Agricultural Sciences

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A comparison of field assessment methods for lucerne inoculation experiments
(Taylor & Francis Group - Informa UK Limited, 2022-08-16) Tang, Lin; Morel, Julien; Halling, Magnus; Öhlund, Linda; Parsons, David
Effective and practical measurement methods for assessing field inoculation experiments are needed to identify inoculants that could improve lucerne establishment. In this study, assessment potential of different existing measurement methods (plant height, Dualex 4 Scientific leaf-clip meter, GreenSeeker handheld crop sensor, drone-acquired orthomosaic calculation, yield, nutrient analysis and nodule assessment) were compared across 12 inoculation treatments applied to lucerne (Medicago sativa L.) at 3 sites. F-values were used to compare the potential of different methods to separate inoculation treatments. The handheld GreenSeeker measuring normalised difference vegetation index (NDVI) showed the greatest potential for separating inoculation treatments in fields where lucerne had not previously been cultivated, followed by visible atmospherically resistant index (VARI) and green-red vegetation index (GRVI) from drone-acquired orthomosaics. These methods are non-destructive, low cost, require low labour input, fast, and do not require sample preparation, and thus are efficient measurement methods for disaggregating treatments in field inoculation experiments.
Acrocomia aculeata fruits from three regions in Costa Rica: an assessment of biometric parameters, oil content and oil fatty acid composition to evaluate industrial potential
(2020) Alfaro-Solís, Jose David; Montoya-Arroyo, Alexander; Jiménez, Víctor M.; Arnáez-Serrano, Elizabeth; Pérez, Jason; Vetter, Walter; Frank, Jan; Lewanowski, Iris
Due to increased global demand for vegetable oils, diversification of the supply chain with sustainable sources is necessary. Acrocomia aculeata has recently gained attention as a multi-purpose, sustainable crop for oil production. However, the information necessary for effective selection of promising varieties for agricultural production is lacking. The aim of this study was to assess variability in fruit morphology and oil composition of individual Acrocomia aculeata plants growing wild in different climatic regions of Costa Rica. Fruits at the same ripening stage were collected at three locations, and biometric features, oil content, fatty acid composition of oils from kernels and pulp, as well as fiber composition of husks were determined. Biometric parameters showed high variability among the regions assessed. Moreover, oil content and relative proportions of unsaturated fatty acids were higher at the most tropical location, whereas lauric acid content was lowest under these conditions, indicating a potential environmental effect on oil composition. Pulp oil content correlated positively with annual precipitation and relative humidity, but no clear relation to temperature was observed. The oil chemical composition was similar to that reported for Elaeis guineensis, suggesting that Acrocomia aculeata from Costa Rica may be a suitable alternative for industrial applications currently based on African palm oil. Analysis of husks as a coproduct revealed the possibility of obtaining materials with high lignin and low water and ash contents that could be used as a solid bioenergy source. In conclusion, Acrocomia aculeata oil is a promising alternative for industrial applications currently based on African palm oil and byproducts of its oil production could find additional use as a renewable energy source.
Act of phosphorus on cell hydraulic state, K+ use efficiency and induction of positive correlations between yield and vegetative traits in chickpea
(Taylor & Francis Group - Informa UK Limited, 2022-01-05) Sadji-Ait Kaci, H.; Chaker-Haddadj, A.; Nedir-Kichou, A.; Aid, F
Salinity is one of the most severe factors that can affect agricultural productivity worldwide particularly in the arid and semi-arid agro-ecological zones. Chickpea seedlings were grown in the field and subjected to different NaCl concentrations (0, 50 and 150 mM) and P application (90 kg ha–1). The experimental design was based on a completely randomised design with three replications. Salinity has disturbed the physiological and ionic state of cells by increasing stomatal resistance and significantly decreased growth and yield parameters (−66%). Under salinity, plant growth traits presented a negative correlation with yield components. P application had positive effect on growth parameters and physiological responses of the plants. Our results suggest that the tolerance of chickpea at (NaCl × P) combination is closely associated with ionic homeostasis and physiological activities of the plants. Phosphorus application allowed salinity tolerance by increasing leaf hydraulic statute, improvement of KUE and consequently enhanced grain yield of chickpea. (P × salinity) combination induced a positive correlation between vegetative traits and yield parameters like unstressed treatment. These results suggest that the use of suitable amounts of phosphorus fertiliser (i. e. 90 kg ha–1) to saline soil is a beneficial starter for plant development, yield components and rehabilitation of degraded soils.
