Phasic development of wheat is largely determined by the interaction of the VRN1 and PPD1 genes with vernalising temperature and photoperiod. VRN1 and PPD1 are regulatory genes, known to influence freezing tolerance, plant morphology and grain yield as well as phasic development. Forty-seven doubled-haploid lines were characterised for Ppd-B1, Ppd-D1, Vrn-A1, Vrn-B1 and Vrn-D1 to determine the effect of allelic combinations of these genes on timing of anthesis and crop growth rate. The lines were grown in replicated field experiments at two locations in Australia. The VRN1 and PPD1 genes accounted for 75% of the genetic variation for time from sowing to anthesis. Vrn-A1 and Vrn-B1 similarly affected time to anthesis, but only Vrn-B1 affected crop growth rate, with the spring Vrn-B1a allele resulting in faster crop growth rates than the winter Vrn-B1v allele. This suggests that the effect of Vrn-B1 on crop growth rate is not a direct consequence of its effect on development per se, but rather due to its influence on other physiological processes.

The faster growth associated with Vrn-B1a may explain the high grain yield of cultivars with this allele in some environments, as shown in a previous study.

Wheat crop response to sulfur (S) depends on nitrogen (N) level, genotype and environmental conditions, demonstrating strong genotype × environment × nutrients interactions. The agronomic-use efficiency of both nutrients has not been evaluated in a wide range of modern genotypes differing in their cycle length and baking quality. The aim of this study was to analyse the effect of N and S fertilisation on yield components and use efficiency of both nutrients in 24 modern, high-yielding bread wheat genotypes (including long and short crop cycles) grown in contrasting environments in the Humid Pampa of Argentina. Two experiments were conducted under contrasting seasonal conditions on a Mollisol in Azul, Buenos Aires. Significant effects of N (range 15–200 kg N ha^–1) on grain yield were observed in all genotypes. By contrast, responses to S (30–100 kg S ha^–1) were found only at high N level in low soil-fertility environments, differing between long and short cycles. Genotype × fertilisation interaction was significant in the environment with higher soil fertility. Sulfur addition improved N-recovery efficiency (0.15 v. 0.32) and agronomic efficiency of the available N (84 v. 93 g g^–1) in the poor-fertility environment, characterised by their N and S deficiency and moderate level of organic matter. Grain N-recovery efficiency was largely explained by increases in grain number, whereas S recovery was also associated with increases in grain nutrient concentration. We conclude that genotype and environment strongly alter fertiliser-use efficiency, providing valuable information for ranking genotypes and optimising site-specific management of wheat crops in the Humid Pampa of Argentina. Grain S percentage may be useful as a physiological marker for selection of bread wheat genotypes with high apparent S recovery.

Synthetic hexaploid wheat and their advanced derivatives (SYN-DERs) are promising sources for introducing novel genetic diversity to develop climate-resilient cultivars. In a series of field and laboratory experiments, we measured biochemical, physiological and agronomic traits in a diversity panel of SYN-DERs evaluated under well-watered (WW) and water-limited (WL) conditions. Analysis of variance revealed significant differences among genotypes, treatments and their interaction for all agronomic and physiological traits. Grain yield (GY) was reduced by 62.75% under WL, with a reduction of 38.10% in grains per spike (GS) and 19.42% in 1000-grain weight (TGW). In a Pearson’s coefficient correlation, GY was significantly correlated with GS, number of tillers per plant and TGW in both conditions. Path coefficient analysis showed that TGW and GS made the highest contribution to GY in WW and WL conditions, respectively. The traits examined in this experiment explained 59.6% and 63.01% of the variation in GY under WL and WW conditions, respectively; TGW, canopy temperature at spike and superoxide dismutase were major determinants of GY under WL conditions. The major flowering-time determinant gene Ppd-D1 was fixed in the diversity panel, with presence of the photoperiod-insensitive allele (Ppd-D1a) in 99% accessions. Wild-type alleles at Rht-B1 and Rht-D1, and presence of the rye translocation (1B.1R), favoured GY under WL conditions. Continuous variation for the important traits indicated the potential use of genome-wide association studies to identify favourable alleles for drought adaptation in the SYN-DERs. This study showed sufficient genetic variation in the SYN-DERs diversity panel to improve yields during droughts because of better adaptability than bread wheat.

