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Dr Clive Francis is amongst a small group of scientists whose efforts have changed the face of Australian agriculture. This special issue of Crop & Pasture Science highlights his broadranging impact delivered through the pasture cultivars he bred, the knowledge that he generated and the influence that he had on peers and policy makers. His cultivars of subterranean clover are still grown on many millions of hectares across southern Australia and his efforts were pivotal in generating momentum for creative research on a wide array of crop and pasture legumes, particularly the collection, evaluation and preservation of genetic resources for use in current and future breeding initiatives.
This paper is a tribute to the legacy of Dr Clive Francis, who directly and indirectly collected >14 000 accessions across 60 genera of pasture, forage, and crop species and their wild relatives around the Mediterranean basin, Eastern Africa, and Central and South Asia from 1973 to 2005. This was achieved by a collaborative approach that built strong interactions between disparate organisations (ICARDA, VIR, CLIMA, and Australian genebanks) based on germplasm exchange, conservation and documentation, capacity building, and joint collection. These activities greatly strengthened Australian pasture, forage, and crop genebanks, and led to widespread germplasm utilisation that has waned in the last 5 years, reflecting changing priorities among industry funding bodies and research providers. This situation must be reversed, given the pivotal role genetic resource collections must play to broaden the genetic and adaptive base of plant breeding, to meet the challenge of feeding an increasing population in a depleting resource base.
Because the use of germplasm subsets that facilitate phenotyping will stimulate wider utilisation of genetic resources, we discuss the application of core collection and germplasm selection through habitat characterisation/filtering in Australian collections. Both are valid entry points into large collections, but the latter has the advantage of enabling both trait discovery and investigation of plant adaptation, and because it is based on a priori hypothesis testing, it increases understanding even when the trait of interest is not identified.
Subterranean clover (Trifolium subterraneum L.) is the most widely sown annual pasture legume species in southern Australia, valued in the livestock and grains industries as a source of high-quality forage and for its ability to fix atmospheric nitrogen. From its initial accidental introduction into Australia in the 19th Century and subsequent commercialisation in the early 1900s, 45 cultivars have been registered in Australia. These consist of 32 cultivars of ssp. subterraneum, eight of ssp. yanninicum, and five of ssp. brachycalycinum and range in flowering time from 77 to 163 days from sowing, enabling the species to be grown in a diversity of rainfall environments, soil types, and farming systems. Eleven of these cultivars are introductions from the Mediterranean region, 15 are naturalised strains collected in Australia, 18 are the products of crossbreeding, and one is derived from mutagenesis. Cultivars developed in Italy have been commercialised for the local market, whereas other cultivars developed in Spain, Portugal, and France have not had commercial seed production. Important traits exploited include: (i) selection for low levels of the oestrogenic isoflavone formononetin, which causes reduced ewe fertility; (ii) increased levels of dormancy imposed by seed-coat impermeability (hard seeds) for cultivars aimed at crop rotations or unreliable rainfall environments; (iii) strong burr-burial ability to maximise seed production; (iv) resistance to important disease pathogens for cultivars aimed at medium- and high-rainfall environments, particularly to Kabatiella caulivora and root rot pathogens; (v) resistance to pests, particularly redlegged earth mites; and (vi) selection for unique leaf markings and other morphological traits (where possible) to aid cultivar identification. Cultivar development has been aided by a large genetic resource of ∼10 000 accessions, assembled from its centre of origin in the Mediterranean Basin, West Asia, and the Atlantic coast of Western Europe, in addition to naturalised strains collected in Australia. The development of a core collection of 97 accessions, representing almost 80% of the genetic diversity of the species, and a genetic map, provides a platform for development of future cultivars with new traits to benefit the livestock and grains industries. New traits being examined include increased phosphorous-use efficiency and reduced methane emissions from grazing ruminant livestock. Economic analyses indicate that future trait development should focus on traits contributing to increased persistence and autumn–winter productivity, while other potential traits include increased nutritive value (particularly of senesced material), increased N2 fixation ability, and tolerance to cheap herbicides. Beneficial compounds for animal and human health may also be present within the species for exploitation.
