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Overcoming the seed production barriers with native grasses

I. Cole 1, W. Johnston 1, J. Metcalfe1, I. Tooth 1, M. Mitchell 2 and T. Koen 1

1N.S.W. Department of Land and Water Conservation, Centre for Natural Resources, Cowra and Wagga Wagga Research Centres, NSW.
2
Agriculture Victoria, RMB 1145, Rutherglen, VIC.

ABSTRACT

Many potentially useful plant cultivars, including some Australian native grass selections developed from non-mainstream species do not reach the marketplace because they are not able to be successfully seed increased. Recognising this, the LIGULE native grass development project built into its methodology a process to ensure that potential cultivars not only performed well in an agronomic and environmental sense, but also produced commercially viable seed yields. Seed yields, determined using commercially available techniques, were an overriding concern in identifying lines suitable for release. Concurrent refinement of harvesting and seeding equipment and screening of lines for useful herbicide tolerances to identify potential selective herbicides was also undertaken. Public release cultivars of six native grass species from the project are currently undergoing commercial seed increase. A special interest group has also been formed to support seedgrowers with best possible information and targeted research.

KEY WORDS

Native grass, seed production, seed yields, breeding program.

INTRODUCTION

The LIGULE project (1) aimed to find, develop and release cultivars of Australian native grasses that have applications in environments where the usual range of introduced pasture species fail, and which have a role in preventing land and water degradation (2). Many potentially useful herbage cultivars including several Australian native grass selections, fail to reach the marketplace because the seed increase program was not adequately supported by appropriate research. Australian native grasses in particular have a reputation of being difficult to establish and harvest, variable in seed yield and seed quality and of possessing difficult dormancy characteristics.

With this in mind, running concurrently with the LIGULE core experiments, an applied seed production research and seed increase program was conducted at Department of Land and Water Conservation, Centre for Natural Resources, Research Centre at Cowra, NSW. This was aimed at identifying and overcoming potential barriers to the development of new cultivars from the wide range of native grasses being tested and ensured that potential cultivars not only performed well in an agronomic and environmental sense, but also produced high, commercially harvestable seed yields.

METHODS

The seed increase component of the project commenced in 1994-95 with seed collected by hand from the core trial plots.

Germination tests

These were conducted in standard germination cabinets and from thermogradient plate studies enabled a preliminary screening of lines based on the quantity of seed produced (some lines produced no seed), the germinability and dormancy ranges, and general seed handling qualities.

Seed production research

Although some preliminary experience had been gained harvesting seed form the core trials, work commenced in earnest with seedlings obtained from the germination experiments, which were transplanted into 100 m2 field nurseries. Seed (floret) was then harvested using commercially appropriate techniques. Accessions with the best commercial seed production potential were identified over 2-3 seasons. These data combined with persistence, production and water use characters measured in the core experiments were used to select potential cultivars. Cultivars which performed well in the core trials and which yielded over than 100kg of seed (floret)/ha at least once during the period were considered potential candidates for release. Six accessions have been chosen for accelerated development and release, with a further five showing significant potential (Table 1).

Seed production technology research

Breeders seed blocks of the six cultivars identified for accelerated development were sown in 1000 m2 areas on Cowra Research Centre. This allowed development, evaluation and refinement of specific commercial scale seed production methods for each cultivar including sowing and establishment, weed control, timing of harvest and harvesting machinery settings for optimal seed yields, drying and storage factors, cleaning options, chaffy seed planting options. Seed yields from these breeders seed blocks have been similar to those indicated from the field nurseries and in some cases even higher.

Herbicides with potential for selective control of both grassy and broadleaf weeds were also screened in a 2-year series of glasshouse and field experiments (Cole et al., 2 papers in preparation). Seed of these new cultivars is now under commercial increase with concurrent research committed to refining current recommendations to better suit a larger scale of operation.

Table 1. Field nursery yields (clean florets) over 3 years:

RESULTS AND DISCUSSION

Screening native grass lines for seed production attributes and the concurrent development of commercially relevant seed production technologies has enabled the LIGULE program to release cultivars to seedgrowers earlier and with far greater confidence in a successful outcome than would have been possible using conventional development program. A multi agency support group has also been formed for the ongoing support of seedgrowers with the best possible information and targeted research. This will result in these cultivars reaching the marketplace earlier, at a price the average landholder can afford. These selected native grasses will eventually be registered and released as public cultivars and should be available from seedgrowers as early as autumn 2003.

ACKNOWLEDGMENTS

The LIGULE (Low Input Grasses Useful in Limiting Environments) project was funded by Land and Water Resources Research and Development Corporation, NSW and Victorian Salt Action, Meat and Livestock Australia, Agriculture Victoria and NSW Department of Land and Water Conservation.

RERERENCES

1. Johnston, W.H., Clifton, C.A., Cole, I.A., Koen, T.B., Mitchell, M.L. and Waterhouse, D.B. 1998. Final Report to the Land and Water Resources Research and Development Corporation; Native perennial grasses for productive sustainable pastures in southern Australia. LIGULE (Low Input Grasses Useful in Limiting Environments).

2. Johnston, W.H., Clifton, C.A., Cole, I.A., Koen, T.B., Mitchell, M.L. and Waterhouse, D.B. 1999. Aust. J. Agric. Res. 50, 29-53.

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