In the Vietnamese Mekong Delta (VMD), alternate wetting and drying (AWD) in rice (Oryza sativa L.) production during the dry season has the potential to reduce greenhouse gas emission and freshwater use. However, its effect on yield compared with continuously flooded systems can vary. To evaluate the effect of AWD on yield and yield-forming processes on genotypes commonly grown in the VMD, field trials over two consecutive dry seasons were conducted at the Loc Troi Group's agricultural research station in the VMD. We observed a significant yield reduction, 7% on average, across all varieties grown under AWD. Analysis of yield components showed that under AWD, genotypes on average produced more tillers, but fewer spikelets, suffered greater spikelet sterility and had a lower 1000 grain weight. The size of this effect differed between dry seasons. Accordingly, we were able to identify and characterize genotypes better suited to AWD. We also could relate shifts in sink-source relationships to the overlap of drying events and key phenological stages other than flowering. Our study shows how successful implementation of AWD requires adaptation to both environment and genotype.

中文翻译：

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湄公河三角洲水稻对干湿交替灌溉的基因型响应

在越南湄公河三角洲 (VMD)，水稻 ( Oryza sativa ) 的干湿交替 (AWD)L.) 旱季生产有可能减少温室气体排放和淡水使用。然而，与连续淹没系统相比，其对产量的影响可能有所不同。为了评估 AWD 对 VMD 中常见基因型的产量和产量形成过程的影响，在 Loc Troi 集团位于 VMD 的农业研究站进行了连续两个旱季的田间试验。我们观察到，在 AWD 下种植的所有品种的产量均显着下降，平均下降 7%。产量构成分析表明，在 AWD 条件下，基因型平均产生更多分蘖，但小穗较少，小穗不育性较高，千粒重较低。这种效应的大小在旱季之间有所不同。因此，我们能够识别和表征更适合 AWD 的基因型。我们还可以将库-源关系的变化与干燥事件和开花以外的关键物候阶段的重叠联系起来。我们的研究表明，成功实施全轮驱动需要适应环境和基因型。