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Genome-wide association analysis of Septoria tritici blotch for adult plant resistance in elite bread wheat (Triticum aestivum L) genotypes
Author(s): Kassie, Molla Mekonnen; Dejene, Tiegist; Desta, Ermias Abate; Tadesse, Wuletaw (Public Library of Science)
Date: 2025-03-10
Type: Journal Article
Status: Open access
Septoria tritici blotch (STB) is a predominant foliar disease of wheat, caused by the pathogen Zymoseptoria tritici. This disease can lead to substantial yield losses warranting control by using expensive fungicides. One effective method of STB control is the utilization of resistant wheat varieties. In this particular study, a panel comprising of 186 bread wheat genotypes was assessed for their adult plant resistance (APR) to STB. Field trials were conducted across five environments in Ethiopia during the 2022 and 2023 growing seasons under natural infestation conditions. The association panel was genotyped using 20K single nucleotide polymorphism (SNP) markers. To determine the relationship between genetic markers and STB resistance, a mixed linear model (MLM) analysis was performed using the statgen GWAS R software package. Heritability estimates for STB resistance ranged from 0.39 to 0.95, underscoring the genetic variability and the potential for selection. The study identified 52 marker-trait associations (MTAs) for STB resistance at maturity (SDSM) and 62 MTAs at heading (SDSH). Chromosome 5A contains a high concentration of MTAs that confer resistance to STB, hosting multiple significant MTAs, including four consistently associated markers (‘Kukri_c10033_724’, ‘RAC875_rep_c116420_103’, ‘TG0019’, and ‘RAC875_c30566_230’). Additionally, chromosomes 1B, 2B, 5B, and 7A were found to harbor important MTAs, contributing to resistance across various environments. Notably, two QTLs, qtSTB23 (5A) and qtSTB38 (7B), exhibited stability across multiple environments, making them robust candidates for breeding programs. Furthermore, novel resistance loci on chromosome 2A were discovered, offering new opportunities for enhancing resistance. Therefore, these findings provide an opportunity for improving STB resistance through gene stacking using marker-assisted selection (MAS).
Assessing technical efficiency of crop–livestock systems under conservation agriculture: exploring the potential for sustainable system transformation in Tunisia
Author(s): Dhehibi, Boubaker; Souissi, Asma; Frija, Aymen; Fouzai, Ayoub; Idoudi, Zied; Abdeladhim, Mohamed Arbi; Devkota Wasti, Mina; Rekik, Mourad (Emerald)
Date: 2025-03-11
Type: Journal Article
Status: Timeless limited access
Purpose
This study was conducted in four semi-arid regions in Tunisia – Kef, Siliana, Zaghouan and Kairouan – which have a similar agroecological system based on crop–livestock integration and experience serious soil erosion. The study objective is to estimate the technical efficiency of farmers engaged in mixed crop–livestock systems under conservation agriculture (CLCA) and conventional agriculture in rainfed areas of Tunisia.
Design/methodology/approach
The study analyzed data from socio-economic surveys conducted in the Tunisian rainfed areas during the 2020–2021 cropping season. A stochastic frontier analysis was used to estimate farm-level technical efficiency and its main driving factors for both adopter and non-adopter farmers.
Findings
The current average technical efficiency level of farmers was 91%. Inputs such as land size and livestock type were significant in increasing farm production. From the estimated coefficients of the inefficiency effects model, five major factors were tested: farmer’s age, education level, dependency ratio, access to credit and extension services. Age and education level positively affected the technical efficiency level.
Research limitations/implications
This study has potential limitations. To estimate measures of productivity and technical efficiency, we need output and input measures that are consistently defined and independently measured. The choice of output measure depends on several factors, including data availability and analytical purpose. Since we are dealing with different farms that have different combinations of enterprises, in this reach we approximated the total output by combining the total values of outputs (from both crops and livestock) into one dependent variable to overcome this threat.
