Date palm (Phoenix dactylifera L., 2n = 36) is a major fruit crop of North Africa and the Middle East, and Sudan holds diverse farmer-selected seedling germplasm that has not been characterised molecularly. This study assessed the genetic diversity of 17 date palm genotypes from River Nile State (seven Hudeiba gene-bank accessions, eight farmer-selected seedling genotypes and the commercial cultivars Barakawi and Wad Lagai) using 18 simple sequence repeat (SSR) markers, and tested for preliminary associations between SSR markers and five morphological traits (fruit length, leaf base width, leaf length, bunch weight and seed length) and six chemical traits (ash, acidity, fibre, moisture, monosaccharides and tannin concentration). Nine of the 18 SSR markers (50%) were polymorphic, with two or three alleles per locus. Major allele frequency ranged from 0.64 to 0.94 (mean 0.74), gene diversity from 0.12 to 0.48 (mean 0.37), observed heterozygosity from 0.13 to 0.71 (mean 0.51) and polymorphic information content (PIC) from 0.11 to 0.40 (mean 0.31), indicating moderate genetic diversity; SSR070 and SSR048 were the most informative loci. Single-marker analysis detected nominally significant associations of SSR085 with leaf length (R² = 0.30), bunch weight (R² = 0.51), acidity (R² = 0.32) and fibre (R² = 0.42); SSR048 with leaf base width (R² = 0.42), moisture (R² = 0.31) and monosaccharides (R² = 0.33); SSR020 with ash (R² = 0.30), fibre (R² = 0.42) and tannin concentration (R² = 0.48); SSR070 with fruit length (R² = 0.39); and SSR035 with fruit length (R² = 0.31) and seed length (R² = 0.36). Because the panel was small and no correction for multiple testing was applied, these associations are preliminary and require validation in larger, independent populations with higher-resolution genotyping before use in marker-assisted selection.
Synthetic fertilisers have supported modern crop production, but nutrient use efficiency remains constrained by losses, nutrient imbalances and the biological processes that regulate nutrient availability. This review examines sustainable nutrient management by integrating three complementary perspectives: soil ecological stoichiometry, soil and rhizosphere microbiomes, and dynamic crop nutrient demand. It synthesises evidence showing that carbon, nitrogen and phosphorus ratios influence microbial growth, nutrient immobilisation and mineralisation, while microbial communities regulate nitrogen transformations, phosphorus mobilisation and root access to nutrients. Crop nutrient requirements are shown to vary with genotype, phenological stage and root acquisition traits, making temporal and spatial synchrony between nutrient supply and crop demand essential. The review also evaluates microbial inoculants, organic amendments and precision nutrient-management approaches, emphasising that their effectiveness depends strongly on soil conditions, resource balance and biological context. An integrated diagnose–amplify–deliver framework is presented in which soil and microbial diagnostics guide the strengthening of biological nutrient supply and the targeted delivery of mineral nutrients according to crop demand. The synthesis indicates that this approach could improve nutrient use efficiency while reducing unnecessary nutrient surpluses, although its practical application requires locally calibrated indicators, field validation, reliable microbiome interventions and accessible decision-support tools. The framework also recognises contrasting regional priorities, from reducing excessive nutrient inputs to rebuilding fertility in nutrient-depleted systems.
Cowpea [Vigna unguiculata (L.) Walp.] is an important nutritional and economic grain legume; however, its productivity in Kenya remains low because of various stresses, including aphid infestation. The use of synthetic insecticides for aphid control negatively affects the environment, thereby limiting continued reliance on them. Introduction of high-yielding and aphid-resistant germplasm could help increase productivity in a sustainable manner. This study aimed to assess the response of 60 cowpea accessions to imposed aphid stress with the goal of identifying resistant accessions. It was conducted using a randomised complete block design with three replications in two trials. Data were recorded on cowpea growth, yield and aphid infestation parameters at various time intervals and subjected to analysis of variance at P = 0.05. Results revealed highly significant (P<0.05) differences for all phenotypic traits assessed. In trial 1, days to 50% flowering ranged from 45 (NA20) to 61 (NA62), and grain yield ranged from 11.3 (NA28) to 1158.8 (MA29) kg/ha; in trial 2, the corresponding ranges were 48 (NA4) to 61 (MA67) days and 15.6 (BS01) to 389.3 (NA57) kg/ha. The grain yield was negatively (P<0.05) correlated with days to 50% flowering, but positively (P<0.05) correlated with leaf length in trials 1 and 2, respectively. There was a significant difference (P<0.05) in aphid population pressure (APP) and aphid damage severity (ADS) at 5 to 21 days after infestation (DAI). At 21 DAI in trial 1, the average number of aphids per plant ranged from 219 (NA71) to 24.5 (MA48), while in trial 2, it ranged from 113.5 (NA20) to 12.2 (MA22). The summarised ADS scores were 4 for 22 accessions and 3 for 38 accessions in trial 1, whereas in trial 2 they were 4 for 2 accessions, 3 for 54 accessions, and 2 for 4 accessions. The accessions with the lowest grain yield loss may be stable against aphids in major cowpea growing regions in Kenya. The four accessions showing great resistance (KK03, MA10, MA22, MA44) to aphid infestation should be evaluated in multiple field sites to confirm their resistance to aphids, followed by deployment to areas prone to high aphid infestation to minimize pesticide reliance and associated negative effects. Furthermore, they should be validated using molecular markers to confirm their resistance genes before incorporating them into farmers’ preferred, but susceptible varieties to boost their resistance to aphids.
