In Australia, crown rot of cereals is predominantly caused by Fusarium pseudograminearum and Fusarium culmorum, and common root rot by Bipolaris sorokiniana. Fusarium graminearum is an important pathogen causing Fusarium head blight worldwide and has also been reported to cause crown rot of wheat. The comparative ability of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana to cause crown rot and common root rot across a range of winter cereal species requires investigation. In glasshouse trials, we inoculated one cultivar each of barley, bread wheat, durum wheat, oat and triticale with two strains of each of the four pathogens. At 21 days after inoculation, the sub-crown internode and leaf sheaths of each plant were visually rated for brown discoloration. Shoot length and dry weight of inoculated plants were compared with those of non-inoculated controls. Barley and bread wheat had the highest disease severity ratings on leaf sheaths and sub-crown internode (64.7–99.6%), whereas oat had the lowest disease severity ratings across all pathogens (<5%). The shoot length of all cultivars was significantly reduced (by 12.2–55%, P < 0.05) when exposed to F. pseudograminearum. This study provides a comparison of pathogenicity of crown rot and common root rot pathogens and demonstrates significant variation in visual discoloration and host response across a range of winter cereals.

Application of boron (B) to wheat in conservation rice–wheat cropping systems may have a residual effect that improves productivity and grain quality of the following rice crop. Two field experiments were conducted to evaluate the effect of soil residual B on the performance, grain quality and grain yield of rice and soil biological properties under puddled transplanted (PuTR) and direct-seeded (DSR) rice systems on silty loam soil. A preceding wheat crop was sown using two different tillage systems, plough tillage (PTW) and no tillage (NTW), in combination with four B application treatments: control (no B), soil application (SA, 1 kg ha^–1), seed priming (0.01 M), and foliar spray (0.01 M). After wheat harvest, rice was planted in PuTR and DSR systems. The conservation tillage system in both wheat and rice (NTW–DSR) significantly increased soil organic carbon (by 18%) and soil microbial biomass carbon (by 5%) over conventional tillage systems (PTW–PuTR). Improved soil health and availability of soil residual B in the NTW-SA–DSR system improved grain yield (by 23–37%) and grain quality (grain protein by 3–8%, amylose content by 26%) over PTW–PuTR irrespective of B application method. Best economic return and net benefit were recorded in the order NTW-SA–DSR > PTW-SA–DSR > NTW-SA–PuTR. Thus, the application of B to NTW had a strong residual effect on grain quality and profitability of the following rice crop. In rice–wheat cropping systems on a silty loam soil, conservation tillage systems (NTW–DSR) significantly improved the availability of soil residual B and soil health and increased economic return.

Maize (Zea mays L.) is one of the main cereal crops grown around the world and is widely used as food, feed and raw material in various industries. However, the crop is sensitive to weather conditions, and this causes large variations in yield between crop seasons. Suboptimal irrigation can be used to secure reasonable yields with increased water productivity. For maize grown offseason in the Cerrado biome of Brazil, there is little knowledge about the benefits of suboptimal irrigation. This study was designed to evaluate the effect of different irrigation amounts and two Brachiaria cultivars intercropped with maize on maize grain yield, biomass production for silage and water productivity in the second crop season. The study was conducted at Embrapa Milho e Sorgo Experimental Station, Sete Lagoas, MG, Brazil, in 2018 and 2019. Six irrigation levels were obtained by using a line-source sprinkler irrigation system. The irrigation levels used ranged from 94% to 11% of the cumulative reference evapotranspiration (ET₀) in 2018, and from 90% to 34% of ET₀ in 2019. Suboptimal irrigation above a certain level did not cause a significant decrease in silage biomass (59% and 71% of the ET₀, in 2018 and 2019, respectively) and grain productivity (48% and 60% of the ET₀, in 2018 and 2019, respectively). Additionally, there was an increase in crop water productivity and irrigation water productivity, for biomass of both silage and grains. The results demonstrate the potential of suboptimal irrigation as a strategy to reduce water resource usage while maintaining acceptable productivity levels.

Sugarcane leaf scald caused by the bacterium Xanthomonas albilineans is a major disease of sugarcane worldwide. Whereas erratic symptoms make phenotypic detection challenging, molecular methods require expensive instruments and labour, and longer sample-to-answer times. We report a novel method for detection of X. albilineans DNA in sugarcane xylem sap. The method involves (i) boiling lysis-based DNA extraction from sugarcane sap; (ii) magnetic purification of target sequences directly from the lysate through use of magnetic bead-bound capture probes; and (iii) DNA sandwich hybridisation platform for HRP/TMB/H₂O₂ reaction-based naked eye visualisation and electrochemical detection of the target. The method is sensitive (limit of detection 100 fM) and reproducible (relative standard deviation <7%) with linear dynamic range 100 fM–1 nM (R² = 0.99). The method was tested on a range of sugarcane cultivars of known resistance ratings (susceptible, intermediate resistant, and resistant) for leaf scald disease from an inoculated field trial. Detection levels agreed with the resistance rating of cultivars tested. In addition, qPCR results strongly correlated with our assay (r = 0.91–0.99, P < 0.01) and cultivar resistance rating. We believe that our assay could be useful for rapid screening as well as sensitive quantification of target pathogen DNA in infected sugarcane plants.

