1996 Volume 41 Issue 3 Pages 225-233
Influence of environmental conditions on seed production of Scirpus juncoides Roxb. subsp. juncoides and S. wallichii Nees was investigated at Tohoku Natl. Agric. Exp. Stn, Omagari, Akita, Japan. The results were as follows;
1. The number of seeds of S. juncoides and S. wallichii per plant decreased when the time of sowing was delayed, althouh a few seeds were produced even when the seeds were sown on August 11. The number of seeds of both species was reduced by shading, and no seeds of either species sown on August 11 were produced under 65% shading (Fig. 1).
2. The number of stems of S. juncoides and S. wallichii per plant was reduced when the time of sowing was delayed, and it decreased by shading (Fig. 2). The number of seeds per plant was highly correlated with the number of stems and the stem air-dry weight of both species, among the plants sown on different dates or grown under different shading conditions (Tables 4, 5).
3. The number of seeds of S. juncoides was reduced by drainage for 1 month, and the effect of drainage varied with the time of treatment in the growing season. The pattern of seed maturation was also affected by drainage (Tables 2, 3).
4. The one-seed weight of S. juncoides decreased with the delay in the time of harvest, when the seeds were sown before early June. However, when the seeds were sown after the latter part of June, the one-seed weight increased with the delay in the time of harvest (Tables 2, 3).
