Effect of night and day temperature on the cover colour and quality parameters of apple

Abstract

Abstract The colour of fruits is considered to be an important quality indicator. Sale ability greatly depends on how well covered the colour is of the specific type of fruits. We used a visual colour scale (0-100 percent) for evaluation of colorization. We distinguished the yellow, green and red cultivars. In the following studies we show those results which consider the red type apples only. Cover colour is one of the phenometric variables and it is a well-known fact that significant differences can be experienced year by year. The experienced oscillation can be the cause of inappropriate water- and nutriment supply; however it can be the result of some kind of plant disease, extremely high or low temperature, setting rate above the average and outstanding fruit density. In the present examination it is postulated that the degree of cover colour is mostly influenced by day and night temperature. Therefore, our study aims to find out whether it is true or not. Cover colour belongs to those phenometric characteristic features, only the final value of which is taken into consideration; due to their nature of establishment or forming time it seems useless to follow closely the change in the time of vegetation. We analysed the ripening groups of apple varieties separately. We have found that at winter ripening cultivars has bigger importance of genetic properties whilst at summer and autumnal ripening ones the weather effects have bigger importance. The research results shows that the day and night temperature has an important role on fruit quality parameters as sugar content, vitamin C content and on acidity also. Because we can modify the canopy temperature by using evaporative cooling system we have a chance to set up an optimal value of day and night temperature difference in the orchards.