水稻纹枯病几种田间病级调查标准的比较研究

以已知抗、感反应不同的5个水稻品种为试验材料,在田间成株期的不同阶段,采用牙签嵌入法进行抗纹枯病接种试验,并于抽穗后30 d采用不同调查标准进行病级调查,研究适宜于水稻纹枯病病情调查的新标准.结果表明:在分蘖末期接种的各参试品种,采用叶鞘位调查标准的结果与常用的Rush调查标准的结果相比较,两者在不同年份间、地点间差异均不显著,相关分析结果显示,2种调查标准间相关系数在不同年份、地点间分别为0.945 5~(**)、0.984 6~(**),表明叶鞘位标准作为1个新的调查标准在田间纹枯病病级调查时完全可替代Rush调查标准;对于小孕穗期接种的各品种,采用相对病级调查标准,各品种间不仅抗性差异极显著,而且品种间抗感差异大于分蘖末期接种采用叶鞘位调查标准的相应对照,并且这2种凋查标准间各品种的抗、感趋势完全一致.讨论了在水稻抗纹枯病遗传研究中,以小孕穗期相对病级作为调查标准的适用范围.

Comparative study some investigation standards for evaluating rice sheath blight(Rhizoctonia solani) disease rating in field

In order to develop more investigation standards suitable for evaluating rice SB disease rating, five rice culti-vats with different levels of resistance to SB were inoculated with toothpick insertion inoculation methods during different times of rice adult stage in field,and three different investigation standards were adopted to evaluate rice SB disease rating ing data of five rice cultivars inoculated at the late tillering stage in different years and locations, which were measured with the common Rush's investigation standard and the order of leaf sheath investigation standard respectively, and the correlation index of SB disease rating data measured with two investigation standards were 0. 945 5, 0. 984 6 respectively in different years and locations, which all differed significantly at 1% levels. This result showed that the order of leaf sheath investigation standard as a new standard could replace Rush's investigation standard completely in evaluating rice inoculated at the small booting stage,which weremeasured with the relative disease rating investigation standard, but also the resistance differences among different cultivars were greater than that of control inoculated at the late tillering stage, which were measured with the order of leaf sheath investigation standard'. The resistant-to-susceptible order among the five cultivars between two investigation standard were consistent completely, which showed that the relative disease rating investigation standard as a new standard could also be used for evaluating rice SB disease rating in some feasible condition. The application scopes of relative disease rating investigation standard in genetic research of resistance to rice sheath blight was discussed.