苹果斑点落叶病抗病性种质评价及遗传分析

Evaluation of resistance of Malus germplasms to apple alternaria blotch(Alternaria mali) and analysis of inheritance for resistance

为评价苹果种质资源对苹果斑点落叶病的抗病性,明确苹果斑点落叶病抗病性遗传规律,利用1株通过组织分离法得到的苹果斑点落叶病菌株(Alternaria mali),对260份苹果种质和1 089株紫塞明珠×富士杂种实生树进行了离体叶片接种鉴定。结果表明:不同类型种质资源的发病率和严重度均表现出丰富多样性,新疆野苹果和西洋苹果发病率较高且严重度较重,而中国苹果和野生苹果资源发病率较低且严重度较轻。发病对不发病表现为显性,发病/不发病表现为质量性状,分离比符合3∶1。最终得到高抗种质29份、中抗27份和低抗48份。发病亚群体的严重度表现为多基因数量性状,其变异由2个主基因分离位点所致,严重度性状主基因遗传率和多基因遗传率分别为86.33%和10.51%。

To evaluate resistance of Malus germplasms to Alternaria mall and definite the inheritance rule of resistance,260 Malus germplasm accessions and 1089 seedlings of Zisaimingzhu x Fuji were inoculated on the detached leaves with the suspension of germinated conidia of a tissue-isolated strain of Alternaria mall. Diverse performance of disease incidence and severity was found among different germplasm accessions. Disease incidence was higher and severity was more serious of Malus sieversii and Malus domestica germplasms than those among Chinese domestica cultivars and wild genotypes. Due to analysis of frequency distribution and calculation of genetic parameters, occurrence is dominant to nonoccurrence, with occurrence/nonoccurrence segregation ratio of 3： 1. According to the evaluation,29 germplasms were highly resistant. While,27 moderately resistant and 48 low resistant accessions were found. The severity is a quantitative character controlled by the segregation of 2 major gene loci. Respectively, heritability of major genes and polygenes for severity is 86.33% and 10.51%.