Pruning reduces yields in grafted tomatoes planted in the field
In 2017 and 2018, field trials were conducted with tomatoes grafted onto the rootstock Beaufort or not grafted to evaluate the effects of various cultural practices: pruning side shoots (up to the first flower cluster), pinching the main stem before planting, spacing (56 vs. 61 cm), and scion cultivar (Tasti-Lee and Mountain Fresh Plus [MFP]). Fruits were harvested five times in each year and marketable yield acre‑1 was calculated for each treatment group. Both scion cultivars grafted onto Beaufort had consistently higher yields than non-grafted tomatoes. Pruning the grafted plants, regardless of scion cultivar, reduced yields over the non-pruned plants in both years. On Tasti-Lee, marketable yields improved by 32 and 57% when grafted plants were pruned or not pruned, respectively, over the non-grafted plants. In MFP, yields improved by 35 and 47% when grafted plants were pruned or not pruned, respectively, over the non-grafted plants. Fruit size also increased when either cultivar was grafted over the non-grafted plants, regardless of spacing, pruning or pinching. Spacing among the grafted plants had no effect on yield or fruit size; both 56 and 61 cm spacings produced statistically similar yields acre‑1. Growers may be able to offset the higher cost of grafted plants by planting fewer plants acre‑1, and not pruning those grafted plants. Pinching significantly increased yields in pruned plants, but the same increase was not present in non-pruned plants.
Ingram, T., Sharpe, S., Louws, F.J. and Meadows, I. (2021). Pruning reduces yields in grafted tomatoes planted in the field. Acta Hortic. 1302, 65-72
vegetable, tomato, grafting, pruning, pinching, spacing, fruit size