The main plant species relied on for forage supply to grazing animals in New Zealand and south-eastern Australia is perennial ryegrass (Lolium perenne L.). Perennial ryegrass has evolved with a fungal endophyte (Neotyphodium lolii, Latch, Christensen & Samuals) that occupies intercellular spaces, and is nourished by its host. The endophyte (referred to as standard or wild-type) provides the plant with protection from a range of insect pests by producing alkaloids, some of which are also toxic to grazing animals, causing ryegrass staggers and/or exacerbating heat stress. Over the last 20 years naturally occurring perennial ryegrass endophytes have been found in Europe that produce less of the alkaloids that cause animal health problems but have similar or enhanced effects as the standard endophyte on deterring insect attack on infected plants, when introduced into New Zealand and Australian-bred ryegrasses. This review provides a summary of endophyte research in New Zealand from the perspective of insect pests, plants (particularly perennial ryegrass) and the animals grazed on ryegrass-dominant pastures. The protocols used to evaluate perennial ryegrass/endophyte associations over the past 30 years are also discussed. Future testing of new grass/endophyte associations should include the utilisation of more environments for agronomic and entomological experiments; routinely carrying out small animal toxicology assays, and the running of short-term indoor feeding experiments with sheep and cows. Implementation of these changes provides the minimum requirements for strengthening the evaluation of new endophyte associations so farmers using these technologies, gain optimal benefits from their adoption.

Rice in Thailand, Laos and Cambodia (the Mekong region) is grown mostly as a mono crop once a year in the wet season in the rainfed lowlands. Some lowland areas have access to irrigation water, and rice double cropping is practised while non-rice crops are grown in a limited area in the dry season after harvesting wet season rice. In all cases wet season rice is grown mostly for subsistence under rainfed with low input, and combined with low soil fertility and frequent occurrence of drought, the yield is generally low with a mean of 2.5 t/ha and the yield increase was slow in recent years. More recently demand for labour in the regional centres has caused labour shortages in the rural area and rice crops may not be managed in the traditional manner such as the practice of manually transplanting of rice seedlings. For the last two decades research efforts have been made to minimise the adverse effect of abiotic factors and to meet the changing nature of the socioeconomic environment, resulting in increased understanding of factors determining productivity of rainfed lowland rice and the cropping systems based on it. This review describes such achievements in five sections – water environment characterisation to quantify drought problems, soil environment and fertiliser management, direct seeding to develop technology to cope with the labour shortage, variety improvement for rainfed lowland rice in drought-prone environment, and crop intensification and diversification that shift practices from traditional subsistence agriculture to more market-oriented agriculture. Each section is concluded with issues for future research need. The last section of the paper describes future research challenges for the rainfed rice-based lowland cropping systems in the Mekong region and possible implication on rainfed lowland rice system on other regions.

Projected increases in atmospheric carbon dioxide concentration ([CO₂]) and air temperature associated with future climate change are expected to affect crop development, crop yield, and, consequently, global food supplies. They are also likely to change agricultural production practices, especially those related to agricultural water management and sowing date. The magnitude of these changes and their implications to local production systems are mostly unknown. The objectives of this study were to: (i) simulate the effect of projected climate change on spring wheat (Triticum aestivum L. cv. Lang) yield and water use for the subtropical environment of the Darling Downs, Queensland, Australia; and (ii) investigate the impact of changing sowing date, as an adaptation strategy to future climate change scenarios, on wheat yield and water use. The multi-model climate projections from the IPCC Coupled Model Intercomparison Project (CMIP3) for the period 2030–2070 were used in this study. Climate scenarios included combinations of four changes in air temperature (0°C, 1°C, 2°C, and 3°C), three [CO₂] levels (380 ppm, 500 ppm, and 600 ppm), and three changes in rainfall (–30%, 0%, and 20%), which were superimposed on observed station data. Crop management scenarios included a combination of six sowing dates (1 May, 10 May, 20 May, 1 June, 10 June, and 20 June) and three irrigation regimes (no irrigation (NI), deficit irrigation (DI), and full irrigation (FI)). Simulations were performed with the model DSSAT 4.5, using 50 years of daily weather data. We found that: (1) grain yield and water-use efficiency (yield/evapotranspiration) increased linearly with [CO₂]; (2) increases in [CO₂] had minimal impact on evapotranspiration; (3) yield increased with increasing temperature for the irrigated scenarios (DI and FI), but decreased for the NI scenario; (4) yield increased with earlier sowing dates; and (5) changes in rainfall had a small impact on yield for DI and FI, but a high impact for the NI scenario.

