Purple seed stain disease, caused by (Cercospora kukuchii), is a major concern in soybean (Glycine max (L.)) in Mississippi, USA, due to its effects on seed quality, reducing soybean seed grade and potential market price at elevators. Therefore, investigating the effects of purple seed stain (PSS) on seed quality (germination and vigor) and seed composition (nutrition) is critical. The objective of this study was to investigate the effects of PSS on seed harvest index, seed germination, seed vigor, and seed composition components (protein, oil, fatty acids, and sugars). A field experiment was initiated in 2019 in Stoneville, MS, at the Delta Research and Extension Center (DREC) on a Commerce silt loam soil (fine-silty, mixed, superactive, nonacid, thermic Fluventic Epiaquepts). Soybean variety Credenz 4748 LL was used. The results showed that infected (symptomatic) seed had a 5.5% greater Seed Index (based on 100 seed weight) when compared to non-infected (non-symptomatic, as control) seed. Non-infected seed had greater percent germination and seedling vigor when compared to infected seed. Germination was 30.9% greater and vigor was 58.3% greater in non-infected seed. Also, the results showed that infected seed with PSS had higher protein content and some amino acids. No changes in total oil and fatty acids. Sucrose and stachyose were lower in infected seed than in non-infected seed. The research showed that PSS impacted seed health and seed quality (germination and vigor) and seed composition (protein, sugars, and some amino acids). Purple stained seed should be avoided when planting and should be managed properly as low germination is a potential risk. Planting population should be adjusted accordingly due to lack of germination and vigor if PSS is present. This research help growers for purple seed management, and scientists to further understand the potential negative impact on seed quality and nutrition. Further research is needed before conclusive recommendations are made.

中文翻译：

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紫色种子污渍对大豆种子品质和组成的影响。

（Cercospora kukuchii）引起的紫色种子色斑病是大豆（Glycine max（L.））在美国密西西比州，由于其对种子质量的影响，降低了大豆种子的等级，并降低了电梯的潜在市场价格。因此，研究紫色种子色斑（PSS）对种子质量（发芽和活力）和种子组成（营养）的影响至关重要。这项研究的目的是研究PSS对种子收获指数，种子发芽，种子活力和种子组成成分（蛋白质，油，脂肪酸和糖）的影响。一项现场实验于2019年在密西根州斯通维尔的Delta研究和扩展中心（DREC）上进行，该试验在Commerce淤泥质壤土（细粉质，混合，超活性，非酸性，热Fluventic甲壳类）上进行。使用了大豆品种Credenz 4748 LL。结果表明，感染的（有症状的）种子为5。与未感染（无症状，作为对照）种子相比，种子指数（基于100种子重量）高5％。与感染的种子相比，未感染的种子具有更高的发芽率和幼苗活力。在未感染的种子中发芽率提高了30.9％，活力提高了58.3％。而且，结果表明，PSS感染的种子具有较高的蛋白质含量和某些氨基酸。总油和脂肪酸没有变化。感染种子中的蔗糖和水苏糖含量低于未感染种子。研究表明，PSS影响种子健康和种子质量（发芽和活力）和种子组成（蛋白质，糖和某些氨基酸）。种植时应避免紫色染色的种子，并且应适当管理，因为低发芽是潜在的风险。如果存在PSS，则由于缺乏发芽和活力，应相应调整种植种群。这项研究帮助种植者进行紫色种子管理，科学家们进一步了解了对种子质量和营养的潜在负面影响。在做出结论性建议之前，需要进一步的研究。