Selection of rice varieties that do not increase N absorppion under high N conditions to achieve both increased soybean yield and good-tasting rice production

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06009
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39020:Crop production science-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: Samejima Hiroaki 国立研究開発法人農業・食品産業技術総合研究機構, 北海道農業研究センター, 上級研究員 (50580073)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 水稲 / ダイズ / 田畑輪換 / 窒素吸収 / 地力窒素

Outline of Final Research Achievements

Application of composted manure is not common in paddy-soybean rotation systems in Japan, where the main focus is on producing good-tasting rice. To achieve both increased soybean yield and good-tasting rice production, we searched for rice varieties that do not increase N absorption even when N supply increases. Various varieties were grown in pots with slow-release fertilizers that mimicked composted manure application to investigate the relationship between N supply and N absorption by rice plants. A variety, Chiba Asahi, which showed little change in leaf area and photosynthetic rate per leaf area under different amount of N supply, and the Osiaa13 mutant, which had fewer lateral roots than the wild type, had increased N absorption with increasing N supply. Among the world rice core collections, only WRC63 and WRC68 did not increase N absorption when N supply increased. However, the N concentrations of these two varieties also increased with the increases in N supply.

Free Research Field

作物生産科学

Academic Significance and Societal Importance of the Research Achievements

地力Nが上昇してもN吸収量が上昇しない（すなわち食味が低下しにくい）イネ品種を探索を行ったところ、調査したほとんど全てのイネ品種でN供給量が増えるほどN吸収量が増加した。したがって、目標とする特徴を持つ品種の選抜は容易でないことが判明した。しかし、N吸収量の増加程度には幅広い品種間差があり、１品種はN吸収量が増加しなかった。大豆増収と良食味米生産の両立を目指す際に、高N条件でもN吸収量を増やさないイネ品種を利用するという戦略は可能であると考えられた。