The effect of priming on seedling emergence of differentially matured watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) seeds

Abstract

The influence of salt priming (KNO3, 3%, 6 day, 20°C) on glasshouse seedling emergence, emergence rate, seedling weight and hypocotyl length of watermelon seeds grown in two production sites and harvested 20, 30 and 40 days after anthesis (DAA) was investigated. The maximum benefit of priming was observed in seeds of 20 DAA for all criteria. Primed seeds of this harvest had 19 and 22% higher seedling emergence percentages, 60 and 96 h faster emergence rate, 68 and 82 mg heavier seedling weights, and 2 and 4 mm longer hypocotyls compared to control ones in sites 1 and 2, respectively. Smaller effects of priming were also seen in the decreased mean emergence time and increased seedling weight and hypocotyl lengths of seeds harvested 30 and 40 DAA. Priming reduced the percentage of seeds that germinated but failed to emerge from 1.3 to 2.3% and 1.3 to 2.7% for 20 DAA seeds. Few (<4%) of the more mature seeds germinated but failed to emerge. Salt priming can therefore be used to increase watermelon emergence and produce well-developed seedlings particularly in early spring sowings at low temperatures in glasshouse conditions. © 2004 Elsevier B.V. All rights reserved.