稻米垩白性状对高温耐性的QTL分析

Identifying QTLs for Thermo-tolerance of Grain Chalkiness Trait in Rice

【目的】本研究旨在筛选与稻米外观品质高温耐性连锁的分子标记,为稻米品质育种提供参考。【方法】以耐热水稻品系996和热敏感水稻品系4628为亲本构建的重组自交系为材料,采用垩白粒率耐热指数、垩白大小耐热指数和垩白度耐热指数为评价指标,对水稻垩白性状的高温耐性QTL进行检测。【结果】采用复合区间作图法两年共检测到垩白性状高温耐性QTL 24个,包括垩白粒率高温耐性QTL 8个,垩白大小高温耐性QTL 12个,垩白度高温耐性QTL 4个。其中,第6染色体上的2个垩白粒率高温耐性QTL和第7染色体上的2个垩白度高温耐性QTL在两年中重复检测到,且这2个稳定表达的垩白度位点与2015年检测到的第7染色体上的垩白粒率位点重合。另外,发现有4个QTL一因多效,同时影响垩白粒率、垩白大小及垩白度。【结论】控制垩白粒率耐热指数的q HTCGR6.1和控制垩白度耐热指数的q HTCD7.1是新的QTL。

【Objective】The molecular markers linked to high temperature tolerance of rice appearance quality were screened for the purpose of providing an important foundation of improvement for rice grain quality.【Method】The quantitative trait loci(QTLs)for heat tolerance of grain chalkiness trait were identified using the recombinant inbred lines(RILs)derived from a cross between the heat tolerant rice line996and the heat sensitive line4628.The heat tolerance indexes of chalky grain rate,chalkiness size and chalkiness degree were used as the heat-tolerance indicators.【Result】24QTLs for heat tolerance of grain chalky traits were detected in two years by using composite interval mapping analysis including eight for heat tolerance of chalky grain rate(HTCGR),twelve for heat tolerance of chalkiness size and fourteen for heat tolerance of chalkiness degree(HTCD).Two HTCGR QTLs on chromosome6and two HTCD QTLs on chromosome7could be detected repeatedly in two years.The two HTCD sites coincided with two HTCGR sites on chromosome7detected in2015.Moreover,anyone of the four pleiotropic QTLs had impacts on the chalky grain rate,chalkiness size and chalkiness degree.【Conclusion】The QTL controlling the heat tolerance index of chalkiness degree qHTCGR6.1and the QTL controlling the heat tolerance of chalkiness degree qHTCD7.1might be new findings..