八棱海棠בM9’杂交后代抗病及耐逆性遗传分析与优系筛选

Segregation and primary selection of apple rootstock hybrids(Malus micromalus בM9') for Valsa canker resistance and abiotic stress tolerance

【目的】评价苹果砧木杂种后代的生根能力、耐盐碱性和对苹果腐烂病的抗病性。【方法】以八棱海棠בM9’杂种后代为试材,在对2 a生实生苗田间黄化指数调查的同时,对杂种后代无性系绿枝扦插苗的生根移栽率、100 mmol·L-1Na Cl处理30 d后的盐害指数、p H 9.0的Na2CO3处理30 d后的碱害指数及落叶后1 a生枝离体接种苹果腐烂病菌后的抗病性进行了观测。【结果】生根移栽率100%的株系占49.63%。田间黄化指数、盐害指数及碱害指数均表现明显变异,变异系数分别为69.17%、98.29%和74.95%。腐烂病感染度变异系数为27.26%。黄化指数观测中,供试的2 007株实生苗分离为高耐黄化、耐黄化、中等耐黄化、低耐黄化和不耐黄化5个等级,分别占群体的10.16%、17.44%、34.78%、21.62%和15.99%;耐盐性观测中,供试的762个株系分离为22.05%高耐盐、41.86%耐盐、25.85%中等耐盐、8.27%低耐盐和1.97%不耐盐;耐碱性观测中,供试的1 016个株系分离为37.60%高耐碱、29.72%耐碱、19.69%中等耐碱、9.74%低耐碱和3.25%不耐碱;黄化指数与盐害指数的相关系数r=-0.001,黄化指数与碱害指数的相关系数r=0.056,盐害指数与碱害指数的相关系数r=0.055。抗腐烂病观测中,供试的1 108株实生苗分离为8.66%抗腐烂病、51.53%中抗腐烂病、26.90%中感腐烂病和12.91%感腐烂病。【结论】杂种实生苗绿枝扦插生根移栽率在100%的株系占49.63%,后代生根能力强。杂种后代在耐盐性、耐碱性和耐田间黄化能力之间的相关性,均未达显著水平。综合上述观测的5个性状的表型,筛选出抗病抗逆初选优系5个。

【Objective】To evaluate the genetic variation of rooting ability,saline-alkali tolerance and Valsa canker resistance in hybrid progenies of apple root stocks.【Methods】Field chlorosis index and rootingrate of leafy cuttings of two-year-old hybrid seedlings from Malus micromalus בM9＇were investigated.Then,cutting propagated plants were treated with 100 mmol·L^-1Na Cl and Na2CO3（ p H=9.0）,respectively,for 30 days in sand culture. Salt and alkaline injury indices were measured. Resistance to Valsa canker of hybrids was evaluated with the excised twigs during dormancy.【Results】The results indicated that the lines with 100 % rooting rate accounted for 49.63% of the population. The field chlorosis index,saltinjury index and alkaline injury index exhibited significant variations,and the variation coefficient was 69.17%,98.29% and 74.95%,respectively,while the variation coefficient of Valsa canker lesion size was 27.26%. According to frequency distribution diagram,field chlorosis tolerance,salt tolerance and alkaline tolerance,all seedings can be divided into 5 levels： highly tolerant,tolerant,moderately tolerant,low tolerant and sensitive,the corresponding percentages were 10.16%,17.44%,34.78%,21.62% and 15.99% for field chlorosis,22.05%,41.86%,25.85%,8.27% and 1.97% for salt tolerance and37.60%,29.72%,19.69%,9.74%,3.25% for alkaline tolerance,respectively. The correlation coefficient between chlorosis index and salt injury index,chlorosis index and alkaline injury index,salt injury index and alkaline injury index was-0.001,0.056 and 0.055,respectively. Resistance to Valsa canker in 1 108 seedlings can be grouped into 4 levels： resistant,moderate resistant,moderately susceptible and susceptible,the corresponding percentages were 8.66%,51.53%,26.90%,and 12.91%.【Conclusion】The lines with 100 % rooting rate accounted for 49.63% of the population. Rooting ability of leafy cuttings is inherited robustly. The salt tolerance,alkaline tolerance and field chlorosis tolerance did not correlated significantly to each other. In summary,5 elite lines were selected out for Valsa canker resistance and abiotic stress tolerance.