Effect of foreign pollen on fruit set and quality of 'Monthong' durian

The effect of foreign pollen on fruit set and quality of ‘Monthong’ durian was studied in two experiments at the Chanthaburi Horticultural Research Center, Thailand. The first experiment investigated the in vitro germination of pollen from five commercial cultivars including ‘Phuangmanee’, ‘Longlublae’, ‘Chanee’, ‘Kadum’ and ‘Monthong’, five lesser-known cultivars namely ‘Nokyhib’, ‘Kobmaethao’, ‘Chomphoosri’, ‘Kanyaosrinak’, and ‘Chaymafai’, and one hybrid ‘Chanthaburi 3’ at different temperatures. ‘Chanthaburi 3’ was found to have the highest germination rates among cultivars across the 10 to 35°C temperature range. Consequently, ‘Chanthaburi 3’ pollen was chosen to study the effect on ‘Monthong’ fruit set under two weather conditions, in comparison with ‘Monthong’ pollen. The percentage of fruit set was not different between 18.5 and 31.6 and 23.3-34.2°C (min-max) temperature conditions. However, the number of fruit set tree^‑1 under the cooler condition was significantly higher, at 81 as compared with 65 fruit tree^‑1. Similarly, pollen of ‘Chanthaburi 3’ did not result in higher fruit set percentage, but the number of fruits tree^‑1 was higher than with ‘Monthong’ pollen. ‘Monthong’ fruit which were pollinated with pollen from ‘Chanthaburi 3’ revealed no significant differences in pulp weight, seed weight, fruit weight, number of aborted seeds and total soluble solids from fruit which were pollinated with pollen from ‘Monthong’. Nevertheless, analysis of volatile compounds from fruit pulp with a gas chromatograph-mass spectrometer, using headspace solid phase micro extraction with DVB/CAR/PDMS coated fiber, revealed a slightly different profile between fruit that had been pollinated with ‘Chantaburi 3’ compared with that of ‘Monthong’ pollen.