GENETIC STABILITY ASSESSMENT OF APPLE MUTANTS 'FUJI KIKU 8' AND 'GALA SCHNIGA' DURING ADAPTATION TRIALS IN IRAN

Genetic stability of mutant cultivars is menaced if imported from far geographic locations. Different cultivars have different degrees of climate adaptation that is influenced by genetic variation. Some mutant cultivars lose their characteristics during adaptation trials in new climate. To assess probable genetic regression of fruit traits in apple mutants, ‘Gala schniga’ and ‘Fuji kiku 8’, pomology of fruit samples was studied for physical, biochemical characteristics and the sensorial analyzes were compared with main mother cultivars ‘Gala’ and ‘Fuji’. The samples were evaluated in the Post-Harvest Laboratory of Horticulture Research Department of SPII. The plants were compared also for fruit set percent based on more biological growth stages. Field investigations were made on morphologies and growth traits in a new geographical condition, Karaj-Iran, characterized by semi-arid climate, high solar radiation and low relative humidity, so different climatic conditions from origin points of the mutants and or the main cultivars that could affect genetic stability of the mutants in particular. The results showed that fruit weight and diameter, eye and stalk cavity width, stalk length and diameter, flesh firmness, total soluble solids (TSS) and pH prevailed in the new mutants related to the mother cultivars, while the mutants presented minor values for fruit diameter, fruit weigh and titrable acidity (TA). Although chlorophyll content, leaf width and length, internode number, lenticels number and diameter of annual shoots resulted higher in the mother cultivars, high rates of sensorial analyzes were achieved for the important features of aroma, sweetness, juiciness, flesh firmness, peel thickness, flesh color and total acceptance in both ‘Fuji kiku’ and ‘Gala schniga’.