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Having substantial and working knowledge on phosphorus fertilization is a pre-requisite to profitable tomato production. Thus, the present research was conducted to determine the optimum phosphorus (P) fertilizer rate for better fruit yield of tomato in Ilorin, a location in the Southern Guinea savannah zone of Nigeria. Five levels of phosphorus (0, 30, 60, 90 and120kgP/ha) were tested on UC82B tomato variety. The experiment waslaid out in a randomized complete block design with 3 replications. Data were collected on plant height, number of leaves, leaf area and number of branches at different growth stages while data on fruit yield as well as its components were collected at harvest. Results showed that application of 30kgP/ha produced plants with the highest leaf area. The control and 30kgP/ha produced the highest number of leaves. Application of 90kgP/ha and 120kgP/ha resulted in production of highest number of fruits while application of 90kgP/ha alone resulted in production of the tallest plants, highest number of branches and highest fruit yield. The yield was 66% better than the control. It was, therefore, concluded that 90kgP/ha should be used for optimum tomato fruit production in the agro-ecological zone of the research and places with the same climatic and edaphic conditions. Keywords: Phosphorus fertilization, tomato, growth improvement and fruit yield

To guard against soil phosphorus (P) toxicity in tuber production and have optimum tuber yield at lesser cost of P-fertilization, better understanding of the dynamics of phosphorus release in sandy loamy soil is inevitable. Therefore, this work was carried out to investigate the trend of P-release from time of application to its optimum release and its effect on sweet potato growth and tuber production. To achieve this, a 5-week incubation study under laboratory conditions was carried out to study P-release dynamics using different P sources. Similar experiment was conducted on the field using the same P sources and application rate to monitor the influence P-release rate on sweet potato production. Data on number of leaves, vine length, tuber yield, soil extractable phosphorus and phosphorus uptake of the plants were taken. Relationships between P-uptake and tuber yield, number of leaves, vine length were also established. It was found that the trend of phosphorus release was a sigmoid shape. Leaf production and vine length were improved by P-application, while yield was suppressed. It is recommended that P-fertilizer should not be applied to the soil at short intervals to avoid nutrient toxicity.

Flooding or submergence is one of the major environmental stressors affecting many man-made and natural ecosystems worldwide. The increase in the frequency and duration of heavy rainfall due to climate change has negatively affected plant growth and development, which eventually causes the death of plants if it persists for days. Most crops, especially rice, being a semi-aquatic plant, are greatly affected by flooding, leading to yield losses each year. Genetic variability in the plant response to flooding includes the quiescence scheme, which allows underwater endurance of a prolonged period, escape strategy through stem elongation, and alterations in plant architecture and metabolism. Investigating the mechanism for flooding survival in wild species and modern rice has yielded significant insight into developmental, physiological, and molecular strategies for submergence and waterlogging survival. Significant progress in the breeding of submergence tolerant rice varieties has been made during the last decade following the successful identification and mapping of a quantitative trait locus for submergence tolerance, designated as SUBMERGENCE 1 (SUB1) from the FR13A landrace. Using marker-assisted backcrossing, the SUB1 QTL (quantitative trait locus) has been incorporated into many elite varieties within a short time and with high precision as compared with conventional breeding methods. Despite the advancement in submergence tolerance, for future studies, there is a need for practical approaches exploring genome-wide association studies (GWA) and QTL in combination with specific tolerance traits, such as drought, salinity, disease and insect resistance.

