Foundation for Arable Research

Introduction Agriculture in New Zealand (NZ) is facing major disruptions due to the impacts from change drivers, such as climate, environmental regulations, and emerging technologies. Strategies to respond to the risks and opportunities associated with these disruptors are needed to transform and strengthen agriculture to achieve economic and environmental objectives. Focusing on the arable sector is of particular importance as it plays a crucial role to ensure carbon neutrality, profitability, and food security. In this paper, we aim to explore potential pathways and interventions to achieve sustainable and resilient arable agriculture by 2050. Methods Working closely with stakeholders from the arable sector, critical scenarios related to food security, climate change mitigation and alternative protein production were co-designed. A decision support tool (DST) that integrates economic, environmental, and production data at the national scale was used to simulate the scenarios. Results Results suggest great opportunities for the sector to change and grow. Enhancing food security by producing 700 k tonnes of wheat (i.e., an extra 25 k hectares) and introducing this wheat in a Dairy livestock system could reduce carbon equivalent biogenic emissions by a factor of eight while using one-third less water for irrigation than is normally used for dairying. Complementing animal diets with 30% locally grown grains and reducing the herd by 10% achieves NZ emissions targets for 2050. Developing a pea and fava bean protein extraction market, with the implementation of a new extraction facility (processing 15 k tonne of peas/year), increase in productivity, area planted, and value (yields up from 3.5 to 5 t/ha; value rise from $960/t to $1,200/t; and land area increase to 25,000 ha) would result in a significant growth in arable agriculture profitability ($375 million) and emissions reductions. Discussion Beyond these quantitative insights, the study demonstrates the value of participatory modelling as a policy-support mechanism: by aligning scientific outputs with stakeholder knowledge, the DST strengthens evidence-based dialogue on land-use planning, regional diversification, and the transition toward carbon-neutral agriculture.

Bacterial pathogens are major causes of crop diseases, leading to significant production losses. For instance, kiwifruit canker, caused by the phytopathogen Pseudomonas syringae pv. actinidiae (Psa), has posed a global challenge to kiwifruit production. Treatment with copper and antibiotics, whilst initially effective, is leading to the rise of bacterial resistance, requiring new biocontrol approaches. Previously, we isolated a group of closely related Psa phages with biocontrol potential, which represent environmentally sustainable antimicrobials. However, their deployment as antimicrobials requires further insight into their properties and infection strategy. Here, we provide an in‐depth examination of the genome of ΦPsa374‐like phages and show that they use lipopolysaccharides (LPS) as their main receptor. Through proteomics and cryo‐electron microscopy of ΦPsa374, we revealed the structural proteome and that this phage possess a T = 9 capsid triangulation, unusual for myoviruses. Furthermore, we show that ΦPsa374 phage resistance arises in planta through mutations in a glycosyltransferase involved in LPS synthesis. Lastly, through in vitro evolution experiments we showed that phage resistance is overcome by mutations in a tail fibre and structural protein of unknown function in ΦPsa374. This study provides new insight into the properties of ΦPsa374‐like phages that informs their use as antimicrobials against Psa.

Vertical transmission of symbiotic Epichloë endophytes from host grasses into progeny seed is the primary mechanism by which the next generation of plants is colonized. This process is often imperfect, resulting in endophyte-free seedlings which may have poor ecological fitness if the endophyte confers protective benefits to its host. In this study, we investigated the influence of host genetics and environment on the vertical transmission of Epichloë festucae var. lolii strain AR37 in the temperate forage grass Lolium perenne. The efficiency of AR37 transmission into the seed of over 500 plant genotypes from five genetically diverse breeding populations was determined. In Populations I–III, which had undergone previous selection for high seed infection by AR37, mean transmission was 88, 93, and 92%, respectively. However, in Populations IV and V, which had not undergone previous selection, mean transmission was 69 and 70%, respectively. The transmission values, together with single-nucleotide polymorphism data obtained using genotyping-by-sequencing for each host, was used to develop a genomic prediction model for AR37 seed transmission. The predictive ability of the model was estimated at r = 0.54. While host genotype contributed greatly to differences in AR37 seed transmission, undefined environmental variables also contributed significantly to seed transmission across different years and geographic locations. There was evidence for a small host genotype-by-environment effect; however this was less pronounced than genotype or environment alone. Analysis of endophyte infection levels in parent plants within Populations I and IV revealed a loss of endophyte infection over time in Population IV only. This population also had lower average tiller infection frequencies than Population I, suggesting that AR37 failed to colonize all the daughter tillers and therefore seeds. However, we also observed that infection of seed by AR37 may fail during or after initiation of floral development from plants where all tillers remained endophyte-infected over time. While the effects of environment and host genotype on fungal endophyte transmission have been evaluated previously, this is the first study that quantifies the relative impacts of host genetics and environment on endophyte vertical transmission.

