Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields

Abstract

To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study.

Root System Architecture and Its Association with Yield under Different Water Regimes in Durum Wheat

“…The aim of this research was to adapt low-cost and high-throughput methods for phenotyping root architecture and exploring the genetic variability among 25 durum genotypes. In addition, deeper and more efficient root systems were demonstrated to be significantly correlated to yield increases in wheat (Kirkegaard et al, 2007;Fang et al, 2017), rice (Oryza sativa L.; Arai-Sanoh et al, 2014), and sorghum [Sorghum bicolor (L.) Moench; Mace et al, 2012]. Analysis of variance revealed significant segregation for all measured traits with strong genetic control.…”

Growing Out of Stress: The Role of Cell- and Organ-Scale Growth Control in Plant Water-Stress Responses

“…There, DRO1 positively regulates cell elongation on the upper side, whereas auxin represses DRO1 expression on the lower side, causing asymmetric growth and downward bending (Uga et al, 2013). A follow-up study demonstrated that having the deeprooting allele at the DRO1 locus enhanced tolerance to drought stress in the field (Arai-Sanoh et al, 2014). Recently, another QTL was identified (DRO3) that affects root growth angle in a DRO1-dependent manner (Uga et al, 2015).…”

Genetic mechanisms of abiotic stress tolerance that translate to crop yield stability

“…2d). The deep-rooting phenotype also enhances nutrient uptake and yield under nondrought conditions in the field 43 , illustrating a tolerance locus that also provides enhanced yield in the absence of stress. Beneficial loci for root traits that should enhance drought tolerance are also known for maize 44 , wheat 45 , sorghum 46 , barley 47 and chickpea 48 .…”