Soils of the savannah zones of Nigeria are low in plant nutrients and peasant farmers; therefore, rely on external inputs in the form of organic and inorganic manure for sustainable yield. They also sow their seeds at suboptimal plant population density, thereby providing opportunity for weeds to thrive. Moreover, farmers use saved seeds from the previous cropping season for planting, which often results in low yield. A study was conducted to assess the growth and yield of two maize cultivars under the influence of organic fertilizer and plant population density. Treatments used were factorial combinations of three levels of poultry manure (0, 2.5, 5.0 t/ha), two population densities (95,556 and 53,333 plants/ha) and two maize varieties (DMR-ESR-Y and Suwan-1-SR). Data were collected on number of leaves, plant height, leaf area, stem girth, root and shoot dry weight, total dry weight, days to tasseling, days to silk appearance, grain yield per hectare, number of seeds per cob, seed rows per cob, weight of 100 seeds and shelling percentage. The results revealed significant improvement (p≤ 0.05) in all parameters examined, when 5 t/ha poultry manure was applied to Suwan-1-SR at density 53,333 plants/ha. However, there was marginal difference between 5 and 2.5 t/ha in grain production. Therefore, application of 2.5 t/ha poultry manure for production of Suwan-1-SR maize variety at plant density 53,333 plants/ha could be used for getting optimum yield, that can feed the growing population of maize consumers coupled with better straw production for animal feed.

Drought is the leading threat to agricultural food production, especially in the cultivation of rice, a semi-aquatic plant. Drought tolerance is a complex quantitative trait with a complicated phenotype that affects different developmental stages in plants. The level of susceptibility or tolerance of rice to several drought conditions is coordinated by the action of different drought-responsive genes in relation with other stress components which stimulate signal transduction pathways. Interdisciplinary researchers have broken the complex mechanism of plant tolerance using various methods such as genetic engineering or marker-assisted selection to develop a new cultivar with improved drought resistance. The main objectives of this review were to highlight the current method of developing a durable drought-resistant rice variety through conventional breeding and the use of biotechnological tools and to comprehensively review the available information on drought-resistant genes, QTL analysis, gene transformation and marker-assisted selection. The response, indicators, causes, and adaptation processes to the drought stress were discussed in the review. Overall, this review provides a systemic glimpse of breeding methods from conventional to the latest innovation in molecular development of drought-tolerant rice variety. This information could serve as guidance for researchers and rice breeders.

The objective of this study was to evaluate the yield and quality of sweet potato under the influence inorganic fertilizer (NPK 15:15:15) at the recommended rate of 130kg/ha, organic fertilizer (Pace Setter) at the recommended rate of 3t/ha and organo-mineral fertilizer (combination of NPK 15:15:15 and Pacesetter organic fertilizer) at the rate of 1.5 t/ha. The fresh and dry weights of the samples were taken after which their proximate analyses were done to determine the levels of the quality determinants (moisture content, crude protein, ether extract, crude fibre, Vitamin A and ash content) in them. At the end of the experiment, harvesting was done to determine the yield per treatments as well as the quality parameters of the leaves and tubers. It was found that organic fertilizer could increase the quantity of ether extract, crude fibre and vitamin A contents of sweet potato tubers above other fertilizer treatments though organic fertilizer competed with the control in increasing the ash and crude protein contents of sweet potato tubers. However, inorganic fertilizer increased only energy content of the tubers above organic and organo-mineral fertilizer treatments. It is, therefore, concluded that organic fertilizer should be used to increase sweet potato tuber quantity and quality. Keywords: Sweet potato, growth, yield, quality and fertilizer treatments

This research was carried out to determine the best phosphorus fertilizer for improvement of sweet potato phosphorus uptake, growth and yield. The phosphorus fertilizer sources used were organic (Pacesetter), single super phosphate and crystallizer while the sweet potato variety used was Shaba. The experiment was laid out in randomized complete block design (RCBD) with three replications. Sweet potato plants from plots treated with crystallizer fertilizer at the rate of 500kg/ha had the highest phosphorus uptake and vegetative growth while control plots produced plants with highest tuberous yield. It is, therefore, recommended that crystallizer applied at the rate of 500kg/ha be used for significant phosphorous uptake which equally leads to better quality sweet potato tuber and appreciable vegetative growth. It is also recommended that the soil phosphorus be maintained at low level around 6.80mg/kg for achievement of high tuberous yield in sweet potato. Keywords: Vegetative growth, yield, phosphorous uptake, phosphorous fertilizers

