Understanding the genetic basis for forage yield traits is essential for forage sorghum and sudangrass hybrid breeding. In this study, we constructed a high-density genetic map using a recombinant inbred line population between sorghum Tx623A and sudangrass Sa using RAD-seq and performed QTL mapping for plant height (PH), stem diameter (SD), tiller number (TN), total shoot fresh weight (FW) and total shoot dry weight (DW). The map consists of 1,065 markers with a total length of 1191.7 cM. A total of 43 QTLs were detected, including three QTLs for PH, eight for SD, ten for TN, ten for FW and twelve for DW. Two QTL clusters contained overlapping QTLs for TN, FW and DW. One cluster (qTN6.2/qFW6/qDW6.1) also overlaps with qTN6.1 and qDW6.2. The sorghum ortholog of a known heterotic biomass gene ARGOS, Sobic.006G092500, was located within all the five QTLs mapped on chromosome 6. Our results showed that a high-density genetic map is useful for dissecting important traits and identifying underlying genes in sorghum and sudangrass hybrid populations.

了解牧草产量性状的遗传基础对于牧草高粱和苏丹草杂交育种至关重要。在本研究中，我们使用高粱 Tx623A 和苏丹草 Sa 之间的重组自交系群体使用 RAD-seq 构建了一个高密度遗传图谱，并对株高 (PH)、茎直径 (SD)、分蘖数 (TN) 进行 QTL 定位、总枝条鲜重 (FW) 和总枝条干重 (DW)。该地图由 1,065 个标记组成，总长度为 1191.7 cM。共检测到43个QTL，其中PH为3个，SD为8个，TN为10个，FW为10个，DW为12个。两个 QTL 簇包含 TN、FW 和 DW 的重叠 QTL。一个簇（qTN6.2 / qFW6 / qDW6.1）也与qTN6.1和qDW6.2。已知杂种优势生物量基因ARGOS的高粱直系同源基因Sobic.006G092500 位于定位在 6 号染色体上的所有五个 QTL 中。我们的结果表明，高密度遗传图谱有助于剖析高粱和高粱中的重要性状和识别潜在基因。苏丹草杂交种群。