甘蔗杂交后代黑穗病抗性评价与抗感池构建

为研究甘蔗杂交后代黑穗病抗性的遗传变异,构建抗病、感病近等基因池,配置了2个杂交组合,其中组合1为CP84-1198×科5,组合2为ROC20×桂糖73-167,对2个组合部分后代进行2次新植人工接种黑穗病抗性鉴定,调查并分析了5个病害参数的关系.相关分析结果显示,病害有关参数中,发病持续期(SSD)与最大累计丛感染率(IPmax)、最大累计茎感染率(ISmax)、病情消长曲线下的面积(∑AUDPC)存在极显著的正相关,IP_与最短潜伏期(LP)在不同作物季间重演性高.应用2个病害流行学参数SSD和LP以及3个病情指数IP_、IS_和∑AUDPC作为聚类指标,采用欧氏距离及最长距离法,对2个组合的杂交后代部分个体的抗性进行聚类分析,构建了2对遗传背景不同的抗、感黑穗病近等基因池,为后续研究奠定了基础.

Evaluation of Smut Resistances in Sugarcane Cross Progenies and the Construction of Resistant and Susceptible Pools

Sugarcane smut induced by Ustilago scitaminea is one of the most important fungus diseases in Mainland China and all over the world, which results in no millable stalk and serious yield loss. Resistant variety breeding is the only effective measure to control the disease. In order to investigate the genetic variation of smut resistance in cross progenies and to construct the corresponding resistant and susceptible near-isogenic pools, some single lines derived from two cross hybrid combinations (CP84-1198×Ke5, ROC20×Gui73-167) were taken as the plant materials, and inoculation experiment was conducted in two crops of plant cane, and consequent relationship among the 5 indexes of infection was analyzed. The results of correlation and resistant stability analysis showed that sustained disease duration(SSD) were significantly correlated at 0.05 or 0.01 levels with index of plants infection (IPmax), index of stalk infection (ISmax), area under disease progress curves (AUPDC), and that the repeatability rate was high in IPmax and latent infection period (LP). In the light of the principle of Euclidean distance and the Longest Distance Method, two sets of resistant and susceptible near-isogenic pools which differed in genetic background were constructed by taking the two disease epidemic parameters(SDD and LP) and three indexes of infection (IPmax, ISmax and AUPDC) as the clustering indexes, which would offer theoretical and practical reference for further study in the future.