This study aimed to investigate the microorganism profile, fermentation quality and rumen digestibility in vitro of maize-stalk silage at different maturity stages. Maize-stalk samples were harvested at the stages milk-ripe, dough, fully ripe, and fully ripe exposed to air for 3 or 10 days. Silage pH, ammonia-N and chemical composition were measured. Thirteen representative lactic acid bacteria (LAB) strains isolated from the raw materials were categorised into five profile clusters: Leuconostoc citreum (23.1%), Weissella paramesenteroides (15.4%), Lactococcus garvieae (23.1%), Enterococcus faecalis (7.7%), and Lactobacillus paraplantarum (30.8%). The total LAB numbers in silages with raw materials reaped at the stages milk-ripe, dough, fully ripe, and fully ripe exposed to air for 3 or 10 days, respectively, were approximately 8, 6, 10, 3.5 and 10 log CFU g^–1. The dominant LAB types of maize-stalk silage at different stages were all different. The epiphytic pathogens Escherichia coli, aerobic bacteria, filamentous fungi and Saccharomycetes were found in silages of all stages. There were significant differences (P < 0.001) in crude protein, ether extract, dry matter, acid detergent fibre and organic matter of silage at different stages; however, no significant difference (P > 0.05) was observed in dry matter digestibility after 24 h of fermentation in vitro, with NH₃-N varying from 0.7 ± 0.1 to 1.7 ± 0.3 mg L^–1.

Downy mildew (Hyaloperonospora parasitica) is a problem for canola production worldwide, including in Australia where it has remained a persistent threat since 1998. Testing of 131 Brassicaceae varieties, including 109 Australian canola varieties (Brassica napus and B. juncea) and 22 diverse Brassicaceae (including B. napus, B. carinata, B. juncea, B. nigra, B. rapa, Crambe abyssinica and Raphanus sativus) highlighted excellent resistance to downy mildew. Using a mixture of 10 H. parasitica isolates, R. sativus Colonel and Boss showed highest resistance to H. parasitica, with per cent disease index (%DI) values of 3.7% and 10.2%, respectively. These were followed by (%DI values): B. carinata ATC 94011 (11.1%), B. napus CB™ Tanami (14.1%) and Komet-741 A (14.3%), B. juncea 397.23.2.3.3 (14.8%), B. napus ATR-Banjo (16.9%), Hyola 575 CL (16.9%), Komet-744 A (18.1%), Cresor-770 B (18.5%), Wamus (18.5%), Surpass 400 (19.2%), Hyola 432 (19.4%) and Hyola 76 (19.4%), and C. abyssinica (19.9%). These varieties were also considered highly resistant. Another five B. juncea genotypes and B. nigra P.23845 were considered highly resistant with %DI of 22.2%. Those considered resistant (but not highly resistant) included hybrid B. napus Hyola 444 TT, Hyola 500 RR, Hyola 504 RR, Pioneer 46Y78, Pioneer 45Y77 and Hyola 650 TT, and the non-hybrid variety ATR-Eyre, all with %DI values 23.1–28.2%. By contrast, B. napus Thunder TT, Hyola 450 TT and ATR-Grace were highly susceptible with %DI values of 90.3%, 88.2% and 81.7%, respectively. Cluster analysis revealed six distinct clusters (highly resistant, resistant, moderately resistant, moderately susceptible, susceptible, very susceptible) for the tested Brassicaceae genotypes that, on average, showed similar responses within each cluster against H. parasitica based on their %DI values. From 2000 onwards (with the exception of Surpass 400), 10 B. napus varieties and one B. juncea released were classified as highly resistant; however, there was no overall correlation between year of variety release and level of resistance expressed against H. parasitica. This is the first study to demonstrate the existence of very high levels of pathotype-independent resistance in Australian canola varieties to H. parasitica. The most resistant varieties identified can be used in canola breeding programs and also directly deployed into regions where downy mildew is prevalent, providing the canola industry with an immediate and effective option for management of this important disease.

