水稻品种对稻瘟病的抗性与病菌生理小种变化的关系研究

THE RELATIONSHIP BETWEEN THE RESISTANCE OF RICE VARIETIES TO RICE BLAST AND THE VARIATION IN THE BIOLOGICAL STRAINS OF THE PEST

本文根据1979～1990年四川省稻瘟病菌生理小种鉴定及研究结果,对稻瘟病菌致病性变化与水稻品种之间的关系进行了分析。结果表明,80年代以来,四川省稻瘟病生理小种组成发生了两次较大的变化。1983年后优势种群由ZG 群变为ZB 群,出现频率由1982年的零上升为1986年的72.17%,导致汕优2号完全丧失抗性;1989年后,ZA 群小种上升,出现频率由1984年的1.54%上升为1989年的25.00%,优势种群ZB 群下降,其频率由1986年的72.17%下降到1990年的47.85%,致使汕优63大面积发病。不同品种的稻瘟病菌各不相同。汕优2号以ZB、ZC 群为主的4群15个小种、汕优63有ZA、ZB、ZC 3群13个小种,其致病率均有差异。杂交稻的抗性主要来自恢复系,但更换不育系也可充分利用和发挥优良恢复系的特性。

Based on the results of an investigation and identification of the physiological races ofrice blast(Pyrieularia oryzae Cav.)in the period of 1979～1990 carried out in Sichuan prov-ince,a preliminary analysis was made of the variation in the composition of the biologicalstrains of the pathogen as related to rice varieties.In the 1980's,two major shifts took placein the composition of the pest in Sichuan.After 1983,ZB gradually replaced ZG and be-came the dominant population of the species,its incidence growing from 0 in 1982 to72.17% in 1986,thus resulting in the complete loss of resistance of the once resistant variety“Shan You 2”.In another case,the incidence of ZA increased from 1.54% in 1984 to25.00% in 1989.Occordingly,the incidence of the former dominant population ZB de-creased from 72.17% in 1986 to 47.85% in 1990.As a result,an epidemic occurred in thecrop of the resistant variety “Shah You 62”.Different varietied are attacked by differentpopulations of the pathogen.“Shah You 2”,for example,is susceptible to four populationsconsisting of 15 races,with ZB and ZC being the main pathogenic populations.The hybridrice varictics normally owe their resistance to rice blast to their restorer lines.A shift of thesterile line,however,may help make full use of the resistance of the restorer line.