Knowledge of the magnitude of genetic variability, heritability and genetic gains in selection of desirable characters could assist the plant breeder in ascertaining criteria to be used for the breeding programmes. Ten open pollinated maize varieties were evaluated at the Teaching and Research farm, University of Ilorin, Nigeria, during 2005 and 2006 cropping seasons to estimate genetic variability, heritability and genetic advance of grain yield and its component characters. The effect of genotype and genotype by year interaction were significant for ear weight and grain y ield, while the effect of year was highly significant (P< 0.01) for all the characters. High magnitude of phenotypic and genotypic coefficient of variations as well as high heritability along with high genetic advance recorded for grain yield, number of grains ear -1 , ear weight, plant and ear heights provides evidence that these parameters were under the control of additive gene effects and effective select ion could be possible for improvement for these characters. Tze Co mp3 C2, Acr 94 Tze Co mp5, Tze Co mp 4-Dmr Srbc2 and Acr 90 Pool 16-Dt were identified as outstanding genotypes for maize grain yield and should be tested at mu ltilocation for their y ield performance.

Context: Development of early maturing maize cultivars that remain productive under low N fertilizer farming system, consistent with the farmers’ technologies is a prerequisite to improving adoption of new varieties without increasing production cost. Objective: To assess the performance of ten early open pollination maize varieties (OPVs) and their F1 hybrids for grain yield and nitrogen use efficiency (NUE), and also identify productive cultivars under low N fertilizer regimes. Materials and Methods: The trials were set up in a split plot arrangement with three N fertilizer levels (0, 45 and 90 kg N ha-1) as main plot and the genotypes as sub-plot. Each plot within N level was four-row, laid out in a randomized complete block design of four replications. Ten OPVs were crossed in a half diallel to generate 45 F1 hybrids during 2004 and 2005 growing seasons. Planting were carried out on 20th July, 2005 and 2nd July, 2006. Agronomic characters studied were grain yield, maize establishment count, days to 50% tasselling and silking as well as plant and ear heights. Results: The year 2005 growing season was better for all observed characters amongst all the genotypes than the year 2006. Although, expressions of these traits in the hybrids were relatively higher than the OPVs including the grain yield. The total increase in grain yield observed was 1.72 t ha-1 and 1.95 t ha-1 for OPVs and hybrids respectively on application of 90 kg ha-1 over no N-application. However, NUE was optimum at 45 kg N ha-1 in both groups. Grain yield and NUE correlated positively with growth characters measured except for days to 50% silking. Higher genetic gains were recorded for plant and ear heights. Conclusion: Two drought tolerant varieties (Acr 90 Pool 16-Dt and Tze Comp3 Dt) that combined well with specific cultivars for grain yield and NUE probably have gene pools for low N-tolerance. DOI: http://dx.doi.org/10.3329/jbs.v19i0.13000 J. bio-sci. 19 43-52, 2011

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.

8%)) went to agricultural sector. The actual spending was 681 billion Naira per year with 11.4 billion Naira for agriculture. Over 25 years, there were low and dramatic walloping of public spending in agriculture relative to large size and importance of agricultural sector in the economy. There is a continuous rise in output from 1987 to 2000 before it dropped in 2001. Land degradation, desert encroachment, drying up of surface waters, coastal inundations, and shift in cultivated crops over time affected the food security in Nigeria. The current available data showed that Nigeria, like most parts of the world is experiencing the basic features of climate change. Therefore, Nigerian government/ private sector partnership should encourage agricultural, industrial and domestic practices which will not contribute to the emission of greenhouse gasses.

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.