CSIRO, Agriculture and Food, Canberra ACTAustralia.
Charles Sturt University, School of Agriculture and Wine Sciences, Wagga-Wagga NSWAustralia.
J Exp Bot. 2022 Oct 18;73(18):6292-6306. doi: 10.1093/jxb/erac306.
Deployment of the Rht-B1b and Rht-D1b dwarfing genes helped facilitate the Green Revolution to increase wheat yields globally. Much is known of the influence of these genes on plant height and agronomic performance, but not of their effects on root architecture. We assessed 29 near-isogenic lines (NILs) representing 11 Green Revolution and alternative dwarfing genes across multiple genetic backgrounds for root architecture characteristics in controlled and field environments. Genetic background did not influence plant height, but had a small and significant (P<0.05) effect on root architecture. All dwarfing gene NILs were significantly (P<0.01) shorter compared with tall controls. The Green Revolution Rht-B1b and Rht-D1b sometimes had longer seedling roots but were not different from their respective tall controls for root depth in the field. The Rht8, Rht12, and Rht18 dwarfing gene NILs produced long seminal roots in seedling pouches, and a greater maximum rooting depth (MRD) and root penetration rate (RPR) in the field. Genotypic increases in MRD and RPR were strongly correlated with increased harvest index and grain yield, particularly in dry environments. Careful root phenotyping highlights the potential of novel dwarfing genes for wheat genetic improvement under water-limited conditions.
Rht-B1b 和 Rht-D1b 矮秆基因的应用有助于推动全球小麦产量的“绿色革命”。人们已经了解到这些基因对株高和农艺表现的影响，但对其对根系结构的影响却知之甚少。我们评估了 29 个近等基因系（NILs），这些 NILs 代表了多个遗传背景下的 11 个绿色革命和替代矮秆基因，以评估其在控制和田间环境下的根系结构特征。遗传背景不会影响株高，但会对根系结构产生微小而显著的（P<0.05）影响。与高秆对照相比，所有矮秆基因 NILs 的株高都显著（P<0.01）降低。绿色革命 Rht-B1b 和 Rht-D1b 有时会使幼苗根更长，但在田间，其根深与各自的高秆对照没有差异。Rht8、Rht12 和 Rht18 矮秆基因 NILs 在幼苗袋中产生长的初生根，在田间具有更大的最大根深（MRD）和根穿透率（RPR）。MRD 和 RPR 的基因型增加与收获指数和籽粒产量的增加密切相关，特别是在干旱环境下。仔细的根系表型分析突出了新型矮秆基因在限水条件下对小麦遗传改良的潜力。