Allelopathic effects of leachates of Juglans regia L., Populus tremula L. and juglone on germination of temperate zone cultivated medicinal and aromatic plants
(Springer Nature, 2021-02) Zubay, Péter; Kunzelmann, Jakob; Ittzés, András; Zámborine, Éva Németh; Szabó, Krisztina
The environmental benefits of agroforestry systems are well known. However, current knowledge of potential allelopathic interactions is inadequate. The decrease in soil fertility, the increasingly rhapsodic distribution of precipitation, and the special metabolism and cultivation of medicinal and aromatic plants are all harbingers of medicinal-agroforestry systems. The authors aimed to discover the allelopathic effects of Juglans regia L. and Populus tremula L. on germination of medicinal and aromatic plants cultivated in a temperate zone. Accordingly, an in vitro germination trial was conducted with leachates of these trees and two juglone concentrations. These allelopathic effects were evaluated for germination vigour, germination rate, and total fresh weight of seedlings of twelve different species. A pronounced species specificity was observed in tolerance of seeds and seedlings to the allelopathic effect of Populus and Juglans. In four of the species studied, the allelopathic effect may inhibit germination, but only initially. Poppy and angelica proved to be the most sensitive to the treatments. The following species had relative tolerance to the allelochemicals, so further research under natural conditions is suggested for: Althea officinalis L. (9.34 ± 5.04–68.66 ± 13.62 GR%), Anethum graveolens L. (12.00 ± 2.00–100.00 ± 6.12 GR%), Cannabis sativa L. (72.66 ± 9.02–91.34 ± 1.16 GR%), Dracocephalum moldavica L. (38.00 ± 2.00–80.00 ± 17.44 GR%), Linum usitatissimum L. (44.66 ± 2.00–58.00 ± 3.46 GR%), and Satureja hortensis L. (52.00 ± 28.22–82.00 ± 8.00 GR%). The aim would be to introduce them into agroforestry systems.
Biocontrol activity of Bacillus, Paenibacillus and Pseudomonas against Fusarium wilt of chickpea in Morocco
(Taylor & Francis Group - Informa UK Limited, 2022-08-03) Elbouazaoui, Amine; Sijilmassi, Badreddine; Maafa, Ilyass; Allal, Douira; Ahmed, Seid
Fusarium wilt caused by Fusarium oxysporum f.sp ciceris is one of the major diseases impacting chickpea productivity. Significant losses are reported by farmers due to the absence of effective wilt management options. Biological control using beneficial microorganisms in agriculture, is one of the promising alternatives and eco-friendly strategies utilised to overcome this disease. The present study investigated the biocontrol effect of 40 bacterial strains isolated from the rhizosphere of healthy chickpea plants collected from major chickpea growing regions in Morocco. Twelve out of 40 strains showed more than 25% in vitro inhibition of the pathogen growth. These strains, using the 16S rDNA gene sequencing, were classified into three genera, namely Bacillus, Paenibacillus, and Pseudomonas, represented by different species. Our finding showed that the mode of antagonism was mainly due to the production of diffusible and volatile compounds as well as lytic enzymes. Moreover, a greenhouse experiment of the three selected antagonistic strains showed a significant reduction in the mean of wilt incidence in different chickpea genotypes, StrainB18 reduced the wilt incidence in the susceptible variety from 90% to 18% Consequently, our antagonistic bacterial strains could be a potential component of integrated management of Fusarium wilt, therefore, increase the yield of chickpea.
