Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina, United States of America.
PLoS One. 2022 May 2;17(5):e0268004. doi: 10.1371/journal.pone.0268004. eCollection 2022.
St. Augustinegrass is a warm-season grass species widely utilized as turf in the southeastern U.S. It shows significant variation in plant growth and morphological characteristics, some of which are potentially associated with drought tolerance. However, the genetic basis of these variations is not well understood. Detecting quantitative trait loci (QTL) associated with morphological traits will provide a foundation for the application of genetic and molecular breeding in St. Augustinegrass. In this study, we report QTL associated with morphological traits, including leaf blade width (LW), leaf blade length (LL), canopy density (CD), and shoot growth orientation (SGO) in a St. Augustinegrass 'Raleigh' x 'Seville' mapping population containing 115 F1 hybrids. Phenotypic data were collected from one greenhouse and two field trials. Single and joint trial analyses were performed, finding significant phenotypic variance among the hybrids for all traits. Interval mapping (IM) and multiple QTL method (MQM) analysis detected seven QTL for CD, four for LL, five for LW, and two for SGO, which were distributed on linkage groups RLG1, RLG9, SLG3, SLG7, SLG8 and SLG9. In addition, three genomic regions where QTL colocalized were identified on Raleigh LG1 and Seville LG3. One genomic region on Seville LG3 overlapped with two previously reported drought-related QTL for leaf relative water content (RWC) and percent green cover (GC). Several candidate genes related to plant development and drought stress response were identified within QTL intervals. The QTL identified in this study represent a first step in identifying genes controlling morphological traits that might accelerate progress in selection of St. Augustinegrass lines with lower water usage.
圣奥古斯丁草是一种暖季型草种，在美国东南部广泛用作草坪草。它在植物生长和形态特征上表现出显著的变异，其中一些可能与耐旱性有关。然而，这些变异的遗传基础尚不清楚。检测与形态特征相关的数量性状位点（QTL）将为圣奥古斯丁草的遗传和分子育种应用提供基础。在这项研究中，我们报告了与形态特征相关的 QTL，包括叶片宽度（LW）、叶片长度（LL）、冠层密度（CD）和茎生长方向（SGO），这些特征存在于一个包含 115 个 F1 杂种的圣奥古斯丁草‘Raleigh’בSeville’作图群体中。表型数据来自一个温室和两个田间试验。进行了单一和联合试验分析，发现所有性状的杂种间均存在显著的表型方差。区间作图（IM）和多 QTL 方法（MQM）分析检测到 CD 的七个 QTL、LL 的四个 QTL、LW 的五个 QTL 和 SGO 的两个 QTL，它们分布在连锁群 RLG1、RLG9、SLG3、SLG7、SLG8 和 SLG9 上。此外，在 Raleigh LG1 和 Seville LG3 上还确定了三个 QTL 共定位的基因组区域。Seville LG3 上的一个基因组区域与先前报道的两个与叶片相对含水量（RWC）和绿色覆盖率（GC）相关的干旱相关 QTL 重叠。在 QTL 区间内鉴定出几个与植物发育和干旱胁迫反应相关的候选基因。本研究中鉴定的 QTL 代表了鉴定控制形态特征的基因的第一步，这可能会加速选择耗水量较低的圣奥古斯丁草品系的进展。
