Genetic Modification – Applications for Forage and Grassland Production Systems

Genetic modification has been extensively used in crops for 25 years but has rarely been a technology used to advance trait expression in forage and grassland species. The exceptions are the use of herbicide tolerance and low lignin traits in alfalfa which are currently commercially available. In crop species genetic modification has been a valuable option for delivering improved economic and environmental outcomes through providing solutions for many of the challenges facing mankind. There are a many beneficial characteristics that genetic modification has the potential to provide in forage and grassland species. Managing these in the environment and understanding consumer views on their use with ruminants and grazing animals is important for their success. Additionally, forage and grassland species provide some challenges for the use of genetic modification including their outcrossing and perennial nature, and often they are associated with or derived from species that can be categorised as weeds in some environments. However, with documented benefits of genetic modification use in crop plants providing increased crop yields, reduced pesticide and insecticide use, reduced carbon dioxide emissions, improved soil structure, improved crop nutritive quality/value, and decreased costs of production it would be remiss to not further examine the use of genetic modification in forage and pasture species

Progress in White Clover Agronomic Performance Through Breeding

White clover (Trifolium repens L.) domestication began in the 16th century in Europe. However, it was not until the early 1920s that broad • agronomic groups were recognised, and not until the early 1930s that selections for improved agronomic performance were made within major ecotypes. Since then more than ·230 cullivars and commercial ecotypes have been developed. Data from 4 trials, 2 from Czechoslovakia, l from New Zealand and I from South Africa, were used io determine whether breeding since the 1930s had significantly improved in white clover performance. Cultivars were coded by decade in which they were developed and mean cultivar performance by decade calculated. Data from all 4 trials showed that since 1930 white clover agronomic performance has improved by about 4% per decade through breeding; this translates to a 25% increase in performance since breeding efforts began - a significant linear advance

Adaptation of Forage Species to Drought

Variability in rainfall is the single greatest cause of variation in forage production for a given site. Current climate scenarios predict future annual rainfall to decrease at some geographic regions. The intensity of future rainfall is also predicted to increase at other regions, with the expectation of greater variability in soil moisture. The adaptation of forage species to drought is an issue that is likely to remain with us into the future. Precise definitions are critical to water relations work, and imprecise use of terms has complicated comparisons of some studies on plant response to drought. Drought is a purely relative term, being abnormally low rainfall. Its duration and intensity will vary between locations. The intensity of drought is measured as water potential (-MPa) (relatively difficult), or water deficit (mm) (well suited to modeling) or soil water content (g/g, cm3/cm3, %). None of these measurements has a linear effect on plants. Drought resistance is a virtually meaningless term. Plant water reserves are trivial compared to the demand from the environment, and plants are virtually incapable of resisting drought. Forage plants do vary in tolerance to the intensity and duration of water deficit. Definition is further complicated by the scale of reference; at the plant-scale the plant might tolerate a level of water deficit, however tissues such as primordial are protected and do not encounter stress. At the tissue-scale certain cell components might be protected by osmotic adjustment, which allows some water loss by the plant but maintains turgor and some plant function

Effect of Method and Intensity of Selection for Yield in White Clover

The effectiveness of various strategies of selection for yield was tested using high performing white clover (Trifolium repens L.) lines derived from crosses between elite Grasslands Huia genotypes and elite genotypes from introduced germpiasm. There appeared to be no clear advantage of selecting genotypes, at the same intensity of selection, in the top 12.5% of families compared with the top 50% of families, There was a weak trend towards higher yielding progeny with increasing selection intensity. It was more effective to use individual selection within families based on performance rather than family selection, However, this effect was specific to first-year growth and subsequently disappeared, Selection by either method gave better-performing progeny than no selection at all. There was no significant difference between progeny from genotypes selected on first-year performance compared with second- and third-year performances, eJ1cept after cycle 1 when tested under sward conditions. Three cycles of recurrent selection, where selection was of the best genotypes of the best lines in year 1 or years 2 and 3 growth, were compared in grazed grass swards. All had a significantly greater yield than Huia except cycle 1, year 2 and 3 selection

Effects of Grazing Damage on White Clover Stolon Morphology

In two trials the effect of white clover stolon growing point removal due to grazing damage by sheep on stolon growth and morphology was investigated. Damage to the main stolon growing point did not affect stolon branch appearance rate, so that with a reduced node appearance rate on main stolons there was an increased proportion of nodes branching on damaged stolons. Compensatory growth by branch stolons after main stolon growing point removal occurred when measured as stolon elongation rate

