Case Study 26 Pollination Aware and Pear Nashi This case study is the primary source of information on potential pollination services for the industry. It is based on data provided by industry, the ABS and other relevant sources. Therefore, information in this case study on potential hive requirements may differ to the tables in the Pollination Aware report (RIRDC Pub. No. 10/081) which are based on ABS (2008) Agricultural Commodities Small Area Data, Australia 2005-06. Introduction Pear trees (Pyrus spp., family Rosaceae) are native to coastal colours ranging from tan to brown and a rough texture. Both and mildly temperate regions of western Europe, North Africa, types grow easily, produce sweet and juicy fruit that are a low and extending east across parts of Asia. The two main types of calorie source of carbohydrates, fibre, and pectin. pear cultivated around the world are the European pear (Pyrus Most pear varieties are considered self-infertile and require communis L) and the Asian pear or ‘nashi’ (Pyrus pyrifolia). For cross-pollination with another variety to set fruit. Honey bees the purpose of this study the European pear is referred to as the are regarded as the most efficient and most important pollinators ‘pear’ and the Asian pear as the ‘nashi’. The fruit mainly carry of pear trees (McGregor 1976; Stern et al. 2004). This is despite the distinctive ‘pear shape’, technically referred to as pyriform (a the fact that pear flowers produce very little nectar, with bees narrow stem area and full bulbous-like base); however, the nashi primarily foraging on them for pollen (McGregor 1976). generally has a more spherical shape. Skin colour varies between varieties and may be smooth yellow, green or red, or may exhibit Pear and nashi production in Australia On a global scale Australia is insignificant as a pear producer, production concentrated in Victoria (88.7% for pear production ranking twentieth in the world and producing just 0.6% of global and 88.5% for nashi production) around the Goulburn and production (FAO 2009). Nonetheless, Australia produced ap- Yarra Valleys. Western Australian is the next largest producer proximately 140,000 tonnes of pears and 3,400 tonnes of nashi with growing regions in the south-west around Donnybrook in the year 2005/06 (ABS 2008) (Table 1). Both pears and nashis and Manjimup, followed by South Australia’s Adelaide Hills, and are grown in very similar regions (Figure 1) with the majority of smaller amounts in Queensland, Tasmania and New South Wales. Table 1 Australian production and percentage of European and nashi pears grown per state (ABS 2008) ACT NSW QLD SA TAS VIC WA Total Pear (t) 1.5 419.2 785.8 5,270.1 730.8 123,350.3 8478.1 139,036.1 Nashi (t) 0.6 26.7 5.6 183.6 4.2 2,993.6 168.6 3,382.9 Case Study 26 Pollination Aware Figure 1 Production regions within Australia for pear (left) and nashi (right) (ABS 2008) F igure 1 Production regions within Australia for pear (left) and nashi (right) (ABS 2008) TheThe production production of pears of pearsis a great is adeal great larger deal than larger nashi than produc nashi- productionare also grown with for pears the fresh grown market for both(Intensive.Pear the 2009). The tionprocessed with pears andgrown fresh for bothfruit theindustry. processed Major and fresh European fruit pear varietiesnashi was grownbrought in to AustraliaAustralia by include Chinese the gold miners in the industry.‘William’s Major BonEuropean Chrétien’ pear varieties (approximately grown in Australia 47% of production),1850s whichand has is been used in mainlycommercial for processing,production for the last 25 includethe ‘Packhamsthe ‘William’s Triumph’ Bon Chrétien’ (approximately (approximately 39%) 47% which of is usedyears. for All the nashis fresh are market grown andfor the the fresh ‘Buerré fruit market with the production),Bosc’, ‘Josephine’ which is used and mainly ‘Corella’ for processing, which are the also ‘Packhams grown formajor the fresh cultivar market being (Intensive.Pear‘Nijisseiki’ (Intensive.Pear 2009). 2009). Triumph’The nashi (approximately was brought 39%) to which Australia is used by for Chinese the fresh gold miners in the 1850s and has been in commercial marketproduction and the ‘Buerré for the Bosc’, last 25 ‘Josephine’ years. All and nashis ‘Corella’ are which grown for the fresh fruit market with the major cultivar being ‘Nijisseiki’ (Intensive.Pear 2009). Pollination in pears and nashi Most pear and nashi varieties are considered self-infertile and require cross-pollination (DPI.VIC 2008; Sakamoto et al. 2009). Therefore a transportation agent (i.e. wind, insects) is required to transfer pollen from a pollinising variety to the stigma of a fruit-bearing variety. The literature does give credit to a number of pollinating insects including several from the orders of hymenoptera, diptera and coleoptera, however it has been well established that honey bees (Apis mellifera) are the Pollinationprimary pollinators of pears in and nashispears (McGregor and 1976; Stern nashi et al. 2004). MostNumerous pear and nashi authors varieties have are