Screening of rice for tolerance to low phosphorus stress

Screening and selecting typical low-P tolerant rice genotype was very important component of both theory and application study.A simple,intuitionistic and representative index was useful to reduce workload,and could increase the reliability in screening.In this study,2472 cultivars from different gene bases screened at seedling stage and whole growing stage was used to examine the indexes for screening low-P tolerant rice genotypes.The results showed that using two steps screening,screening and rescreening at seedling stage,combined with the verification for whole growing stages not only could obtain typical low-P tolerant rice genotypes,but also increase screening efficiency with the anastomotic ratio of screening and rescreening equivalent to 67%.Under the condition of available P content of tested soil being lower than 5(mg/kg),and screening density being four plants/ 600g soil,adopting P 50(mg/kg) soil as low P limit; At seeding stage,tiller and its relative value were regard as the main indexes for evaluating rice with different P efficiency,and dry weight of shoot as the reference one.But at whole growing stage,grain yield and its relative value were the reliable verifying(indexes),and effective head had decisive effect on grain yield.