Metabolic analysis of two wheat (Triticum aestivum L.) cultivars in response to Russian wheat aphid (Diuraphis noxia Kurdjumov) infestation

An Integrated Approach to Studying the Wheat-Diuraphis noxia Interaction for Identifying Aphid Biotypes and Assessing Plant Responses.

Genetic architecture of Karnal bunt resistance in wheat: A review

OVERWINTERING OF WHEAT BLAST IN BANGLADESH: EVIDENCE OF STUBBLE-BORNE PERSISTENCE WITHOUT ALTERNATIVE HOSTS

The fungal disease wheat blast, caused by Magnaporthe oryzae pathotype Triticum (MoT), threatens wheat production in Bangladesh and other South Asian countries, causing substantial yield losses. Identifying its overwintering mechanisms and potential alternative hosts is crucial but information on these aspects remains limited under South Asian conditions. The study investigated potential alternative hosts and assess pathogen survivability in wheat stubble. One study examined five common grass weed species, namely jungle rice (Echinochloa colona), barnyard grass (Echinochloa crus-galli), goose grass (Eleusine indica), crab grass (Digitaria sanguinalis), and Bermuda grass (Cynodon dactylon), along with cereal crops rice (Oryza sativa) and maize (Zea mays) in controlled conditions. A second experiment examined the survivability of the wheat blast pathogen in blast-infected wheat stubble in the laboratory. PCR analysis using the MoT-specific marker MoT3 confirmed infection only in the susceptible wheat cultivar BARI Gom 26, which developed typical blast symptoms with 84% disease severity and produced the expected 361-bp amplicon, whereas no PCR amplification or blast symptoms were detected in the tested grass weed species, rice, or maize. MoT remained detectable in infected wheat stubble for up to six months post-harvest; however, spore abundance progressively declined, and no spores were detected after seven months. While the five grass weed species, rice, and maize were evaluated in the study, they are unlikely to serve as alternative hosts for MoT under the conditions of this study. However, MoT can persist in wheat stubble for up to six months after harvesting. These findings are critical for managing wheat blast effectively in Bangladesh and other wheat-growing regions with similar agroecological conditions.

Evaluation of Bread Wheat (Triticum aestivum L.) Advanced Lines and Commercial Varieties to the Response of Septoria tritici blotch in Northwestern Ethiopia.

Septoria tritici blotch (STB), caused by Zymoseptoria tritici is among the most damaging foliar diseases of wheat, with yield losses reaching up to 82% under favorable conditions. To identify resistant sources, one hundred sixty bread wheat genotypes were screened at Dabat and Adet in northwestern Ethiopia during the 2023 and 2024 cropping seasons using an alpha lattice design with two replications. Disease severity was assessed at three growth stages and agronomic traits were recorded across environments. Combined analyses revealed that 17.5% of the tested genotypes exhibited resistant responses to STB, producing superior grain yield (≥ 4.5 t ha⁻¹) and thousand-kernel weight (≥ 45.41 g). Additionally, 52.5% of genotypes were moderately resistant, whereas 30% showed moderately susceptible reactions. Highly significant differences (P < 0.0001) were observed among genotypes for all studied traits, which were negatively correlated with disease parameters. The highest grain yield (5160.88 kg ha⁻¹) was obtained from genotype G81. This genotype also exhibited significantly lower disease severity at maturity (24.35%) and a significantly reduced AUDPC (968.6) compared with most of the tested genotypes. These findings highlight promising genetic resources for STB resistance, and further molecular studies such as QTL mapping and GWAS are recommended to identify resistance loci and accelerate their utilization in wheat breeding programs.

Management of sorghum rust caused by Puccinia purpurea Cooke by employing an integrated approach

Sorghum (Sorghum bicolor L.) is an important cereal crop grown in semi-arid, subtropical, tropical and temperate regions and it ranks fifth in worldwide cereal crop production. Rust of sorghum (Puccinia purpurea Cooke) is an important emerging disease in most sorghum growing areas of the world, which can increase susceptibility to other pathogens. Thus, there is a need to focus more on managing the disease. An attempt was made to manage the disease by integrating effective fungicides, botanicals, indigenous technical knowledge (ITKs) and bioagents under in vitro and in vivo conditions. In vitro studies revealed that among the different fungicides, botanicals, ITKs and bioagents tested, tebuconazole 50 % + trifloxystrobin 25 % and hexaconazole 5 % EC recorded 100 % uredospore germination inhibition. Among the botanicals, turmeric extract at 25 %, neem extracts at 50 % (78.39 %) while panchagavya (52.07 %) and combination of Trichoderma harzianum (5 g/L) and Pseudomonas fluorescens (5 g/L) (82.91 %) which recorded highest mean per cent inhibition of uredospore germination irrespective of concentration tested. Among 11 integrated spray schedules evaluated in a field study at the Main Agricultural Research Station (MARS), Dharwad during rabi seasons of 2021 and 2022, tebuconazole 50 % + trifloxystrobin 25 % at 0.05 % was significantly superior spray schedule. It recorded the lowest per cent disease index (PDI) of about 16.01 with highest grain yield (16.25 q/ha) and cost-benefit ratio (B:C ratio) of 1.87 followed by hexaconazole 5 % EC at 0.1 % (18.84 PDI; 15.76 q/ha). However, the highest PDI (92.50), lowest grain yield (9.63 q/ha) and B:C ratio (1.17) was recorded in the unsprayed control. The findings of this study highlight the potential of integrated disease management approaches combining chemical, biological and botanical components to achieve sustainable and economically viable control of sorghum rust and enhance productivity under semi-arid agro-ecological conditions.

Fungicide Application Frequency and Wheat Varietal Response to Yellow Rust ( Puccinia Striiformis f.sp. tritici ) Disease in Western Amhara, Ethiopia

Wheat is a major staple crop in Ethiopia, but its productivity is severely constrained by yellow rust ( Puccinia striiformis f.sp. tritici ), the most economically important wheat disease. A rain-fed field experiment was conducted in 2019 in the mid-highlands of East Gojjam ( Goncha Siso Enesie district, Enesie Qole Kebele ) to evaluate integrated management options combining fungicide application frequency and varietal resistance. Three bread wheat varieties (Tay, Picaflor, and Kubsa) with differing reactions to yellow rust were tested under four Tilt 250 EC (propiconazole) application frequencies (0, 1, 2, and 3) in a randomized complete block design with three replications. Terminal disease severity was recorded at 18.2% for Tay, 23.0% for Picaflor, and 44.0% for Kubsa under untreated conditions. When fungicides were applied three times at 10?day intervals, the highest percent disease control (PDC) achieved was 59.2% in Tay, 52.9% in Picaflor, and 71.9% in Kubsa. Yield and thousand kernel weight increased significantly (p<0.01) with three applications: up to 40.9% and 27.7% in moderately resistant Tay, 48.3% and 55.2% in moderately susceptible Picaflor, and 41.2% and 70.4% in highly susceptible Kubsa. These results demonstrate that combining host resistance with optimal fungicide frequency effectively manages yellow rust in bread wheat. Further research is needed to deploy eco-friendly management strategies.