P.PSH.1036 - Novel dual purpose perennial cereals for grazing

Summary

Field experiments were established to evaluate different perennial wheat breeding material, their compatibility with legumes, the effects of common agronomic practices such as nitrogen fertiliser and plant density, and screen the mineral profile of a range of candidate legumes.

This project established the suitability of perennial wheat forage for sheep, which was observed to be quite similar in quality and mineral profile to conventional grazing wheat. The inclusion of a legume increased dietary intake, enhanced the concentration of health-claimable compounds in the meat of grazing lambs and reduced the need for mineral supplementation compared to a pure cereal diet, but grain yields were generally reduced. Lucerne was suggested to be a poor choice of companion due to its low forage sodium (Na) concentrations and perennial growth habit. Self-regenerating annual legumes such as subterranean clover or serradella, both of which have higher forage Na concentrations than lucerne, may be better companions with perennial wheat, although this needs to be validated over a longer timeframe.

Objectives

1. Recommendations for farmers and their advisors on how to more efficiently grow and graze dual purpose cereals with companion legumes.
2. A network of stakeholder engagement sites which demonstrate the novel concept, and explore practical considerations (species selection, herbicide options, seasonal growth patterns) which farmers and advisors will need to consider.
3. At least two field days annually to extend research findings to stakeholders.
4. Defined benefits to meat production and trade-off’s in growing cereal crops in mixtures with legumes.
5. Defined thresholds of the legume abundance required in a cereal-based diet in order for financial benefits in lamb production to be achieved.
6. Defined meat quality parameters of pH, intra-muscular fat content, colour and tenderness for animals produced from grazing cereals
7. At least 3 scientific conference papers within the life of the project describing the results of growing dual-purpose cereal crops in mixtures.
8. At least 2 papers within the life of the project submitted to an appropriate international scientific journal,
9. A plain-English fact sheet delivered at the end of the project which describes the tradeoff’s
and key learnings of growing dual purpose crops with companion legumes.

Key findings

1. Sheep grazing any of biculture perennial wheat /legume diets examined continue to require supplementation with Na and Mg, but the addition of lucerne alleviated the need for Ca supplementation.
2. Perennial wheat forage either as a monoculture or fed with lucerne can deliver lamb meat that meets consumer expectations. This observation is based on consumer sensory scores and instrumental measures for tenderness, flavour, juiciness and overall liking. The colour and oxidative status of meat from lambs fed perennial wheat were within ranges defined for consumer satisfaction with product freshness and nutritional value.
3. Immediate adoption of this research is inhibited by the fact that perennial crops are not available to farmers in Australia. Nevertheless, momentum in perennial crop development continues to increase globally as pressure mounts to produce food and fibre with the lowest environmental footprint possible.
4. Intercropping cereals with forage legumes generally had a trade-off with grain yield, with some resources devoted to growing the legume. If the extra dry matter produced by the legume can be used to balance the mineral intake of grazing animals, as well as provide nitrogen to the system, then some of this trade-off can be compensated. In this regard annual legume species such as subterranean clover or serradella may offer a viable alternative to lucerne, as both these species had substantially higher Na concentrations compared to other species tested. Their growth habit also reduced the competition for resources over summer.

Benefits to industry

This project established the suitability of perennial wheat forage for sheep, which was observed to be quite similar in quality and mineral profile to conventional grazing wheat. The inclusion of a legume increased dietary intake, enhanced the concentration of health-claimable compounds in the meat of grazing lambs and reduced the need for mineral supplementation compared to a pure cereal diet, but grain yields were generally reduced. Lucerne was suggested to be a poor choice of companion due to its low forage sodium (Na) concentrations and perennial growth habit. Selfregenerating annual legumes such as subterranean clover or serradella, both of which have higher forage Na concentrations than lucerne, may be better companions with perennial wheat, although this needs to be validated over a longer timeframe.

MLA action

Immediate adoption of this research is inhibited by the fact that perennial crops are not available to farmers in Australia.

Perennial grains remain an emerging technology globally and as such, there are many aspects that require further research. Further breeding of more suitable varieties will require long tern development and then evaluation. At this stage MLA has taken no further action to continue investment in this research.

Future research

The highest priority is, arguably, to improve the longevity of perennial crop genotypes through breeding and selection. The existing hybrid perennial wheat breeding material does not persist reliably beyond the second year.

The domesticated breeding lines of Kernza and mountain rye are longer-lived than the hybrid material, and probably represent the best near-term prospect for a viable perennial crop in Australia. Further breeding and selection of this species would likely target increased yields and longevity by addressing floret infertility and selecting for earlier-maturing genotypes.