Development of a New Cultivation Technology for Cold Stress Escape through Flowering Time Manipulation by Water Management in the Highlands of East Africa
| Autor: | Wainaina, Cornelius Mbathi, Makihara, Daigo, Samejima, Hiroaki, Kikuta, Mayumi, Menge, Daniel Makori, Kimani, John Munji, Inukai, Yoshiaki |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | 農学国際協力. 15:32-41 |
| ISSN: | 1347-5096 |
| Popis: | Cold stress is a major abiotic factor limiting rice production by reducing spikelet fertility. Under field conditions, cold stress varies with years and seasons in terms of its intensity, duration, and timing of occurrence. To reduce the risk of cold damage because of its unpredictable nature, crop adaptation strategies, such as management practices, that complement breeding are required. Flowering time (heading time) is a key trait that can be used to adapt rice to changing climatic conditions. Therefore, we screened a rice mutant line (T6-16) that has very shallow root system and exhibits delayed heading time under moderate drought stress conditions. This mutant line was used in breeding and development of a new cultivation technology for cold stress escape by introgression of its genetic segments into the background of a recurrent parent of New Rice for Africa (NERICA), WAB56-104. The mutant-type F2 plants grown under moderate drought stress conditions showed delayed heading by an average of 11 days. Three F2 plants that showed delay of heading by 11−17 days and maintained over 95% grain weight under the stress conditions were identified. These F2 plants could be useful in breeding for cold stress escape. These results suggest that the utilization of rice plants introgressed with the mutation gene and proper water management practices for rice cultivation based on the predicted length of cold periods could escape the cold stress through delaying heading time. 低温ストレスは、種子稔性の低下を通してイネの収量を大きく低下させる。低温の程度や継続期間は年や季節によって異なるため、最も気温が低下する時期を回避して開花させうる新技術の開発が求められる。一般に、乾燥ストレスは出穂を遅延させる傾向があり、また根が浅く張る浅根性品種は軽微な乾燥ストレスに敏感に反応することが知られている。そこで本研究では、軽微な乾燥ストレス下で出穂期の遅延を示す突然変異体（T6-16）を選抜し、アフリカで有望視されているネリカ品種の反復親の1つであるWAB56-104と交配することで、本変異遺伝子の有用性を評価した。F2個体群のうち、変異体型個体の出穂日は軽微な乾燥ストレス下で平均11日間遅延する傾向を示した。特に3つのF2個体では、11〜17日間出穂日が遅延したが収量の低下は見られなかった。これらの結果は、浅根性に関わる遺伝子座の利用と軽微な灌水量の制限により、収量の減少を伴うことなく、最も厳しい低温期を回避して開花させうる新技術確立の可能性を示している。 |
| Databáze: | OpenAIRE |
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