Seed Production of eggplant under different climatic condition

Abstract

Eggplants, variety“Kitta”, were grown in three different localities in 1955 and 1957 to study the effect of climatic conditions on seed production. These localities and their elevations are as follows:Locality Height above sea levelHiratsuka (Dept. Hort., Nat. Inst.Agr. Sci., Kanagawa Pref.) 8 metersRyuo (Yamanashi Agr. Exp. Sta., Yamanashi Pref.) 260 (Yamanashi Agr. Exp.Sta., Yamanashi Pref.) 703 All plants used in the experiments were raised from the same seed source each year, planted in seed bed at Hiratsuka, and the seedlings were transported to the other localities from Hiratsuka on the same date in late May, about 70 days after planting, and then they were planted in Wagner pots (1/2000 are). To reduce the effects of difference in soil conditions, the soil used was prepared at Hiratsuka and transported to the other localities with the seedlings. The same amounts of fertilizers were applied to each pot according to the fixed schedule. The plants were trained to three main stems. Fruits were thinned to three per plant in one plot and were unthinned in the other.The vegetative growth of plants, especially the height of plants and number of leaves in both thinned and unthinned plots at Ryuo were far superior to those at the other localities every year. Similar trends were observed on the weight and number of ripe fruits and seed yield per plant in both plots.During the experiment periods for these years, Ryuo had wider daily temperature ranges than the other localities, and daily mean temperatures at Ryuo and Hiratsuka were approximately the same, while they were lower at Yatsugatake than at Ryuo and Hiratsuka.Thus the favorable effect on the growth and seed production of eggplant at Ryuo may be attributed to higher day temperatures and lower night temperatures, or wider ranges of daily temperature during the growing season. Yatsugatake has a wider daily temperature range than Hiratsuka, but the daily mean temperatures are lower and unfavorable for eggplant growth. This seemed to be the reason why the growth of plants, fruiting, and seed yield at Yatsugatake were inferior to those at Ryuo and Hiratsuka. The daily temperature ranges at Hiratsuka, the coastal area, are small, and the climatic conditions are fairly favorable for the growth and seed production of eggplant, but the plants at this locality showed generally less growth and seed yield than those at Ryuo.These differences in fruiting and seed yield of eggplant among localities are indicated to be more marked in the unthinned plants than in the thinned. The results at Ryuo in 1955 showed that the weight and germination percentage of the seeds produced from earlier three fruits on each plant in unthinned plot were approximately the same as those in thinned plot. However, the seeds produced from later three fruits in unthinned plot were inferior to those from earlier three fruits in unthinned plot and in thinned plot.These results suggest that, if daily mean temperature is optimal, wide daily temperature range is favorable for the growth and seed production of eggplant.