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A nulli-haploid plant (2n = 20) was found in the progeny of an induced monosomic line of Avena sativa L. var. Rodney (2n = 6x = 42). At metaphase 1, the number of associations ranged from 1 to 6 with a mean frequency of 3.5. The pairing frequency can best be explained by the absence of a genetic system, similar to that of chromosome 5B in Triticum aestivum, which would control the diploidisation of hexaploid oats.Chromosomes were associated terminally with an occasional interstitial chiasma. Closed bivalents were rare, and the frequency of trivalent associations was low. This meiotic behaviour confirms the genetic evidence as to the homoeology of the three genomes of the hexaploid oats, but seems to indicate a great deal of structural divergence between them.It is suggested that the long sub-terminal chromosome 7 might carry the gene for diploidisation.

Four tests were conducted on three soil types, at Ottawa, Ont., and Ste. Anne de la Pocatière, Que., to study the comparative behaviour of birds-foot trefoil (Lotus corniculatus L.) in various mixtures. Data show that birdsfoot trefoil was more persistent than alfalfa in long-term leys on imperfectly drained soils. It also persisted longer than ladino or alsike clovers on the two soil types where these crops were compared. Data confirm previous findings that it possesses very little competitive ability. Accordingly, to reduce competition, birdsfoot trefoil should be used in simple mixtures with non-aggressive species. Timothy seemed generally to be the best companion grass. Red clover should be used with great care since it has a marked detrimental effect on its contribution to the crop. Preliminary results suggest the value of an orchardgrass-birdsfoot trefoil mixture in dry habitats.

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During winter 1994 and spring-summer 1994, seedlings of Impatiens wallerana 'Accent Coral' and Pelargonium × hortorum 'Orbit Hot Pink' were grown in a commercial substrate (PRO-MIX 'BX') or in one of 24 substrates composed of perlite (35% by volume), peat moss and of six organic residues (composted water-treated sludge, forestry compost, fresh or composted used peat extracted by biofilter during treatment of municipal water, and fresh or composted paper sludge). The purpose of the study was to determine the maximal proportion of these residues to be incorporated into a peat substrate to obtain quality plants. Growth parameters (growth index, top dry weight, and visual quality) generally decreased with increasing proportion (5, 10, 25 or 40% per volume). During the winter experiment, growth of control plants was superior to growth of plants grown in substrates composed of residues. An incorporated proportion of 25% per volume was shown to be maximal for the production of impatiens and geraniums. Key words: Impatiens wallerana, Pelargonium × hortorum, water treated sludge, composted wastes, peat moss, subirrigation