Biological N2 fixation, C accumulation and wateruse efficiency (δ 13C) of chickpea grown in three different soil types: response to the addition of biochar from poultry litter and acacia
(Taylor & Francis Group - Informa UK Limited, 2022-10-05) Lusiba, S. G.; Maseko, S. T.; Odhiambo, J. J. O.; Adeleke, R.
Adding biochar to soil can alter soil properties and thus affect plant growth; however, the effect of biochar on biological nitrogen fixation, carbon accumulation and water-use efficiency of chickpea in tropical soils is not fully understood. Therefore, this study assessed the efficacy of biochar derived from poultry litter (denoted as PLB) and acacia (denoted as ACB) feedstocks on biological nitrogen fixation, carbon accumulation and water-use efficiency (δ13C) of chickpea grown in three contrasting soils of Fernwood (Arenosol) and Griffin (Helvic Acrisol) and Pinedene (Gleyic Acrisol). The biochars were applied at the rate of 0.5%, 1% and 2% (w/w) with control (0%) and replicated four times. Chickpeas grown in PLB treatments in Griffin and Pinedene soils investigated accumulated more N and C, for greater biomass production, resulting in an average total N-fixed of 77 and 52 mg N/plant, respectively. Nitrogen fixation and carbon accumulation of chickpea increased by the addition of 0.5% PLB and ACB in the Fernwood soil. The findings of this study demonstrate the potential of improving N inputs through biological nitrogen fixation with poultry litter biochar application in soils with varying nutrient status and texture, which is important in arid environments with limited N inputs.
Blue stem weevil (Ceutorhynchus sulcicollis) – a potential threat to oilseed rape production
(Taylor & Francis Group - Informa UK Limited, 2021-09-15) Sulg, Silva; Kaasik, Riina; Willow, Jonathan; Veromann, Eve
Oilseed rape (Brassica napus) has numerous insect pests, some of which are stem-miners. Currently, blue stem weevil (Ceutorhynchus sulcicollis) is not considered a pest of oilseed rape. In the present study, a total of 60 (30 untreated, 30 insecticide-treated) oilseed rape plants were dissected; and stem-mining larvae were collected, and subsequently allowed to pupate in soil. After pupation, all emerged adult weevils were identified as either blue stem weevil (C. sulcicollis) or cabbage stem weevil (Ceutorhynchus pallidactylus). We report that under favourable conditions C. sulcicollis was capable of reaching pest status, and was significantly more abundant than C. pallidactylus, indicating a critical need for future studies regarding C. sulcicollis.
Breeding for silicon-use efficiency, protein content and drought tolerance in bread wheat (Triticum aestivum L.): a review
(Taylor & Francis Group - Informa UK Limited, 2022-10-04) Christian, Marylyn M.; Shimelis, Hussein; Laing, Mark D.; Tsilo, Toi J.; Mathew, Isack
The production and quality of wheat are affected by abiotic constraints including water stress and soil nutrient deficiencies. It is imperative to develop drought-tolerant wheat varieties with high yield potential and enhanced grain protein content for food security. Silicon (Si) is important for plant growth and development but its role in abiotic stress tolerance has been overlooked in breeding programs. Identifying the underlying functional genes controlling drought tolerance, protein content and grain yield is essential for wheat improvement, especially under drought stress. Silicon uptake is conditioned by several Si transporter genes such as Lsi1, Lsi2 and Lsi6 and aquaporins, which facilitate transport of silicon and water between cells. The objectives of this review are to examine the role of Si in improving plant nutrition and drought tolerance, and to appraise the genetic control of Si uptake and breeding methods for improving Si uptake for drought adaptation and improved grain yield and quality. The review highlights the limited progress made in breeding for drought tolerance in wheat, especially in sub-Sahara Africa where the challenge is prevalent. Limited understanding of the genetic basis for Si uptake and physiology contribute to the limited progress in its exploitation in wheat improvement programs.
