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Cadmium (Cd) is a toxic heavy metal that is mainly accumulated through the consumption of foods produced in Cd-contaminated fields. Phytoremediation is one of the most effective methods to reduce the soil Cd concentration. In this study, we bred a new rice line, 'Akita 119', for Cd phytoremediation. 'Akita 119' was obtained by a soft X-ray mutation of 'Cho-ko-koku', a naturally high-Cd-accumulating rice cultivar. The heading date of 'Akita 119' was about 2 weeks later than that of 'Akitakomachi', which is the leading cultivar in Akita Prefecture, Japan. 'Akita 119' has a short culm length and many panicles. The shattering resistance and lodging resistance of 'Akita 119' were improved compared to 'Cho-ko-koku'. The thousand-grain weight of 'Akita 119' was much smaller than that of 'Akitakomachi', and grains of 'Akita 119' could be easily distinguished from general japonica cultivars. When 'Akita 119' was grown in Cd-contaminated fields, the shoot dry weight and Cd concentration were similar to those of 'Cho-ko-koku'. These results demonstrate that 'Akita 119' has improved agronomic characteristics compared to 'Cho-ko-koku' while retaining the ability to extract Cd. Therefore, it should be considered a promising candidate for Cd phytoremediation in paddy fields in northern parts of Japan.

Reduction in crop yield and quality due to global warming is a major concern. In this study, we investigated the effects of high temperature during endosperm development on the level of starch biosynthetic enzymes, including granule-bound starch synthase I (GBSSI), branching enzyme (BE)IIb, and SSI, and structure of starch in the endosperm using japonica rice cultivar, ‘Akitakomachi’. We also performed palatability sensory evaluation of rice grown under different temperatures after cooking. At high ripening temperature, the number of seeds showing opaque regions was significantly increased, and seed weight was significantly decreased. The apparent amylose content and ratio of short to long chains of amylopectin in seeds developed at high temperature was significantly lower and higher, respectively, than that in seeds developed at lower temperature; this was because of low levels of GBSSI and BEIIb, respectively. In general, the amylose content correlates negatively with the stickiness and taste of cooked rice. Rice grains developed at high temperature were less palatable after cooking than those developed under normal conditions, although their amylose content was lower, indicating that the structure of amylopectin has a major impact on the palatability of cooked rice.