Floral sex expression and pollination affects low fruit set of mango cvs. Khiew Sawoey and Falan.
Issarakraisila M.
Author Affiliation: Institute of Agricultural Technology, Walailak University, Nakhon Sri Thammarat 80160, Thailand.
Thai Journal of Agricultural Science 31 : 184-195
Abstract : Studies on factors affecting fruit set of mango cv. Khiew Sawoey were investigated at two locations in the central region of Thailand (Chachoengsao and Suphan Buri provinces). Factors affecting fruit set in cv. Falan were also examined at Chachoengsao. Anthesis at both locations was in January 1997. The percentages of hermaphrodite flowers on Khiew Sawoey inflorescences at Chachoengsao and Suphan Buri were only 3.0 and 4.6%,respectively. Pollen viability of Khiew Sawoey flowers collected from each place during the flower-opening period varied between 50 and 75%. The viability of Khiew Sawoey pollen at Chachoengsao was slightly lower than at Suphan Buri. The viability of Falan pollen was lower than that of Khiew Sawoey at Chachoengsao. Pollination of mango flowers at Chachoengsao, as measured by the number of hermaphrodite flowers which had germinated pollen in their stigma, was very low reaching only 14% at the end of anthesis. However, pollination at Suphan Buri was between 13 and 25% through the anthesis period. The combination of both a low hermaphrodite flower ratio and pollination was reflected in fruit set. Fruit set at Chachoengsao was only 3.6% as measured by the number of inflorescences which had a fruitlet compared with 10.9% at Suphan Buri. Observation at mid-anthesis showed that the peak number of insect visitations on mango flowers at Chachoengsao was only 5 per hour per 20 inflorescences whereas the number at Suphan Buri was 14. Causes and effects of low fruit set on mango cv. Khiew Sawoey and horticultural implications to improve the fruit set are discussed.