Practical implications
Providing farmers with accurate and reliable extension information through both conventional and non-conventional technologies (e.g. video, and mobile phones) and improving their educational level through farmers’ field schools are crucial. Combining CLCA practices with improving technical efficiency of farmers in optimal use of inputs through providing training programs, extension services and access to credit for inputs (e.g. small machinery and livestock feed) can contribute substantially to farm productivity, thus enhancing food security in the face of climate change in Tunisian semi-arid areas and other similar contexts.
Originality/value
This empirical research provide evidence on how to improve crop-livestock productivity through diversification under conservation agriculture (CA) system, and reduce the effect of climate variability, it is imperative to provide the enabling environment that will facilitate and encourage production of these output combinations among smallholders in rainfed areas.
Characterizing Wheat Rhizosphere Bacterial Microbiome Dynamics Under Salinity Stress: Insights from 16S rRNA Metagenomics for Enhancing Stress Tolerance
Author(s): Mahmoud, Nourhan Fouad; M. El-Zayat, Emad; Amr, Dina; A. El-Khishin, Dina; M. Abd-Elhalim, Haytham; Hafez, Amr; Radwan, Khaled; Hamwieh, Aladdin; Tadesse, Wuletaw (Multidisciplinary Digital Publishing Institute (MDPI))
Date: 2025-03-26
Type: Journal Article
Status: Open access
Salinity is one of the most important abiotic stress factors affecting wheat production. Salt in the soil is a major environmental stressor that can affect the bacterial community in the rhizosphere of wheat. The bacteria in the plant’s rhizosphere promote growth and stress tolerance, which vary by variety and location. Nevertheless, the soil harbors some of the most diverse microbial communities, while the rhizosphere selectively recruits according to the needs of plants in a complex harmonic regulation. The microbial composition and diversity under normal and saline conditions were assessed by comparing the rhizosphere of wheat with soil using 16S rRNA gene amplicon sequencing, highlighting the number of operational taxonomic units (OTUs). Taxonomic analyzes showed that the bacterial community was predominantly and characteristically composed of the phyla Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Verrucomicrobia, and Fibrobacteres, representing the usual microbial profile for the rhizosphere of wheat. Idiomarinaceae, Rheinheimera, Halomonas, and Pseudomonas (a strain of Proteobacteria), together with Gracilibacillus (a strain of Firmicutes Bacilli), were recognized as microbial signatures for the rhizosphere microbiome under saline conditions. This was observed even with unchanged soil type and genotype. These patterns occurred despite the same soil type and genotype, with salinity being the only variable. The collective action of these bacterial phyla in the rhizosphere not only improves nutrient availability but also induces systemic resistance in the plants. This synergistic effect improves plant resistance to salt stress and supports the development of salt-tolerant wheat varieties. These microbial signatures could improve our understanding of plant–microbe interactions and support the development of microbiome-based solutions for salt stress.
Crop catalogue of farmers’ preferred crop cultivars and varieties in western Kenya
Author(s): Niane, Abdoul Aziz; Otieno, Gloria; Nyambok, Anne; Aluso, Lillian; Kemal, Seid Ahmed; Bishaw, Zewdie; Termote, Celine; Fadda, Carlo (International Center for Agricultural Research in the Dry Areas (ICARDA), 2024-12-31)
Date: 2024-12-31
Type: Manual
Status: Open access
This catalogue is an output of collaborative work of the Genetic Resources Research Institute (GeRRI) of the Kenya Agricultural and Livestock Research Organization (KALRO), the International Center for Agricultural. Research in the Dry Areas (ICARDA), and the Alliance of. Bioversity International and CIAT. The development of the catalogue is funded under the CGIAR Nature Positive Solutions Initiative. The aim of the collaboration is to develop a farmer preferred crop cultivars and varieties catalogue to facilitate registration, quality-declared seed production, certification, and commercialization.
Periodic Technical Report – Part B : Internal 27 months report
Author(s): Bassi, Filippo
Date: 2025-02-19
Type: Internal Report
Status: Timeless limited access
The report highlights all research advancements within the MountainHer project for the seven work packages during the 27 months (July 1st 2022 to October 31st 2024) of the project.