Can co-application of silicate rock powder and humic-like acids increase nutrient uptake and plant growth in weathered tropical soil?
(Taylor & Francis Group - Informa UK Limited, 2022-05-31) Busato, Jader Galba; dos Santos, Luiz Fernando; de Paula, Alessandra Monteiro; Sodré, Fernando Fabriz; de Oliveira, Aline Lima; Dobbss, Leonardo Barros; Martins, Éder de Souza; Jindo, Keiji
Silicate rock powder (SRP) restores the fertility of weathered soils. However, its slow nutrient release is a disadvantage for short-duration crops. Humic-like acids (HLAs) are plant biostimulants that enhance root development and nutrient uptake. This work evaluates the effects of the co-application of HLA extracted from a vermicompost and SRP on the nutrient uptake and growth of maize cultivated in weathered soil in Brazil. The chemical composition of HLA was assessed using Fourier-transform infrared spectroscopy and 13Carbon-nuclear magnetic resonance, revealing an overall characteristic of hydrophobicity. A preliminary trial with different HLA concentrations (0, 20, 40, 80, and 160 mg L−1) revealed that 40 mg L−1 HLA resulted in the highest increase in the root area, dry root weight, H+ efflux, and the number of lateral roots, compared with other concentrations. The main experiment using soil treated with SRP at different rates (0, 600, 1200, 1800, and 2400 kg ha−1) showed that the co-application of SRP and HLA caused a significant difference in the root and total plant weights, compared with the sole SRP application. Furthermore, it increased the nutrient content of the plants. These effects are mainly because of increased proton pump activity and the hydrophobicity of HLA.
Comparative efficacy of cucurbitacin phytonematicides and Velum on growth and fruit quality of watermelon cultivar ‘Congo’ and suppression of Meloidogyne enterolobii under field conditions
(Taylor & Francis Group - Informa UK Limited, 2021-11-07) Pofu, Kgabo Martha; Mashela, Phatu William
Globally, the guava root-knot nematode (Meloidogyne enterolobii) is becoming an emerging threat of note in crops with or without Mi resistance genes. Watermelon (Citrullus lanatus) cultivars are highly susceptible to Meloidogyne species, with all cultivars without genotypes with resistance to the genus. In contrast, nematode management options for watermelon production had since the withdrawal of fumigant nematicides been constrained. The objective of this study was to investigate the comparative efficacy of the locally-developed cucurbitacin phytonematicides and commercially available synthetic chemical nematicide Velum on growth and fruit yield and quality of watermelon cv. ‘Congo’, along with its accumulation of foliar nutrient elements and suppression of M. enterolobii population densities under field conditions. Nemarioc-AL and Nemafric-BL phytonematicides were each applied biweekly at 2% per seedling using 500 ml solution, while Velum was applied once using 500 ml solution at 0.08 ml/15 L chlorine-free water. At 90 days after the treatments, relative to untreated control, the two phytonematicides and Velum (a.i. fluopyram) significantly increased plant growth, fruit yield and quality, although with the accumulation of phosphorus in leaf tissues, with efficacies of the three products being comparable. Similarly, relative to untreated control, the three products significantly reduced nematode eggs and juveniles in roots and juveniles in soil, with efficacies that were significantly comparable. In conclusion, the benefits of phytonematicides on the productivity of watermelon cv. ‘Congo’ and suppression of population densities of M. enterolobii were comparable.