The cool-season grain legume industry in Australia, comprising field pea (Pisum sativum L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), lentil (Lens culinaris ssp. culinaris Medik.), and narrow-leaf lupin (Lupinus angustifolius L.), has emerged in the last 40 years to occupy a significant place in cropping systems. The development of all major grain legume crops—including field pea, which has been grown for over 100 years—has been possible through large amounts of genetic resources acquired and utilised in breeding. Initially, several varieties were released directly from these imports, but the past 25 years of grain legume breeding has recombined traits for adaptation and yield for various growing regions. Many fungal disease threats have been addressed through resistant germplasm, with varying successes. Some threats, e.g. black spot in field pea caused by Mycosphaerella pinodes (Berk. and Blox.) Vestergr., require continued exploration of germplasm and new technology. The arrival of ascochyta blight in chickpea in Australia threatened to destroy the chickpea industry of southern Australia, but thanks to resistant germplasm, it is now on its way to recovery. Many abiotic stresses including drought, heat, salinity, and soil nutritional toxicities continue to challenge the expansion of the grain legume area, but recent research shows that genetic variation in the germplasm may offer new solutions. Just as the availability of genetic resources has been key to successfully addressing many challenges in the past two decades, so it will assist in the future, including adapting to climate change. The acquisition of grain legume germplasm from overseas is a direct result of several Australians who fostered collaborations leading to new collection missions enriching the germplasm base for posterity.
The narrow-leafed lupin (Lupinus angustifolius L.) is a legume with much to offer to agriculture and human wellbeing through its adaptation to nitrogen- and phosphorus-deficient, acid, sandy soils, and production of nutritious, very low glycemic index grain with manifold health benefits. However, the industry has exploited only a small fraction of the genetic and adaptive diversity of the species, reflecting a short and fragmented domestication history. Given declining global production, unlocking the potential residing in untapped sources of genetic diversity to maximise yield and value is critical for the future of the crop.
To this end, a wide range of genetic resources is under evaluation. The Australian Lupin Collection comprises almost 4600 diverse, mostly wild accessions, many of which have been genotyped using DArT (Diversity Array Technology) markers, and collection sites characterised to facilitate ecophysiology of contrasting material. Additional exotic genetic resources include recombinant inbred line and mutant populations, as well as inter-specific crosses. These resources are being used to investigate specific adaptation and genetic and molecular control of key traits, all of which will be expedited by current efforts to provide a reference genome sequence for L. angustifolius. Genetic base broadening is the current breeding focus, combining distantly related wild and domestic material with elite cultivars in double-backcrosses or topcrosses, with dramatic effects on yield. In future this will be complemented by marker-based, targeted trait introgression to improve narrow-leafed lupin adaptation, quality/value, and fit into the farming system.
Trifolium tumens (Talish clover) is a perennial legume species not previously domesticated for use in world agriculture. It is native to areas of the eastern Mediterranean, Caucasus and mountainous areas of the Middle East with a warm temperate or cool Mediterranean environment. The species has been identified by pasture researchers in Australia as a having sufficient drought and grazing tolerance to fill a gap created by the lack of a well adapted perennial legume for dryland pasture systems across low rainfall (450 to 750 mm annual average rainfall), temperate regions of Australia. The need to expand available genetic diversity of this species resulted in a germplasm collecting mission to Azerbaijan in 2004. The successful mission collected seed from 35 populations of T. tumens across 7 agro ecological zones, including 5 climatic zones. This collection increased the number of accessions held in ex situ local and international collections from 21 to 56. The range of adaptation and frequency of the collection of T. tumens was far greater than expected with accessions found at altitudes ranging from 12 to 1700 m above sea level, in soils with pH (1:5 H20) ranging between 5.0 and 9.0 and rainfall varying from 300 to 1300 mm. T. tumens was found growing alongside a diverse range of companion species in heavily grazed lowland pastures up to lightly grazed alpine meadows. This material has been characterised by the Tasmanian Institute of Agriculture (TIA), with promising accessions contributing to a breeding program to develop a commercial cultivar adapted to temperate environments (<750 mm rainfall).
