THE EFFECT OF CUTTING COCKSFOOT (DACTYLIS GLOMERATA L.) GROWN FOR PRODUCTION OF SEED

Abstract

An experiment is described in which cocksfoot, grown for production of seed, was cut annually for 3 years in either autumn, winter or spring. No significant increases in yield of seed/ac were obtained from any treatment compared with an uncut control, and a cut in late April in one year seriously reduced the yield of seed. Additional N applied after a defoliation in October did not increase the yield of seed compared with that from plots which were cut at the same time but not fertilized. The production of tillers was not affected by cutting on any date. The percentage fertility of tillers was increased by cutting in the first year, when the number of tillers was smallest; the fertility was less consistently affected in the second year, and was generally unaffected in the third year. The weight of seed produced per ear was usually reduced by the cutting treatments. In the third year of the experiment it was shown that the penetration of light to the base of the shoots was increased substantially by defoliation, but it is deduced that maximum interception of light by the whole plant is more important for the production of seed than increasing by cutting that proportion which penetrates to the base of the plant.

COMPETITION BETWEEN PLANTS OF COCKSFOOT (DACTYLIS GLOMERATA) GROWN FOR SEED

“…It was found that often only a small proportion of the tillers became reproductive, and the percentage of tillers that produced inflorescences fell each year as the plants aged and the number of tillers per plant increased. Applied N-even applications up to 6 times as large as conventional applications of 100 to 200 kg N/ha-had little effect on the proportion of tillers that produced inflorescences, although the number of tillers, and therefore of infiorescences, per plant was increased by N. When the penetration of light into the plants was increased by defoliating at a height of 6-5 cm above ground, the percentage of tillers which produced inflorescences in the first year was also increased, but the effect diminished in subsequent years when the number of tillers per plant was greater (8).…”

“…It was assumed, therefore, that competition between plants was more important than competition within plants in determining the proportion of tillers that produced inflorescences. In the defoliation experiment (8), both penetration of light and the rate of application of N were varied, but there was no indication that N became limiting when the penetration of light was increased. However, in that experiment the amount of light reaching the smaller tillers was increased but the total interception of light by the whole plant was reduced.…”

“…In an attempt to obtain a better understanding of the infiuence of environmental factors on the production of seed from herbage grasses grown in the field, the effects of plant density (5), application of nitrogenous fertilizer (5,6,7) and defoliation (8) were studied in cocksfoot. It was found that often only a small proportion of the tillers became reproductive, and the percentage of tillers that produced inflorescences fell each year as the plants aged and the number of tillers per plant increased.…”

FERTILE TILLER PRODUCTION AND SEED YIELD IN MEADOW FESCUE (FESTUCA PRATENSIS L.)

“…Lambert (5) reporting on defoliation effects on cocksfoot, also found reduced yield potential after cutting and associated this result with a shortage of metabolites, which brought about a restriction in fioral parts or influenced the filling of the seed.…”

The Position in the Plant and the Date of Origin of Tillers Which Produce Inflorescences

“…and thereby extend knowledge of the capacity of tillers arising on different dates to produce inflorescences from an annual basis (2,5,6,7,13) to the complete life-span of more persistent tillers. Evidence demonstrating which tillers in the plants produced inflorescences, and the dates of origin of such tillers, is presented in this communication.…”