The effect of fly ash on plant growth and yield of tomato
A gradual increase in fly ash concentrations in the normal field soil (0, 10, 20 … 100% volume/volume) increased the porosity, water holding capacity, pH, conductivity, C.E.C., sulphate, carbonate, bicarbonate, chloride, P, K, Ca, Mg, Mn, Cu, Zn and B. Fly ash additions to soil caused significant reductions in nitrogen content, it being almost nil in 90 and 100%. Tomato plants grown in the ash-soil mixture showed luxuriant growth with bigger and greener leaves. Plant growth, yield, (flowering, fruiting, fruit weight/plant, mean fruit weight), carotenoids and chlorophylls were mostly enhanced in the treatments with 40–80% fly ash, being optimal at 50 or 60%. From 60 or 70% onwards, the measured parameters tended to reduce. At 100% fly ash, yield (weight of fruits/plant) was considerably reduced. The boron content of tomato leaves displayed a gradual increase with fly ash addition from 20% onwards, while response of foliar nitrogen was just the opposite. The most economic level of fly ash incorporation was 40%, which improved the yield and market value of tomato fruits (mean weight) by 81 and 30%, respectively. 
Interactive effects of salinity and nitrogen on growth and yield of tomato plants
Tomato (Lycopersicon esculentum var. VF 145) plants were grown with Typic Xerofluvents soil in a greenhouse irrigated with recycled nutrient solutions having increasing levels of N and salinity. Positive response of plants to increasing levels of N was obtained at the lowest initial salinity level of 1 dS/m (dS/m=mmho/cm, referenced at 25°C). At the higher initial salinity levels of 5 and 9 dS/m, increasing N was ineffective in counteracting adverse effects on growth and yield caused by the presence of enhanced salt concentrations of the nutrient solution. Total N uptake was linearly correlated with the total water uptake and was severely suppressed by impaired growth associated with the two higher initial salinity levels, irrespective of N levels. The effect of salinity on leaf N concentrations changed over time. Leaf Cl and P concentrations indicated a possible suppressing effect of Cl on P uptake into plant tops. 
Physiological response and yield of paclobutrazol treated tomato plants (Lycopersicon esculentum Mill.)
Experiments were conducted to study the physiologicaleffect of the plant growth retardant paclobutrazol(PBZ) and its impact on the yield of tomato plants(cv. Precador). Seedlings were treated at the time of prickingout with soil and foliar applications of PBZ atconcentrations of 1.0 and 25.0 mg l-1respectively. The results established that:
— The reduced height and the increased thickness ofthe young plant stem, as well as the accelerated rootformation are a significant advantage of the PBZtreatment, contributing to the improvement of seedlingquality at planting.
— Soil treatment (1 mg l-1) and foliar treatment(25 mg l-1) with PBZ improves the photosyntheticactivity and water balance of tomato cv. Precador.
— PBZ accelerates fruit formation and increases earlyfruit yield.
— The concentrations of the retardant used and themode of its application ensure the production offruits without any residual retardant and harmless tohuman health from a phytosanitary point of view. 
Growth and Yield of Tomato (Solanum lycopersicum L.) as Affected by Hydroponics, Greenhouse and Irrigation Regimes
Climatic and technical factors influence tomato (Solanum lycopersicum L.) production in hydroponics and greenhouse, but there is not much research on management of red volcanic rock as substratum, as well as on water and nutrient solution. Therefore, the effect of the concentration of nutrient solution, irrigation frequency and the volume of substratum on growth, dry matter and fruit production was evaluated, and the economical impact was compared according to costs and yield. During 2007 and 2008, in the Experimental Field of the Universidad Autónoma Chapingo, Chapingo Mexico, concentrations of nutrient solution (100, 75, and 50%), irrigation frequency d-1 (1, 4, 7, and 10), and volumes of substratum plant-1 (5, 10, and 15L) were assessed in a completely randomized block design in a factorial treatment arrangement replicated three times. The results showed significant differences (P<0.05) between years, concentrations of nutrient solution, irrigation frequency, and volumes of substratum in growth and yield of dry matter and fruit. In 2008, there was major growth and yield of dry matter and fruit, compared to 2007. Nutrient solution at 75% diminished the fruit yield by 4.8% compared to 100%. With 7 irrigations d-1, stem thickness was reduced by 2.1, 1.8, and 1.7%, and the index of leaf area, and fruit yield, respectively, was compared to ten irrigations d-1. There were no differences between 10 and 15L in fruit yield. It is concluded that it is convenient to utilize the nutrient solution at 75% in seven irrigations d-1 and substratum volume of 10L for tomato production in hydroponics and greenhouse in order to obtain the highest profit (73.9%). 
Tomato Value Chain in Nigeria: Issues, Challenges and Strategies
The study was carried out to appraise tomato value chain in order to promote the development of tomato production and processing industry in Nigeria. Currently in Nigeria, about 1.8 Million tonnes of fresh tomato are produced per year, but over 50% of these are lost due to poor storage system, poor transportation and lack of processing enterprises. This makes it important to develop strategies for the development of tomato value chain. The method employed in this study includes semi-structured informal interviews with key value chain actors such as producers, intermediate traders, retailers and input suppliers and a critical review of available literature. The study revealed that there are good varieties of tomatoes in Nigeria, but only a few are suitable for industrial processing with regard to quantity and quality. The research also revealed that Nigeria is still not a major exporter of either fresh or processed tomato products despite the high production of fresh tomatoes. This was found to be due to inadequate supply of good quality seeds, inadequate storage facilities, poor disease and pest management, and poor processing facilities. The development of tomato for industrial use is currently gaining momentum, in the area of production of tomato juice, paste, ketchup, puree, and powder. Strategies identified to overcome the challenges include: policy shift to encourage Small and Medium Enterprises (SMEs) as well as Industries along the value chain; improved input supplies; organisation of farmers into cooperatives so as to initiate innovative funding mechanism for them; establishment of clusters for processors; improvement in marketing strategies including guaranteed price for fresh tomato products; adjustment in tariff regime to favour local manufacturers including outright ban on importation of processed tomato products; increased investments in Research and Development (R&D) to produce improved seed varieties and develop technologies for storage and processing; adoption of Good Agricultural Practice (GAP) by farmers and a strong National Commodity Association or Network. 
 Khan, M.R. and Wajid, M., 1996. The effect of fly ash on plant growth and yield of tomato. Environmental pollution, 92(2), pp.105-111.
 Papadopoulos, I. and Rendig, V.V., 1983. Interactive effects of salinity and nitrogen on growth and yield of tomato plants. Plant and Soil, 73(1), pp.47-57.
 Berova, M. and Zlatev, Z., 2000. Physiological response and yield of paclobutrazol treated tomato plants (Lycopersicon esculentum Mill.). Plant Growth Regulation, 30(2), pp.117-123.
 Suazo-López, F., Zepeda-Bautista, R., Castillo, F. S.-D., Martínez-Hernández, J. J., Virgen-Vargas, J. and Tijerina-Chávez, L. (2014) “Growth and Yield of Tomato (Solanum lycopersicum L.) as Affected by Hydroponics, Greenhouse and Irrigation Regimes”, Annual Research & Review in Biology, 4(24), pp. 4246-4258. doi: 10.9734/ARRB/2014/11936.
 Ugonna, C. U., Jolaoso, M. A. and Onwualu, A. P. (2015) “Tomato Value Chain in Nigeria: Issues, Challenges and Strategies”, Journal of Scientific Research and Reports, 7(7), pp. 501-515. doi: 10.9734/JSRR/2015/16921.