Yoichiro Kato

Aerobic culture is a water-saving technique for direct-seeded rice cultivation. Growing rice under continuously unsaturated soil conditions can maximize water-use efficiency and minimize both labor requirements and greenhouse-gas emissions. Under a temperate climate, aerobic culture can produce a rice yield greater than 9 t ha–1 especially in central Japan (11.4 t ha–1). Aerobic culture using large-scale center-pivot sprinklers is being established in the central United States, where yields can

Spikelet number per panicle is a major target trait for improving rice ( Oryza sativa L.) yield in upland fields and is strongly affected by water stress. The rice panicle consists of rachis branches and spikelets, in which preflowering spikelet abortion often occurs. We investigated the effect of timing and intensity of water stress at the early reproductive stage on the morphology of rice panicles in field and pot experiments. In the field experiment, water stress caused high rates of preflowe

Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψ(leaf). Ψ(leaf) may reduce even if K(pa) is not significantly changed, but the lower Ψ(leaf) would certainly occur in case K(pa) reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep rooting.

Floods are major constraints to crop production worldwide. In low-lying, flood-prone areas of the tropics, longer-term partial submergence (stagnant flooding [SF]) greatly reduces rice yield. This study assesses shoot growth and several physiological mechanisms associated with SF tolerance in rice. Five rice genotypes with contrasting responses to SF were evaluated in field ponds. Following transplanting, floodwater was gradually increased at a rate of ∼2 cm day(-1) to reach a final depth of 50

The total water supply (irrigation plus rainfall) would determine biomass production. This study aimed to elucidate the effects of water supply and cultivar differences on the dry matter production of rice grown under upland conditions. Three rice cultivars ('Yumeno-hatamochi ', YHM; 'Lemont ', LMT; 'Nipponbare ', NPB) were used on an upland site with three water regimes (rain-fed, RU; irrigated, IU; water deficit during the panicle-formation stage, WD) and in a flooded lowland (FL) in Japan fro

Abstract Background and Aims Rice ecosystems in the tropical coastal areas are subject to two types of flooding stress: transient complete submergence and long-term water stagnation (stagnant flooding). Here, we aimed to dissect the mechanisms for stagnant flooding tolerance of rice genotypes carrying SUB1, a quantitative trait locus for submergence tolerance. Methods We screened 80 elite genotypes under stagnant flooding stress in the lowland rice fields in the wet and dry seasons, and examined