Appearance and development of tillers in herbage grass species 2. Timothy (Phleum pratense L.)

Abstract

AbstractThe persistence of timothy in grasslands was investigated in the present study. Seeds were sown in August and October 1999 and March 2000. Following transplantation in September and November 1999 and April 2000, plant length and dry matter weight of each organ were measured in every tiller every three months.The results were obtained under the limited conditions of uninterrupted growth of timothy plants in the sward. The seasonal changes in plant lengths of the first year of establishment differed with the sowing times. In the second year, the tillers were divided into two by means of seasonal changes in plant length: some tillers increasing rapidly during the growing season from spring to late spring and the others gradually from autumn to winter. In the second year, the seasonal changes in the total tiller numbers of differing sowing times showed almost the same pattern, and secondary and tertiary tillers alternating with the main culm and primary tiller predominated. The changes in dry matter weight of each organ, especially the changes of the haplocorms, corresponded with the alternations of generations of tillers. That is, the parental tillers provided nutrients to haplocorms until the main tillers bore ears and developed. The parental tillers suppressed the appearance of tillers of the next generation to avoid competition. The tillers of the next generation began to emerge after the parental tillers died. The mechanism of the harmonious alternation of tiller generations composed of several tiller order groups was inferred to be one of the factors allowing the persistence of the timothy sward.