Seeding rate and seed spacing modulate root yield and recovery of slicer and dicer carrots differently

Abstract

Field experiments were conducted on carrot ( Daucus carota var. sativus), involving a slicer variety, Caro choice; and a dicer variety, Red Core Chantenay (RCC), to determine the interactive effects of seeding rates (SR) and line spacings (LS), to identify optimal SR and LS and to understand the influence of various seed spacings on yield and root recovery. Caro choice and RCC were sown at various seeding rates: 18, 22, 27, 33 (slicer); 9, 12, 14, 18 (dicer) seeds 30 cm −1 at three different line spacings: 2.5, 3.8 and 5.7 cm. The interaction between SR and LS on total root yield and yield of supreme quality roots (1.9–3.1 cm diameter) was not significant whereas, the interaction for recovery of root grades was significant for Caro choice. In contrast, the interaction between SR and LS was marginally significant for the total yield and for the yield of supreme quality roots (3.8–5.1 cm diameter) but not for the recovery percentage of any of the root grades in RCC. A line spacing of 3.8 cm and SR of 22 seeds 30 cm −1 for Caro choice, and LS of 5.7 cm and SR of 18 seeds 30 cm −1 for RCC were optimal to obtain the highest total and supreme quality root yield, respectively. Seed spacing between the range of 4.6–38 cm 2 exhibited a significantly negative relationship with total root yield and marginally significant positive relationship with the recovery percentage of 1.9–3.8 cm roots in Caro choice. Neither total yield nor recovery percentage of 3.8–5.1 cm roots showed any significant relationship with seed spacing in RCC, suggesting that RCC may be less sensitive to the spatial variations compared to Caro choice and would adjust physiologically and/or morphologically to equalize yield.