Changes in bio-chemical properties of fruits of some pear genotypes under stress conditions

Pear is a type of fruit grown in a temperate climate, and Turkey is an important pear producer. In today's conditions (drought, climate change, etc.), different genotypes should be used in order not to affect the current production. In this study, pomological properties (width, height, weight, bottom and top peel color, hardness), total soluble solids (TSS), pH, titratable acidity (TA), vitamin C, total phenolic content and antioxidant capacity values of ten different pear genotypes under naturally occured stress conditions that observed in the year of the study (high temperatures and drought at early stage of fruit growth), was determined and compared. In the selected pear genotypes, the average fruit width of the astringent and non-astringent genotypes varies from 45.77 - 92.00 mm, fruit length is 59.40 - 120.10 mm, fruit weight is 59.71 - 504.00 g, and fruit firmness is varied between 3,40 - 7.80 kg/cm2. Sub peel color values were higher in non-astringent genotypes compared to astringent ones, on the contrary, ºh value was detected higher in astringent genotypes. The difference between all the upper peel color values except for the C value was significant, L, b and °h values were found higher in non-astringent genotypes, a value was higher in astringent genotypes. In addition, the biochemical values of the genotypes, SÇKM were statistically higher in astringent genotypes, and pH was found to be higher in non-astringent genotypes, in contrast to SÇKM. The mean values of titratable acidity (TEA) and vitamin C were statistically higher in astringent genotypes than in non-astringent genotypes. Total phenol and antioxidant capacity did not make a statistically significant difference between genotypes.