Pan William L, Kidwell Kimberlee K, McCracken Vicki A, Bolton Ronald P, Allen Monica
Nutrient Cycling, Rhizosphere Ecology Laboratory, Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States.
College of Agricultural, Consumer, and Environmental Sciences, Urbana, IL, United States.
Front Plant Sci. 2020 Feb 25;10:1790. doi: 10.3389/fpls.2019.01790. eCollection 2019.
Improvements in market value of hard red spring wheat (HRS, .) are linked to breeding efforts to increase grain protein concentration (GPC). Numerous studies have been conducted on the identification, isolation of a chromosome region () of Wild emmer wheat ( spp. ) and its introgression into commercial hard wheat to GPC. Yet there has been limited research published on the comparative responsiveness of these altered lines and their parents to varied N supply. There is increased awareness that wheat genetic improvements must be assessed over a range of environmental and agronomic management conditions to assess stability. We report herein on economically optimal yield, protein and nitrogen use efficiency (NUE) component responses of two Pacific Northwestern USA cultivars, Tara and Scarlet compared to backcrossed derived near isolines with or without the allele. A field experiment with 5 N rates as whole plots and 8 genotypes as subplots was conducted over two years under semi-arid, dryland conditions. One goal was to evaluate the efficacy of the allele under a range of low to high N supply. Across all genotypes, grain yield responses to N supply followed the classic Mitscherlich response model, whereas GPC followed inverse quadratic or linear responses. The introgression had no major impact on grain protein, but grain N and total above ground crop N yields demonstrated quadratic responses to total N supply. Generally, higher maximum grain yields and steeper rise to the maxima (Mitscherlich c values) were obtained in the first site-year. Tara required less N supply to achieve GPC goals than Scarlet in both site-years. Genotypes with produced comparable or slightly lower Mitscherlich A values than unmodified genotypes, but displayed similar Mitscherlich c values. Target GPC goals were not achieved at economic optimal yields based on set wheat pricing. Economic optimization of N inputs to achieve protein goals showed positive revenue from additional N inputs for most genotypes. While N uptake efficiency did not drop below 0.40, N fertilizer-induced increases in grain N harvest correlated well with unused post-harvest soil N that is potentially susceptible to environmental loss.
硬红春小麦（HRS）市场价值的提高与旨在提高籽粒蛋白质浓度（GPC）的育种工作相关。针对野生二粒小麦（Triticum spp.）的一个染色体区域的鉴定、分离及其向商业硬粒小麦的渗入以提高GPC，已经开展了大量研究。然而，关于这些改良品系及其亲本对不同氮素供应的比较响应，发表的研究有限。人们越来越意识到，必须在一系列环境和农艺管理条件下评估小麦的遗传改良，以评估其稳定性。我们在此报告了美国太平洋西北部的两个品种Tara和Scarlet与具有或不具有该等位基因的回交衍生近等基因系相比，在经济最优产量、蛋白质和氮素利用效率（NUE）组成部分方面的响应。在半干旱旱地条件下，进行了一项为期两年的田间试验，以5种氮素水平作为整区处理，8个基因型作为副区处理。一个目标是评估该等位基因在低至高氮供应范围内的功效。在所有基因型中，籽粒产量对氮素供应的响应遵循经典的米氏响应模型，而GPC则遵循反二次或线性响应。该等位基因的渗入对籽粒蛋白质没有重大影响，但籽粒氮和地上部作物总氮产量对总氮供应表现出二次响应。一般来说，在第一个试验年份获得了更高的最大籽粒产量和更陡的产量上升至最大值（米氏c值）。在两个试验年份，Tara比Scarlet实现GPC目标所需的氮素供应更少。具有该等位基因的基因型产生的米氏A值与未改良基因型相当或略低，但表现出相似的米氏c值。根据设定的小麦价格，在经济最优产量下未实现目标GPC值。为实现蛋白质目标而对氮素投入进行经济优化表明，大多数基因型额外投入氮素可带来正收益。虽然氮素吸收效率未降至0.40以下，但氮肥诱导的籽粒氮收获量增加与收获后土壤中潜在易受环境损失影响的未利用氮素密切相关。
