Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs, is a serious constraint on wheat yields in the Southern Cone region of South America. A 2-year experiment was conducted to evaluate fungicide deposition, disease development and grain yield. Three spray nozzles were evaluated: an air-induction flat fan (AI), a wide-angle flat fan (TT), and an extended-range flat fan (XR). A systemic fungicide containing azoxystrobin and cyproconazole was used in both years. Tan spot severity and the area under non-green leaf area disease progress curve (AUNGLA) were analysed. There were no significant differences in deposition among nozzles, and no significant interactions between nozzles and leaf layers in the first year. In both years, AUNGLAs were similar for the three nozzles types, and the tan spot severity in untreated plots was significantly higher than in fungicide-applied plots. Grain yield was higher in the fungicide-applied plots, and there were no significant differences among nozzles in both years. Droplet size had no effect on the fungicide’s efficacy for tan spot control in Uruguay across three susceptible wheat cultivars. The use of drift-reducing nozzles and a systemic fungicide in these trials led to satisfactory performance for spray deposition, canopy penetration and control of the tan spot disease of wheat in the same way as expected from conventional nozzles.

Effective plant improvement depends on understanding grain yield genotype by environment (G × E) interactions. Studies focusing on more heritable (secondary) traits provide a way for interpreting the nature of these interactions and assist selection by adapting hybrids to specific adaptation patterns. The objective of our study was to explore some specific traits to help describe G × E interactions for yield in grain sorghum. A set of 22 representative hybrids were grown at eight different environments varying mainly in water and nitrogen availability. Studied traits were yield, phenology (time to anthesis and grain-filling duration), numerical yield components (grain number and individual grain weight) and physiological components (biomass at maturity and harvest index).

The G × E interaction to G component variance represented 3.48 for grain yield, 1.03 for grain-filling duration, 0.87 for biomass at maturity, 0.71 for time to anthesis, and less than 0.5 for the rest of the traits. Although the G × E interaction for yield was large, the relative genotypic contribution of most studied traits suggests that G × E interaction is not a major impediment for attaining high selection responses to these traits. Pattern analysis applied to G × E best linear unbiased predictors defined three genotype and three environmental groups. Environments were grouped suggesting different water stress levels during early or pre-flowering stages, whereas genotype groups depicted different yield responses across environmental groups. Phenology differences among genotypes explained a large portion of the G × E interaction throughout its influence on grain weight. Late flowering genotypes performed poorly in terms of grain weight and yield across all environments, showing that these materials are not the best option for our production system. Longer grain filling contributed to grain weight and yield at environments with low stress levels, particularly when combined with intermediate or short maturity. Early materials contributed to grain weight and yield at the highest stressful environments. We provide useful information to sorghum breeders at temperate environments, and described secondary traits that could assist selection at particular environments.

Water deficit is a serious environmental stress during the soybean growth and production season in Australia. Soybean has evolved complex response mechanisms to cope with drought stress through multiple physiological processes. In this study, the roots of a previously identified drought-tolerant soybean genotype, G21210, and a sensitive genotype, Valder, were subjected to comparative proteomic analysis based on 2-dimensional electrophoresis, under mild or severe drought conditions. The analysis showed that the abundance of 179 protein spots significantly changed under stress. In total, 155 unique proteins were identified from these spots, among which 70 protein spots changed only in G2120 and 89 spots only in Valder, with 20 proteins changed in both soybean genotypes. Bioinformatics analysis revealed that these drought-induced changes in proteins were largely enriched in the biological function categories of defence response, protein synthesis, energy metabolism, amino acid metabolism and carbohydrate metabolism. For the drought-tolerant genotype, the differential abundance was decreased for 24 proteins and increased for 46 proteins. For the drought-sensitive genotype, the abundance was reduced for 46 proteins, increased for 40 proteins and changed differently for three proteins in mild and severe drought. The different patterns of change of these proteins in G2120 and Valder might be attributed to the difference in their drought-tolerance capacity. This study, combined with our previously reported proteomics study in soybean leaves, further clarifies the change in proteins under drought stress in different organs and provides a better understanding of the molecular mechanisms under drought stress in soybean production.

In Australia, soybean (Glycine max (L.) Merr.) is planted at a low density in wide rows, and weeds substantially reduce yield because of opportunities for their growth in the wide rows. Field studies were conducted over 2 years at the University of Queensland farm, Gatton, Australia, to assess the effect of row spacing and seeding rate on the competitiveness of soybeans with a model weed, Rhodes grass (Chloris gayana Kunth). The experiment was conducted in a split-split plot design, replicated three times. Main plots comprised two seeding rates (40 and 80 kg ha^–1), subplots two row spacings (25 and 75 cm), and sub-subplots four Rhodes grass infestation periods (weedy from planting to maturity, weedy from 3 weeks after planting (WAP) to maturity, weedy from 6 WAP to maturity, and weed-free from planting to maturity). The results showed that seed rate did not influence Rhodes grass biomass or soybean yield. Soybean yield was greater and Rhodes grass biomass was less in the 25-cm rows than the 75-cm rows. For the 25-cm rows, Rhodes grass biomass in the plots infested beyond 3 WAP was 81–89% less than in the season-long weedy plots, whereas for the wider row crop, this reduction was only 60–75%. For the 25-cm rows, soybean yield in the plots infested with Rhodes grass beyond 3 WAP was 30–36% less than under weed-free condition. However, for the 75-cm rows, this reduction was 56–65%. The results suggest that planting soybean in wider rows caused greater reduction in yield and required an earlier weed management program than planting in narrow rows. The study also suggested that narrowing row spacing was more important than increasing seeding rates for improving weed control and soybean grain yield.

