Influência de porta-enxertos e do uso de etileno nas características físico-químicas da laranja ‘PERA CNPMF D6’

Abstract

Brazil is one of the world's largest citrus producers, with 'Pera' orange grafted onto Rangpur lime' rootstock predominating in the orchards of the Northeast. To reduce the susceptibility of orchards to pests and diseases, diversification is essential, as the predominance of a single scion/rootstock combination makes plants more vulnerable, increasing the risks of infestation and disease spread. To enhance competitiveness and meet more demanding markets, rootstock diversification becomes essential. Thus, the present study aimed to evaluate the physicochemical attributes of 'Pera CNPMF D6' orange fruits grafted onto seven rootstocks and cultivated in the Coastal Tablelands of Bahia, as well as to investigate the influence of 2- chloroethylphosphonic acid (ethephon) on fruit degreening. To study the quality of 'Pera' oranges produced on the rootstocks 'Sunki Tropical' mandarin, 'Riverside' and 'San Diego' citrandarins, 'BRS Victoria' trifoliate, 'BRS Cunha Sobrinho' hybrid, and 'Cravo' lemon, the following parameters were determined: juice yield, acidity, total soluble solids (TSS), ratio, peel coloration, phenolic compounds, flavonoids, carotenoids, vitamin C, and antioxidant activity. To evaluate the effect of ethephon on degreening, three concentrations (0, 500, and 1000 mg L−1) were initially tested, along with immersion times (3 and 5 minutes) and storage environments (light and dark). It was found that the 'Cravo' and 'Sunki Tropical' rootstocks induced higher juice yield, while 'Riverside' promoted higher acidity; 'BRS Victoria' and 'Riverside' showed higher levels of phenolic compounds, and 'BRS Cunha Sobrinho' resulted in a high flavonoid content and a yellow-green coloration. Among all the studied fruits, those from plants grafted onto 'Sunki Tropical' and 'San Diego' proved to be the best scion/rootstock combinations, as they favored higher juice percentage and biochemical and antioxidant characteristics similar to or superior to those of fruits from 'Cravo' rootstock. Regarding the effect of ethephon on the fruits, a concentration of 500 mg L−1, after six days of storage, was sufficient to promote color change without compromising internal fruit quality. Furthermore, applying ethephon for 3 minutes, followed by storage in a light environment, resulted in the most efficient fruit degreening. These results indicate the potential use of ethephon in the degreening of citrus fruits.