The Influence of Sowing Depth and Seed Size on Seedling Emergence Time and Relative Growth Rate in Spring Cabbage (Brassica oleracea var. capitata L.)

The effects of seed size and sowing depth on the time of seedling emergence and on the growth of spring cabbage studied in greenhouse and field experiments. Seed size had little effect on seedling emergence time, but plants derived from large seeds were larger than those from small seeds. Increased sowing depth delayed seedling emergence and reduced seedling relative growth rate (RGR). To our knowledge, these effects of sowing depth on RGR independent of inter-plant competition have not been reported previously for any species. Sowing depth had no effect on the net assimilation rate (NAR) of seedlings, indicating that the lower RGR of seedlings from deep sowings was associated with a low light interception by small cotyledons which in turn resulted from disproportionately low partitioning of assimilates to the cotyledons during pre-emergence growth in favour of producing hypocotyls of greater length.