Modelling the effect of temperature on seed germination in some cucurbits

Abstract

The prediction of germination percentage (GP) and germination speed (GS) of the seeds for some cucurbits (watermelon, melon, cucumber, summer squash, pumpkin and winter squash) was investigated by mathematical model based on temperature. The model, D = [a-(b x T) + (c x T(2))] of Uzun et al. (2001), was adapted to predict both the GP and GS in relation to 12 different temperatures, namely 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42 and 45 degrees C. In addition, optimum temperature (T(o) = -b / 2 x c) for GP and GS were calculated by using the coefficients obtained from the regression models developed. Observed and predicted optimum temperature (T(o)) for GP and GS varied among species and cultivars and strong correlations were established between observed and predicted GP and GS based on temperature. The predicted T(o) ranged from 21.6 degrees C (summer squash, pop. Urfa) to 27.8 degrees C (watermelon, cv. Amazon F(1)) for GP and from 25.5 degrees C (winter squash) to 30.4 degrees C (melon, cv. Hasanbey-1) for GS. These results indicated that predictions based on this mathematical model were highly reliable and that it could be confidently used to predict GP and GS for the evaluated cucurbits.