不同果桑种质对桑实杯盘菌抗性差异的研究OA

The fruit mulberry industry is an important component of the diversified utilization of mulberry trees,and hypertrophic sclerotiniosis is one of the key factors restricting the development of this industry.Among them,hypertrophic sclerotiniosis is a common disease caused by Ciboria shiraiana,which is widespread in major fruit-mulberry planting regions.Therefore,using C.shiraiana as the inoculum,this study selected 421 fruit mulberry germplasm from the National Mulberry Germplasm Repository(Zhenjiang)for indoor detached leaf identification,and further conducted field identification on 284 high-yielding accessions,systematically evaluating the resistance of mulberry germplasm resources to hypertrophic sclerotiniosis.A five-level resistance evaluation standard was established using the relative resistance index(RI)combined with K-means cluster analysis.The effects of germplasm type,species,and geographical origin on resistance were analyzed,and the correlation between resistance and main fruit nutritional components was also investigated.The results showed extremely significant differences in resistance among the tested germplasm.The indoor disease development rate of the 421 accessions ranged from 0.17 to 4.16 cm2/d,and they were classified into five resistance levels(86 highly resistant,143 moderately resistant,111 moderately susceptible,64 susceptible,and 17 highly susceptible).Among them,the coefficient of variation of the single-branch diseased fruit rate for the 284 high-yielding accessions was 121.54％.The average indoor disease development rate of wild germplasm(1.07±0.81 cm2/d)was significantly lower than that of cultivated germplasm(1.69±0.75 cm2/d)(P＜0.001),indicating that wild germplasm are generally more resistant.Among different mulberry species,Morus cathayana exhibited the strongest resistance(average disease development rate approximately 0.6 cm2/d,with the highest proportion of highly resistant accessions),while Morus alba and Morus multicaulis were generally susceptible(average disease development rate approximately 1.6 cm2/d,with a relatively high proportion of susceptible accessions).Geographical origin had no significant effect on resistance(P=0.421),indicating that resistance is primarily determined by genetic background.Ten high-yielding and highly resistant varieties,including Zhongshen 3 and 72C002,were selected(single-branch diseased fruit rate＜2.58％,indoor disease development rate＜0.76 cm2/d).No significant correlations were found between disease resistance and quality traits such as total flavonoids and anthocyanins;however,a weak negative correlation was observed between disease development rate and total soluble sugar content in susceptible germplasm(P＜0.05).This study established an RI-based resistance evaluation system for mulberry germplasm,clarified the resistance differences among germplasm,and identified elite resistant sources,providing important references for disease-resistant breeding,rational germplasm deployment,and further research on resistance mechanisms.