To identify genetic factors underlying phosphorus (P) uptake and use efficiency under low-P stress in rice (Oryza sativa L.), 84 selected genotypes (recombinant inbred lines) and their parents (which differed in tolerance for low-P stress) “IR20” and IR55178-3B-9-3, were cultured in liquid medium supplemented with adequate and low P levels in a greenhouse. Plants were sampled after 6 weeks in culture for measurements of plant dry weight, P concentration, P uptake and P use efficiency under both P sufficient and stress conditions. A total of 179 molecular markers, including 26 RFLPs and 153 AFLPs, mapped on all 12 chromosomes of rice based on the 84 selected genotypes were used to detect the quantitative trait loci (QTLs) underlying tolerance for low-P stress. Three QTLs were detected on chromosomes 6, 7 and 12, respectively, for relative plant dry weight (RPDW) and relative P uptake (RPUP). One of the QTLs flanked by RG9 and RG241 on chromosome 12 had a major effect which explained about 50% of the variations in the two parameters across the population. The results coincided with the QTLs for low-P stress based on relative tillering ability from the same population from a cross between Nipponbare and Kasalath under soil condition. The identical major QTL for P uptake and plant growth under low-P stress in both liquid medium and soil strongly suggests that the ability of P uptake mainly controls rice tolerance for low-P stress.
应用AFLP与RFLP 标记研究水稻磷吸收与利用率的数量性状位点
吴平1 倪俊健2
（1. 浙江大学生命科学学院生物科学系，杭州华家池310029；
2. 浙江大学农业与生物技术学院农学系，杭州华家池310029）
摘要：从耐低磷胁迫水稻 (Oryzasativa L .)品种“IR2 0”与低磷敏感品系IR5 5 178_3B_9_3杂交发展的重组自交系群体中选择的 84个系在液体培养条件下 ,测定了相对生物量 ,植株相对磷含量及相对磷利用率 ;在酸性土壤盆栽条件下测定了相对分蘖力与相对地上部生物量。用选择的 84个系构建了包括 2 6个RFLP标记与 15 3个AFLP标记的分子标记图谱用于基因定位分析。溶液培养条件下在第 12 ,6 ,7三条染色体上检测到与相对生物量及相对磷含量变异关联的重要数量性状位点 (QTLs) ,其中第 12条染色体上的QTL分别解释相对生物量与相对磷含量变异的 5 0 %左右。仅在第 9条染色体上检测到一个影响相对磷利用率变异的QTL。研究结果与用相对分蘖力为参数的分析结果一致 ,与已报道的在土壤条件下的研究结果也具一致性。低磷胁迫下水稻磷吸收主效QTL在溶液培养与土壤盆栽条件下的一致性提示 :根系吸收面积与吸收转运效率是水稻耐低磷胁迫的主要机制。
关键词： 水稻；数量性状位点；磷吸收；磷利用率
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