Late harvest and delayed cooling induce internal browning of 'Ya Li' and 'Seuri' Chinese pears

Brown discoloration of the core, carpels, and flesh areas of 'Ya Li' and 'Seuri' Chinese pears (Pyrus bretschmeideri (Rehd.)) depended on harvest date. Fruit harvested no later than 180 days after full bloom (3000 degree days) did not develop the disorder. Browning of the core and flesh tissues increased when cooling was delayed, but was not influenced by subsequent storage temperatures of 0,10, or 20C. In both cultivars, the onset of internal browning was evident after storage in fruit that had been harvested when skin color had changed from green to light green-yellow. Thus, skin color can be used to determine harvest date to avoid internal browninincidence during storage of 'Ya Li' and 'Seuri' Chinese pears. The development of brown to dark-brown water-soaked areas in the core and/or flesh of 'Ya Li', 'Seuri', 'Tsu Li', 'Dansui Li', and 'Shin Li' Chinese pears during storage has been reported in several growing areas in the United States (Beutel, 1990). These symp- toms appear in the core, flesh, or both, but there is no visible external indication of their presence (Crisosto et al., 1992). Whether browning of the core and flesh is induced by the same conditions is unknown, but both limit the opportunity to store and market Chinese