Crop-management solutions that simulate plant water-saving strategies might help to mitigate drought damage in crops. Winter canola (Brassica napus L.) is significantly drought-sensitive from flowering to mid-pod development, and drought periods lead to significant yield losses. In this study, the drought-protection efficacy of different chemicals with antitranspirant activity applied just before key drought-sensitive phenological stages was tested on field-grown canola in two years. Drought was artificially imposed with rain shelters. The results suggest that in-field application of 1 L ha^–1 of antitranspirant (Vapor Gard (VG), a.i. di-1-p-menthene) at GS6.0 (BBCH growth scale, initiation of flowering) mitigated drought-induced yield loss leading to a 22% seed-yield benefit on average over 2 years of experiments compared with the unsprayed unirrigated plots. No significant yield responses were found from application at GS7.0, with increasing VG concentrations (i.e. 2 and 4 L ha^–1), or with an antitranspirant with short-lasting effectiveness. The data suggest that in field conditions where drought occurs during the flowering stage, application of 1 L ha^–1 of VG just before the drought event can reduce yield loss. This result should encourage further work on water-saving management strategies during key drought-sensitive phenological stages as drought mitigation tools in canola and under different environments.

In the Czech Republic, increases in the area sown with oilseed rape (Brassica napus L.) and shifts to intensive crop farming systems have contributed to increased incidence and harmfulness of phoma stem canker. This study comprised a large-scale survey of the occurrence of two closely related causal agents of the disease, Leptosphaeria maculans and L. biglobosa, in oilseed rape tissues and the country-wide distribution of each fungal species. In the 2007–11 growing seasons, 1132 leaves with phoma leaf spot symptoms were sampled; from those, 977 L. maculans-type and 477 L. biglobosa-type leaf spots were sampled and analysed by species-specific PCR without pathogen isolation. There were 1159 leaf spots confirmed as infected by Leptosphaeria spp., with 65% of 907 L. maculans-type leaf spots infected by L. maculans only and 35% co-infected by both species; and with 88% of 252 L. biglobosa-type leaf spots infected by L. biglobosa only and 12% co-infected by both species. Furthermore, 217 monopycnidial isolates were collected from selected leaf spots and identified based on pigment production during solid- and liquid-media culture and PCR assay. Most (82%) isolates originating from L. maculans-type leaf lesions were L. maculans, and most (69%) isolates collected from L. biglobosa-type leaf lesions were L. biglobosa. Co-infection by both species was found in both L. maculans-type and L. biglobosa-type leaf lesions. In 2007–12, 708 stems with phoma stem canker symptoms and 2635 plant tissues from upper stem, stem base, root collar and taproot of each stem were sampled for PCR; symptoms on the four parts of each stem were assessed before taking tissue samples. There were 1495 plant tissues confirmed as infected by Leptosphaeria spp., with the proportion of plant tissue in which only L. biglobosa DNA (62%) was amplified greater than that with only L. maculans DNA (11%) or with both L. maculans and L. biglobosa DNA (27%). Although both species were detected in leaf samples in autumn, L. biglobosa was the more frequently detected species in stem samples in summer, suggesting that L. biglobosa is the more successful in colonising oilseed rape tissues in later growth stages of the plant in the Czech Republic.

Millions of people have an inadequate intake of selenium (Se) and zinc (Zn), and foliar biofortification may minimise these problems. To evaluate the efficacy of combined foliar Se and Zn fertilisation in field pea (Pisum sativum L.) grains, foliar Se and Zn applications were tested individually and in all combinations (0, 0.03% or 0.06% (w/v) NaSeO₄, and 0, 0.25% or 0.5% (w/v) ZnSO₄.7H₂O) at early grain filling. Plant growth was not influenced by any of the treatments. There was a positive relationship between total Se or Zn concentration in raw or cooked grains and respective Se or Zn application dose. Grain Zn accumulation was positively influenced by the combined application of Se and Zn. Grain cooking caused a slight decrease in grain Se (by 7.4%) and Zn concentrations (by 19%); however, cooking enhanced Zn bioavailability. The consumption of 100 g of cooked, biofortified field peas would provide ∼50% of recommended daily intake of Zn and 45% of Se. The present study successfully biofortified field peas with Se and Zn, with the combined foliar application of Se and Zn being the best option.

