Monday, 7 February 2022

Intense selection sifts out best varieties


Terms like ‘high performance liquid chromatography, PCR testing and monoclonal anti-body immunoblot assays’ are not normally associated with the breeding of forage grasses and crops.

They refer to a range of scientific, laboratory-based tools that Cropmark Seeds undertakes as part of its plant breeding-related research and development.

Historically, plant breeding was primarily undertaken in the field or in glass houses, but with scientific and technology advances over recent years, the focus has now shifted to the leading-edge lab-based science technology to fast-track development of varieties.

Today, it is not just about the plant breeding itself, but also the endophyte embedded into the plant.

Endophytes are natural fungi which have evolved within the cells of plants over millennia to provide the plant with protection against insect pests. At the same time, these endophytes deter grazing by animals as a survival mechanism through decreasing palatability or creating heat stress and grass staggers.

Plant scientists have the task of removing the existing ‘toxic’ endophyte from the grass and replacing it via inoculation with a more animal-benign one, which has the beneficial traits of insect pest resistance and therefore improved plant persistence.

This is what the terms above actually refer to. The compounds within or produced by the endophyte need to be evaluated before inoculating into the grass and once inoculated the grass needs to be tested to ensure that the endophyte is present and viable within the plant.

Plant breeding is not a short-term exercise. A high-performance forage grass variety is usually the culmination of well over a decade of research and development, millions of dollars investment, and hundreds of thousands of hours of work.

The numbers within the company’s research and development are huge, by any standard.

Each year up to 200,000 individual plants are sown into root trainers to select from; a total of 35,000 plants are selected each winter from that number and sown into single-plant nurseries for further evaluation, and over 100,000 endophyte tests are conducted on varieties.

The selection pressure is huge. From all of this, each year the company will identify the very best 100 or more grass varieties which it will enter into company run trials at locations across New Zealand and Australia to ensure that the grass that farmers buy lifts on-farm productivity.

These trials are all run as fully replicated plot trials on commercial farms and include ‘cut and weigh’ trials as well as grazed trials where they are evaluated for several years. Factors such as seasonal growth performance, dry matter yield production, metabolisable energy, digestibility, grazing preference, disease and insect pest tolerance and persistence are all measured during that time.

And following that, any endophyte-containing grasses then enter into Animal Ethics Committee approved animal safety trials where they are tested for their effect on animal health and performance, before eventually being commercialised if they meet the grade.

Each year, only one or two varieties reach this outcome at the end of this very stringent programme.

Cropmark Seeds has its plant breeding programme based in Canterbury, and exports forage grass seed to the world. It is New Zealand’s sole remaining locally owned forage grass and crop plant breeding and supply company, and also Ravensdown’s commercial partner in forage seeds supply.

Together with Cropmark Seeds, Ravensdown can supply farmers with a full range of forage grass, clovers, brassicas and forage herbs requirements, including forage mixes, delivered to nearest local Ravensdown stores, or direct to farm.

Its experienced agronomy staff will provide expert pasture and crop husbandry advice.

Call the customer centre on 0800 800 123 to get in touch with your local Ravensdown Agronomy representative.