Seed quality in carrots: the effects of seed crop plant density, harvest date and seed grading on seed and seedling variability

Abstract

SummaryCarrot seeds (Chantenay types) harvested 44–61 days after anthesis (early harvest) had higher coefficients of variation (CVs) of embryo length and subsequent seedling weight than those of seeds harvested 70–92 days after anthesis (late harvest). Seed grading after harvesting the seed crop reduced the CVs of some of the early harvested seed crops. Seed crops grown at high plant density (80 plants m—2) compared with low density (10 plants m-2) produced seed with lower CVs but the effects were small. Averaged over three experiments the CVs of seedling weight from early- and late-harvested seeds were 53% and 43%, respectively. For high- and low-density crops the corresponding figures were 49% and 47% and for ungraded and graded seeds 50% and 45%. The CV of seedling weight and the ‘spread’ of seedling emergence times were closely related to the CV of embryo length but not to the CV of seed weight. This suggests that, in addition to estimates of viability determined by standard tests, a measurement of th...