Distribution of common bacterial blight and anthracnose diseases and factors influencing epidemic development in major common bean growing areas in Ethiopia
(Taylor & Francis Group - Informa UK Limited, 2022-04-20) Girma, Fedeke; Fininsa, Chemeda; Terefe, Habtamu; Amsalu, Berhanu
Common bean is an important legume consumed as a source of food and used as a cash crop worldwide. However, its production and productivity are mainly constrained by bacterial and fungal diseases. A field survey was conducted to determine the prevalence, incidence, severity and association of factors influencing common bacterial blight (CBB) and anthracnose epidemics in major bean growing areas of Ethiopia, during 2019. In three regions within six zones from 12 districts, a total of 180 common bean fields were assessed for CBB and anthracnose. The results revealed that CBB and anthracnose were 100% prevalent though CBB was more severe than anthracnose. The logistic regression model showed CBB and anthracnose components were significantly associated with biophysical factors. High CBB incidence (>70%) at Ambo, Arsi-Negele and Shashemene-zuriya and high severity (>30%) at Ambo, Boricha and Shahsemene-zuriya were strongly associated with sole cropping, July sowing, poor weeding practices, maturity stage and own saved seeds. Anthracnose incidence of >50% and severity of >30% had high probabilities of associations with zones, sole cropping, own saved seeds, variety, poor weeding practices and maturity stages. The study indicated that CBB and anthracnose are severe and 100% prevalent in Ethiopia, and efforts should be done towards the usage of clean seeds, weeding practices, following appropriate sowing dates and other appropriate agronomic practices to manage the diseases.
Drought tolerance screening of rice genotypes in mid-hills of Nepal using various drought indices
(Taylor & Francis Group - Informa UK Limited, 2022-05-22) Kandel, Bishnu Prasad; Joshi, Laxmi Prasad; Sharma, Subarna; Adhikari, Prabha; Koirala, Barsha; Shrestha, Kumar
Drought is a major abiotic factor causing rice yield loss in rainfed and drought-prone areas, so screening of the cultivars for drought tolerance is crucial. Our study screens 10 commercial rice cultivars grown in the mid-hills of Nepal and four pipeline genotypes. Our objective is to identify the superior drought-tolerant cultivar and suitable indices for screening. The 14 rice genotypes were evaluated under both drought stress and non-stress conditions in randomized complete block design with three replications. The yield reduction for the cultivars ranged from 12-54% during water-stressed conditions. The drought indices mean productivity, geometric mean productivity and stress tolerance index showed a positive and high correlation with grain yield. Based on drought indices, genotype NR 119 showed the highest mean productivity, geometric mean productivity, stress tolerance index and lowest yield loss. Further, principal component analysis bolsters our results by clustering similar drought indices and drought tolerant cultivars. The NR 119 is followed by Chaite 5 and Chaite 4 as a drought-tolerant genotype, therefore, we recommend it for drought-prone areas of the mid-hill region of Nepal. We identified mean productivity, stress tolerance index and geometric mean productivity as important drought indices, so we recommend using this for drought screening.
Effect of contour rainwater-harvesting and integrated nutrient management on sorghum grain yield in semi-arid farming environments of Zimbabwe
(Taylor & Francis Group - Informa UK Limited, 2022-01-06) Kubiku, Friday N. M.; Nyamadzawo, George; Nyamangara, Justice; Mandumbu, Ronald
The application of insufficient amounts of mineral fertiliser, coupled with unreliable precipitation, has caused a drastic reduction in the yield of sorghum in the smallholder-farming areas of Zimbabwe. This calls for innovative interventions to improve production under changing climatic conditions. This study evaluated the effect of contour-based rainwater-harvesting methods and the use of cattle manure + N nutrient amendment on sorghum yield. A split-split plot experiment was conducted where rainwater-harvesting practice, sorghum variety, cattle manure + N and distance from rainwater-harvesting structure were treatment factors. The results showed that the yield of sorghum was significantly higher under the tied contour and infiltration pits than standard contour at all distances from rainwater-harvesting practices and seasons. In all seasons sorghum varieties Macia and Sc Sila showed higher yield under the tied contour and infiltration pits than standard contour. However, regardless of the distance from rainwater-harvesting practice and season the sorghum variety, Macia showed a higher grain yield than Sc Sila. At each incremental level of N application to cattle manure, Macia had a higher grain yield than Sc Sila, and no significant grain yield benefits were shown in each variety at N application to cattle manure above 50 kg N ha−1.
