Lin Ying-Chen, Weng Yiqun, Fei Zhangjun, Grumet Rebecca
Department of Horticulture, Graduate Program in Plant Breeding, Genetics and Biotechnology, Michigan State University, East Lansing, MI 48824, USA.
Department of Plant and Agroecosystem Sciences, University of Wisconsin, Madison WI 53706, USA.
Hortic Res. 2024 Dec 4;12(3):uhae340. doi: 10.1093/hr/uhae340. eCollection 2025 Mar.
Commercial value of cucumber is primarily driven by fruit quality. However, breeding goals frequently focus on production constraints caused by biotic and abiotic stresses. As sources of resistances are often present in unadapted germplasm, we sought to provide morphological and genetic information characterizing the diversity of fruit quality traits present in the CucCAP cucumber core collection. These 388 accessions representing >96% of the genetic diversity for cucumber present in the US National Plant Germplasm System harbor important sources of resistances and extensive morphological diversity. Data were collected for skin color, length/diameter ratio (L/D), tapering, curvature, and spine density for young fruits [5-7 days postpollination (dpp)], and length, diameter, L/D, skin color, netting, seed cavity size, flesh thickness, hollowness, and flesh color for mature fruits (30-40 dpp). Significant associations of single nucleotide polymorphisms (SNPs) with each trait were identified from genome-wide association studies. In several cases, quantitative trait loci (QTL) for highly correlated traits were closely clustered. Principal component analysis, driven primarily by the highly correlated traits of fruit length, young and mature L/D ratios, and curvature showed a clear divergence of East Asian accessions. Significant SNPs contributing to the longest fruits, including development-stage specific QTL, were distributed across multiple chromosomes, indicating broad genomic effects of selection. Many of the SNPs identified for the various morphological traits were in close vicinity to previously identified fruit trait QTL and candidate genes, while several novel genes potentially important for these traits were also identified.
黄瓜的商业价值主要取决于果实品质。然而，育种目标常常聚焦于由生物和非生物胁迫导致的生产限制因素。由于抗性来源通常存在于未适应的种质资源中，我们试图提供形态学和遗传学信息，以表征CucCAP黄瓜核心种质库中果实品质性状的多样性。这388份种质代表了美国国家植物种质系统中黄瓜遗传多样性的96%以上，蕴藏着重要的抗性来源和广泛的形态学多样性。我们收集了幼果（授粉后5 - 7天）的果皮颜色、长度/直径比（L/D）、果形渐尖度、弯曲度和刺密度数据，以及成熟果实（授粉后30 - 40天）的长度、直径、L/D、果皮颜色、网纹、种子腔大小、果肉厚度、空心度和果肉颜色数据。通过全基因组关联研究确定了单核苷酸多态性（SNP）与每个性状之间的显著关联。在一些情况下，高度相关性状的数量性状位点（QTL）紧密聚集。主成分分析主要由果实长度、幼果和成熟果实的L/D比以及弯曲度等高度相关性状驱动，结果显示东亚种质明显不同。对最长果实有贡献的显著SNP，包括发育阶段特异性QTL，分布在多条染色体上，表明选择具有广泛的基因组效应。为各种形态性状鉴定出的许多SNP与先前鉴定的果实性状QTL和候选基因紧密相邻，同时还鉴定出了几个可能对这些性状重要的新基因。
