Methane is a potent greenhouse gas with a global warming potential ∼28 times that of carbon dioxide. Consequently, sources and sinks that influence the concentration of methane in the atmosphere are of great interest. In Australia, agriculture is the primary source of anthropogenic methane emissions (60.4% of national emissions, or 3 260 kt^–1 methane year^–1, between 1990 and 2011), and cropping and grazing soils represent Australia’s largest potential terrestrial methane sink. As of 2011, the expansion of agricultural soils, which are ∼70% less efficient at consuming methane than undisturbed soils, to 59% of Australia’s land mass (456 Mha) and increasing livestock densities in northern Australia suggest negative implications for national methane flux. Plant biomass burning does not appear to have long-term negative effects on methane flux unless soils are converted for agricultural purposes. Rice cultivation contributes marginally to national methane emissions and this fluctuates depending on water availability. Significant available research into biological, geochemical and agronomic factors has been pertinent for developing effective methane mitigation strategies. We discuss methane-flux feedback mechanisms in relation to climate change drivers such as temperature, atmospheric carbon dioxide and methane concentrations, precipitation and extreme weather events. Future research should focus on quantifying the role of Australian cropping and grazing soils as methane sinks in the national methane budget, linking biodiversity and activity of methane-cycling microbes to environmental factors, and quantifying how a combination of climate change drivers will affect total methane flux in these systems.

Changes in soil fertility following long periods of crop production in the south-west of Western Australia (WA) may have implications for phosphorus (P) fertiliser recommendations for wheat production. When the sandy soils of the region were first cleared for agricultural production, they were typically marginally acidic to neutral, with soil extractable-P levels inadequate for crop production. Recent surveys have shown that 87% of soils in south-west WA exceed the critical soil extractable-P level required for 90% of maximum grain yield, and ∼70% of soils have a surface-soil pH_Ca <5.5. There has also been a shift towards a high frequency of wheat in the crop sequence. We conducted a field experiment to begin to quantify the importance of the interactions between soil pH and crop sequence on wheat response to P fertiliser. For grain yield, the magnitude of the response was greatest for rate of P applied, followed by lime treatment and then crop sequence. There were no interactions between these treatments. Our analysis of the grain-yield response to rates of P fertiliser showed no significant difference between the shape of the grain-yield response curve for treatments with and without lime. However, we did find a significant interaction between lime treatment and rate of P fertiliser applied for shoot P concentration and that soil P was more plant-available in the lime than the –lime treatment. There is justification for making realistic adjustments to yield potential based on soil pH or crop sequence, although further work is required to determine whether the shape of the grain-yield response curve varies with these two factors.

Wheat alien chromosome addition lines possess abundant genetic resources and they are usually used for transferring desired genes or traits into wheat. The screening and characterisation of addition lines for target traits is one of the prerequisites for efficient utilisation of the alien chromosomes. In order to understand the properties and potential utilisation of wheat addition lines, the effects of additional chromosomes on agronomic and photosynthetic traits of common wheat were evaluated using 34 addition lines with the same genetic background of Chinese Spring. The results showed that most of the alien chromosomes decreased plant height (61.8%) and grain number per spike (47.1%), whereas some increased spike length and tiller number. Alien chromosomes of Agropyron intermedium G, Elymus trachycaulus T5HL5HL, El. trachycaulus 5SS and Haynaldia villosa 1V performed well in improving yield components. None of the alien chromosomes studied had negative effects on photosynthetic traits. Higher net photosynthetic rates were observed in Aegilops umbellulata 5U, El. trachycaulus 5H and rye 1R addition lines. Regarding seedling traits, 21 lines (61.8%) showed improvement in different root traits, whereas 26.5% of the chromosomes decreased coleoptile length. Addition lines with better performance for some specific traits were identified and discussed.

Genetic variation for improving water-stress tolerance has been lost during selection and modern breeding in wheat. Thus, finding genetic sources for drought tolerance is more likely in landraces and wild species than in modern varieties. The objectives of this study were to determine variations for water-stress-induced apical sterility and some related characters among Iranian landraces and wild species, and to analyse the contribution of apical sterility and related characters to grain production of the genotypes. The results showed considerable variation among wheat genotypes for water-stress-induced apical sterility and its related characters. Variations were also observed between ploidy levels for some of these characters. However, the amount of variation observed among the genotypes was not the same for all characters and in all treatments. Considerable significant pair-wise differences were also observed between genotypes for apical sterility under water-stressed conditions. In addition, regression analysis revealed that grain yield per plant is mainly dependent on ovary weight under well-watered conditions and on anther weight under water-stressed conditions.

This study was undertaken to evaluate the response of teosinte (Zea mexicana L.) and intersubspecific hybrids to heat stress, in particular productivity. Unlike maize (Zea mays L.), teosinte demonstrated thermophilic properties, namely lower heat injury, sustained chlorophyll content under heat stress (36−45°C) and high percentage survival of seedlings (at 55°C). Teosinte also had the ability to produce large plant biomass (27% and 55% higher yield than maize under non-stressed and stress conditions, respectively) and therefore could be exploited as a forage crop. However, teosinte forage had low animal intake (1.48 kg day^–1) because of high pubescence density (10.38 view^–1) and low sweetness (9.90°Brix). There was a high percentage of heterosis in variable intersubspecific crosses and traits, and a high magnitude of over-dominance for many traits, for example 5.93–7.06 for total biomass plant^–1. Hybrids showed additional advantages, including high oil (20% and 4%) and protein (14% and 25%) contents compared with teosinte under non-stressed and stress conditions, respectively. Moreover, inter-subspecific hybrids were also resistant to heat stress, with the capacity for sustaining growth for a longer period (20% and 33% higher than maize under non-stressed and stress conditions, respectively). Genetic distance between parents—calculated from stable agronomic traits—could be used to select parents for high heterosis under both heat stress and non-stressed conditions.

