ABSTRACT: This study evaluated grain yield stability and genotype × environment interactions among rice genotypes across diverse Nigerian lowland environments. The experiment was carried out across five different locations. Treatments were 12 rice genotypes. Data were collected on plant height, number of tillers, 50% flowering, number of panicles, 1000 grain weight, panicle length and grain yield. Data collected were subjected to analysis of variance. The grain yield data was subjected to Additive Main effect and Multiplicative Interaction (AMMI) analysis, Genotype by Genotype by Environment Interaction (GGE). The results revealed that there were significant differences at p≤0.05 for all traits measured for genotype, environment and genotype by environment interaction. The first two interaction components explained over 86% of the G×E variation. FARO 67 was identified as the most stable genotype, while SC2019, SC2024, and SC2028 showed broad adaptability and are recommended for adoption.
Keywords: Rice genotypes, Grain yield, Stability, Genotype × environment interaction, Lowland rice

ABSTRACT: Cassava is grown for human consumption in Asia, Latin America, and Africa as cheap source of carbohydrate and feed for livestock and is a significant industrial crop in many countries including Nigeria. Recently, cassava has received significant attention by research workers and many varieties have been released. However, little is known of the yield determinants for identifying promising genotypes. The present study aimed to screen cassava germplasm under field conditions at the University of Ibadan for dry storage root yield (DSRY). Genotypes were evaluated across two growing seasons in Ibadan, Nigeria, using randomized complete block design with two replications. Data were collected on cassava mosaic disease (CMD) severity at 1, 3 and 5 months after planting (MAP) on a scale of 1–5. At 12 MAP, data on yield, and related agronomic traits were collected and analyzed using analysis of variance (ANOVA) and correlation analysis. Majority of the genotypes (approximately 79%) showed low CMD severity (resistant), while a small proportion (approximately 21%) exhibited moderate to high severity (susceptible). The genotypes exhibited considerable variation in dry matter content (DMC), harvest index (HI), fresh storage root yield (FSRY), and dry storage root yield (DSRY), indicating substantial genetic diversity. This diversity suggests potential for selecting superior genotypes with desirable yield and quality traits such as resistance to CMD, for breeding and cultivation. There was a strong correlation between DSRY and FSRY (r = 0.94), which suggests that FSRY was more important to DSRY than DMC (0.07) and HI (0.44), therefore breeding programmes should pay premium attention to improving FSRY. Genotypes Karagba, IITA-TMS I090509, and COB-1-103 exhibited superior DSRY and low CMD severity, indicating their potential as promising candidates for further multi-environment evaluation and as parents in breeding programmes aimed at improving cassava dry root yield and CMD resistance.
Keywords:Breeding programmes, cassava mosaic disease, dry matter content, dry storage root yield, harvest index.

ABSTRACT: The experiment was conducted to evaluate the agronomic traits in local cassava varieties cultivated in Okuku alongside some improved varieties between January 2023 and January 2024. The experiment was laid out in a Randomized Complete Block Design (RCBD) with four replications. Data collected were subjected to analysis of variance (ANOVA) and means separation was done using Least Significant Difference (LSD). The Analysis of Variance showed significant differences (p < 0.05) among the cassava varieties evaluated. TMS-IBA980581 recorded the highest mean value 9.00 for days to 50% sprout followed by Nwjeni which had 8.25 while the rest of the varieties had the lowest mean value of 8.00. Akwatakwa had the highest tuber yield with 6.28t/ha followed by Obanyanyam and Nwajeni with yield values of 4.91t/ha and 2.77t/ha respectively. The lowest yield value was 0.39t/ha obtained from TMS-IBA980581. Rank summation index was used for all the traits studied to identify and select the best performer amongst the varieties. Rank summation index identified and selected Akwatakwa with RSI value of 10 as the best performer in the study area followed by, Obanyanyam and Nwajeni with RSI value of 23 and 35 respectively.
Key Words: cassava, varieties, evaluation, agronomic traits, rank summation index.

ABSTRACT: Bacterial panicle blight of rice (B.P.B.) is one of the most serious diseases hampering the yield of rice around the world. B.P.B. is a highly destructive disease caused by Bacteria Burkholderia glumae. It has been reported to cause up to 75% yield losses, alongside quality reduction such as grain weight and total amylose content. Despite the adverse effect of the B.P.B., comprehensive information about this disease and its pathogenicity remains scarce. This paper focuses on a critical review of the causative pathogen, pathogenesis, the disease cycle, and epidemiology. Besides, the novel control measures such as the exclusion technique, resistance approach, use of chemicals, biocontrol, and cultural practices for the B.P.B. management and their limitations were discussed in this report. More so, the integration of control measures showed a positive result in reducing the damage caused by the B.P.B. disease. The most efficient and long-term approach to mitigating the damage caused by B.P.B. to rice yield is the development and use of resistant cultivars. Though, the use of this technology is yet to be fully explored.

Keywords: bacterial panicle blight, Burkholderia glumae, control measures, pathogenesis, genetic resistance, .

