Plant density and crop establishment studies with tomatoes for mechanical harvest : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Horticultural Production at Massey University

Using three cultivars, chitting tomato seed and priming tomato seed with P. E. G. was found to have no effect on the early relative growth rate of the seedlings, when compared with untreated seed. However, because chitted seeds emerged earlier than primed seeds, which in turn emerged earlier than untreated seed, at any one time, the plants from chitted seed were larger than those from primed seed, and both were found to be larger than those from untreated seed. The seed treatments along with a high quality transplant treatment were compared in a field study to determine plant weight and fruit yield at four plant densities (62,500, 160,000, 200,000 and 591,716 plants per hectare). Castlong was found to give heavier total fruit yields than either VF 145-B7879 or Fireball. This is attributed to the higher proportion of fruit total plant weight that this variety develops. Castlong also produced a higher proportion of ripe total fruit at all harvests, this is considered to be due to this cultivar's early maturity combined with its excellent field storage characteristics. Transplanted plants in all cases yielded heavier and matured earlier than any of the three seed treatments. The yields and maturity characteristics were not significantly different from any of the three seed treatments. Increasing the plant density from 62,500 plants per hectare to 591,716 plants per hectare increased fruit number and yield per unit area and also tended to increase the proportion of the fruit that was ripe. The number of fruit per plant decreased as plant density increased