Proceedings of the New Zealand Grassland Association 60: 233–241 (1998) 233 Thinopyrum intermedium (Host) Barkw. & Dewey – a review, and evaluation of intermediate and pubescent wheatgrass for dryland agriculture in New Zealand B.J. WILLS1, G.B. DOUGLAS2, J. McKENZIE3, K.D. TRAINOR1 and A.G. FOOTE2 1AgResearch, PO Box 228, Kelman St, Alexandra 2AgResearch, Grasslands Research Centre, PB 11008, Palmerston North 3Belfield, Hakataramea Valley, RD, Kurow Abstract significant advantage is that no stock health, pest or plant disease problems have been noted as yet Intermediate and pubescent wheatgrasses with any of the wheatgrass varieties available in (Thinopyrum intermedium) are potentially useful New Zealand. as dryland forage grasses in New Zealand. The recent literature on their international and local use Keywords: dryland agriculture, New Zealand, in pasture and cropping situations is reviewed. Thinopyrum, wheatgrass Under semi-arid conditions at Bendigo Station over a 13-year period, cv. Luna wheatgrass has spread Introduction several metres from the original drill lines and it provides very high ground cover. In terms of Many wheatgrass species, including western, slender dryland soil resource conservation this contrasts and crested wheatgrasses, have been evaluated in New with adjacent cocksfoot and, to a lesser extent, Zealand for revegetating depleted, erosive, dry and semi- lucerne plots which have wide-spaced plants arid country, and for forage production. Investigations interspersed with litter and much bare ground. In a with wheatgrasses and other dryland species, sited mixed drilling containing wheatgrass, hairy mainly in the South Island, have been conducted dorycnium, birdsfoot trefoil and sheep’s burnet, periodically since the mid 1900s. This research originally the first two species now dominate. At Takapau, concentrated on the soil conservation attributes of the central Hawke’s Bay, annual yields from plants but latterly has also investigated on-farm intermediate and pubescent wheatgrasses produced applications. Recent North Island trials have concen- over 80% of the yield of 10 New Zealand cultivars trated on forage production. in spring, summer and autumn, and 65% in the Intermediate and pubescent wheatgrasses are winter. Of the wheatgrasses, cv. Topar intermediate considered to have potential as useful dryland forage wheatgrass and a pubescent wheatgrass (unnamed grasses in New Zealand, both on hill country and on line) were the lowest yielding, whereas cv. Oahe lower altitude agricultural land. Internationally they and cv. Mandan produced the highest yields. Cv. are useful in cereal breeding programmes and as grain Greenleaf pubescent wheatgrass had higher foliar crops. nitrogen content than all other species, but in vitro This paper 1) reviews historical use of wheatgrasses organic matter digestibility was less than 700 g in New Zealand and recent overseas literature, 2) OM/kg DM. Although the wheatgrasses had provides management information from research and satisfactory herbage yield and nutritional value, practical farming viewpoints for wheatgrasses in South better alternative species are available for pastoral Island dryland farming situations, and 3) presents farming in central Hawke’s Bay. On Belfield in the selected yield and nutritional data from a spaced-plant Hakataramea Valley, cv. Rush has been the most evaluation of wheatgrasses in the lower North Island. vigorous wheatgrass for establishment and it seems to handle cold winds and frost well. Hay made Literature review from a wheatgrass/ lucerne mix is considered better than that from the individual species as this can Most wheatgrasses (Family Poaceae, Tribe Triticeae), increase production by 40–50%, depending on soil many of which are perennial relatives to wheat, are and climatic conditions. Usually only one cut per adapted to steppe or desert with subhumid to arid year is taken from the mixed pasture. Crop climates. About 30 species are native to North America maintenance includes the application of 200 kg/ha and 100 to Eurasia, with a few species occurring in of sulphur super extra every 3–4 years and the pH South America, New Zealand, Australia and Africa is maintained at about 5.9–6.4 by liming. A (Asay & Knowles 1985; Jarvie & Barkworth 1993). 