Noble Research Institute, LLC., 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.
California Cooperative Rice Research Foundation, Rice Expt. Station, 955 Butte City Highway, Biggs, CA, USA.
Sci Rep. 2020 Sep 3;10(1):14539. doi: 10.1038/s41598-020-71488-8.
Summer dormancy is an important stress avoidance mechanism of cool season perennial grasses to persist well under harsh summer conditions. QTL associated with summer-dormancy related traits in tall fescue has significant breeding implications. An F pseudo testcross population was developed by crossing a Mediterranean (103-2) to a Continental parent (R43-64). The population was genotyped using 2,000 SSR and DArT markers. Phenotyping was done in growth chambers and in two Oklahoma, USA locations. Total length of R43-64 and 103-2 maps were 1,956 cM and 1,535 cM, respectively. Seventy-seven QTL were identified in the male and 46 in the female parent maps. The phenotypic variability explained by the QTL ranged between 9.91 and 32.67%. Among all the QTL, five summer dormancy related putative QTL were identified in R43-64 linkage groups (LGs) 4, 5, 12, 20 and 22 and two in 103-2 LGs 5 and 17. All the putative summer dormant QTL regions in male map showed pleiotropic responses and epistatic interactions with other summer dormant and stress responsive QTL regions for plant height, new leaf and dry biomass weight. The flanking markers related to the QTL reported in this study will be useful to improve tall fescue persistence in dry areas through marker-assisted breeding.
夏季休眠是冷季型多年生禾草在夏季恶劣条件下良好生存的重要避胁迫机制。与高羊茅夏季休眠相关性状相关的 QTL 具有重要的育种意义。通过将一个地中海型品种（103-2）与一个大陆型品种（R43-64）杂交，构建了一个 F2 伪测交群体。该群体使用 2000 个 SSR 和 DArT 标记进行了基因型分析。表型分析在生长室和美国俄克拉荷马州的两个地点进行。R43-64 和 103-2 的图谱总长度分别为 1956cM 和 1535cM。在父本图谱中鉴定出 77 个 QTL 雄性，46 个 QTL 雌性。QTL 解释的表型变异范围在 9.91%到 32.67%之间。在所鉴定的所有 QTL 中，有 5 个与夏季休眠相关的推定 QTL 分别位于 R43-64 连锁群 4、5、12、20 和 22，有 2 个位于 103-2 的连锁群 5 和 17。雄性图谱中所有推定的夏季休眠 QTL 区域均表现出与株高、新叶和干生物量等夏季休眠和应激响应 QTL 区域的多效性反应和上位性互作。本研究报道的与 QTL 相关的侧翼标记将有助于通过标记辅助选择来提高高羊茅在干旱地区的生存能力。
