Relationships between blossom blight and brown rot incidence at postharvest vary within seasons, peach cultivars and maturation period

This paper aimed to evaluate the relationships between blossom blight and brown rot incidence at postharvest on peach cultivars with different maturation periods under the subtropical conditions of Brazil. The cultivars ‘Aurora 1’, ‘Premier’ and ‘Vanguarda’ (early maturing); ‘Chimarrita’, ‘Coral’, ‘Granada’, ‘Leonense’, ‘Maciel’, ‘Marli’ (intermediate maturing) and, ‘Eldorado’ and ‘Chiripᒠ(late maturing) were grown in commercial orchards in three consecutive seasons. Completely open flowers were collected and incubated at 25°C for three days and then 4°C for another three days to assess presence of the pathogen. Harvested mature fruit were maintained under artificial white light (60 W) at room temperature (23 + 4°C) and the incidence of brown rot was evaluated daily until the tenth day after harvest. An AMMI biplot analysis was carried out allowing grouping of cultivars based on the similarity of performance across diverse environments (seasons). The incidence of the disease in the flower and postharvest did not follow a uniform pattern between ripening periods, cultivars and seasons. The incidence of blossom blight varied from 6 to 11%, during the first season. It was the best season for differentiating the cultivars. There was a significant correlation between blossom blight and brown rot in only one early maturing cultivar (R=0.87) and one late cultivar (R=0.75). The later the ripening period of the cultivar, the higher the incidence of postharvest disease. According to the AMMI model and biplot graph, the incidence of blossom blight and brown rot was above average in the ‘Chimarrita’ and ‘Leonense’ (intermediate) and ‘Eldorado’ and ‘Chiripᒠ(late) cultivars.