Borrell Andrew K, van Oosterom Erik J, Mullet John E, George-Jaeggli Barbara, Jordan David R, Klein Patricia E, Hammer Graeme L
Queensland Alliance for Agriculture and Food Innovation (QAAFI), Hermitage Research Facility, University of Queensland, Warwick, Qld, 4370, Australia.
New Phytol. 2014 Aug;203(3):817-30. doi: 10.1111/nph.12869. Epub 2014 Jun 4.
Stay-green is an integrated drought adaptation trait characterized by a distinct green leaf phenotype during grain filling under terminal drought. We used sorghum (Sorghum bicolor), a repository of drought adaptation mechanisms, to elucidate the physiological and genetic mechanisms underpinning stay-green. Near-isogenic sorghum lines (cv RTx7000) were characterized in a series of field and managed-environment trials (seven experiments and 14 environments) to determine the influence of four individual stay-green (Stg1-4) quantitative trait loci (QTLs) on canopy development, water use and grain yield under post-anthesis drought. The Stg QTL decreased tillering and the size of upper leaves, which reduced canopy size at anthesis. This reduction in transpirational leaf area conserved soil water before anthesis for use during grain filling. Increased water uptake during grain filling of Stg near-isogenic lines (NILs) relative to RTx7000 resulted in higher post-anthesis biomass production, grain number and yield. Importantly, there was no consistent yield penalty associated with the Stg QTL in the irrigated control. These results establish a link between the role of the Stg QTL in modifying canopy development and the subsequent impact on crop water use patterns and grain yield under terminal drought.
持绿性是一种综合的干旱适应性状，其特征是在终末期干旱条件下灌浆期呈现出独特的绿叶表型。我们利用高粱（双色高粱）这一干旱适应机制的宝库，来阐明支撑持绿性的生理和遗传机制。在一系列田间和可控环境试验（七个实验和14个环境）中，对近等基因高粱品系（品种RTx7000）进行了表征，以确定四个单独的持绿性（Stg1 - 4）数量性状位点（QTL）在花后干旱条件下对冠层发育、水分利用和籽粒产量的影响。持绿性QTL降低了分蘖和上部叶片的大小，从而在花期减小了冠层大小。这种蒸腾叶面积的减少在花期前保存了土壤水分，以供灌浆期使用。与RTx7000相比，持绿性近等基因系（NILs）在灌浆期增加的水分吸收导致了花后更高的生物量生产、籽粒数量和产量。重要的是，在灌溉对照中，持绿性QTL没有导致一致的产量损失。这些结果建立了持绿性QTL在改变冠层发育中的作用与随后对终末期干旱条件下作物水分利用模式和籽粒产量的影响之间的联系。
