Prediction of Tomato Yield on the Basis of Solar Radiation Before Anthesis under Warm Greenhouse Conditions

Abstract

Effects of solar radiation and temperature in different periods before and after anthesis on yield of tomato ( Solanum lycopersicum ) in summer greenhouse cultivation were investigated. Fluctuations in yield were caused mainly by the variation in fruit number rather than fruit weight. The number of harvested fruit and the yield of plants grown in summer and fall were significantly and positively correlated with solar radiation during the days before anthesis. Although the fruit number and yield were also significantly correlated with air temperature before anthesis, the correlations were weaker than the correlations with solar radiation. There was no significant correlation between the air temperature in the periods encompassing 3 weeks before harvesting and the fruit number and yield. Therefore, fluctuations in fruit number and yield could be predicted by a model based on the solar radiation from 10 to 4 days before anthesis. Validation based on data sets independent of the one used to develop this model showed good correlations between observed and predicted results for plants grown in summer and fall. Thus, solar radiation before anthesis was one of the important factors in prediction of tomato yield under warm greenhouse conditions.