CSIRO Agriculture and Food, Canberra, ACT, Australia.
Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia.
J Exp Bot. 2021 Feb 2;72(2):445-458. doi: 10.1093/jxb/eraa481.
Gibberellin (GA)-insensitive dwarfing genes Rht-B1b and Rht-D1b that are responsible for the 'Green Revolution' have been remarkably successful in wheat improvement globally. However, these alleles result in shorter coleoptiles and reduced vigour, and hence poor establishment and growth in some environments. Rht18, on the other hand, is a GA-sensitive, dominant gene with potential to overcome some of the early growth limitations associated with Rht-B1b and Rht-D1b. We assessed progeny from both a biparental and a backcross population that contained tall, single dwarf, and double dwarf lines, to determine whether Rht18 differs from Rht-D1b and hence verify its value in wheat improvement. Progeny with Rht18 had an almost identical height to lines with Rht-D1b, and both were ~26% shorter than the tall lines, with the double dwarf 13% shorter again. However, coleoptile length of Rht18 was 42% longer than that of Rht-D1b. We detected no differences in time to terminal spikelet and anthesis, and few differences in stem or spike growth. Both dwarfing genes diverted more dry matter to the spike than tall lines from prior to heading. No differences were detected between Rht18 and Rht-D1b that could prevent the adoption of Rht18 in wheat breeding to overcome some of the limitations associated with the 'Green Revolution' genes.
赤霉素不敏感的矮化基因 Rht-B1b 和 Rht-D1b 是“绿色革命”中负责小麦改良的重要基因。然而，这些等位基因导致了更短的胚芽鞘和活力降低，因此在某些环境中表现出较差的建立和生长。另一方面，Rht18 是一个赤霉素敏感的显性基因，具有克服与 Rht-B1b 和 Rht-D1b 相关的一些早期生长限制的潜力。我们评估了来自双亲和回交群体的后代，这些群体包含高秆、单矮和双矮系，以确定 Rht18 是否与 Rht-D1b 不同，从而验证其在小麦改良中的价值。含有 Rht18 的后代与含有 Rht-D1b 的系几乎一样高，比高秆系矮约 26%，而双矮系则矮 13%。然而，Rht18 的胚芽鞘长度比 Rht-D1b 长 42%。我们没有检测到 Rht18 和 Rht-D1b 在终花穗和开花时间上的差异，在茎或穗的生长上也只有少数差异。这两个矮化基因在抽穗前将更多的干物质转移到穗上，比高秆系更多。在 Rht18 和 Rht-D1b 之间没有发现任何差异，这可能会阻碍 Rht18 在小麦育种中的应用，以克服与“绿色革命”基因相关的一些限制。
