Two experiments were conducted between 1983 and 1985. In each case, timothy was established with or without barley, red clover, broadleaf weeds and grassy weeds. Four and six weeks after seeding, botanical composition, soil water-content, soil nutrient-content, light interception, and plant coverage data were obtained. The plots were then harvested once during establishment year and twice during subsequent years. At harvest, yield, botanical composition, and forage quality were obtained. Companion-cropping precluded forage cut during establishment and decreased forage yield during the first production year. Establishment with barley had little effect on forage quality but it favored the development of perennial broadleaf weeds. Inter-cropping with red clover decreased timothy yield but total forage production was increased and forage quality was improved. Red clover also reduced the development of perennial broadleaf weeds. The absence of broadleaf weed control increased productivity during establishment but timothy contribution was reduced and perennial broadleaf weeds development was accelerated. Perennial broadleaf weeds reduced yields during the first production year. Establishment without grassy weed control increased yield during establishment (but quality was lessened) and reduced it during the first production year. Establishment with grassy weeds had little effect on the weeds growing thereafter. In presence of both types of weeds, the grassy species were suppressed and the results reflected the situation observed in presence of broadleaf weeds. Finally, principal component analyses showed 12 factors that could be used to predict crop yield. The interpretation suggested that early measurements of weed density along with weed and crop coverage data would give good predictions of crop loss.

No description available.

Three cycles of recurrent restricted phenotypic selection (RRPS) were carried out on two cultivars each of timothy (Phleum pratense L.) and orchardgrass (Dactylis glomerata L.). The selections were conducted at the E. A. Lods Agronomy Research Center of Macdonald Campus of McGill University from 1984 to 1988. Individual plant selections were based on dry matter yields of 25 plants. Within each of 16 grids, the five highest yielding genotypes were selected (i.e. 80 genotypes overall) and allowed to interpollinate. Equal weights of seeds from each of the 80 selected plants were mixed in each cycle. Evaluation trials were carried out in both sward and spaced stand from 1989 to 1993 to assess the effectiveness of selection in improving dry matter yield. Several other morphological and physiological characteristics of cycles were recorded to find possible associated changes. / Three cycles of RRPS were not effective in increasing forage dry matter yields. The lack of response may be due to a narrow genetic base in the source populations and/or the population size under selection may have been too small, resulting in inbreeding depression. Another explanation for the ineffective selection may be non-random pollination among selected plants. The selection for forage yield produced some minor changes in other characteristics. There was a tendency towards increased plant height and circumference in orchardgrass; however, for timothy, height and circumference were reduced by selection. Cycle 3 of Avon orchardgrass was one day later in maturity and there was also a tendency for later maturity for timothy.

No description available.