PR-01

Consistency of long-term marketable yield of carrot cultivars grown on organic soils in Ontario, Canada in relation to seasonal climate
M.T. Tesfaendrias, M.R. McDonald and J. Warland

Carrot variety trials have been conducted at the University of Guelph’s Muck crops Research Station, in the Bradford/Holland Marsh (44° 5' N, 79° 35' W), Canada, for several decades with an average of 22 carrot varieties assessed per year in replicated trials. The weather during each growing season can vary from year to year, and it is important to growers to choose cultivars that will yield well regardless of the weather. Five fresh market carrot cultivars, Cellobunch, Canada Super X, Six Pak, Six Pak II and Sunrise were selected because they had been in the variety trials for more than 10 years. Weather data was recorded by a CR21 X data logger at a weather station within 400 m of the trial plots. Carrots were grown according to provincial recommendations.  After harvest, cultivars were assessed for total yield, crown shape, root size and length, resistance to greening, disease symptoms and insect damage. Carrots with defects were discarded and carrots with diameters over 2 cm were included in marketable yield. Carrot cultivar  Cellobunch exhibited the most consistent marketable yield with above average or average yield during years the cultivars were evaluated. Carrot cultivars Six Pak II, Canada Super X and Sun Rise had less consistency when marketable yield was compared with the grand mean marketable yield each year. The cultivars had 50% of the years either above or below average yield. Carrot cultivar Cellobunch had the highest mean marketable yield (95.4 t ha^-1) throughout the years followed by Sun Rise (86.0 t ha^-1), which is higher than the average marketable yield (84.0 t ha^-1) of all the cultivars entered each year. Marketable yield of carrot cultivars was correlated with various weather parameters.