Effect of different types of sweet potato (Impomea batatas) cultivars on growth performance in woven polypropylene plastic bags
(Taylor & Francis Group - Informa UK Limited, 2022-09-13) Ndwamato, Mudalahothe; Yvonne, Maila; Given, Shadung; Pontsho, Tseke
The sweet potato is one of the exceptionally healthy foods that requires low inputs for production. However, in South Africa the majority of people purchase their staple food, owing to land scarcity. The woven polypropylene plastic bag (WPPB) planting technology, could be a solution for food production in limited spaces. The objective of this study was to investigate the effect of different sweet potato cultivars on growth performance using the WPPB technology. Compared to the standard (‘Blesbok’) cultivar, all the tested cultivars (‘Bosbok’, ‘Bophelo’, ‘Mafutha’ and ‘Mvuvhelo’) had higher chlorophyll content. ‘Bophelo’ and ‘Mvuvhelo’ obtained thickest (0.40 and 0.45 cm) stem diameters. ‘Mafutha’ achieved the highest (64.30 cm) vine length and number of shoots (4.64). Noticeably, ‘Mafutha’ produced the highest (4.50) number of flowers compared to the standard. ‘Bophelo’ obtained the highest (122 g) dry shoot mass and ‘Bosbok’ recorded the highest (11.2) number of enlarged roots (NER). Contrary to that, ‘Mafutha’ had the lowest (3.4) NER. In conclusion, ‘Mafutha’ performed well in terms of the above-ground plant parameters, whereas ‘Bosbok’ was best with regard to the below-ground plant parameters. Therefore, planting ‘Bosbok’ and ‘Mafutha’ cultivars in WPPBs achieved the best below and above growth performances, respectively.
Effect of long-term fertilisation on enzyme activities and microbial community composition in the rice rhizosphere
(Taylor & Francis Group - Informa UK Limited, 2022-01-06) Li, Weitao; Kuzyakov, Yakov; Zheng, Yulong; Liu, Ming; Wu, Meng; Dong, Yuanha; Li, Zhongpei
Mineral fertilisers differ in changing soil properties, and revealing how the rhizosphere and non-rhizosphere respond could provide a robust assessment of fertiliser regimes. Rhizosphere and non-rhizosphere soils were sampled from five fertilisation treatments in a long-term (24 year) experiment. Enzyme activities and total phospholipid fatty acids (PLFA) content in the rhizosphere soil were 85.8% and 51.3% higher than in the non-rhizosphere soil, respectively. Fertilisation increased enzyme activities, especially the N-cycling enzyme β-1,4-N-acetylglucosaminidase in NP fertilised soil (1.5 and 2.5 times for rhizosphere and non rhizosphere soil, respectively). The PLFA composition indicated that fungi cominated in the rhizosphere fertilised with P, whereas bacteria were more common in the non-rhizosphere soil. The PLFA contents and enzyme activities in the rhizosphere of P-fertilised plants were lower than those in the non-rhizosphere soil because P availability was lower in the rhizosphere. The redundancy analysis showed that the microbial community in the rhizosphere soil was different from that of the non-rhizosphere soil, mainly because there were differences in the 15:1ω6c and 16:0. Long-term (24 year) fertilisation strongly increased nutrient contents, and microbial biomass and activity in paddy soil. It is advisable to apply P fertiliser in the root zone to increase fertiliser use efficiency.
