HOW FRUIT TRAITS INFLUENCE CRACKING OF POMEGRANATE (PUNICA GRANATUM L.)

The present study investigated the effect of different factors on cracking of pomegranate. These factors included fruit skin thickness, fruit volume, fruit shape, total arils weight and Ca ion and depolymerized pectin. ‘Malas-e-Saveh’ and ‘Yusef-Khani’ as two sensitive and resistant pomegranate cultivars, respectively, were selected for this study. Data were analyzed in a frame of CRBD using a SAS software program. Logistic regression was applied to determine the effect of each factor on cracking. Results showed that fruit skin thickness was significantly different between the two cultivars. However, the recent factor had no effect on fruit resistance to cracking. With increasing trends of fruit volume fruit cracking rate was increased. Fruit shape in ‘Malas-e-Saveh’ pomegranate was oblate while ‘Yosef-Khani’ was more spheroidal. This deviation from a perfect spheroid increased pressure to skin and caused a higher cracking rate. Total arils weight was different among cracked and non-cracked fruits and the recent factor had positive effect on fruit cracking. The recent result indicated that arils were the principal sources of pressure to the fruit skin. In this respect with increasing trend of arils weight in number or volume pressure to skin had increased impressively and subsequently fruit cracking emerged. Physiological characters of fruit skin such as higher Ca ion and lower pectin content in sensitive cultivars increased skin inflexibility and decreased elasticity, resulting in a higher cracking rate.