Evaluation of Genetic Diversity and Marker Trait Association for Yield and Fiber Quality-Related Traits in Upland Cotton

Cotton is the most extensively grown non-food crop and its lint serves as a source for textile industries. The diversity in upland cotton (G. hirsutum L.) varieties was low. Hence, genetic diversity and marker trait associations were performed in twenty cotton genotypes. Rasi Magic, Platinum, LHBT 2, LHBT 6 and LHBT 7 recorded highest seed and lint yield. Based on PCA, LHBT 6 and LHBT 7 had higher upper half mean fiber length, uniformity index, fiber strength; Rasi Magic and LHBT 2 had high yield. Seed cotton yield (SCY) showed significantly positive association with number of bolls (NB), number of sympodial branches (NSP), boll weight (BW), ginning out turn (GOT) and plant height (PH). The average polymorphic information content and Shannon’s diversity index value were 0.66 and 1.4 per SSR marker locus respectively. Six clusters and six subpopulation groups were observed; LHBT 16 and LHBT 7 were grouped near checks showing genetic similarity. Association study identified high significant associations in markers, BNL1122 (NB), BNL1227 (NB, BW, Plot yield (PY), SCY, Lint yield (LY)), DPL0852 (BW, PH), JESPR204 (Number of Monopodia), MGHES0012 (Lint index (LI), NB, BW, PY), MGHES0021 (SCY), MGHES0036 (NSP, GOT, LY), MGHES0060 (NSP), MUSS162 (LI) and MUSS193 (LI).

棉花是全球种植规模最大的非粮食作物，其棉纤维是纺织工业的重要原料来源。陆地棉（G. hirsutum L.）的品种遗传多样性偏低。为此，研究团队对20份棉花基因型开展了遗传多样性分析与标记-性状关联分析。Rasi Magic、Platinum、LHBT 2、LHBT 6及LHBT 7的籽棉与皮棉产量表现最优。基于主成分分析（Principal Component Analysis, PCA）结果，LHBT 6与LHBT 7的上半部平均纤维长度、整齐度指数、纤维断裂比强度均较高；Rasi Magic与LHBT 2则具有较高的产量水平。籽棉产量（SCY）与铃数（NB）、果枝数（NSP）、铃重（BW）、衣分（GOT）及株高（PH）均呈极显著正相关。每对简单序列重复（Simple Sequence Repeat, SSR）标记位点的平均多态信息含量与香农多样性指数分别为0.66和1.4。供试材料可划分为6个类群与6个亚群体；其中LHBT 16与LHBT 7与对照品种聚为一类，遗传相似性较高。关联分析鉴定出多个极显著的标记-性状关联位点：BNL1122与铃数（NB）相关；BNL1227与铃数（NB）、铃重（BW）、小区产量（PY）、籽棉产量（SCY）及皮棉产量（LY）相关；DPL0852与铃重（BW）、株高（PH）相关；JESPR204与叶枝数（Number of Monopodia）相关；MGHES0012与皮棉指数（LI）、铃数（NB）、铃重（BW）、小区产量（PY）相关；MGHES0021与籽棉产量（SCY）相关；MGHES0036与果枝数（NSP）、衣分（GOT）、皮棉产量（LY）相关；MGHES0060与果枝数（NSP）相关；MUSS162与皮棉指数（LI）相关；MUSS193与皮棉指数（LI）相关。