Fast development of seedling leaf area is a relevant trait in order to increase early resource acquisition. The use of semi-dwarf genotypes of wheat has decreased early vigour of modern cultivars. We studied early vigour of 20 cultivars cropped in Argentina, and our main objectives were: (i) to analyse the genotypic variability in early vigour; (ii) to study morphological traits that can be good indicators of early vigour, such as seed mass, leaf width, and specific leaf area; and (iii) to determine whether increased dry mass allocation to roots impacts negatively on early vigour. Experiments with non-size-selected and size-selected seeds were carried out in a greenhouse. A field trial was also conducted in order to test the reliability of the greenhouse results. Seeds mass was the main parameter related to early vigour. However, results from the experiment with seeds selected by size (45–50 mg seed^–1) showed that seed mass per se only partially explains early vigour, since a significant coefficient of determination was observed between the seedling leaf area of each cultivar in both experiments (i.e. with randomly chosen or size-selected seeds).

We observed a high coefficient of determination between net assimilation rate and changes in the ranking of early vigour of the cultivars with time after transplant. Root biomass was positively correlated with leaf area, indicating that the traits were not mutually exclusive. We built simple models by multiple regression to predict early vigour, including some parameters that were easy to measure. Seed mass and leaf width taken together showed better fit than seed mass or leaf width alone. We found a significant coefficient of determination between early vigour in greenhouse and field experiments; thus, screening for early vigour under semi-controlled conditions may be feasible.

Barley (Hordeum vulgare L.) is a major crop in Australia and powdery mildew (Blumeria graminis f. sp. hordei) is one of its most common diseases. Genes for resistance to powdery mildew were postulated for 86 Australian barley varieties and nine advanced breeding lines using 40 reference isolates of the pathogen. Fifty isolates collected in Australia in 2011 were used for additional tests of some varieties. In total, 22 known resistance genes [mlo, Mla1, MlaAl2, Mla3, Mla6, Mla7, Mla8, Mla9, Mla12, Mla13, Mlat, Mlg, MlGa, Mlk1, MlLa, Mlra, Ml(Ab), Ml(Ch), Ml(Dr2), Ml(He2), Ml(Lo) and Ml(St)] were detected. The most frequent genes were Mla8 and Mlg present in 43 and 34 varieties, respectively, while MlGa was found in 12 varieties. Each of the specific resistance genes Mla1, Mla3, Mla6, Mla9, Mla13, Ml(St) and the non-specific recessive gene mlo was found in one variety only. The varieties Maritime and Stirling appear to carry no specific resistance genes. Fifteen unknown resistances were detected. It is recommended that Australian barley breeding programs exploit European varieties possessing mlo to improve the resistance to powdery mildew in new varieties.

European winter canola (Brassica napus L.) cultivars harbour genes for durable resistance to the fungus Leptosphaeria maculans, which causes blackleg disease under Australian environmental conditions. Previous studies have shown that resistance in winter-type cultivars Maxol and Columbus is controlled by two genes, Rlm1 and Rlm3, which have been mapped using randomly amplified polymorphic DNA markers onto chromosome A7. We mapped a doubled-haploid population that consisted of 101 lines from a cross between Maxol*1 and Westar-10 using diversity arrays technology and simple sequence repeat (SSR)-based markers. Two SSR marker loci, Xol12-e03 and Xra2-a05b, flanked the Rlm1 locus at an interval of 6.7 cM, which corresponds to ∼3.2 Mb of the Brassica rapa genomic sequence; this region contains several genes encoding putative kinase and leucine-rich repeat-type disease-resistance proteins. SSR markers were further tested for their linkage with the Rlm1 locus in an independent population derived from Columbus*3/Westar-10. Our results showed that SSR markers linked to Rlm1 can be useful for monitoring Rlm1 gene introgression in breeding populations derived from Maxol and Columbus.

