The impact of fruit temperature dynamics on heat stress tolerance of selected oil pumpkin genotypes

Abstract

Fruit temperature is a key parameter for fruit growth and quality which is affected by climate, plant vigorousity, solar exposure and fruit thermal properties. In the present study, the variability in temperature dynamics of Styrian oil pumpkin fruits and selected interspecific hybrids involving Cucurbita argyrosperma, C. moschata, C. pepo was analysed in two different periods of hot weather. The temperatures were measured with thermistors on (a) attached fruits, (b) detached fruits exposed to the sun and (c) artificially black coloured fruits. The highest average temperatures were determined in the Styrian oil pumpkin, whereas the lowest temperatures were determined in genotypes with lighter fruit exteriors suggesting that those are less sensitive to heat stress conditions and may represent a good option for the improvements of adaptability to climatic changes. In order to combine lighter and harder pericarp, the most promising genotypes were crossed with wild Cucurbita okeechobeensis. The histological analysis showed that C. okeechobeensis was a good source of genes for obtaining a thicker sclerenchymatic layer within pericarp