The oilseed camelina (Camelina sativa (L.) Crantz) was grown extensively in Northern Europe up to the 1950s. Increasing fuel prices coupled with a ‘diet-conscious’ society have revived interest in camelina for food and biofuel uses. This study assessed the agronomic potential of the crop under Mediterranean dryland conditions and the scope for selection in a diverse collection for food and biofuel use. Yield trials were conducted in the Western Australian wheatbelt between 1999 and 2008. In 14 environments, camelina gave an average yield of 1.04 t ha–1 compared with the canola (Brassica napus L.) control yield of 1.48 t ha–1. Camelina outyielded canola significantly at one site, whereas canola significantly outyielded camelina at five sites. Thirty accessions of camelina from five countries were compared in the field in 2011. Agronomic characteristics were recorded and fatty acid analyses performed; significant differences were observed. Accessions were identified with desirable biofuel qualities, and others selected as having fatty acid characteristics suitable for food use. Averaged over accessions, erucic acid content was high at 4.0%, ranging from 5.2% to a low of 2.5% in accession 4130. However, this line was tested in the agronomic trials and its fatty acid profiles varied greatly across environments. For stockfeed use, the protein content of the seed was found to be in range 23.2–29.1%.
We hypothesised (i) that sheep grazing a monoculture of tedera (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata and var. crassiuscula) would not show signs of photosensitisation or ill health, and (ii) that when given free grazing choice they would show a repeatable preference for certain accessions of tedera related to their chemical composition. We tested this by grazing a group of young merino wethers on a monoculture containing seven accessions of tedera for 21 days. General health was assessed via daily visual checks for skin pinkness on the nose and ears, weekly measures of liveweight, condition score, and blood analysis compared with a group of control sheep fed wheaten hay ad libitum. The Chesson–Manly selection index was used to examine the relative preference of sheep for the seven accessions of tedera over the 21 days. Each accession of tedera was sampled weekly to estimate the dry matter on offer, and these samples were also analysed for crude protein, neutral detergent fibre, acid detergent fibre, in vitro digestibility, water soluble carbohydrates, minerals, and concentrations of the furanocoumarins psoralen and angelicin. None of the sheep showed any signs of ill health, with all blood parameters being within the normal reference range. All sheep gained weight and body condition over the 21 days. The difference in the rate of gain in condition score in favour of the sheep grazing tedera over the 21 days (0.014 v. 0.002 unit/sheep.day) was significant (P < 0.001). Sheep showed repeated preference for accessions T31 and T43 (α >0.143). Nutritive value of all accessions of tedera was high. However, only acid detergent fibre and neutral detergent fibre affected the relative preference of the sheep (P < 0.05) and they were only weakly correlated (r2 = 0.208 and 0.165, respectively). We conclude that there are accessions of tedera that are preferred by sheep that could be used to fill the autumn feed gap experienced in the south of Western Australia without any risk to the health of the sheep.
Biserrula (Biserrula pelecinus L.) is an important annual pasture legume for the wheatbelt of southern Australia and has been found to have lower levels of methane output than other pasture legumes when fermented by rumen microbes. Thirty accessions of the biserrula core germplasm collection were grown in the glasshouse to examine intra-specific variability in in vitro rumen fermentation, including methane output. One biserrula cultivar (Casbah) was also grown at two field locations to confirm that low methanogenic potential was present in field-grown samples. All of the biserrula accessions had significantly reduced methane [range 0.5–8.4 mL/g dry matter (DM)] output compared with subterranean clover (28.4 mL/g DM) and red clover (36.1 mL/g DM). There was also significant variation in fermentability profiles (except for volatile fatty acids) among accessions of the core collection. Methanogenic potential exhibited 86% broad-sense heritability within the biserrula core collection. The anti-methanogenic and gas-suppressing effect of biserrula was also confirmed in samples grown in the field. In conclusion, biserrula showed variability in in vitro fermentation traits including reduced methane production compared with controls. This bioactivity of biserrula also persists in the field, indicating scope for further selection of biserrula as an elite methane-mitigating pasture.
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