The Future of Clovers in Forage Systems and as Cover Crops

Clovers (Trifolium spp.) are the most widely used genera of legumes in forage systems, although only a limited number of the hundreds of perennial and annual species are commercially available. The number of varieties available within each of the main commercial species can be high and demonstrates past breeding achievements. Success relates to any clover’s ability to persist in mixtures with other forage species, across a range of soil types, management systems, and climates, while providing animal nutrition and biologically fixed nitrogen benefits. Uses range from traditional pasture mixtures with grasses to inclusion in multi-species mixtures, and as cover crop mixes as part of annual cropping systems. Both conventional breeding and genetic modification will lead to better adapted and performing varieties as well as new traits that provide additional benefits for improved animal nutrition and environmental outcomes. The use of genotyping by sequencing (GBS) to determine genetic variation and population structure for clover improvement programs shows great promise. Selection for improved seed yields while maintaining good agronomic performance will ensure cost effective seed production of commercial varieties. Seed coating with effective rhizobia is paramount for nitrogen fixation benefits to be realised. Management systems research to increase the use and economics of clover varieties in future pasture, cover crop, and carbon farming sustainability systems is critical but challenging

Response to Drought of White Clover Lines Selected for Different Stolon Morphologies

White clover (Trifolium repens L.) lines were selected from within large and small-leaved cultivars of Grasslands Kopu and Grasslands Tahora, respectively, for long or short internodes, and for high or low branching frequency from plants grown in sun and shade (50% full sunlight). Lines were compared for drought tolerance in a perennial ryegrass (Lolium perenne L.) sward in boxes. Prior to imposing drought branching frequency selections did not differ in branching frequency, although the low branching frequency selection had a higher percentage of rooted nodes. After an imposed drought treatment sun-selected lines grew better than shade-selected lines relative to their non-stressed controls suggesting that white clover selected under full-sun may be more drought-tolerant than lines selected in shade. Selections for different stolon morphologies did not differ in stolon and root growth at the end of the drought

Physiological response of White Clover Genotypes to Water Deficit

Three plants from each of 2 white clover (Trifolium repens L.) cultivars, Grasslands Kopu and a breeding line selected from germplasm of Syrian origin, were grown in large pots of soil and physiological characteristics measured during a continuous drying phase of 18-37 days. By the end of the experiment, leaf water potential was -2.5 MPa, gravimetric soil water content was 13% (considerably lower than -1.5 MPa), and leaf relative water content was 60%. A 91- fold increase in leaf praline concentration indicated that water stress had altered plant metabolism. Differences in the rate of soil drying occurred between eultivars, but expression of physiological measurements against soil water content showed the differences between cultivars were relatively small. Variation in node appearance rate and stolon extension rate, within cultivars was high. In general, the response functions between cultivars were more similar than the response functions of individual plants (genotypes) within a cultivar

Effect of Management and Cultivar on Nodal Root Development of White Clover

Nodal root development of white clover (Trifolium repens L.) swards was monitored by harvesting marked nodes from late autumn to spring and by taking tiller plugs over 15 months. At a hill country site Grasslands Huia and a large-leaved French eultivar, Crau, had greater nodal root development, in terms of root length, than a small­leaved hill country ecotype. Compadson of the effects of rotational sheep and cattle grazing at both lowland and hill country sites showed greater nodal root development root length and lateral root production under cattle grazing. Percentage of nodes with roots was greater under rotational than set-stocked grazing in winter and early spring but differences were not apparent in late spring, summer or autumn. In late spring percentage of nodes with roots was greater under set­stocked than rotational sheep grazing, Numbers of nodal roots per m2 were 75-140% greater under rotational grazing than set-stocked grazing in autumn and winter but similar in summer and spring. Reduced nodal development during winter under set-stocked sheep grazing was associated with reduced carbon export to young nodal roots developed on shaded stolons (simulating stolon burial) which were severely defoliated. Under more lenient defoliation which occurs under rotational grazing, carbon export to young nodal roots is greater on shaded compared with unshaded stolons

Intellectual Property Protection – Stimulating or Constraining Innovation and Technology Transfer?

Grassland farming is becoming more technically advanced leading to improvements in productivity, environmental outcomes and animal welfare. As a result, farmers have an increasing range of new innovations being made available to them. The question examined here is whether widespread uptake of new innovations by farmers is more effective when driven by marketing through dedicated paths to market where the intellectual property (IP) is controlled or through multiple paths to market where there is no IP control? The role of IP in stimulating the development, manufacture and sale of new technologies is hotly debated. For plant breeders and patent owners, strong IP protection offers an effective form of security; and more importantly brings returns on investment through licences and commercialisation arrangements. When launching new products IP protection not only provides legal security but is confirmation that the product is unique, distinctive and of value. Some view IP rights as a way to foster innovation and invention by encouraging individuals to develop/invent new ideas from which they can potentially gain a return. Without the ability to capitalise on their work innovators have little incentive, other than an altruistic motive, to produce any invention. However, there is an opposing view that patents and plant variety rights are “killing freedom to operate and crushing science with rules”, and in so doing are stifling innovation rather than encouraging it. Some believe that IP rights holders abuse the system to unfairly extend their monopoly on a technology and prevent others from using it to the benefit of the industry and the economy as a whole. We propose to examine the value and motivations for IP protection, and examine the different forms of IP protection available. Case studies will be used to show how IP protection may be a benefit or disadvantage to grassland farmers