Productive Ability of Seed Sweet Potatoes for Direct Planting as Affected by the Growing Conditions of the Mother Plants

[摘要] (1) The rate of thickening of directly planted seed roots themselves was found to pe larger when they had been produced by the plants which were grown up from slips lately set out. But the total yield per plant was larger by the seed roots grown by early season cuttage. (2) Shading treatment of the mother plants resulted in heavier thickening ability of the seed roots when directly planted. Higher soil temperatures during the growth periods of mother plants caused the latters to produce seed roots of larger productive ability in the variety Gokuoimo while in the variety Okinawa No.100 the effect was reversed. As for the soil moisture, the higher, the moisure centent the larger was the thickening rate in the seed roots by the variety Norin No.1. (3) Nitrogen supply for the mother plant showed no effect. On the other hand, the less the amount of phosphorous or potassium supplied to the mother plant, the larger thickening ability in direct planting shown by the seed roots produced by formers.

[学科分类] 农业科学（综合）