Anthracnose ratings of switchgrass cultivars and clones

Anthracnose (caused by Colletotrichum navitas) has the potential to significantly reduce biomass yield of switchgrass (Panicum virgatum L.); however, limited information is available on the impact of growing environment on tolerance of switchgrass to anthracnose. Therefore, the major objectives of this study were to (i) examine genotype–environment (G × E) effects on anthracnose severity in populations of switchgrass cultivars and individual genotypes and (ii) determine clonal repeatability estimates and stability analysis of anthracnose tolerance on individual switchgrass genotypes. Two experiments were conducted at one prime and two marginal soil locations in New Jersey. In all, 14 switchgrass cultivars were established from seed in 2008 for experiment 1 and 50 replicated switchgrass clones were planted in 2009 for experiment 2 at all three locations. Anthracnose was rated visually in 2010 for experiment 1 and in 2010 and 2011 for experiment 2. Significant G × E interactions were detected for both experiments (P = 0.05) and anthracnose severity varied by location and cultivar. Clonal repeatability estimates for disease tolerance among clones was 0.78 on a clonal basis and 0.32 on a single-plant basis. Lowland ecotypes exhibited less disease overall than upland ecotypes. Results from this study indicate that selection for improved tolerance to anthracnose should be conducted after evaluation across several environments over multiple years (NEWBio). Feedstock Improvement Data Thrust. doi: http://dx.doi.org/10.1094/PDIS-01-16-0006-RE

炭疽病（由Colletotrichum navitas引起）具备显著降低柳枝稷（Panicum virgatum L.）生物量产量的潜力，但现有关于生长环境对柳枝稷抗炭疽病特性影响的研究信息较为匮乏。因此，本研究的核心目标为：(i) 探究基因型-环境交互效应（Genotype–environment interaction, G × E）对柳枝稷品种群体及单个基因型炭疽病发病程度的影响；(ii) 估算柳枝稷单个基因型抗炭疽病特性的无性系重复率，并开展其稳定性分析。本研究在新泽西州的1个优质土壤点位与2个边际土壤点位开展了两项试验。试验1于2008年以14个柳枝稷品种的种子建植而成；试验2则于2009年在全部3个点位种植了50个重复柳枝稷无性系。试验1的炭疽病发病情况于2010年通过目视法评定，试验2的评定分别在2010年与2011年进行。两项试验均检测到显著的G×E交互作用（P=0.05），且炭疽病发病程度随点位与品种的不同存在显著差异。无性系间的病害抗性重复率在无性系水平上为0.78，在单株水平上为0.32。整体而言，低地生态型的病害发生程度显著低于高地生态型。本研究结果表明，针对炭疽病抗性改良的选择工作，应在多环境、多年份的综合评价后开展（NEWBio）。原料改良数据研究计划（Feedstock Improvement Data Thrust）。doi: http://dx.doi.org/10.1094/PDIS-01-16-0006-RE