ABSTRACT The study assessed growth, flowering behaviour, pollen stainability, and fruiting performance of four eggplant genotypes—NHEP 0073, NHEP 0093, European Merdan 465 F1 hybrid, and a farmer-selected local genotype- under high rainfall and humid conditions in Port Harcourt, Rivers State, Nigeria. The experiment was conducted at the Department of Plant Science and Biotechnology, Rivers State University, using a Completely Randomized Design (CRD) with six replications. Seedlings were raised for approximately 35 days and transplanted singly into perforated polypropylene woven bags containing 20 kg of loamy soil amended with 200 g of poultry manure. Data were collected on vegetative growth traits, reproductive traits, pollen stainability, reproductive efficiency, and selected qualitative characters. Data collected were subjected to analysis of variance. The results revealed highly significant (p ≤ 0.05) differences among the genotypes for all measured traits, indicating the presence of substantial genetic variability. The farmer-selected local genotype and the European Merdan 465 F1 hybrid consistently exhibited superior vegetative vigour, higher pollen stainability, enhanced flower-to-fruit conversion efficiency, and significantly greater fruit yield when compared with NHEP 0073 and NHEP 0093. Observed variation in qualitative traits further demonstrated exploitable genetic diversity within the evaluated germplasm. The performance of the local genotype suggested the presence of favourable adaptive alleles conferring tolerance to high humidity and rainfall, while the superior yield of the F1 hybrid reflects the contribution of heterosis. These genotypes therefore possess high breeding value and can be strategically utilized as parental materials in selection and hybridization programmes aimed at developing climate-resilient, high-yielding eggplant varieties for humid tropical agro-ecologies of southern Nigeria.

Keywords: Flower abscission, Flower bud, Genetic variability, Pollen stainability, Solanum melongena..

ABSTRACT: Seedling-stage drought stress significantly constrains rice production in Nigeria’s rainfed ecosystems. This study evaluated genetic variation, combining ability, gene action, and performance of rice topcross hybrids for drought tolerance at the seedling stage. Using a line × tester mating design, 125 F₁ hybrids were generated from five cytoplasmic male-sterile (CMS) lines and 25 testers, then screened under greenhouse moisture stress using morphological traits, survival, recovery parameters, and drought-tolerance indices in a Completely Randomized Design with three replications. Drought effects were more pronounced in recovery traits than early injury symptoms, indicating stronger genetic differentiation during post-stress regrowth. Significant line × tester interactions for drought recovery score, survival rate, and plant height confirmed predominant non-additive gene action governing seedling resilience. Genetic parameters showed moderate additive variance and heritability for leaf rolling, leaf drying, and plant height (h² = 0.18-0.24), while drought injury, survival, and recovery traits were largely influenced by environmental and non-additive effects. Correlation analyses revealed stress tolerance index (STI) showed near-perfect negative association with stress susceptibility index (SSI). Superior hybrids identified included IR75596A × IRRI 186, IR79125A × IR112899-11-2-1, and IR93559A × IR60912-93-3-2-3-3R, combining low injury, high survival, and strong recovery. Female line IR75596A contributed drought avoidance through reduced leaf symptoms, IR93559A enhanced recovery ability, while tester IRRI 186 showed outstanding combining ability for recovery traits.
Keywords: Combining ability, Drought recovery, Hybrid rice, Line × tester, Seedling-stage stress

ABSTRACT: In light of the challenges posed by climate change and limited availability of drought-tolerant rice varieties, this study examined the effects of gamma-irradiation doses (100, 200 and 300 Gy) on growth and yield attributes of two rice varieties, FARO 67 and FARO 68, under contrasting water regimes- rainfed and irrigated conditions, in the 2023/2024 planting season. Seeds were exposed to gamma-irradiation derived from a cobalt-60 source and were sown in a randomised complete block design (RCBD) in three replicates. Data on agromorphological parameters were recorded and analysed following standard procedures. Results showed significant differences (p < 0.05) among irradiation treatments for most traits in both varieties across the two water regimes. The effect of irradiation doses on FARO 67 and FARO 68 was different for most traits. Also, results revealed significant variability in the plant’s response for some traits under different growth conditions. Gamma irradiation significantly decreased seedling emergence, seedling survival and plant height of both varieties in both irrigated and rainfed plots. Low doses of 100 and 200 Gy significantly decreased the days to heading in rainfed and irrigated plots (9-21 d). Irradiation dose of 200 Gy significantly increased flag leaf length in irrigated FARO 67 (30.7 cm), while 300 Gy increased flag leaf length in irrigated FARO 68 (24.1 cm). Tillering was significantly influenced by a dose of 100 Gy in rainfed FARO 67. Gamma irradiation at low doses of 100 and 200 Gy significantly (p < 0.05) increased the number of grains per panicle in rainfed FARO 67 (193.1 and 194.9), while all irradiation doses significantly increased the number of grains per panicle in rainfed FARO 68. This study revealed variation in plant radiosensitivity and highlights the potential of gamma-irradiation in creating variability for crop improvement in different environmental conditions.
Keywords: Gamma-irradiation; genotype; mutants; rice; variability

ABSTRACT: A field experiment was carried out in the 2025 cropping season at the Teaching and Research Farm within the Department of Crop Production at Joseph Sarwuan Tarka University, Makurdi, Nigeria. The study employed a Randomized Complete Block Design (RCBD) with three replications to evaluate the effects of different organic manures on radish. The experimental materials were radish variety (Sora) and four types of organic manure (Poultry Manure, cow dung, goat manure and a control plot that received no manure. Data were collected on growth and yield parameters, including plant height, number of leaves, leaf area index (LAI), crop growth rate (CGR), chlorophyll content, root weight, days to maturity, number of roots, and yield. The results indicated that all measured parameters were significantly (P<0.05) influenced by the application of organic manure. Among the treatments, poultry manure consistently produced superior results. It led to the highest values in plant height (8.23 cm), number of leaves (12.84), leaf area index (3.23 cm²), crop growth rate (3.27 g/m² per day), chlorophyll content (34.45 mg/g), root weight (621.89 g), root length (15.67 cm), root diameter (8.45 cm), and yield (3.50 t/ha) as compared to the other manure types and the untreated. Based on these findings, it is concluded that poultry dropping is the most effective organic manure for enhancing radish growth and yield in the study area. Consequently, it is recommended that local farmers adopt the use of poultry manure at a rate of 15 tons per hectare to achieve optimum radish production.

Keywords: Radish, Sora, Organic manure, growth and yield.