Experiment Station Record 41: 42-43 (1919)

Planting Depth and Position of Seed in Pod
B. D. Halsted

Studies on heredity and environment, B. D. Halsted (New Jersey Stas. Rpt. 1917, pp. 372-394).—Studies on heredity and environment (E. S. R., 39, p. 746) were continued with corn, beans, soy beans, peas, and tomatoes.

Several F1 corn crosses were tested to determine the relation of ear type in the F1 to the character of the following crop. Some results are given
for two crosses, but no general deductions have thus far been made from the accumulated data.

Six types of corn kernels were used in a test of the influence of depth of planting upon viability of the seeds and vigor of the plants. Samples of the corn were planted at depths ranging from 1 to 8 in. The number of kernels failing increased uniformly to 4 in., rose rapidly to nearly 50 per cent at 6 in., and still more rapidly at the maximum depth of 8 in., where the viability was only 28.7 per cent Large kernels were more viable at great depth than small kernels, and field corn was more viable than sweet corn. The several depths did not seem to exert much influence upon the length of the stalks. Suckers were more numerous in the deeply planted rows and next in the shallow planted rows. Suckers were more numerous in rows planted with floury kernels than with rows planted with either flinty or sweet kernels. Sweet corn suckered least. Suckers were more numerous from large grains at each depth.

With five varieties of beans planted at depths of from 1 to 4 in., there was a large decrease in plants from the 3-in. depth and still more from the maximum depth. The 1-in. depth gave somewhat more plants than the 2-in. depth. Similar differences were noted in the percentage of seed viability. The number of pods per plant did not vary greatly among the four depths of planting. The Henderson Lima beans gave the greatest yield from seed planted 3 in. deep, whereas the four varieties of field beans tested declined in yield as the planting depth increased. The viability of soy beans was nearly the same for all depths excepting the 4-in. depth, where it was only 56 per cent.

Some results are given of a preliminary test conducted with soy beans to determine whether a somewhat constant relationship exists between the position of the seed in the pod and its weight, size, and value for cropping. The largest crop of pods came from the seeds borne at the tip of 3-seeded pods and the lowest yield from seeds at the base of the same pods. Seed from 2-seeded pods averaged the highest yield of pods, and seed from 1-seeded pods the lowest. A high percentage of 1-ovuled 1-seeded pods was associated with the crops from 1-seeded pods and the basal ends of 3-seeded pods. The highest percentage of 2-ovuled 2-seeded pods was associated with the crops from 2-seeded pods with both the basal and tip seeds. The highest percentage of 3-ovuled 3-seeded pods was associated with the crops from tipped seeds of 3-seeded pods. The test indicates that, if possible, it might be well before planting to eliminate the basal seeds from the 3-seeded pods and all 1-seeded pods.

The yield of seeds was best in the 3-seeded tip crop and poorest from the 3-seeded basal crop. For pods as a whole the best average yield of seed was from the 2-seeded pods and the poorest from the 1-seeded pods. Among the full pods the heaviest seed was in the 1-seeded pods, the weight diminishing as the pods increased in number of seeds. In pods containing more than 1 seed the tip seeds were heavier than those at the base. In 3-seeded pods the middle seed was somewhat heavier than the tip seed. Abortiveness was much more frequent in the basal ovules than in the tip ovules, and was in positive correlation with weight of seed.

Some data are given on a similar study of two widely different varieties of Lima beans, the Henderson representing the type with small thin-walled pods bearing small seeds, and the Burpee having comparatively large thick-walled pods and large seeds. The seeds in the basal position were lightest in all types of pods in both varieties, while those of the middle position of 3 and 4 ovuled pods were somewhat heavier than those at the tip. The position giving the lightest seeds within a given type of pod yielded the largest number of abortive ovules. No planting tests were conducted with these seed.

A test was conducted with 100 plants of the New Wonder bean with the view of determining the relation of period of growth of plant to pods and seeds. The percentage of pods having 1 or more ovules aborted was very large and increased from the first to the last picking. Pods picked during the midseason had the greatest number of seeds, and those picked during the latter part of the season the lowest. The heaviest seeds were found in the last picking and the lightest in the midseason picking. In 4-ovuled pods seed weight gradually increased from the base to the tip of the pod. In pods with more than 4 ovules seed weight appeared to be greatest near the middle of the pod. Abortiveness was highest in the midseason pods and lowest in those of the last picking. Within the type of pod the greatest percentage is in the 3-ovuled pods and decreases with the increase in the number of ovules per pod.

Some data are given on a study of the weight of tomatoes as related to position in the cluster. With one exception the basal fruits were heaviest and the terminal fruit lightest.

A number of pea vines were examined to determine the relation between the section of plant to the character of pod and seed. The results of the test, as a whole, indicate that the first pods to form upon all vines of the Alaska type had a larger number of ovules than those formed later. The middle section of the plant produced the largest number of the pods and the heaviest seeds with far the lowest percentage of abortiveness. The abortiveness is chiefly in the basal tip position of the pod.