APPRAISAL OF EARLY RICE TOLERANCE TO GLEYIC PADDYSOIL IN CENTRAL AND EASTERN HUNAN

The gleyic paddysoil, characterized by excess Fe⁺⁺ Mn⁺⁺, S^-- low Eh, low temperature of water and soil, and excess organic acids, is the most important adverse soil type in eastern and central Hunan, Five early indica rice varieties （lines, including one hybrid rice） were used in the field （gleyic paddysoil） evaluation from 1987 to 1989 Changsha, Hunan, aiming at evaluating the differences in eco-adaptability to the adverse soil and screening out some tolerant varieties. lines and hybrid rice. We have put forward a comprehensive system for evaluating the tolerance of rice to the stress soil condition and established the evaluating method with aseries of progressive Fe⁺⁺ added solution.The results show that root mass and root oxidizing activity at booting stage, tillering rate at early tillering stage, dry matter production at late tillering stager, catalase GDI and photosynthesis rate of flag leaf at milk stage, are useful appraisal indexes to evaluate the tolerance of rice to gleyic paddysoil. Using these appraisal indexes we found the hybrid combination "Weiyou 49" shows the best tolerance, while new lines, "Changtaofu No, 2" and "Changtaofu No. 1", show intemediate, but the local widely-cultivated varieties, "Zhefu 802" and "Xiangzhaoxian No. 4", show the weakest tolerance to the gleyic paddysoil, Main differences exist at rootsystem characters and agronomic characters. In conclusion. these appraisal indexes can be used in study of rice ecoadaptability to gleyic paddysoil and the breeding of gleyic paddysoil tolerance of early indica rice in order to raise the efficiency of selection.