Effects of caprifig (Ficus carica var. caprificus) storage temperature and duration on the fruit productivity and quality of 'Bursa Siyahi' figs

Abstract

Caprification is the process of hanging caprifig fruits on edible fig trees to transfer the pollen inside the caprifig to the edible fig via the wasp (Blastophaga psenes) living in the caprifig. It needs to be repeated several times for the proper fruit set of edible figs. The present study was conducted to determine the change in the number of Blastophaga psenes, the duration of Blastophaga's exit, and pollen viability in case the caprifigs to be used in the caprification process are stored until use. The number of Blastophaga and in vitro pollen viability were tested at day 0 (harvest day) and after 4, 8, 12, 16 and 20 days of storage at three different temperatures (0, 4, and 8 degrees C). Afterwards, the effect of pollination frequency on the edible fig fruit set and quality was determined by using Blastophaga psenes as a vector in the pollination of stored caprifig fruits, pollinating five times with 4-day intervals and three times with 8-day intervals. Approximately a 50% reduction in the number of B. psenes was detected after 4 (180.22), 12 (174.11) and 16 (192.66) days of caprifigs storage at 0, 4, and 8 degrees C, respectively. The pollen germination percentage of the caprifigs increased with storage and was higher in those stored at 8 degrees C (43.96%) and 4 degrees C (41.70%). The highest fruit set was obtained when the caprifigs stored at 4 degrees C (76.41%) and 8 degrees C (71.38%) five times with 4-day intervals were used for pollination. The pollination practice repeated five times with 4-day intervals resulted in a lower proportion of extra-large fruits with a weight of >100 g, a higher proportion of fruits with no or slight ostiole damage and early ripening of fruits. These results suggest that B. psenes and pollen viability can be preserved by storing caprifigs at 4 or 8 degrees C and that fruit set and fruit characteristics would be positively affected with the use of stored caprifigs in the pollination practice repeated five times with 4-day intervals.