Salt-alkaline stress generally leads to soil compaction and fertility decline. It also restricts rice growth and nutrient acquisition, so reduces rice yield. However, little is known about the effect of salt-alkaline stress on the carbon and nitrogen metabolism of rice. In this study, two relatively salt-alkaline tolerant (Changbai 9 and Dongdao 12) and sensitive (Jinongda 138 and Tongyu 315) rice cultivars were grown in a field experiment conducted with two soil types including black soil and salt-alkaline soil to evaluate the characteristics of yield, carbon and nitrogen metabolism in rice. Results showed that yield and nitrogen use efficiency (NUE) in rice greatly decreased under salt-alkaline stress. Changbai 9 (CB9) and Dongdao 12 (DD12) showed higher NUE than Jinongda 138 (JND138) and Tongyu 315 (TY315) under the salt-alkaline stress. Additionally, carbon and nitrogen metabolism enzyme activity and compound content were significantly affected by salt-alkali stress; different performances were observed between cultivars under salt-alkaline stress. In conclusion, our results indicate that salt-alkaline tolerant rice cultivars may have more stable carbon and nitrogen metabolism than sensitive genotypes under salt-alkaline conditions.

Verticillium wilt of alfalfa (Medicago sativa) is a widespread and destructive disease caused by the soil-borne fungal pathogen Verticillium alfalfae (formerly V. albo-atrum before 2011). Owing to an inadequate understanding of the pathogenicity, systemic colonisation, and host range of V. alfalfae, it has been challenging to develop an effective control measure against this disease. In the present study, seven inoculation methods, including seed inoculation, leaf spraying (LS), fungal plugs placed on leaves (FP), stem injection (SI), root dipping (RD), root injuring and dipping (RI), and watering conidia suspension into soil (WI) were used to analyse the pathogenicity and systemic colonisation of V. alfalfae on alfalfa. The typical verticillium wilt symptoms including V-shaped necrosis of leaves and leaf wilting were observed in alfalfa plants with all inoculation methods. The shortest incubation period (9 days) was observed with stem injection and the longest (40 days) with root dipping. Alfalfa plants inoculated by stem injection showed the highest disease incidence (91%), disease index (65%), and percentage of infected plants (80%), which resulted in the highest shoot biomass loss rate (34%). However, the plants inoculated by fungal plugs showed the lowest disease index (4%), percentage of infected plants (10%), and root biomass loss rate (2%). Further, the stem injection method was used to assess the host range of V. alfalfae on seven non-alfalfa plant species including erect milkvetch, sainfoin, common vetch, sunflower, potato, cotton, and bluish dogbane. The artificial inoculation of V. alfalfae by stem injection successfully infected these plants, with disease incidence ranged from 13 to 100% and disease index ranged from 10 to 69. This indicates that host range of V. alfalfae is not only alfalfa, but also other plant species.

In many areas of Australia’s mixed farming zone, cropping rotations are dominated by cereals and some areas have few suitable broadleaf alternatives. Forage brassicas are widely used in high rainfall livestock systems, but this study shows that several genotypes offer an alternative to forage oats in drier environments within Australia’s mixed farming zone. We compared a diverse set of forage brassica genotypes sown in autumn and winter with benchmark species, principally oats, across 10 experimental site-years. In both early (800–1300 growing degree days after sowing) and late (1600–2100 growing degree days after sowing) grazing windows, several forage brassica genotypes had forage production similar or superior to oats and dual-purpose canola. Many forage brassica genotypes produced higher yields of metabolisable energy (ME) and crude protein (CP), particularly in the late grazing window. In the early grazing window, Rival and Green globe turnips and HT-R24 forage rape consistently produced ∼15% above the site mean for all productivity measures, whereas kale produced ∼40% less than the site mean. In the late grazing window, oats produced the greatest amount of edible biomass (∼44% higher than the site mean); however, Goliath and HT-R24 forage rapes, Pallaton raphanobrassica and dual-purpose canola had the highest yields of ME and CP (∼16% higher than the site mean). Green globe turnip, Hunter leafy turnip and Regal kale produced ∼22% less than the site mean in this late grazing window. Multi-environment analyses revealed no genotype × environment interactions within the early grazing window. In the late grazing window, there were several genotypic adaptations, particularly for Pallaton, which performed better in low–medium production environments than the other genotypes. We show that forage brassicas offer superior yields of ME and CP, indicating that they may be better able to meet the energy and protein demands of grazing livestock than forage oats.