The peduncle vascular system of maize is critical for the transport of photosynthetic products, nutrients, and water from the roots and leaves to the ear. Accordingly, it positively affects the grain yield. However, the genetic basis of peduncle vascular bundle (PVB)-related traits in maize remains unknown. Thus, 15 PVB-related traits of 386 maize inbred lines were investigated at three locations (Yongcheng, 17YC; Kaifeng, 20KF; and Yuanyang, 20YY). The repeatability for the 15 traits ranged from 35.53% to 92.13%. A genome-wide association study was performed and 69 non-redundant quantitative trait loci (QTL) were detected, including 9, 41, and 27 QTL identified at 17YC, 20KF, and 20YY, respectively. These QTL jointly explained 4.72% (SLL) to 37.30% (NSVB) of the phenotypic variation. Eight QTL were associated with the same trait at two locations. Furthermore, four pleiotropic QTL were identified. Moreover, one QTL (qPVB44), associated with NSVB_20KF, was co-localized with a previously reported locus related to kernel width, implying qPVB44 may affect the kernel width by modulating the number of small vascular bundles. Examinations of the 69 QTL identified 348 candidate genes that were classified in five groups. Additionally, 26 known VB-related homologous genes (e.g. VLN2, KNOX1, and UGT72B3) were detected in 20 of the 69 QTL. A comparison of the NSVB between a Zmvln2 EMS mutant and its wild type elucidated the function of the candidate gene ZmVLN2. These results are important for clarifying the genetic basis of PVB-related traits and may be useful for breeding new high-yielding maize cultivars.

中文翻译：

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通过全基因组关联研究解剖玉米花梗维管束相关性状的遗传结构

玉米的花梗维管系统对于光合产物、营养物质和水分从根部和叶子到耳朵的运输至关重要。因此，它对粮食产量产生积极影响。然而，玉米花梗维管束（PVB）相关性状的遗传基础仍然未知。因此，在三个地点（永城，17YC；开封，20KF；元阳，20YY）调查了 386 个玉米自交系的 15 个 PVB 相关性状。15 个性状的重复性在 35.53% 到 92.13% 之间。进行了全基因组关联研究，检测到 69 个非冗余数量性状基因座 (QTL)，其中分别在 17YC、20KF 和 20YY 鉴定出 9、41 和 27 个 QTL。这些 QTL 共同解释了 4.72% (SLL) 到 37.30% (NSVB) 的表型变异。八个 QTL 在两个位置与相同的性状相关。此外，鉴定了四个多效性QTL。此外，一个 QTL (与 NSVB_20KF 相关的qPVB44）与先前报道的与内核宽度相关的基因座共定位，这意味着qPVB44可能通过调节小维管束的数量来影响内核宽度。对 69 个 QTL 的检查确定了 348 个候选基因，分为五组。此外，在 69 个 QTL 中的 20 个中检测到26 个已知的 VB 相关同源基因（例如VLN2、KNOX1和UGT72B3 ）。Zmvln2 EMS突变体与其野生型之间NSVB的比较阐明了候选基因ZmVLN2的功能. 这些结果对于阐明 PVB 相关性状的遗传基础具有重要意义，并可能有助于选育新的高产玉米品种。