THE ROLE OF EFFECTIVE INSECT POLLINATORS IN IMPROVING FRUIT CHARACTERISTICS OF SOME HORTICULTURAL CROPS

Abstract

ABSTRACT The present study was carried out on three plum cultivars; Golden Japanese, Hollywood and Santarosa at Elkalubia Governorate during 2012 & 2013 to study the behavior of bee foragers and the response of sequential increase of honeybee visits/ flower on plum cultivars on fruit set and fruit characteristics on the studied cultivars. Several sequential treatments were applied from 1 bee visit/ flower up to ten bee visits/ flower besides zero visit (control) and open pollination treatments. Investigations on Annona species (Annona atemoya, Annona cherimoya and Annona squamosa) was conducted at El-Mansouria district, during 2014 & 2015 to identify insects visitors and also study the effect of insect pollination treatment on fruit set and fruit characteristics in comparison with hand pollination (control). In general, Hollywood plum cv. was significantly more attractant to bee foragers than Santarosa and Golden Japanese cvs. with highest activity at 2 p.m. The activity of honey bee foragers in collecting of pollen, nectar or both from flowers was investigated. Highest percentage of pollen gatherers was recorded on flowers of Hollywood cv. followed by Golden Japanese then Santarosa flowers and reached to its peak at 11 a.m. In the other hand, Golden Japanese flowers were significantly attracted the nectar foragers than Santarosa and Hollywood flowers with peak at 2 p.m. The collection of both nectar and pollen in the same trip by one forager was also observed on the three studied plum cvs. Santarosa flowers attained the first rank encouraging honeybee workers for gathering the both types of food. This activity pattern concentrated at early morning or late afternoon with no significant difference between them. On the present study, bee foragers showed significant benefit to plum cvs. and significant improving as a result of increasing bee visits/ flower when compared with self-pollination (control) on final fruit set as well as on fruit characteristics; fruit weight, volume and T.S.S. Increasing honey bee visits/ flower improved fruit quality through decreasing fruit firmness. Thus, it can be recommended from the obtained results to maintain sufficient honey bee colonies in Golden Japanese, Hollywood and Santarosa plum orchards that offer at least ten bee visits/ flower to increase fruit set and to achieve satisfactory improvement in yield and fruit characteristics. In Annona, Carpophilus hemipterus was the most abundant insect visitor to Annona species under investigation. Insect pollination treatment was carried on Annona species by Carpophilus hemipterus beetles results in high improvement in fruit set and fruit characteristics compared with hand pollination treatment (control). Key words: Plum, Annona, Cross-Pollination, Honeybee, beetle pollination, Fruit Set, Fruit Characteristics.