Turf-type bermudagrass is susceptible to winterkill when grown in transition zone climates. Minimizing water use in turfgrass management is of societal significance. African bermudagrass (Cynodon transvaalensis Burtt-Davy) has been extensively used to cross with common bermudagrass (C. dactylon Pers. var. dactylon) in the creation of F₁ hybrid cultivars. Little information regarding the molecular basis of winter survivability and drought resistance in African bermudagrass is available. Accordingly, the objectives of this study were to quantify genetic variability and identify quantitative trait loci (QTL) associated with winter survivability traits (spring greenup, SG; spring greenup percent green cover, SGPGC; winterkill, WK), and leaf firing (LF) in African bermudagrass. A total of 109 first-generation self-pollinated (S₁) progeny of ‘OKC1163’ were evaluated in a field trial in a randomized complete block design with three replications for four seasons. Significant genetic variation existed for all the traits examined, and the broad-sense heritability estimates ranged from .36 to .54 for the winter survivability traits and .80 for LF. Ten QTL were identified for winter survivability traits and two for LF based on a preexisting high-density linkage map, which was aligned, reoriented, and renamed as to a recently published reference genome. Seven of 12 QTL were consistently identified at least in 2 yr. The colocation of two QTL, one for winter survivability and another for LF, suggests the possibility of improving both traits together. Findings provide new insights to genetic control of winter survivability traits and LF and contribute genetic resources for marker-assisted selection in turf-type bermudagrass improvement.

中文翻译：

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非洲百慕大草冬季生存能力和叶片燃烧的遗传变异性和 QTL 作图

草坪型百慕大草在过渡带气候条件下生长时易受冻害。最大限度地减少草坪草管理中的用水量具有社会意义。非洲狗牙根 ( Cynodon transvaalensis Burtt-Davy) 已被广泛用于与普通狗牙根 ( C. dactylon Pers. var. dactylon ) 杂交创建 F ₁杂交品种。关于非洲百慕大草冬季生存能力和抗旱性的分子基础的信息很少。因此，本研究的目的是量化遗传变异性并确定与冬季生存性状（春季绿化，SG；春季绿化百分比绿色覆盖率，SGPGC；winterkill，WK）和叶片燃烧（LF）相关的数量性状位点（QTL）在非洲百慕大草中。第一代自花授粉（S ₁) 'OKC1163' 的后代在田间试验中进行了评估，采用随机完整区组设计，三个重复，持续四个季节。所有被检查的性状都存在显着的遗传变异，冬季生存性状的广义遗传力估计范围为 0.36 至 0.54，LF 为 0.80。基于先前存在的高密度连锁图谱，根据最近发表的参考基因组进行比对、重新定向和重命名，确定了 10 个冬季生存性状 QTL 和 LF 两个 QTL。12 个 QTL 中的 7 个至少在 2 年内得到一致鉴定。两个 QTL 的共定位，一个用于冬季生存能力，另一个用于 LF，表明有可能同时改善这两种性状。