Clonal variation in the effects of nitrogen applied to mother plant on the sprouting behavior of tubers of arrowhead, Sagittaria trifolia l.

Clonal variation in the influence of different levels of nitrogen applied (0, 8, 16 and 32kg/10a) to mother plants on tuber sprouting behavior was investigated for 19 clones of Sagittaria trifolia L., which were collected from six locations in the southern part of Kyoto prefecture.Differences in the nitrogen levels affected the days to tuber sprouting; the period to sprouting at 32N were shorter than those at the other three nitrogen levels. There was wide clonal variation not only in the days to sprouting at each nitrogen level, but also in the nitrogen response of this characteristic. Based on the nitrogen response of the days to sprouting, the 19 clones were divided into four groups, A, B, C and D, of nine, two, five and three clones, respectively: A: those in which the days to sprouting only at 32N was significantly shorter than at 8N; B: those in which the days to sprouting at 0 and 32N were significantly shoter than at 8N; C: those in which the days to sprouting at 0, 16 and 32N were significantly shorter than at 8N; D the remaining clones.The effects of the nitrogen levels applied to the mother plants on the relative frequency of the days to tuber sprouting also differed among clones. The sprouting pattern of group A was not so different among 0, 8 and 16N, while the tubers of 32N sprouted more quickly and synchronously. The tubers of group B of 0N sprouted more quickly than those of 8 and 16N, and those of 32N sprouted the most quickly and simultaneously among four nitrogen levels. The tubers of group C at 8N sprouted gradually over a long period, while tubers at the other three nitrogen levels sprouted more quickly and simultaneously.The relationship between percent dry matter or dry weight of tubers and the period to sprouting displayed remarkable variations. The days to sprouting of tubers of clone No. 1 increased with the increase of percent dry matter or dry weight in comparison with the other clones, and this tendency differed with the nitrogen dosage. This relationship was not recognized in clone Nos. 5, 10, 12 and 16.