Brazilian sugarcane yield is below its physiological potential, which has compromised the crop’s profitability. This, together with the expansion of the crop to marginal areas with limiting climatic conditions, requires studies to quantify crop yield gaps (YG) and to identify their main causes (i.e. droughts and/or crop management). One way to determine YG is through crop simulation models, which vary in complexity, mainly in terms of input data requirements. This study evaluated whether a simple agrometeorological crop yield model could be suitable for estimating sugarcane YG at a national level, in order to consider and suggest practices to mitigate yield losses. The model was calibrated and evaluated for different conditions across the country. The calibrated model was used to estimate plant and ratoon sugarcane potential (Yp) and best farmer (Ybf) yields for 259 locations representing all regions of the country where sugarcane is grown. Weather data from 1984 to 2013 and general local soil information were used as inputs. The Yp and Ybf simulations were performed for 30 growing cycles, with the final yields being weighted by the proportion of plant (20%) and ratoon (80%) canes in each area. These data were compared with actual average yields (Yavg), obtained from official surveys. Sugarcane yields varied considerably across the country: Yp range was 68.5–232.7 t ha^–1, Ybf 61.7–123.3 t ha^–1, and Yavg 11.2–101.1 t ha^–1. These yields resulted in an average total YG of 133.2 t ha^–1. The main source of YG was water deficit, accounting for 75.6% of total losses, while crop management was responsible for 24.4%. Considering the main sources of YG for sugarcane in Brazil, the use of drought-tolerant cultivars, irrigation, and deep soil preparation seems the best strategy to mitigate the risks, improving yields. Based on these results, the simple agrometeorological crop yield model proved suitable to estimate sugarcane YG at national level.

The introduction of kikuyu (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone) into Australia in 1918 has seen it become established and adapted to several geographic regions in a wide range of ecologies and environmental situations. After it naturalised to local conditions, researchers and farmers recognised the value of kikuyu in marginal and previously unproductive sites, where forage quality and quantity made this species popular with dairy farmers and pastoralists. Its versatility and prostrate, mat-forming characteristics also led to the adoption of kikuyu by local governments, homeowners and sporting organisations in urban environments as turf. Kikuyu has the ability to alleviate soil contamination and remediate soils, thus enhancing the use of previously unproductive land. However, the aggressive growth habit of the species, considered a problem in certain regions of the world, has led to a noxious weed classification in some states of the USA. This review includes information on expected changes to world agricultural and urban environments and the potential expanded role of kikuyu. The origin of kikuyu grass, genetic variability, tolerances to soil salinity and drought, and potential for genetic improvement are also discussed.

This article aims to discuss the arcsine–log calibration curve (ALCC) method designed for the Better Fertiliser Decisions for Cropping Systems (BFDC) to calibrate relationships between relative yield (RY) and soil test value (STV). Its main advantage lies in estimating confidence limits of the critical value (CSTV). Nevertheless, intervals for 95% confidence level are often too wide, and authors suggest a reduction in the confidence level to 70% in order to achieve narrower estimates. Still, this method can be further improved by modifying specific procedures. For this purpose, several datasets belonging to the BFDC were used. For any confidence level, estimates with the modified ALCC procedures were always more accurate than the original ALCC. The overestimation of confidence limits with the original ALCC was inversely related to the correlation coefficient of the dataset, which might allow a relatively simple and reliable correction of previous estimates. In addition, because the method is based on the correlation between STV and RY, the importance to test it for significance is emphasised in order to support the hypothesis of a relationship. Then, the modified ALCC approach could also allow a more reliable comparison of datasets by slopes of the bivariate linear relationship between transformed variables.