Hard-seed content of alfalfa grown in Canada

Abstract

. 1991. Hard-seed content of alfalfa grown in Canada. Can. J.Plant Sci. 7l: [437][438][439][440][441][442][443][444]. The hard-seed content of alfalfa (Medicago spp.) grown in Canada in relation to genotype and geographic location of production was surveyed for the commercial growing regions in Manitoba, Saskatchewan, Alberta and British Columbia. The average hard-seed content of all pedigreed production over a 5-yr period, ranged from 22 to 3'l % andthat in nonpedigreed production was between 74 and3O%. A database ofthe five widely grown cultivars revealed that the hard-seed content of alfalfa in the most northerly growing areas in the Peace River region of Alberta and British Columbia ranged from 3 1 to 5l% , while hard seed content of alfalfa produced elsewhere varied from 22 to 38% . There was no apparent effect of latitude on the proportion of hard seeds, while there was a small increase for two of the five cultivars in production areas further west. Of particular interest was the trend in viable seed production. There was consistent evidence suggesting that the proportion ofviable seeds decreased in production areas further north, but increased in production areas further west. However, the minimum viability was always in excess of 85%. There was no correlation between hard and viable seed. (Fig. 1). (3) Analyses as in (2)

Cultivar and storage effects on germination and hard seed content of alfalfa

“…Time lag between harvest and germination may have played a role; the age of seed at germination was not ascertained in the For personal use only. study reported by Fairey and Lefkovitch (1991). Seed germination and hard seed content can be influenced by environmental conditions during seed development (Vorovenci and Craiu 1987) and this may have contributed to the observed discrepancy between the two studies.…”

“…The hard seed content of four Canadian alfalfa cultivars was close to 70%, much higher than the 31 to 51% reported for the Peace River region of Alberta and British Columbia and the 22 to 38% elsewhere in western Canada (Fairey and Lefkovitch 1991). Since Fairey and Lefkovitch (1991) suggested no latitudinal effect on hard seed content and since two out of four cultivars were common in the two studies, the method of handling the seed may have influenced this difference. Mechanical abrasions of the seed coat during harvesting, cleaning and packaging have been reported to affect hard seed content (Bass et al 1988).…”

“…The proportion of hard seeds may reach 100% in hand-harvested alfalfa seed (Bass et al 1988). Hard seed contents of 22 to 51% have been reported for alfalfa seed harvested by machine in western Canada (Fairey and Lefkovitch 1991).…”

“…falcata in their genetic background have exhibited high levels of hard seeds (Lute 1928;Watson 1948). Alfalfa seed produced under the warm growing conditions of southern California usually contains less than 20% hard seeds, while in the cooler Pacific Northwest 40 to 50% hard seed content is not uncommon (Fairey and Lefkovitch 1991). The proportion of hard seeds may reach 100% in hand-harvested alfalfa seed (Bass et al 1988).…”

Structuration of alfalfa genetic diversity using agronomic and morphological characteristics. Relationship with RAPD markers

“…It is also genetically influenced. Lute [24] and Watson [36] cited by Fairey and Lefkovitch [10] reported that M. falcata and M. media had more hard seeds. Delgado-Enguita [7] also found a higher rate of hard seeds in the Mielgas.…”