Comparative study on maturity prediction in 'Elstar' and 'Jonagold' apples

Fruit development was observed in apple cvs. 'Elstar' and 'Jonagold' by rec ording the relative fruit growth, respiration, fruit firmness and starch de gradation. Results were obtained by measurements on 60 fruits every week ov er a period of 4 months. Additionally spectral reflectance in the visible r ange was recorded nondestructively on fruit skin and associated tissue in o rder to determine the chlorophyll content decrease during fruit ripening. M aturity determination was improved by using spectral reflectance data. Pred iction of fruit development stage was further enhanced by separating the an alysis for unripe and ripe fruits.