Abstract
Experiment was carried out at field set up in reclaimed land where is usually seen a high prodection of unfilled peanut fruits, and the results obtained are summarized as follows: 1. By the size, it was unable to distinguish unfilled fruit from normal one, as the both showed normal development. 2. Meanwhile, the growth of seeds involved is quite different. In unfilled fruit it is abnormally retarded, showing a slightly brown colored spot on the seed surface at beginning, which changes later into dark brown coloration spreading over the whole surface and make the seeds shrink when extremely advanced. This coloration was certified as not induced by pathological disease, and is applicable as a special sig to identify the unfilling. 3. The unfilled fruit began to appear at the stage of 15 days after penetration of gynophore into soil, and increased suddenly at 20th-day stage up to about 70% of total unfilled fruits occurred, and further added the number slightly by 50th-day stage resulting in about 70% of total fruits produced. Thus the abnormal unfilling seeds involve various sizes of defferent stages. 4. Calcium showed beneficial effect for filling as reported by previous authors. When the soil was separated into fruiting zone and rooting zone by tin-plate cylinder, the aplication of calcium for the former produced the unfilling less than 20%; applicetion to the latter showed more than 30%, while the both zone application induced perfect filling in striking contrast with the on calcium plot where unfilling occurs more than 70%. 5. The unfilling initiates at one cavity of two-seeded fruit at beginning, and advances later to another one, inducing perfectly unfilled fruit. This fact means the unfilling is the lighter the less is the two-cavities unfilling.
