Distribution of dry matter between shoot and storage root of field-grown carrots. I. Onset of differences between cultivars

Abstract

SummaryGrowth, dry matter distribution and yield of nine cultivars of carrot, Daucus carota L., grown in the field, is compared over 125 days from sowing. The heaviest yields of fresh root were from the Autumn King type and the lightest from the globe-shaped Paris Market type. Higher root yields tended to be associated with larger shoots. The lower fresh root yield of the Paris Market type was compensated by a greater dry matter content (13%) than was found in the other cultivars (8–10%), suggesting the presence of some sink limitation of growth in this cultivar. Seedling absolute growth rates for each cultivar were related to initial mean seed weights, but seedling relative growth rates (RGR) were similar for all cultivars during the first 41 days from sowing. Both before and after this (27–48 days), differences between cultivars in shoot and root RGR were recorded. Ratios of RGR of shoot to that of the storage root estimated during this time were significantly and positively correlated with shoot to root weight ratio at final harvest. Differences between cultivars in shoot growth were reflected more by mean leaf weights of the different cultivars than by their leaf numbers.