Oil content is a primary trait in soybean and determines the quality of soy food, feed and oil product. Increasing oil content is a major objective of soybean breeding. The aims of the present study were to identify quantitative trait loci (QTLs) and epistatic QTLs associated with oil content in soybean seed by using 129 recombinant inbred lines derived from a cross between cultivar Dongnong 46 (oil content 22.53%) and the semi-wild line L-100 (oil content 17.33%). Phenotypic data were collected from 10 tested environments including Harbin in the years 2012–15, Hulan in 2013–15 and Acheng in 2013–15. A genetic linkage map including 213 simple sequence repeat markers in 18 chromosomes (or linkage groups) was constructed, covering ∼3623.39 cM. Seven QTLs, located on five chromosomes (or linkage groups), were identified to be associated with oil content, explaining 2.24–17.54% of the phenotypic variation in multi-environments. Among these identified QTLs, five (qOIL-2, qOIL-4, qOIL-5, qOIL-6 and qOIL-7) were detected in more than five environments. Seven QTLs had additive and/or additive × environment interaction effects. QTLs with higher additive effects were more stable in multi-environments than those with lower additive effects. Moreover, five epistatic, pairwise QTLs were identified in different environments. The findings with respect to genetic architecture for oil content could be valuable for marker-assisted selection in soybean breeding programs for high oil content.

Growth responses of perennial ryegrass (Lolium perenne L.) diploid cv. Alto and a tetraploid breeding line of Alto infected with wild-type fungal endophyte to three types of stress were studied in a semi-controlled environment. The stresses imposed were: soil-moisture deficit (wilting point vs field capacity), severe defoliation (2.5 vs 6 cm cutting height), and root-feeding invertebrate infestation (nil vs 600 grass grubs (Costelytra zealandica) m^–2). Stress treatments were applied simultaneously in a fully factorial design for 8 weeks followed by a 4-week recovery period. Total plant biomass was reduced to a similar extent for both ploidies by soil-moisture deficit (43% reduction), severe defoliation (31% reduction) and root-feeding invertebrates (13% reduction) at the end of the treatment period. At the end of the recovery period, feeding by grass grubs reduced root biomass by 34% and total plant biomass by 25% in the tetraploid cultivar, but there was no effect in the diploid cultivar. Although compensatory growth occurred during the recovery period, one or more aspects of plant growth (e.g. tillering, biomass) remained lower in previously stressed plants at the end of the recovery period. The lower tiller density and total biomass of the tetraploid, in combination with greater allocation of resources to shoot growth and greater susceptibility to root-feeding invertebrates, may compromise its persistence in the field.

Tedera (Bituminaria bituminosa var. albomarginata) has been proposed as an alternative perennial forage legume to lucerne in the mixed farming zone of Australia. Simulation of growth and production of tedera would be a useful tool for assessing its integration into Australian farming systems and agronomic and management options. This paper describes the development and testing of a model of the growth and development of tedera in Agricultural Production Systems Simulator (APSIM). The existing APSIM-Lucerne was modified to develop APSIM-Tedera. The key physiological parameters for tedera were obtained from the literature or by measuring and comparing the phenology and growth characteristics of tedera and lucerne in glasshouse experiments and partially from field experiments. The model was tested using data from a diverse range of soil and climatic conditions. Using the modelling approach, the production of tedera and lucerne was also assessed with long-term (1951–2015) weather data at Arthur River, Western Australia. Biomass simulations of tedera (n = 26, observed mean = 510 kg dry mass ha^–1) explained 66% of the observed variation in field experiments (root mean square deviation = 212 kg dry mass ha^–1). Long-term simulations of a 4-year pasture phase showed that more total annual biomass (5600 kg ha^–1) would be obtained from lucerne than tedera if the pasture forage was harvested four times a year. Less biomass (400 kg ha^–1) was also simulated for tedera in summer under this management. When the pasture forage was harvested when biomass was more than 2000 kg ha^–1, tedera and lucerne produced similar accumulated biomass in the second (8000 kg ha^–1), third (12 000 kg ha^–1) and fourth (15 000 kg ha^–1) years, but much less in the first 2 years for tedera. The model can be used for assessing tedera production, agronomic and management options in the Mediterranean climate of Australia. The present preliminary study indicates that tedera is not as effective as lucerne for total biomass production, but it may provide useful feed in situations where the summer-autumn feed gap is a major constraint to production. Further research is also necessary to determine the potential role of tedera in areas where lucerne is not well adapted.