Effects of the arbuscular mycorrhizal (AM) fungus Glomus tortuosum on carbon (C) and nitrogen (N) metabolism of Zea mays L. grown under low-temperature stress was investigated. Maize plants inoculated or not inoculated with AM fungus were grown in a growth chamber at 25°C for 4 weeks and subsequently subjected to two temperature treatments (15°C, low temperature; 25°C, ambient control) for 2 weeks. Low-temperature stress significantly decreased AM colonisation, plant height and biomass. Total N content and activities of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase of AM plants were higher than those of non-AM plants. AM plants had a higher net photosynthetic rate (Pn) than non-AM plants, although low temperature inhibited the Pn. Compared with non-AM plants, AM plants exhibited higher leaf soluble sugars, reducing sugars, root sucrose and fructose contents, and sucrose phosphate synthase and amylase activities at low temperature. Moreover, low-temperature stress increased the C : N ratio in the leaves of maize plants, and AM colonisation decreased the root C : N ratio. These results suggested a difference in the C and N metabolism of maize plants at ambient and low temperature regimes. AM symbiosis modulated C metabolic enzymes, thereby inducing an accumulation of soluble sugars, which may have contributed to an increased tolerance to low temperature, and therefore higher Pn in maize plants.

Considerable uncertainty exists about future climatic predictions but there is little doubt among experts that the future will be warmer. Climate change and the associated elevation in atmospheric CO₂ level and temperatures will provide novel challenges and potential opportunities for cultivated plant species. Plant breeding and domestication can contribute to improvements in both yield and quality of native grasses, legumes and forage shrubs. This review explores the use of functional traits to identify native Australian grasses, legumes and forage shrubs suitable for domestication, to meet the challenges and opportunities under a changing climate in pastoral areas in Australia. The potential of these species in terms of life history, regenerative traits, forage quality and quantity, drought tolerance and invasiveness is examined. The paper focuses on three Australian pastoral regions (high-rainfall temperate south, tropical and subtropical grasslands, low-rainfall semi-arid shrublands), in terms of future climate predictions and potential of selected native species to meet these requirements. Selection for adaptation to new climatic environments is challenging but many native species already possess the traits required to cope with the environment under future climate scenarios.

Physiological breeding for improving drought tolerance in perennial forage legume species has been a complex task because of the low association between single physiological traits and dry matter (DM) production under drought conditions. The combination of physiological traits in selection indices may be a more effective alternative in identifying drought-tolerant genotypes. In this work, some physiological and agronomical traits were evaluated in 100 Lotus tenuis genotypes. Traits were measured in spaced plants under irrigation and rainfed conditions during two growing seasons in Chillán, Chile. Three multi-physiological trait indices were calculated based on multiple linear regression (SI1), Euclidean distance (SI2) and descriptive statistical parameters (SI3). SI1 and SI2 were significantly correlated with DM production under rainfed conditions, with correlation coefficients of 0.61 and –0.52, respectively. On the other hand, all single physiological traits showed broad genetic variability in the L. tenuis population but a low association with DM production under drought conditions. Therefore, the multi-trait indices are a more effective tool to select drought-tolerant genotypes.

This study assessed the flooding tolerance of the tropical grasses Chloris gayana Kunth and Panicum coloratum L. at different times of the year: (i) late winter flooding for 50 days (WF), (ii) early spring flooding (SF) for 20 days, and (iii) long-term flooding covering both periods (WF   SF, 70 days). A growth period under well-watered conditions was allowed after each flooding event to assess recovery of plant species. Plants were harvested after each flooding event and at the end of the recovery period. Panicum coloratum had higher tolerance to WF than C. gayana. Treatment WF did not affect biomass in P. coloratum, whereas it reduced biomass of flooded plants by 38% in C. gayana. Treatment SF did not differentiate the species for tolerance; both registered moderate reduction in their growth (20–30%). Under WF   SF, C. gayana showed additional reduction in its growth over that observed when subjected separately to either WF or SF, whereas P. coloratum did not. Both species displayed remarkably fast recovery from flooding when temperatures rose during early summer, attaining biomass equivalent to that of non-flooded plants 1 month after water subsided. Therefore, although P. coloratum appears slightly more tolerant during flooding than C. gayana, both species are promising for introduction in temperate lowland grasslands.

Replace para 2, p. 491 with:

“TheBFDCInterrogator can be used to re-examine published estimates of the critical P concentrations. For example, Holford and Cullis (1985a) concluded that the critical value (90% Ymax) was 25 ± 4 mg/kg for the Colwell soil P test on a 0-10 cm soil sample. The treatment series within the BFDC Interrogator for the NSW wheatbelt covering a similar area (approximately bounded by the Murray River in the south, and Cootamundra in the north) gave a critical value for Colwell-P of 27 (20ndash;36) mg/kg over 126 experiments with a soil pHCaCl2 <5.6. This was consistent with the value reported by Holford and Cullis (1985a).

In the northernNSWSlopes and Plains, the previously reported critical Colwell value ranged from 30 mg/kg (Holford and Doyle 1992) to 57 mg/kg (Holford and Cullis 1985b). The latter and higher estimate was derived from 49 sites reported by Colwell and Esdaile (1968) and Colwell (1970). Based on all 49 sites, which have been entered in the BFDC National Database, the critical value for Colwell-P estimated by BFDC Interrogator was 25 (18–34) mg/kg, suggesting that the value of 57 mg/kg was misleading.”

Corrigendum: References, p. 495