Influence of low-P stress on the biological characteristics of different rice genotypes at different stages

Phosphorus deficiency is one of the limited factors on the growth of rice. Evaluating traits of P-tolerant genotypes offered the materials and basis for identifying genes involved in phosphorus efficiency and genetic mechanism. The biological characteristics of P stress tolerant rice genotypes were studied at tillering, booting and maturity stages with pot culture, setting different levels of phosphorus deficiencies. The responses of various rice genotypes to low-P stress were different at different stages. At tillering stage, P-tolerant genotypes had different relative numbers of tillers, green leaves and shoot dry weight than P-sensitive genotypes. However, no characteristics were good indicators of P-tolerance at this stage. As for booting stage, the relative values of tiller, green leaves and shoot dry weights of P-tolerant genotypes were still higher than P-sensitive genotypes. Compared with tillering stage, however, relative shoot dry weight became the primary indicator of P stress tolerance. At maturity stage, relative shoot dry weight of P-tolerant genotypes was a much better indicator than other biological characteristics. The relative grain yield of P-tolerant genotypes was higher than that of P-sensitive genotypes. There wasn’t obvious difference between P-tolerant and P-sensitive genotypes in relative plant height, leaf width and leaf length at any stage.