A New Mutant Rice Line 'Tashukei 1066' with Light-Colored Leaves and Low [Beta]-carotene Contents

In Japan, the high [Beta]-carotene content of whole-crop rice silage makes it unsuitable as feed for beef cattle in the production of high quality beef. For the purpose of breeding a cultivar for whole-crop silage with low [Beta]-carotene content, a rice line with light-colored leaves was selected from progenies obtained from artificial mutants of 'Hoshiaoba', a cultivar for whole-crop silage use. The selected line was designated 'Tashukei 1066' and its [Beta]-carotene contents and agronomical characteristics were compared with those of 'Hoshiaoba'. There were no significant differences in culm length, panicle number and dry weight between Tashukei 1066 and Hoshiaoba. However, at the heading stage, the [Beta]-carotene contents of Tashukei 1066 was lower than that of Hoshiaoba, although the difference was not clear at the yellow ripening stage. At both stages, the SPAD readings of Tashukei 1066 were significantly lower than those of Hoshiaoba. In conclusion, further examination is necessary before Tashukei 1066 can be used practically as a low [Beta]-carotene content cultivar, but this line is expected to be useful as a parental line for breeding of a cultivars with a low [Beta]-carotene content.