Introducing a quantitative trait locus, MP3, improves rice panicle numbers in nutrient-poor soils
DescriptionThe majority of paddy fields in sub-Saharan Africa (SSA) are characterized by nutrient-poor soils. In such fields, tillering in rice plants is severely restricted, which results in a reduced number of panicles and thus a decrease in grain yield. Therefore, genetic improvement to increase rice tillering may ensure sufficient panicles in nutrient-poor soils and thus lead to increase in rice productivity. Because we previously detected a quantitative locus, MP3 (MORE PANICLES 3), to be effective at increasing the number of panicles in nutrient-rich fields, we expected that MP3 will also be effective in enhancing rice productivity in nutrient-poor soils.
In this study, we used a high-yielding indica cultivar, Takanari, and its near-isogenic line bearing the MP3 allele derived from a japonica cultivar, Koshihikari (NIL-MP3). They were first grown in pots that contain nutrient-poor soils from Madagascar at various P application rates. The pot experiment demonstrated vigorous tillering in NIL-MP3 compared to Takanari from the early vegetative stage even under low P levels (Fig. 1). We next conducted multiple field trials in Madagascar with a total of 12 experimental conditions using the two varieties. The experiments produced grain yields ranging from 1.3 to 4.1 t ha−1 and panicle numbers ranging from 107 to 270 m−2. The results revealed that NIL-MP3 produced a greater number of panicles and spikelets m−2 (19% and 12%, respectively) than Takanari, with grain yields ranging from 2.0 to 4.1 t ha−1, but not in extremely low yield environments (< 1.3 t ha−1) (Fig. 2).
The results of this study indicate that MP3 is effective at increasing the number of panicles in nutrient-poor soils in SSA. However, utilization of MP3 in conjunction with fertilizer management may be necessary in extremely low yield environments (< 1.3 t ha−1). We are currently introducing MP3 into a local Madagascar cultivar, X265, which is adapted to the environments in SSA, to verify the effect of MP3 on grain yield in such environments.
Fig. 1. Changes in the number of tillers between Takanari and NIL-MP3 grown in pots that contain nutrient-poor soils in Madagascar at various P application rates.
** and * show significance at 1% and 5% levels, respectively.
Fig. 2. Comparison of the number of panicles (A) and spikelets (B) between Takanari and NIL-MP3 across 12 field experiments in Madagascar
Yield level shows mean yield between Takanari and NIL-SPIKE in each experiment.
*** shows significance at 0.1% level.
Japan International Research Center for Agricultural Sciences Biological Resources and Post-harvest Division
- Program name
- Research Project
Breakthrough in Nutrient Use Efficiency for Rice by Genetic Improvement and Fertility Sensing Techniques in Africa
- Term of research
- Responsible researcher
Takai Toshiyuki ( Biological Resources and Post-harvest Division )
Tsujimoto Yasuhiro ( Crop, Livestock and Environment Division )KAKEN Researcher No.: 20588511
Asai Hidetoshi ( Crop, Livestock and Environment Division )KAKEN Researcher No.: 30599064
Nishigaki Tomohiro ( Crop, Livestock and Environment Division )KAKEN Researcher No.: 80795013
Ishizaki Takuma ( Tropical Agriculture Research Front )
Sakata Mitsukazu ( Kochi University )
Rakotoarisoa Njato Mickaël ( Centre National de Recherche appliquée au Développement Rural, Madagascar )
- Publication, etc.
Takai T et al. (2021) Crop Science, 61(1):519-528https://doi.org/10.1002/csc2.20344
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＊ Affiliation at the time of implementation of the study.