Effect of two seeding rates on yield and yield components of winter and spring faba bean
(Taylor & Francis Group - Informa UK Limited, 2022-01-17) Neugschwandtner, Reinhard W.; Bernhuber, Alexander; Kammlander, Stefan; Wagentristl, Helmut; Klimek-Kopyra, Agnieszka; Bernas, Jaroslav; Kaul, Hans-Peter
In Central European cropping systems, there is increasing interest in winter faba bean (Vicia faba L. minor), which is traditionally used as a spring crop. But limited knowledge on yield and yield formation and optimum seeding rate exist. Therefore, the purpose of this assessment was to compare soil coverage, yield and yield components of two winter faba bean varieties (Diva and Hiverna) with a spring faba bean (Alexia) with two seeding rates (SR), 25 versus 50 germinable seeds m−2 (S), in a two-year field experiment under Pannonian climate conditions in eastern Austria. Both winter faba bean varieties produced a high grain yield with 25 S, whereas that of Alexia tended to be higher with 50 S. The grain yield of Diva and Hiverna was with 25 S and that of Diva also with 50 S higher than that of Alexia. The higher SR caused in winter faba beans a higher intraspecific competition resulting in less stems plant−1. Pod density of Alexia was higher with 50 S compared to 25 S, while grains pod−1 and thousand kernel weight of all three varieties were not affected by SR. Results show that winter faba bean can be sown in Central Europe with lower seeding rates compared to spring faba bean without suffering a grain yield loss.
Genetic diversity and population structure of sorghum [Sorghum bicolor (L.) Moench] in Ethiopia as revealed by microsatellite markers
(Taylor & Francis Group - Informa UK Limited, 2022-09-11) Nemera, Bethlehem; Kebede, Mulugeta; Enyew, Muluken; Feyissa, Tileye
Ethiopia is the center of origin of sorghum (Sorghum bicolor L.). Understanding of the genetic diversity of the species is fundamental to design appropriate conservation and management strategies. The present study addressed the genetic diversity of sorghum accessions collected from major growing regions of Ethiopia. Eighty sorghum accessions representing five populations namely Amhara, Dire Dawa, Oromia, Southern Nations, Nationalities and Peoples (SNNP) and Tigray were analyzed with 11 simple sequence repeat (SSR) markers. Analysis of molecular variance (AMOVA) was conducted to evaluate genetic variation within and among populations. The unweighted neighbour-joining-based cluster analysis, principal components of analysis (PCoA) and structure analysis were done to elucidate clustering of populations. The polymorphic information contents (PIC) ranges from 0.50 to 0.86. A high within populations genetic diversity was confirmed with gene diversity values ranging from 0.51 to 0.77. AMOVA revealed 93.26% of the total genetic variation within populations and 6.74% among populations. Cluster analyses did not show clear grouping of accessions according to their geographical origins, confirming gene flow (Nm = 6.65) among populations. In conclusion, the SSR markers used were polymorphic and highly informative Oromia and Amhara populations displayed genetic diversity greater than mean value of 0.67 suggesting possible target populations for breeding and conservation.
Influence of genotype and environment on grain yield among cowpea (Vigna unguiculata (L.) Walp) genotypes under dry land farming system
(2022-05-10) Gumede, Mbali Thembi; Gerrano, Abe Shego; Modi, Albert Thembinkosi; Thungo, Zamalotshwa
The identification of high-yielding and stable genotypes for cultivation across differential production regions is among the key breeding objectives in cowpea improvement programs. This study was aimed to determine genotype-by-environment interaction (GEI) for grain yield to select high-yielding and stable cowpea genotypes for production in South Africa and identical agro-ecologies, and for cultivar development. Fifty cowpea genotypes were tested for grain yield across seven environments of South Africa using a 10 × 5 alpha lattice design replicated three times, during the 2019/2020 and 2020/2021 planting seasons. Grain yield data were subjected to analysis of variance (ANOVA), additive main effects and multiplicative interaction (AMMI) and the genotype-by-environment interaction (GGE) biplot analyses. ANOVA and AMMI showed significant genotype, environment and GEI effects. High grain yield was recorded for genotypes G35 (0.47 t ha−1), G1 (0.45 t ha−1) and G47 (0.43 t ha−1) across test environments. AMMI stability values (ASV); identified Acc-Cowp44 as the most stable genotype across all sites, recording the lowest ASV of 0.03. The comparison view of GGE biplot revealed Acc-Cowp29, Acc-Cowp38 and Acc-Cowp5 as ideal genotypes, possessing high grain yield of 0.19, 0.47 and 0.36 t ha−1 , respectively. The identified genotypes are recommended for production and inclusion in subsequent breeding activities.
