Ambreen Heena, Kumar Shivendra, Kumar Amar, Agarwal Manu, Jagannath Arun, Goel Shailendra
Department of Botany, University of Delhi, New Delhi, India.
Front Plant Sci. 2018 Mar 29;9:402. doi: 10.3389/fpls.2018.00402. eCollection 2018.
L. (safflower) is an important oilseed crop producing seed oil rich in unsaturated fatty acids. Scarcity of identified marker-trait associations is a major limitation toward development of successful marker-assisted breeding programs in safflower. In the present study, a safflower panel (CartAP) comprising 124 accessions derived from two core collections was assayed for its suitability for association mapping. Genotyping of CartAP using microsatellite markers revealed significant genetic diversity indicated by Shannon information index ( = 0.7537) and Nei's expected heterozygosity ( = 0.4432). In Principal Coordinate Analysis, the CartAP accessions were distributed homogeneously in all quadrants indicating their diverse nature. Distance-based Neighbor Joining analysis did not delineate the CartAP accessions in consonance with their geographical origin. Bayesian analysis of population structure of CartAP demonstrated the unstructured nature of the association panel. Kinship analysis at population ( ) and individual level ( ) revealed absence of or weak relatedness between the CartAP accessions. The above parameters established the suitability of CartAP for association mapping. We performed association mapping using phenotypic data for eight traits of agronomic value (., seed oil content, oleic acid, linoleic acid, plant height, number of primary branches, number of capitula per plant, 100-seed weight and days to 50% flowering) available for two growing seasons (2011-2012 and 2012-2013) through General Linear Model and Mixed Linear Model. Our study identified ninety-six significant marker-trait associations (MTAs; < 0.05) of which, several MTAs with correlation coefficient () > 10% were consistently represented in both models and in both seasons for traits ., oil content, oleic acid content, linoleic acid content and number of primary branches. Several MTAs with high -values were detected either in a majority or in some environments (models and/or seasons). Many MTAs were also common between traits (., oleic/linoleic acid content; plant height/days to 50% flowering; number of primary branches/number of capitula per plant) that showed positive or negative correlation in their phenotypic values. The marker-trait associations identified in this study will facilitate marker-assisted breeding and identification of genetic determinants of trait variability.
红花是一种重要的油料作物，其种子油富含不饱和脂肪酸。已鉴定的标记-性状关联的稀缺是红花成功开展标记辅助育种计划的主要限制因素。在本研究中，对一个由来自两个核心种质的124份材料组成的红花群体（CartAP）进行了关联作图适用性分析。利用微卫星标记对CartAP进行基因分型，结果显示香农信息指数（= 0.7537）和内氏期望杂合度（= 0.4432）表明存在显著的遗传多样性。在主坐标分析中，CartAP材料均匀分布在所有象限，表明其具有多样性。基于距离的邻接法分析并未根据CartAP材料的地理来源对其进行清晰划分。对CartAP群体结构的贝叶斯分析表明该关联群体具有非结构化性质。在群体（）和个体水平（）上的亲缘关系分析表明CartAP材料之间不存在或仅有微弱的相关性。上述参数确定了CartAP适用于关联作图。我们使用两个生长季节（2011 - 2012年和2012 - 2013年）可获得的八个农艺价值性状（如种子油含量、油酸、亚油酸、株高、一级分枝数、单株头状花序数、百粒重和50%开花天数）的表型数据，通过一般线性模型和混合线性模型进行了关联作图。我们的研究鉴定出96个显著的标记-性状关联（MTA；< 0.05），其中，对于种子油含量、油酸含量、亚油酸含量和一级分枝数等性状，几个相关系数（）> 10%的MTA在两个模型和两个季节中均一致出现。在大多数或某些环境（模型和/或季节）中检测到了几个具有高值的MTA。许多MTA在表型值呈正相关或负相关的性状之间（如油酸/亚油酸含量；株高/50%开花天数；一级分枝数/单株头状花序数）也很常见。本研究中鉴定出的标记-性状关联将有助于标记辅助育种以及性状变异遗传决定因素的鉴定。
