Harnessing underutilized gene bank diversity and genomic prediction of cross usefulness to enhance resistance to Phytophthora cactorum in strawberry

The development of strawberry Fragaria x ananassa cultivars resistant to Phytophthora crown rot (PhCR), a devastating disease caused by the soil-borne pathogen Phytophthora cactorum, has been challenging, partly because resistance phenotypes are quantitative and only moderately heritable. To develop deeper insights into the genetics of resistance and build the foundation for applying genomic selection, a genetically diverse training population was screened for resistance to California isolates of the pathogen. Here we show that genetic gains in breeding for resistance to PhCR have been negligible (3% of the cultivars tested were highly resistant and none surpassed early twentieth-century cultivars). Narrow-sense heritability for PhCR resistance ranged from 0.35-0.57. Using multivariate GWAS, we identified a large-effect locus (predicted to be RPc2) that appears to be ubiquitous, slowed symptom development, explained 43.6-51.6% of the genetic variance, was necessary but not sufficient fo...针对由土传病原菌恶疫霉（Phytophthora cactorum）引发的毁灭性病害疫霉冠腐病（Phytophthora crown rot, PhCR），培育抗该病害的凤梨草莓（Fragaria × ananassa）品种一直颇具挑战，这在一定程度上是因为其抗性表型属于数量性状且仅具有中等遗传率。为深入解析抗性遗传机制并为基因组选择育种奠定基础，研究团队对一套遗传多样性丰富的训练群体开展了针对该病原菌加州分离株的抗性筛选试验。本研究结果显示，疫霉冠腐病抗性育种的遗传增益几乎可以忽略：受试品种中仅3%表现为高抗，且无任何品种能超越20世纪早期的抗病品种。疫霉冠腐病抗性的狭义遗传率区间为0.35~0.57。通过多变量全基因组关联分析（multivariate GWAS），研究人员鉴定到一个大效应基因座（预测为RPc2），该位点似乎广泛分布，可延缓症状发展，解释了43.6%~51.6%的遗传变异，且是抗性形成的必要而非充分条件……