Research Topics

Soil degradation such as salinization is a major threat to crop production as a result of climate change. Although conditions for crop production are getting worse, we have to cope with an increasing demand for food due to population growth. The yield and quality of crops should be improved under both favorable and unfavorable environments. We are conducting research on crop characteristics in relation to high and quality yield, and stress resistance.

Improvement of salinity resistance in rice

We are exploring plant physiological and morphological attributes to assure high yield under soil salinity in rice. New rice for Africa (NERICA) is a new group of interspecific progeny between African and Asian rice varieties, which have a high competitive ability against weeds and a high yielding ability, respectively. To improve rice yields in saline lands, the salinity tolerance of NERICA is evaluated. Rice salinity tolerant QTLs are also being explored. We found that, in saline lands, creating a low saline layer may increase rice yields and that seedling age at transplanting changes rice yields.

White head in rice

White head is damage induced by environmental stress such as high temperature-dry wind, drought and soil salinity. The mechanisms of its occurrence are being studied in terms of silicon deposition and water relations in rice panicle.

Quality soybean seeds

Seed coat cracking is a challenge to maintain the quality of soybeans under climate change. It degrades the external appearance and reduces the commercial value. Varietal differences of seed coat cracking are found. We are conducting studies on seed coat cracking in relation to silicon nutrition, application of fertilizer and weather conditions during grain filling.

Publication List

• Haburi, Tsuda, M. and Hirai, Y.: Water use and growth of rice (Oryza sativa L.) cultivated on saline soils with various amount of soil and water. Japanese Journal of Crop Science 83, 32-38 (2014).
• Tsuda, M., Ueda, Y. and Hirai, Y.: The effect of prevention of root injury on growth, development and dry weight in rice (Oryza sativa L.) transplanted to saline soil. The Scientific Reports of The Faculty of Agriculture, Okayama University 101, 7-12 (2012).
• Haburi, Tsuda, M. and Hirai, Y.: Water use in wheat and barley grown on saline soils. Japanese Journal of Crop Science, 81, 64-70 (2012).
• Sone, C., Tsuda M. and Hirai, Y.: Effects of salinity on sodium accumulation in interspecific hybrid rice (NERICA) lines grown on different types of soil. Japanese Journal of Crop Science 80, 333-340 (2011).
• Hirai, Y., Tsushima, H. and Tsuda, M.; Effects of fertilization at flowering stage and environmental condition during seed-filling stage on soybean seed coat cracking of different types. Japanese Journal of Crop Science 80, 183-189 (2011).
• Tsuda, M., Endo, M. and Hirai, Y.: Effects of top dressing on growth and panicle dry weight as affected by soil water stress at early panicle-development stage in rice (Oryza sativa L.). Plant Production Science 13, 37-44 (2010).
• Sone, C., Tsuda, M. and Hirai, Y.: The salinity tolerance in an interspecific progeny NERICA 1 derived from the cross between O. sativa L. and O. glaberrima Steud. Japanese Journal of Crop Science 79, 184-191 (2010).
• Tsuda, M., Yokomizo, Y. and Takami, S.: Saline irrigation using ion-exchange resin and reverse osmosis membrane in wheat and barley. The Scientific Reports of The Faculty of Agriculture, Okayama University 99, 36-70 (2010).
• Hirai, Y., Numa, K., Nakai, K. and Tsuda, M.: Varietal difference in the cost of dark respiration for panicle growth and carbohydrate mobilization. Japanese Journal of Crop Science 79, 53-61 (2010).
• Wang, J., Tsuda, M. and Hirai, Y.: Increase in the water stress sensitivity at early panicle-development stage in rice under saline soil conditions. Japanese Journal of Crop Science 76, 540-547 (2007).

Introduction Video