Abstract:

Phosphorus (P) shortage in soil is a key-limiting factor in agricultural production. There are P-efficiency differences among different rice genotypes, screening and cultivating low-P tolerant cultivars have become very important. To evaluate the screening method and identification indexes, Chenghui 448（GP1）, the recurrent parent, M401（GP4）, the donor parent, low-P tolerant line GP9 and low-P sensitive line GP14 identified from backcross progenies of Chenghui 448/M401 were used in pot soil cultural experiments with three treatments, including the original P concentration of supplied soil (P2, 2.31 mg/kg), and two supplementary P application levels of P30 (30 mg/kg) and P80 (80 mg/kg). The concentration P80 was used as the normal control; the effects of different inorganic phosphorus supply on relative number of tillers, relative leaf area, relative number of green leaves, relative leaf age, relative chlorophyll content and relative plant height of cultivars were investigated. The main results were summarized as follows: Genotypic differences were found distinctly in many traits with P2 treatment, which was better than P30 treatment to distinguish low-Pi tolerant genotypes from those sensitive to P deficiency at seedling stage. Under P2 condition, the differences among the relative number of tillers in different lines for 52 d, 59 d and 66 d were significant, indicating that relative number of tillers may be used as main index for screening and identifying the tolerance to Pi deficiency. In addition, relative leaf area, relative number of green leaves and relative leaf age can be employed to evaluate the tolerance to Pi deficiency in rice germplasm, comprehensively.

Key words: Rice, Tolerance to Pi deficiency, Screening criteria