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Floral initiation in Bromus species and the effect of planting time on seed production of Bromus inermis climatypes at Beaverlodge, Alberta Clarke, John Mills


The times of floral initiation of Bromus inermis varieties Carlton (northern-type) and Redpatch (southern-type) and B. pumpellianus from three latitudes were determined under field conditions at Beaverlodge, Alberta. This was done by recording developmental stage of apical meristems of tillers during the spring and fall. A dates of seeding trial involving Carlton and Redpatch was also undertaken. It was found that both types of B. inermis underwent floral initiation in the spring at Beaverlodge. Both types started development after April 26 of 1971 and 1972. It was concluded that temperature was the major factor governing the onset of floral development in B. inermis. The B. pumpellianus accessions all underwent floral initiation in the fall, prior to soil freeze-up. Polar bromegrass, which has both B. inermis and B. pumpellianus ancestry, behaved in a similar manner. There were small differences in the times at which floral development started. It is probable that day length is the prime factor governing floral initiation of B. pumpellianus and Polar bromegrass in the fall. On the basis of one year's seed yield data, it was suggested that Carlton and Redpatch should be seeded after mid-May but before mid-July when grown as seed crops at Beaverlodge. It was also found that plants which produced seed in the year following seeding had developed more than one tiller prior to freeze-up in the year of seeding. Larvae of Hylemya sp. were found to be damaging tiller bases and apical meristems of Bromus spp. The extent of the larval infestation varied seasonally and yearly.

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