Alqarni et al., J. Anim. Plant Sci. 25(6):2015 1667 EVALUATION OF ACACIA GERRARDII BENTH. (FABACEAE: MIMOSOIDEAE) AS A HONEY PLANT UNDER EXTREMELY HOT-DRY CONDITIONS: FLOWERING PHENOLOGY, NECTAR YIELD AND HONEY POTENTIALITY Abdulaziz Saad Alqarni 1 , Awad Mohamed Awad 1* and Ayman Ahmad Owayss 1 , 1 Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, P.O. Box 2460, Saudi Arabia. * Corresponding author’s email: awad.univ@gmail.com ABSTRACT The nature of both bee-plant interactions and pollination ecology critically depends on flowering phenology and nectar yield. These two factors determine whether the plant has the potential to produce honey by honey bees. Here, we characterized flowering phenology, quantified nectar yield and calculated honey potentiality of Talh (Acacia gerrardii Benth.). Talh is a widespread melliferous species distributed in Africa and the Middle East. Field investigations were performed in Rawdhat-Khoraim oasis, Riyadh, Saudi Arabia, from April to August for 3 years (2011-2013). Flowering phenology, nectar yield and tree canopy area data were used to predict the honey production potential of Talh trees. The bloom season of Talh trees began around mid-May and ended in mid-August. Flower density varied significantly (p 0.001) among months, while the general mean (±SE) was 148±14 flower heads (FHs) per m 2 per day. The total soluble solids (TSS) secreted were 30.4 mg/ FH/ day. Talh trees may produce potential honey weighing 495 ± 60 g/ tree/ day and 45,032 ± 6,359 g/ tree/ season. In conclusion, Talh trees have a high potential for honey production. Further studies are needed to estimate the actual honey production and to understand other aspects of flowering. Key words: Apis mellifera; Acacia gerrardii; flowering; honey; honeybees; nectar; pollination; Saudi Arabia. INTRODUCTION Honey bees (Apis mellifera Linnaeus) obtain nectar, pollens and resins from plants. Bee flora is the most important factor dictating honey bee activities and honey production (Keasar and Shmida, 2009). Previous studies have quantified and characterized the quality of nectar in numerous plant species. These studies have been primarily restricted to the pollination biology of the studied species (Castellanos et al., 2002; Galetto and Bernardello, 2004). Fewer studies have addressed nectar yield or honey potentiality (Masierowska, 2003; Kim et al., 2011; Adgaba et al., 2012). The nectar of some acacia species has been studied in Africa, Australia and South America (Sedgley et al., 1992; Baranelli et al., 1995; Stone et al., 1998; Kenrick, 2003; Stone et al., 2003; Fleming et al., 2007). These studies focused on pollination but not honey potential. Talh trees (Acacia gerrardii Benth.) are relatively common throughout Africa and the Middle East in woodlands, wooded grasslands, dry river valleys scrubs, thornveld and bushveld. Talh trees are beneficial to their ecosystems and have multiple uses in traditional medicine (Dharani, 2007). Talh trees are among the major melliferous plant species of Saudi Arabia (Alqarni et al., 2011). Honey bees produce one of the most popular honeys in Saudi Arabia from the flower heads (FHs) of Talh (Al-Khalifa and Al-Arify, 1999). The English name of this acacia is “red thorn”, and the common Arabic name is “Talh.” Hence, honey produced from Talh FHs is called “Talh” honey (Bahaffi and Al-Lihaibi, 2005). However, data on Talh flowering phenology and nectar yield are not available. To date, no study has estimated the potentiality of Talh honey in Saudi Arabia or elsewhere. Information on several important aspects of Talh trees found in arid regions regarding their flowering behavior, nectar yield, and honey potential in scanty and the present study aims to characterize the flowering phenology, measure the nectar yield and to estimate the honey potentiality of Talh trees. MATERIALS AND METHODS Site of study: Field investigations were conducted in Rawdhat-Khoraim, an oasis located 120 km northeast of Riyadh city, Saudi Arabia (between 25°30'- 25'' N and 47°46'- 30'' E at 1829 ft.). This oasis is approximately 18 km long and 1 to 2.5 km wide. This region is extremely dry (10% RH) and hot (37 ˚C) when Talh blooms. A sizeable Talh population occurs in this region with other plant communities. Talh growth in this region depends on estuaries flowing from the surroundings during autumn, winter and spring. A pilot study was conducted during 2011 to test and improve sampling procedures. Field investigations were recorded from May to August in 2011, 2012 and 2013. The Journal of Animal & Plant Sciences, 25(6): 2015, Page: 1667-1674 ISSN: 1018-7081