The associations among yield-related traits and the pattern of influence on rice grain yield were investigated. This evaluation is important to determine the direct and indirect effects of various traits on yield to determine selection criteria for higher grain yield. Fifteen rice genotypes were evaluated under tropical condition at five locations in two planting seasons. The experiment was laid out in a randomized complete block design with three replications across the locations. Data were collected on vegetative and yield components traits. The pooled data based on the analysis of variance revealed that there were significant differences (p<0.001) among the fifteen genotypes for all the characters studied except for panicle length and 100-grain weight. Highly significant and positive correlations at phenotypic level were observed in grain weight per hill (0.796), filled grains per panicle (0.702), panicles per hill (0.632), and tillers per hill (0.712) with yield per hectare, while moderate positive correlations were observed in flag leaf length to width ratio (0.348), days to flowering (0.412), and days to maturity (0.544). By contrast, unfilled grains per panicle (-0.225) and plant height (-0.342) had a negative significant association with yield per hectare. Filled grains per panicle (0.491) exhibited the maximum positive direct effect on yield followed by grain weight per hill (0.449), while unfilled grain per panicle (-0.144) had a negative direct effect. The maximum indirect effect on yield per hectare was recorded by the tillers per hill through the panicles per hill. Therefore, tillers per hill, filled grains per panicle, and grain weight per hill could be used as selection criteria for improving grain yield in rice.

Genetic based knowledge of different vegetative and yield traits play a major role in varietal improvement of rice. Genetic variation gives room for recombinants which are essential for the development of a new variety in any crop. Based on this background, this work was carried out to evaluate genetic diversity of derived mutant lines and establish relationships between their yield and yield components using multivariate analysis. To achieve this objective, two field trials were carried out on 45 mutant rice genotypes to evaluate their growth and yield traits. Data were taken on vegetative traits and yield and its components, while genotypic and phenotypic coefficients, variance components, expected genetic advance, and heritability were calculated. All the genotypes showed variations for vegetative traits and yield and its components. Also, there was positive relationship between the quantitative traits and the final yield with the exception of number of tillers. Finally, the evaluated genotypes were grouped into five major clusters based on the assessed traits with the aid of UPGMA dendrogram. So hybridization of group I with group V or group VI could be used to attain higher heterosis or vigour among the genotypes. Also, this evaluation could be useful in developing reliable selection indices for important agronomic traits in rice.

To forestall wastage and determine the optimum level of complete fertilizer needed for better production of cowpea, the application of NPK 16:16:16 fertilizer on the growth and yield of the crop was investigated. The field experiment was conducted on the Teaching and Research Farm of the Faculty of Agriculture, University of Ilorin. A medium-maturing cowpea variety IAR- 48 was tested with five NPK fertilizer rates viz: 200kgNPK/ha, 400kgNPK/ha, 600kgNPK/ha, 800kgNPK/ha and 0kgNPK/ha as the control. The experiment was laid out in a randomized complete block design, replicated twice. Data were collected on plant height, number of leaves, leaf area, number of branches, number of pods per plant, number of seeds per pod, weight of 100seeds and grain yield per treatment. All data were subjected to Analysis of Variance (ANOVA) using GENSTAT package while separation of significant means was done using Least Significance Difference (LSD) at 5% probability level. Results showed that NPK fertilizer at the rate of 200kg/ha improved pod production, weight of 100seeds, pod weight and final grain yield per hectare. It could, therefore, be inferred that, subject to further research, if NPK 16:16:16 is applied at rate of 200kgNPK/ha or less, better yield and reduction in the cost of production will be achieved with cowpea variety IAR- 48 in Ilorin, a location in the Northern Guinea Savanna Zone of Nigeria. Keywords: Complete fertilizer, cowpea, vegetative growth, yield potential and yield improvement