Seeds of processing tomato (variety UC 82 B) were primed in a solution of K2HPO4 and KNO3 (-1,25 MPa) for 12 days at 15°C and air-dried afterwards. Seeds were sown in a farmer’s field in Darlington Point, Australia, to evaluate under practical conditions the effect of seed priming on the emergence, growth, development and harvestable yield of processing tomatoes. An early season and a mid-season sowing were made in each of two growing seasons.
Processing tomato seed priming reduced growing degree days of air temperature above 10°C, required for 80% emergence, by about 35% from each sowing (Table 1). Primed seedlings emerged 4 to 5 days earlier than unprimed in the early sowings and 1 to 2 days in the later sowings. Seed priming did not result in larger plants; unprimed plants reached the same size at a later date. The earliness of the primed crops was maintained throughout the ontogeny, with no change in the final yield.
Table 1. Growing degree days of primed and unprimed seeds in two growing seasons.