In Division of citrus research, we are developing new citrus cultivars with excellent cultivability and market competitiveness as well as breeding materials using genomic information. The latest cultivars are mandarin type cultivar "Asuki", which has excellent processing suitability, and lemon cultivar "Rinoka". As a current issue, we are creating distinctive cultivar series with a high content of functional ingredients β-cryptoxanthin. In terms of cultivation technology, we are aiming to develop labor saving technology at low cost for stable production of premium fruits in order to increase the global competitiveness of domestic citrus fruits and to cope with labor shortage due to the declining birthrate and aging population in Japan. In modern production of high sugar content premium Satsuma mandarin fruit, sheet mulch cultivation is widespread, in which the ground under the canopy is covered with a water-proof sheet to prevent rainwater from soaking into the ground. However, this technique was not effective whenever rainwater seeps under the mulch through the gap as well as the roots extended to the outside of the mulch coating. Therefore, we are developing shielding mulch cultivation (NARO S. Mulch) to improve these problems and are working on research to further increase its utility.
