为材料,设置正常供水和干旱2个处理,采用干旱-复水-干旱-复水的处理方法,通过测定旱害指数、叶片萎蔫指数、地上部鲜重胁迫指数、地上部干重胁迫指数、根鲜重胁迫指数、根干重胁迫指数、植株总鲜重胁迫指数、植株总干重胁迫指数等指标,评价油菜种质耐旱性变异,筛选理想的耐旱评价指标.结果表明,干旱严重抑制了甘蓝型油菜的生长,8个评价指标均表现出显著差异,并呈正态分布.地上部鲜重胁迫指数、植株总鲜重胁迫指数和旱害指数3个指标之间显著相关,可作为甘蓝型油菜苗期耐旱性的主要评价指标,其中地上部鲜重胁迫指数最为简便、准确和有效;综合应用这3个评价指标,明确了107份微核心种质耐旱性,筛选出2份高耐旱种质,为耐旱相关研究及育种提供了评价方法和材料.