To understand the genetic background of root growth of rice (Oryza sativa L.) seedlings under different water supply conditions, quantitative trait loci (QTLs) and epistatic effect on seminal root length, maximum adventitious root length, adventitious root number, total root dry weight and ratio of root to shoot were detected using molecular map including 103 restriction fragment length polymorphism (RFLP) markers and 104 amplified fragment length polymorphism (AFLP) markers mapped on a recombinant inbred line (RIL) population with 150 lines derived from a cross between an lowland rice IR1552 and an upland rice Azucena in both solution culture (lowland condition) and paper culture (upland condition). Six QTLs and twenty-two pairs of epistatic loci for the four parameters were detected. Three QTLs detected for maximum adventitious root length in solution culture (MARLS), total root dry weight in both solution culture and paper culture (TRDWS and TRDWP) accounted for about 20%, 23% and 13% of the total variations, respectively. Only epistatic loci were found for maximum adventitious root length and adventitious root number in paper culture (MARLP and ARNP), and for ratio of root to shoot in both paper and solution culture (R/SP and R/SS), which accounted for about 12%-61% of the total variations in the parameters, respectively. No identical QTL or epistatic loci were found for the parameters in both solution and paper culture. The results indicate that there is a different genetic system responsible to root growth of rice seedlings under lowland and upland conditions and epistasis might be the major genetic basis for MARLP, ARNP, R/SP and R/SS.
不同供水条件下水稻幼苗根系形成的遗传分析
张卫萍 吴平* 沈晓莹 吴运荣
（浙江大学生命科学院植物科学研究所，杭州华家池310029）
摘要：利用分子标记图谱对溶液培养与旱作培养(纸培养)下的水稻(Oryza sativa L.)幼苗的种子根与最长不定根长、不定根数、总根干重、根冠比等性状进行了基因定位与遗传分析.4种参数共检测到6个数量性状位点(quantitative trait loci,QTLs)与22对上位性互作位点.其中溶液培养中的最长不定根长、总根干重和旱作培养中的总根干重检测到的QTLs位点对总变异的贡献率分别为20%、23%和13%左右;旱作培养中的最长不定根长、不定根数、根冠比和溶液培养中的根冠比仅检测到上位性位点,对表型变异的贡献率在12%～61%之间.溶液培养与旱作条件下没有一个或一对检测到的QTL或互作位点完全相同,提示溶液培养和旱作条件下影响幼苗根系生长的遗传机制差异.上位性作用对旱作培养条件下的根生长具重要影响.
关键词： 水稻；根系形成；溶液培养；旱作培养；数量性状座位；上位性
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