Seed dispersal is both a spatial and a temporal phenomenon, although most studies focus on spatial aspects. Seed initiation on the maternal plant may occur over a considerable period, especially in indeterminately flowering species, and thus seeds may be exposed to a wide range of environmental conditions during their development. The result is variation in the timing of seed development, the anatomy of structures related to the dispersal process, and the behaviour and fate of seeds post-dispersal. A key resource during the growth and development of summer-maturing species in most areas, and one that is thus likely to modify these processes, is water. Two experiments were therefore undertaken to describe (i) the development of Raphanus raphanistrum fruits and the timing of fruit dispersal, and (ii) the effects of water availability on the timing of fruit dispersal. Fewer seeds were produced and subsequently dispersed by later emerging plants. The duration of fruit dispersal became shorter when the plants emerged progressively later than the crop, and the time of maximum dispersal was later. For cohorts of fruits initiated at the same time, those that developed under mild and severe water deficit reached their final length sooner, and were dispersed sooner, than those receiving a plentiful supply of water. Thus, the phenology of the maternal plant and the nature of its environment can modify the timing of propagule maturity and consequently dispersal. Such information may provide an opportunity for managers to reduce weed seed return to their field or, conversely, to regulate the amount of contaminated grain or reduce dispersal to other locations.

Yellow bristle grass (Setaria pumila) and summer grass (Digitaria sanguinalis) are summer-active annual grass weeds which infest temperate dairy pastures. A study was undertaken over 2 years to compare hand-sown yellow bristle and summer grass establishment, survival, and seed production in pastures grazed by dairy cows and based on (i) tetraploid perennial ryegrass (Lolium perenne), (ii) tetraploid perennial ryegrass and white clover (Trifolium repens), and (iii) tall fescue (Festuca arundinacea) and white clover, to determine which pasture type offered the greatest resistance to these grass weeds. Ingress of grass weeds was similar in all three pasture types. Total dry matter production was similar for all pasture types for the first year and lower in tall fescue   clover than perennial ryegrass pasture in the second year. All pasture types had a similar distribution of microsite types (bare ground ± canopy, basal cover ± canopy) in both years. The annual grass weeds were most prevalent in bare ground   canopy microsites, which were also the most frequent of the four microsite types. In the first year, <5% of microsites were occupied within 2 months of sowing, whereas in the second year, microsite occupation remained >13% for all assessments. In the first year, panicle production of yellow bristle and summer grass was similar (averaging 4.1 panicles plant^–1); in the second year, panicle production was greater for summer grass (0.80 v. 0.16 panicles plant^–1, respectively). Where present, these annual grass weeds are likely to spread in dryland dairy pastures sown with either perennial ryegrass or tall fescue. Variability in their panicle production between years shows how their impact on pasture performance and consequent need for control measures will also vary from year to year.

The perennial legume Bituminaria bituminosa (L.) C.H. Stirt. var. albomarginata (tedera) has been identified as a promising fodder plant for the southern Australian wheatbelt, but little is known about its drought resistance as a seedling. This study was conducted to (i) examine physiological and morphological responses to water stress of seedlings of tedera, in comparison with lucerne (Medicago sativa L.), biserrula (Biserrula pelecinus L.) and Afghan melon (Citrullus lanatus Thunb.), and (ii) investigate drought adaptation mechanisms of tedera seedlings.

Seedlings were grown in a reconstructed field soil profile in pots in a glasshouse. By 25 days after sowing (DAS), plants of all species in the drought-stressed (DS) treatment had experienced water stress, with an average leaf relative water content (RWC) of 66% in DS compared with 79% in well-watered (WW) plants. Tedera, biserrula and Afghan melon maintained a higher RWC than lucerne. At 25 DAS, reductions in shoot dry matter in the DS treatment differed between species: 52% for Afghan melon, 36% for biserrula, 27% for lucerne, and no significant reduction for tedera. Paraheliotropic leaf angles of biserrula, lucerne and tedera were all higher in the DS treatment than in the WW treatment at 25, 32 and 52 DAS.

This study revealed significant differences in rooting depth and stomatal conductance between the three legume species when under water stress, with tedera being the most drought-resistant. Traits that may allow tedera to survive a dry period following opening rains include vigorous seedling growth, early taproot elongation, effective stomatal control and paraheliotropic leaf movements.