Abstract
Fundamental growth response patterns to fertilizer and low- and high-fertilizer-prone characteristics in rice plants were examined with 35 rice varieties of different ecotypes and growth types, which were grown until the 8.5-leaf stage under seven levels ot nutrient concentrations of Kimura B culture solution. Though varietal differences in response of RGR to fertilizer did not appear clearly before the 6.5-leaf stage, four types of responses were found at the following growth stage. They were based on the changes in the specific leaf area (SLA) and nitrogen content per leaf area (NCLA), which showed four typical patterns to nutrient level. On the other hand, three patterns to nutrient level were found in nitrogen content per leaf dry weight (NCLW). These results show that both high NCLW and NCLA under low nutrient level, found in a few indica rice, are important characteristics for low-fertilizer-prone varieties, while higher stable RGR with small increases of SLA under high nutrient level, found in most of japonica rice, is for high-fertilizer-prone ones.