Genetic analysis of seed production and the effect of water stress on seed and forage production have not been addressed simultaneously in orchardgrass (Dactylis glomerata L.). Thirty-six genotypes of orchardgrass were clonally propagated and evaluated in the field under two moisture environments (normal and water stress) during 3 years (2013–15). A high degree of variation was observed among genotypes for all of the measured traits. Water stress had a negative effect on seed weight per plant and dry matter biomass per plant, and it reduced genotypic variation for most of the traits. A significant and positive correlation was found between seed weight per plant and dry matter biomass per plant, which suggested that simultaneous selection for both traits is possible in normal as well as water-stress environments. The results also indicated that traits explaining seed and forage production variability were not exactly the same in water-stress and non-stress environments. Therefore, indirect selection based on seed weight and dry matter biomass components under normal and water-stress conditions may result in genotypes with different performances. In both normal and water-stress environments, some genotypes were identified as superior with respect to high seed weight and dry matter biomass per plant. These genotypes can be used for further studies to improve seed weight and dry matter biomass per plant, simultaneously.

Lotus uliginosus (greater lotus, GL) and L. corniculatus (birdsfoot trefoil, BT) are species markedly different in their genetics, morphology and environmental adaptation. We evaluated the hybrids and parental species under differential conditions: in vitro culture, growth chamber and open field environments. The experimental evaluation included biochemical, physiological, developmental and productive parameters. Parental species exhibited significant differences in root growth under different osmotic potentials generated by polyethylene glycol, and hybrids exhibited variability in their response compared with their parents. Plants grown in pots and subjected to drought exhibited differences in biochemical parameters. Proline accumulation and oxidative damage measured by lipid peroxidation were higher in birdsfoot trefoil than any other genotype, and the lowest values were observed in greater lotus. The total phenolic content in shoot ranged from 147 to 279 mg gallic acid equivalents 100 g^–1 dry mater. With regard to antioxidant capacity estimated by 2,2-diphenyl-1-picrylhydrazyl, greater lotus had the highest value and birdsfoot trefoil the lowest, at almost one-third, whereas hybrids had intermediate values. Under stress conditions, water-use efficiency showed significant differences between both parental species. In the field, under either irrigation or drought, the dry matter accumulated by the hybrids was higher than that of the parents. Hybrids express recombination of features, making them an interesting material to continue evaluation.

The biased ratio (1 : 2.7–1 : 19) of long-styled Pin and short-styled Thrum flowers (anisoplethy) in common buckwheat (Fagopyrum esculentum) with low seed set (9.8–33.1%) is documented for the first time in two cultivars (Kora, Panda) and two strains (PA13, PA14). To establish the reasons for low grain yield we studied pollen, embryo sacs, embryos, counted stigmas with compatible pollen and with compatible pollen tubes, and recorded seed set under semi-controlled conditions with open access of pollinators. We also sought to improve seed yield via exogenous application of eight biostimulants at the beginning of flowering.

Pin pollen supply to Thrum stigmas was low, due to the imbalance of flower morphs. This did not affect seed set or male success in either flower morph. The pollen of Pin or Thrum was highly viable (97.9–99.9%) in all studied cultivars and strains, germinating well on compatible stigmas. The female success of both flower types was much lower; 49–59% of the ovules exhibited signs of degeneration (whole flower buds, ovules only) or abortion (mature embryo sacs, proembryos, embryos); the highest share of mature embryo sac abortions resulted from degeneration of synergids or the whole egg apparatus. Three biostimulants (Gibberellic acid, putrescine, Asahi SL) in PA13 and six (1-Naphthaleneacetic acid, Gibberellic acid, TYTANIT, putrescine, 6-Benzylaminopurine, Asahi SL) in PA14 decreased embryo abortions (4–12 fold) and increased seed set (0.4–2.4 times), but seed set was still low and never exceeded 33% (the highest value of the untreated with biostimulants plants). Biostimulant treatments were most effective on PA14 strain increasing seed set in 7 out of 8 treatments. These were Gibberellic acid, putrescine and Asahi SL improving seed set of two among four analysed genotypes.

Plant growth and production are greatly affected by water deficit worldwide and particularly in Tunisia. In this context, a study was conducted to analyse the response of three vetch species (Vicia narbonensis, V. sativa and V. villosa) to four water treatments: 100% (Control), 80%, 60% and 40% of field capacity. Water stress led to important changes of both leaf physiology and anatomy. V. narbonensis kept cells turgor by adjusting the osmotic potential without changes in cell walls elasticity. V. sativa showed the most pronounced reductions of leaf water potential and the lowest osmotic adjustment under water stress although cell walls elasticity has not changed. However, V. villosa kept a higher fraction of apoplastic water over V. sativa that allowed it to maintain cells turgor despite the rigidity of its cell walls. Drought did not affect lamina thickness but increased the palisade parenchyma at the expense of spongy parenchyma. It was characterised by leaf lamina increase and constant thickness of the spongy parenchyma: a strategy to cope with drought. Moreover, stomata were reduced in size but were increased in number in order to avoid water loss.