Table_3_Genotype × Environment Studies on Resistance to Late Leaf Spot and Rust in Genomic Selection Training Population of Peanut (Arachis hypogaea L.).docx

Foliar fungal diseases especially late leaf spot (LLS) and rust are the important production constraints across the peanut growing regions of the world. A set of 340 diverse peanut genotypes that includes accessions from gene bank of International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), elite breeding lines from the breeding program, and popular cultivars were screened for LLS and rust resistance and yield traits across three locations in India under natural and artificial disease epiphytotic conditions. The study revealed significant variation among the genotypes for LLS and rust resistance at different environments. Combined analysis of variance revealed significant environment (E) and genotype × environment (G×E) interactions for both the diseases indicating differential response of genotypes in different environments. The present study reported 31 genotypes as resistant to LLS and 66 to rust across the locations at 90 DAS with maturity duration 103 to 128 days. Twenty-eight genotypes showed resistance to both the diseases across the locations, of which 19 derived from A. cardenasii, five from A. hypogaea, and four from A. villosa. Site regression and Genotype by Genotype x Environment (GGE) biplot analysis identified eight genotypes as stable for LLS, 24 for rust and 14 for pod yield under disease pressure across the environments. Best performing environment specific genotypes were also identified. Nine genotypes resistant to LLS and rust showed 77% to 120% increase in pod yield over control under disease pressure with acceptable pod and kernel features that can be used as potential parents in LLS and rust resistance breeding. Pod yield increase as a consequence of resistance offered to foliar fungal diseases suggests the possibility of considering ‘foliar fungal disease resistance’ as a must-have trait in all the peanut cultivars that will be released for cultivation in rainfed ecologies in Asia and Africa. The phenotypic data of the present study will be used for designing genomic selection prediction models in peanut.

叶部真菌病害，尤其是晚斑病（late leaf spot, LLS）与锈病，是全球各花生种植区的重要生产制约因子。本研究选取340份遗传多样性丰富的花生基因型材料，涵盖国际半干旱热带作物研究所（International Crops Research Institute for the Semi-Arid Tropics, ICRISAT）基因库的种质资源、育种项目中的优良育种系以及主流栽培品种，在印度3个试点的自然与人工病害流行条件下，针对LLS、锈病抗性及产量性状开展了筛选。研究结果表明，不同环境下各基因型对LLS和锈病的抗性存在显著差异。联合方差分析显示，两种病害均存在显著的环境效应（E）与基因型×环境（G×E）互作，表明不同基因型在各环境中的响应存在分化。本研究在各试点的播后90天（days after sowing, DAS）进行调查，共鉴定出31份抗LLS的基因型、66份抗锈病的基因型，供试材料的生育期为103至128天。另有28份基因型在所有试点中均表现出对两种病害的抗性，其中19份源自卡德纳斯花生（A. cardenasii）、5份源自栽培花生（A. hypogaea）、4份源自长毛花生（A. villosa）。通过试点回归分析与基因型×基因型×环境（GGE）双标图分析，共鉴定出8份对LLS抗性稳定的基因型、24份抗锈病稳定性优异的基因型，以及14份在病害胁迫下各环境中荚果产量稳定的基因型，同时还鉴定出了各试点专属的最优基因型。9份同时抗LLS和锈病的基因型，在病害胁迫下的荚果产量较对照提升77%~120%，且其荚果与籽仁性状表现优良，可作为抗LLS与锈病育种的潜在亲本材料。叶部真菌病害抗性带来的荚果产量提升，表明在亚洲和非洲雨养生态区推广的所有花生栽培品种中，将‘叶部真菌病害抗性’列为必备性状具有可行性。本研究获得的表型数据，将用于构建花生基因组选择预测模型。