Coleophora deauratella (red-clover casebearer moth, RCCB) was first confirmed as present in New Zealand during late 2016. It devastated red-clover seed crops throughout the mid-Canterbury region during the 2016/17 growing season but its distribution and control options were unknown. Therefore, traps containing a male pheromone specific to RCCB were located inside either red-clover seed crops or hay crops at 27 sites throughout the South Island and lower North Island during summer 2017/18. Moth numbers were monitored at 7—14-day intervals between November and February. RCCB was confirmed as present at all 27 sites (from Invercargill to Masterton). Peak flights occurred during December with mean moth catch well correlated in thermal time, with half of adult emergence occurring 285˚C days from 1 July (baseline temperature=12oC). Laboratory-based trials were conducted against live moths to evaluate the effectiveness of various organophosphate and synthetic pyrethroid insecticides. Tau-fluvalinate, lambda cyhalothrin and chlorpyrifos each provided >90% control of moths so chemical control is possible, if required. However, an integrated pest-management control strategy needs to be tested and evaluated.

Rust diseases are serious threats to New Zealand cereal crops. Beside the use of fungicides, resistant varieties are an important option for managing these diseases. Changes in rust pathotypes commonly occur due to mutations in existing populations or exotic incursions. Information on these changes is the basis of gene-based disease management. Rust-infected leaves were collected from cereal crops from 2012 to 2015. The pathotypes of these and some historic samples were determined in glasshouse studies, using specific differential host sets. Eight pathotypes of Puccinia triticina (Pt, causal agent of wheat leaf rust), five of P. striiformis f. sp. tritici (Pst, causal agent of wheat stripe rust) and two of P. hordei (Ph, causal agent of barley leaf rust) were identified. The Pst ‘WA’ pathotype was most frequently found. Wheat varieties ‘Empress’ and ‘Torch’, previously resistant to Pt, were found to be susceptible to leaf rust for the first time. The ‘WA’ pathotype of Pst is likely to have arrived in New Zealand from Australia, and is now widespread. The two Pt pathotypes could have overcome resistance gene Lr24 in ‘Empress’ and ‘Torch’.

Context Bird damage to horticultural crops causes significant economic losses for growers around the globe. However, bird damage is unpredictable and pest-bird movements and abundance patterns are poorly understood. Aims To assess whether habitat management is likely to be an effective approach for controlling two pest-bird species (house sparrow, Passer domesticus, and greenfinch, Carduelis chloris) in New Zealand’s arable landscape. Methods Breeding- and winter-bird and habitat surveys were carried out over a 3-year period (2003–05) on 19 1-km × 1-km squares with arable crops on the Canterbury Plains, New Zealand. Bird abundance and/or distribution were analysed with respect to both temporal and spatial (crop- and boundary-habitat composition) variables. Results Estimated breeding-season densities for house sparrow were higher but more stable than those for greenfinch (which increased by 70% over a 3-year period), and for individual farms were more predictable across years than were winter densities. Boundary habitat was the best predictor of bird densities and distribution in the breeding season; features associated with enhanced seed abundance or access were important in the winter. However, habitat composition alone could not account for temporal and spatial variation in bird densities on farms. Conclusions Either habitat management or the reduction of key seed resources could potentially control pest-bird numbers. However, habitat management is likely to have adverse consequences for other important functions (such as the shelter and biodiversity benefits of shelterbelts), and any form of bird control applied at the farm scale is unlikely to be effective. Implications To make control actions both effective and economically viable, a coordinated program involving multiple farms is likely to be needed. We recommend investigating the effectiveness of an experimental manipulation of key food resources at the landscape scale.

We conducted phylogenetic analyses of the fern family Grammitidaceae using sequences from two cpDNA genes and from morphological characters. Data were obtained for 73 species from most recognized genera in the family. The genera Adenophorus, Ceradenia, Calymmodon, Cochlidium, Enterosora, and Melpomene were each strongly supported as being monophyletic. Other recognized genera that were not supported as monophyletic included Ctenopteris, Grammitis, Lellingeria, Micropolypodium, Prosaptia, and Terpsichore. Several previously unrecognized clades were identified, some of which are characterized by distinctive morphological features. Analyses of the distribution of morphological character states on our inferred phylogeny showed extremely high levels of homoplastic evolution for many different characters. Homoplasy for morphological characters was considerably greater than for molecular characters. Many of the characters that exhibited high levels of convergent or parallel evolution across the phylogeny are features that have been commonly used to circumscribe genera in this group (e.g., leaf blade dissection, various rhizome scale characters, and glandular paraphyses). Conversely, some of the characters that exhibited relatively low levels of homoplasy have either not been regarded as having taxonomic value or have been ignored (e.g., root insertion, rhizome scale sheen). Our data support a New World origin of Grammitidaceae, with Old World taxa generally being more evolutionarily derived. Several clades are either primarily Neotropical or primarily Paleotropical but also have a few members distributed in the opposite hemisphere. Thus, we postulate multiple, independent dispersal and colonization events in several lineages.