demonstrated considered self-infertile the value andof honey Numerousbees in pollinating authors have pears, demonstrated some dating the value back of honey bees in requireas far cross-pollination as 1900 have (DPI.VIC been cited 2008; by McGregorSakamoto et (1976) al. 2009). and demonstratepollinating pears, increases some datingin yield back and as farfruit as 1900 have been cited Thereforeshape/quality a transportation of pears agent when (i.e. bees wind, are insects) put onto is required a flowering by crop. McGregor Although (1976) the and same demonstrate amount increasesof in yield and to transferliterature pollen is notfrom available a pollinising for varietynashis, to given the stigma that bothof a pearsfruit and shape/qualitynashi share veryof pears similar when planting bees are putand onto a flowering fruit-bearinggrowing variety.needs and The itliterature is well doesknown give that credit honey to a numberbees have crop.been Althoughused extensively the same amountin the pollination of literature ofis not available for of pollinatingnashi in Victoriainsects including (DAF 2005)several andfrom New the orders Zealand of (Rohitha nashis,and Kli givennac that1990) both, the pears pollination and nashi share very similar planting hymenoptera,requirements diptera for and nashi coleoptera, are considered however toit hasbe beenvery wellsimilar toand that growing of pears. needs and it is well known that honey bees have established that honey bees (Apis mellifera) are the primary pol- been used extensively in the pollination of nashi in Victoria (DAF linatorsHigh of concentrationspears and nashis (McGregorof foraging 1976; bees Sternin the et crop al. 2004). have not2005) only andbeen New shown Zealand to ensure (Rohitha a goodand Klinac fruit 1990),set, the pollina- but will also increase seed numbers in each pear and nashition fruit. requirements This in turn for nashiensures are consideredbetter, even to- be very similar to shaped fruit and improved storage qualities (DPI.VIC 2008)that. of Langridge pears. and Jenkins (1975) considered the role of honey bees in the transport of pollen for fertilisation of ‘Winter Nelis’ pears in a pear orchard in Victoria. Trees were open pollinated and caged to exclude honey bees. Results revealed that enclosing the trees in bee-proof cages caused a marked decline in fruit yields and number of seeds per fruit (Table 2). Page 2 197 and Pear Nashi High concentrations of foraging bees in the crop have not only Table 2 Pollination of ‘Winter Nelis’ pears been shown to ensure a good fruit set, but will also increase (Langridge and Jenkins 1975 seed numbers in each pear and nashi fruit. This in turn ensures better, even-shaped fruit and improved storage qualities (DPI. Open trees Caged Statistical VIC 2008). Langridge and Jenkins (1975) considered the role of trees significance honey bees in the transport of pollen for fertilisation of ‘Winter Fruit 52.75 4.95 P<0.01 Nelis’ pears in a pear orchard in Victoria. Trees were open pol- set/100 linated and caged to exclude honey bees. Results revealed that clusters enclosing the trees in bee-proof cages caused a marked decline in fruit yields and number of seeds per fruit (Table 2). Yield per 87.8 11.5 P<0.01 tree (kg) Seeds 5.0 2.9 P<0.01 per fruit Pollination management for pears and nashi in Australia There are a number of factors within the orchard which have a of hives and thus inefficient pollination. Ensuring the direct bearing on the pollination efficiency of honey bees: beekeeper has good access will aid in placement of hives and be mutually beneficial to the grower (increased pollination efficiency) and the beekeeper (decreased labour effort). Orchard layout • Tree and blossom density: The most common tree arrange- ments for intensive pear/nashi production are single row or Pollinisers Most pears/nashi’s are considered self-infertile (cannot produce open tatura trellis (double row) systems. Tree density is one fruit from their own pollen) and require cross-pollination with of the most important factors influencing the production of another cultivar. If cross-pollination is insufficient then there fruit in an orchard and many studies with various varieties may be reduced yields and misshapen fruit. It is important to and rootstocks have shown that increasing tree densities ensure that compatible varieties (pollinisers) have a flowering increases earlier production and yields because of greater period that coincides with the bearing variety and are planted light interception by the orchard canopy. The classification within the orchard in a suitable configuration so that honey bees of what constitutes high and low density planting varies can effectively and efficiently pollinate an orchard. Bees also between production regions but in general low density is tend to fly down rows and not across them so full-row systems anything with less than 1,000 trees per hectare, high density of pollinisers (often used in older low-density orchards) may is anything between 2,500 and 5,000 trees per hectare have limited effectiveness in intensive production systems.