Abiola Samson Olaniyi, Lacasa Josefina, Carver Brett F, Arnall Brian D, Ciampitti Ignacio A, de Oliveira Silva Amanda
Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, United States.
Department of Statistics, Kansas State University, Manhattan, KS, United States.
Front Plant Sci. 2024 Dec 16;15:1493901. doi: 10.3389/fpls.2024.1493901. eCollection 2024.
Increasing wheat ( L.) yield and grain protein concentration (GPC) without excessive nitrogen (N) inputs requires understanding the genotypic variations in N accumulation, partitioning, and utilization strategies. This study evaluated whether high protein genotypes exhibit increased N accumulation (herein also expressed as N nutrition index, NNI) and partitioning (including remobilization from vegetative organs) compared to low-protein genotypes under low and high N conditions. Four winter wheat genotypes with similar yields but contrasting GPC were examined under two N rates (0 and 120 kg N ha) across two environments and four growing seasons in Oklahoma, US. As expected, the high-protein genotypes Doublestop CL+ (Dob) and Green Hammer (Grn) had greater GPC than the medium- (Gallagher, Gal) and low-protein genotypes (Iba), without any difference in grain yield. Total plant N accumulation at maturity showed diminishing increases for greater grain yield, and low-protein genotype showed greater N utilization efficiency (NUtE) than high-protein genotypes. The high-protein genotype Grn tended to achieve higher GPC by increasing total N uptake, while Dob exhibited a tendency towards higher N partitioning to grain (NHI). The allometric relationship between total N accumulation and biomass remained unchanged for both high- and low-protein genotypes. The N remobilization patterns differed between high- and low-protein genotypes. As N conditions improved, the proportional contributions of remobilized N from leaves tended to increase, while contributions from stems and chaff tended to decrease or remained unchanged for high-protein genotypes. This study highlights the importance of both N uptake capacity and efficient N partitioning to the grain as critical traits for realizing wheat's dual goals of higher yield and protein. Leaf N remobilization plays a critical role during grain filling, sustaining plant N status and contributing to protein levels. The higher NUtE observed in the low-protein genotype Iba likely contributed to its lower GPC, emphasizing the trade-off between NUtE and GPC. The physiological strategies employed by high-protein genotypes, such as genotype Grn's tendency for increased N uptake and Dob's efficient N partitioning, provide a foundation for future breeding efforts aimed at developing resource-efficient and nutritionally superior wheat genotypes capable of achieving both increased yield and protein.
在不过量施氮的情况下提高小麦（L.）产量和籽粒蛋白质浓度（GPC），需要了解氮素积累、分配和利用策略的基因型差异。本研究评估了在低氮和高氮条件下，与低蛋白基因型相比，高蛋白基因型是否表现出氮素积累增加（在此也表示为氮营养指数，NNI）和分配增加（包括从营养器官的再转运）。在美国俄克拉荷马州的两个环境和四个生长季节中，对四种产量相似但GPC不同的冬小麦基因型在两种施氮量（0和120 kg N ha）下进行了研究。正如预期的那样，高蛋白基因型Doublestop CL+（Dob）和Green Hammer（Grn）的GPC高于中蛋白基因型（Gallagher，Gal）和低蛋白基因型（Iba），籽粒产量没有差异。成熟时植株总氮积累量随籽粒产量增加的增幅逐渐减小，低蛋白基因型的氮利用效率（NUtE）高于高蛋白基因型。高蛋白基因型Grn倾向于通过增加总氮吸收来实现更高的GPC，而Dob则表现出向籽粒分配更多氮的趋势（NHI）。高蛋白和低蛋白基因型的总氮积累与生物量之间的异速生长关系保持不变。高蛋白和低蛋白基因型的氮再转运模式不同。随着氮条件改善时，高蛋白基因型中，叶片再转运氮的比例贡献趋于增加，而茎和颖壳的贡献趋于减少或保持不变。本研究强调了氮吸收能力和向籽粒高效分配氮作为实现小麦高产和高蛋白双重目标的关键性状的重要性。叶片氮再转运在籽粒灌浆期间起着关键作用，维持植株氮素状况并影响蛋白质水平。在低蛋白基因型Iba中观察到的较高NUtE可能是其GPC较低的原因，这强调了NUtE和GPC之间的权衡。高蛋白基因型所采用的生理策略，如基因型Grn增加氮吸收的趋势和Dob高效的氮分配，为未来培育旨在开发资源高效且营养优良、能够实现产量和蛋白质双增的小麦基因型的育种工作奠定了基础。