234 The most promising species for New Zealand (NZ) Schulze-Schaeffer & Ditterline (1991) registered are intermediate wheatgrass (Thinopyrum intermedium several vegetatively propagated parental lines of (Host) Barkw. & Dewey, syn. Agropyron intermedium intermediate wheatgrass (MT6-MT15), all with forage (Host) Beauvois, Elymus hispidus (Opiz) Melderis, yields equal to or higher than Oahe. The strong resistance Elytrigia intermedia (Host) Nevski), and its close of intermediate wheatgrass to barley yellow dwarf relation pubescent wheatgrass (T. intermedium ssp. luteovirus and several rusts has recently been exploited barbulatum (Schur) Barkw. & Dewey, syn. A. to improve wheat genetics via backcrossing to fertile trichophorum (Link) Richter, Elymus hispidus ssp. amphiploids (Larkin et al. 1995). barbulatus (Schur) Melderis, Elytrigia trichophora (Link) Nevski). Both have been evaluated in the South Establishment Island since about 1940, including the Pisa Flat trials, Based on US experience, wheatgrasses should be drilled Central Otago (Calder 1944), and in trials in the at a depth of 10 mm on medium to fine-textured soils Mackenzie Basin during the 1950s (Douglas 1974), but and no more than 25 mm deep on coarse-textured soils. commercial interest did not develop until the mid 1980s Single species seeding rate recommended for (Wills 1984; Wills et al. 1987). intermediate and pubescent wheatgrasses is 11–14 kg/ ha Pure Live Seed (PLS). A firm weed-free seedbed Description enhances stand establishment. They are compatible with other pasture species, particularly lucerne, and stand Intermediate and pubescent wheatgrasses are long-lived longevity and productivity can be enhanced by seeding (50+ years) perennial, cool-season grasses with short with a legume. rhizomes and a deep-feeding root system. Leaves are Best dryland results are obtained from seeding in 4–8 mm wide, green to blue-green and sometimes early spring on heavy to medium textured soils and in drooping, and plants grow to a height of 1–1.5 m. The late autumn on medium to light textured soils. Irrigated seed spikes may be 100 to 200 mm long. As the common areas should be seeded in spring through summer name implies, the spikes, spikelets, glumes, lemmas (Lawrence 1983; Wheeler 1950; USDA-PMC 1997). and leaves of pubescent wheatgrass are densely covered For mined lands, roadsides and other critical areas, the with hairs whereas intermediate wheatgrass vegetative seeding rate should be increased to 18–20 kg/ha PLS. structures are mostly smooth, but may have ciliate hairs on the leaf margins. Intermediate and pubescent Management wheatgrasses readily cross and commercial seed often Intermediate wheatgrass is very productive early in the contains both types (Wheeler 1950; Asay & Knowles life of a stand (Asay & Knowles 1985) and although the 1985; USDA-PMC 1997). Interspecific hybrids with newer cultivars are better, they are sometimes criticised other Triticeae species have also been reported (Napier in the USA for their lack of longevity when mismanaged & Walton 1981). or subjected to environmental stress. Pubescent wheatgrass is better adapted to droughty, In the Hakataramea Valley (South Island, NZ) infertile loamy to sandy and shallow soils while Woodman & Fraser (1991) observed that intermediate intermediate wheatgrass can provide abundant high wheatgrass, along with cocksfoot, tall oatgrass and quality forage on fertile sites with well drained loamy- smooth brome, had potential as a productive and to clayey-textured soils, and at higher elevation. Both sustainable pasture grass with a wide seasonal growth will tolerate slightly acidic to mildly saline conditions, pattern. Hunter et al. (1994) noted that production of are cold tolerant (pubescent wheatgrass is considered Luna in Marlborough/mid-Canterbury improved with more winter hardy), can withstand moderate periodic time, especially on stony loam soils, that it grew well flooding in the spring, and are very tolerant of fire into summer but less so in autumn, and was highly (USDA-PMC 1997). They grow poorly on wet, palatable. waterlogged or moderately saline to alkaline soils, or Wheatgrass produces good hay yields both under prolonged inundation (Hafenrichter et al. 1968; individually and combined with lucerne where its stiff Hull 1974). stems help keep the legume from lodging. Several Several cultivars of intermediate wheatgrass, cultivars have been selected for hay production (Table developed in the US, are available: Amur, Chief, Clarke, 1). Regrowth after cutting is slow, so a single cut for Greenar, Oahe, Ree (discontinued), Reliant, Rush, Slate hay each season is best. Intermediate and pubescent and Tegmar. Pubescent wheatgrass cultivars include wheatgrasses respond well to irrigation with similar Greenleaf, Luna, Mandan, Manska and Topar (Asay production to cocksfoot; however, the latter will 1992). The origins and attributes of these cultivars are normally out-produce them for hay production in summarised in Table 1. multiple cutting situations. 235 Table 1 Intermediate and pubescent wheatgrasses – cultivar attributes* Cultivar Type Origin Released Attributes Intended Use Manchuria, Leafy, vigorous-growing, strong seedling vigour, good seed Disturbed land revegetation,