Integration of host resistance and fungicides reduced ascochyta blight pressure and minimised yield loss in field pea (Pisum sativum L.) in southern Ethiopia
(Taylor & Francis Group - Informa UK Limited, 2022-11-01) Mengesha, Getachew Gudero; Terefe, Habtamu; Yae, Abu Jambo; Arato, Asnake Abera; Betire, Merihin Gimja; Shago, Tamirat Samuel; Bires, Zemenu Fentahun; Boran, Biniyam Boraysho; Abebe, Shiferaw Mekonnen
Ascochyta blight complex causes substantial yield losses and deteriorates seed quality of field pea worldwide. Field experiments were conducted to determine the effectiveness of an integrated approach consisting of host resistance and fungicides to reduce ascochyta blight progression and enhance yield performances of field pea for two seasons at Bonke and Chencha, Southern Ethiopia. Three field pea (Bursa, Burqitu and Tegegnech) varieties and three systemic (Carbonchlor, Matico and Othello-Top) fungicides, along with unsprayed controls, were arranged in a factorial randomised complete block design with three replications. Results showed that fungicide treated plots of each variety recorded the lowest progress rate, while control plots of Bursa, Burqitu and Tegegnech recorded the highest rate parameter (0.67, 0.60 and 0.451 units day−1), respectively at Bonke. Terminal mean severities were reduced by up to 24.6–43.7% and 20.1–43.7% due to fungicide applications over unsprayed plots at Chencha and Bonke, respectively. Moreover, triple applications of Othello-Top enhanced grain yield by 211% (Bursa), 204% (Burqitu) and 140% (Tegegnech) as compared to control plots at Bonke. A related pattern was noticed at Chencha areas. Economically, Burqitu with Othello-Top showed the highest net benefit and benefit–cost ratio of $2.35 × 103 ha−1 and 4.77 (Bonke) and 2.27 × 103 ha−1 and 3.76 (Chencha) in that order of presentation, followed by Matico, and found to be the most profitable management option due to monetary advantage; and it could be suggested for field pea growers.
Male and stale? Questioning the role of “opinion leaders” in agricultural programs
(Springer Nature, 2023-02-19) Matous, Petr
Social networks can influence people’s behaviour and therefore it is assumed that central individuals in social networks, also called “opinion leaders”, play a key role in driving change in agricultural and food systems. I analyse the outcomes of an intervention (that encouraged Sulawesi smallholder farmers to take a specific action toward improving the health of their cocoa trees) to assess the impact of engaging opinion leaders in agricultural programs that aim to change farmers’ practices. The intervention has been implemented through (a) 18 opinion leaders identified by interviews and a social network survey of 1885 cocoa farmers; and (b) 18 randomly selected farmers who were not central in local social networks. The obtained social networks and statistical data were quantitatively analysed and the results were interpreted with input from the field staff. Contrary to expectations, the highly socially central opinion leaders were not more effective in promoting the initiative in their communities. On average, randomly selected low-centrality farmers convinced almost twice as many of their peers to take the recommended action as compared to the identified opinion leaders (17.1 versus 8.6) but the variation within the random group was also significantly higher. Importantly, while the identified opinion leaders were mostly senior men, women performed better in influencing others into taking action even when their centrality in local social networks of agricultural advice was lower. I discuss the implications of the conventional selection of perceived opinion leaders as model farmers for achieving sustainable and equitable change at scale in agriculture and propose practical alternatives.

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