A field experiment was conducted during the 2015 and 2016 cropping seasons to assess the genetic response of groundnut genotypes to the severity of early and late leaf spot diseases at the Teaching and Research Farm of the Federal University of Agriculture, Makurdi, Benue State, Nigeria. Thirteen treatments (groundnut genotypes) used in the disease assessment were Campalla, Samnut-10, Aloshi, Tisha-1, Benue AGR, Ijiwanda, Samnut-22, Borno Brown, Borno Red, Dan-Bomboyo, Samnut-21, Shar-nya, and Ex-Dakar. The treatments were laid out in a randomised complete block design (RCBD) and replicated four times on a 40 x 17 m area containing 52 subplots; each subplot measured 3 x 2 m. Two seeds were sown per hole on each of four ridges, and no synthetic chemical was used. The results revealed significant (P ≤ 0.05) differences among the groundnut genotypes in establishment count, disease severity, combined disease severity, leaf defoliation, fresh leaf yield (kg/ha), fresh pod yield, and 1000-seed weight in both cropping seasons. All treatments expressed different levels of early leaf spot disease severity from 50 to 57 DAS and late leaf spot disease severity from 64 to 71 DAS in both seasons. Combined disease severity showed that Borno Brown, Campalla, Samnut-10, Samnut-21, Samnut-22, and Tisha-1 were resistant (R) to early leaf spot disease; Ijiwanda was moderately susceptible (MS), whereas the remaining groundnut genotypes were moderately resistant (MR) at 57 DAS. Similarly, Aloshi, Benue AGR, Borno Red, Campalla, Dan-Bomboyo, Ex-Dakar, Ijiwanda, and Shar-nya were highly susceptible (HS) to late leaf spot disease; Borno Brown, Samnut-22, and Tisha-1 were very susceptible (VS); Samnut-10 was moderately resistant (MR); and Samnut-21 was moderately susceptible (MS) at 71 DAS. Samnut-21, Samnut-10, Tisha-1, and Samnut-22 had higher fresh leaf yields in 2015, while Tisha-1, Samnut-21, and Samnut-22 recorded higher fresh leaf yields in 2016. Samnut-21, Samnut-22, and Samnut-10 had higher fresh pod yields in 2015, while Samnut-21, Samnut-10, and Tisha-1 had higher fresh pod yields than the other genotypes in 2016. Samnut-21 and Campalla had higher 1000-seed weights than the other groundnut genotypes in both seasons. Hence, resistant and moderately resistant groundnut genotypes with high-yielding traits are recommended as a suitable alternative management option for groundnut leaf spot (Cercospora spp) diseases in this region because of their economic benefits compared with synthetic fungicides, which may be economically infeasible and may pose environmental and human health risks.
Pearl millet (Pennisetum glaucum (L.) R. Br.) is an important climate-resilient cereal crop with considerable potential for improving food and nutritional security in dryland regions. This study evaluated 23 pearl millet genotypes for physical and proximate grain-quality traits and quantified the magnitude of genetic variability and expected response to selection. The evaluated traits included 100-seed weight, granule size, swelling power, moisture content, crude protein, crude fat, crude fibre, crude ash and carbohydrate content. Substantial phenotypic variation was observed among genotypes. The 100-seed weight ranged from 0.5 to 1.7 g, granule size from 1.6 to 10.9 mm³, and swelling power from 1.5 to 1.8%. Moisture content ranged from 4.9 to 6.2%, while crude protein, fat, fibre, ash and carbohydrate contents ranged from 15.4–17.2%, 3.3–4.6%, 7.2–11.6%, 1.0–2.4% and 28.7–34.5%, respectively. The genotype FSN-5 recorded the highest protein (17.2%), fibre (11.6%) and carbohydrate (34.5%) contents, whereas the genotype Sheikan had the highest fat (4.6%) and ash (2.4%) concentrations. Analysis of variance showed highly significant genotypic differences (P < 0.001) for the major proximate traits. Genetic parameter estimates further demonstrated strong genetic control, with broad-sense heritability ranging from 91.5% for crude fat to 99.7% for crude fibre. GCV and PCV were closely comparable, particularly for fibre (37.4 and 37.5%) and ash (37.6 and 37.8%), indicating limited environmental influence on phenotypic expression. Genetic advance as a percentage of the mean was highest for crude fibre (179.3%), followed by ash (122.8%), fat (119.7%) and carbohydrate (63.0%). The results demonstrate substantial exploitable genetic variation for pearl millet grain nutritional quality and indicate strong prospects for phenotypic selection, particularly for fibre, ash, fat and carbohydrate content. The identified variability provides useful opportunities for developing pearl millet cultivars with improved nutritional and processing attributes.
