Evaluation of Some Genotypes of Guava Trees Grown Under Alexandria Governorate Condition II- Compositional Changes During Fruit Ripening

The present study was carried out during 2012 and 2013 seasons in a private orchard belongs to Air Force Institute at EL-Maamoura Zone, East of Alexandria, on the best 5 genotypes (2,5,6,9 &12) of guava seedling trees, which were selected from 15 genotypes from pervious study. The aim of this study was to study the compositional changes during fruit ripening. The ripening stages were (1) yellowish-green, (2) greenish- yellow and (3) full-yellow, for skin color (hue°) and lightness (L). The hue values significantly decreased with fruit ripening, while lightness (L) values increased significantly with fruit ripening. Fruit firmness decreased with fruit ripening, however total soluble solids (TSS) values increased with fruit ripening, the highest values were in stage 3 (full yellow). There were no significant differences between guava genotypes in fruit weight and fruit diameter, length and width during fruit ripening. Fruit acidity (%) significantly decreased with fruit ripening and the lowest values was in stage 3 (full-yellow), it was associated with significant increase in total sugars (%), reducing and non-reducing sugars contents, which increased and then declined. For V.C content there were no significant differences observed between stages of ripening in 2012, while it increased significantly and then decreased with fruit ripening in 2013. As for the pectin (%), it significantly decreased with maturity stages and fruit ripening in both seasons of study. Generally, there were significant differences between genotypes under this study in fruit compositional changes during ripening and we can choose the best, which can be a base-line information to assist in controlling the best time of fruit harvest for either local marketing or export and storage.