水稻稻瘟病菌小种间相对生存力研究

RELATIVE SURVIVAL ABILITY OF DIFFERENT RACES OF MAGNAPORTHE GRISEA IN RICE

选用水稻稻瘟病菌ZA_(49)、ZD_3和ZE_3 3个小种,各2个小种为一组合,以等孢子量混合,于相同条件下在秀水620和秀水48两个感病品种上进行继代接种,经5个世代的转接结果表明:在秀水620上ZA_(49)小种较ZD_3和ZE_3小种具更强的致病力,在秀水48上,ZE_3小种较ZA_(49)和ZD_3小种具更强的致病力,同样其相对生存力也强,两者呈正相关。病菌小种间相对生存力的强弱与病菌小种在品种上单独接种时产生的病斑数、病斑大小和产孢量有关。相对生存力强的小种在病菌群体中易取得优势,从而导致寄主品种的病害量增加。因此认为小种间相对生存力差异也是影响水稻稻瘟病菌群体小种组成发生变化的因素之一。

The relative survival ability of three Magnaporthe grisea (anamorph = Pyric-ularia oryzae) races ZA49, ZD3 and ZE3 on two cultivars Xiushui 48 and Xiushui 620 were studied. The conidia of two of the three races were equally mixed and inoculated to the two cultivars. The diseased seedlings were used to re-inoculate the cultivars from generation to generation. Race ZA49 has higher virulence and greater relative survival ability than that of the races ZD3 and ZE3 on Xiushui 620 while the race ZE3 has stronger virulence and greater relative survival ability than that of the races ZD3 and ZE3 on Xiushui 48. There was a positive relationship between relative survival ability and virulence of the races. The relative survival ability of pathogen was related to the number of lesions, lesion size and the number of sporulation on the cultivars after inoculation with a single race. The race with greater relative survival ability predominated after five generations, resulting in an increase in amount of disease on the cultivars. The presented results indicated that the relative survival ability of different races of M. grisea is one of the factor that influences the changed of physiological race of the pathogen.