Fruit Physiological Disorders:
Internal Browning of Chinese and Korean Pears Occurrence: Chinese pear cultivars such as ‘Ya Li,' ‘Daisui Li,' ‘Seuri,' ‘Tse Li,' ‘Shin Li,' and ‘Korean' pears such as ‘Shingo,' ‘Okysankichi,' and Dan be.' Importance: Internal browning on Asian pears is the main consumer complaint. This is a worldwide problem. Symptoms: Development of brown to dark brown water-soaked areas in the core and/or flesh occur during storage. There is no visible external indication of internal browning. Causes: The cause of internal browning is still unknown. Ripening predisposes the fruit to the disorder while it is in cold storage. Control: Internal browning can be avoided by harvesting Chinese pears earlier than is presently done commercially in the San Joaquin Valley of California. Fruit grown under California conditions and picked later than 180 days (3000 degree days) after full bloom are likely to develop browning during storage. The fruit should be picked when most of the pears on the tree are still green, although a few at the top may begin to develop some light-yellow spots. Fruit picked when the skin is completely yellow will develop internal browning within one month after harvest. Prompt cooling of fruit is recommended as delays in cooling increase the incidence of internal browning in pears that are beginning to turn yellow. We suggest that growers who are having internal browning problems in Chinese pears keep records of the number of days after full bloom needed for their fruit to start turning light yellow to help them decide when to pick in subsequent years. References:
Crisosto, C. H., Kevin R. Day, Steve Sibbett, David Garner, and Gayale Crisosto. 1994. Late harvest and delayed cooling induce internal browning of ‘Ya Li' and ‘Seuri' Chinese pears. HortScience 29(6) 667-670. Porritt, S. W., M. Meheriuk, and P. D. Lindster. 1982. Postharvest disorders
of apples and pears. Agr. Canada Publ. 1737/E.
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