Low soil Nitrogen (low‐N) is one of the most important abiotic stressors responsible for significant yield losses in maize (Zea mays L.). The development and commercialization of low‐N–tolerant genotypes can contribute to improved food security in developing countries. However, selection for low‐N tolerance is difficult because it is a complex trait with strong interaction between genotypes and environments. Marker‐assisted breeding holds great promise for improving such complex traits more efficiently and in less time, but requires markers associated with the trait of interest. In this study, 150 BC2F1 families of CML 444 × CML 494 were evaluated at two locations for two consecutive seasons to identify SNP markers associated with quantitative trait loci (QTL) for yield and other agronomic traits under low‐ and high‐N environments. A total of 13 QTL were identified with 158 SNP markers, of which nine and four QTL were detected under low‐ and high‐N environments, respectively. Five QTL one each for grain yield (qgy‐1), days to silking (qdts‐1) and anthesis‐ silking interval (qasi‐6), and two for stay green characteristic (qsg‐1 and qsg‐4) were close to their adjacent markers, with an interval of 0.7 to 5.2 cM between them and explained phenotypic variance of 9 to 21%. These QTL would be invaluable for rapid introgression of genomic regions into maize populations using marker‐assisted selection (MAS) approaches. However, further validation of these QTL is needed before use in MAS.

In spite of efforts by national and international scientists to improve crop productivity, varieties of crops grown in Africa have low productivity.

Low soil nitrogen (low N) threatens maize production in sub-Sahara Africa (SSA). We examined the mode of gene action conditioning grain yield of intermediate maturing inbreds and evaluated lines in hybrid combinations for high yield, stability and tolerance to low N. Thirty-two sets of inbreds were crossed to three elite testers (87036, 1368 and 9071) to generate 96 F1 hybrids. The testcrosses plus four hybrid checks were evaluated under low (30 kg/ha) and high (90 kg/ha) N environments at three locations for 2 years in Ghana. Significant general combining ability (GCA) and specific combining ability (SCA) effects were detected for grain yield and most measured traits across test environments, indicating that both additive and non-additive gene action governed the inheritance of the traits. GCA effects were greater than SCA effects, indicating that most traits were controlled predominantly by additive gene action and that inbreds with positive significant GCA effects for grain yield and other traits would contribute favourable alleles to progenies across environments. Hybrid CZL 0001 × 9071 possessed high GY, increased EPP, desirable EHT and PLHT and was the highest yielding under each of two research conditions. Significant genetic correlations were observed between GY and PLHT, EPP, EHT, CA and PA implying that improvement of these traits would lead to significant gains in grain yield under low-N conditions. Hybrids CLWN 247 × 9071, ZM523B-29-2-1-1-B*6 × 9071, TZD II 68 × 1368 and P43SCRq Fs100-1-1-8 × 9071 were high-yielding, stable and low-N tolerant and should be tested on-farm and commercialized.

Heavy metals contamination and other physico chemical changes in underground and surface water by acid mine drainage (AMD) were determined on the impact on creeks or streams. High levels of these metals have been reported in mmmg areas over the years; however, investigations indicates that less monitoring has been done on water discharged as effluent for effective maintenance mechanisms to be effected. Field and laboratory studies were carried out within the mining community on Latitude S 2" 35 W and Longitude N 5° 31W to investigate the levels of heavy metals (As, Fe, Cu, Zn, Mn and Cd) and physico-chemical changes (pH, temperature, E.C, D.O, alkalinity, sol·, free CN) in both underground and surface water for seven sampling sites. Results from atomic absorption spectrometry (AAS) determination indicated an average concentrations of iron (6.185 mg/I) and manganese (2.271 mg/I) in both surface and underground waters which are higher than threshold limits for mmmg effluent. The physico-chemical changes were determined using standard methods. Results also indicated higher levels of electric conductivity (1435.0)1s/cm) and sulphate (344.0 mg/I). Differences in pH, temperature, E.C, alkalinity, S042-, Fe, Cu, Zn and Mn levels in the seven water samples were statistically significant (p :'S 0.05). This may be attributed to the higher release of metals, relative to H+. Result also showed significant impact of AMD on water quality in the mining area. This effect could be attributed to the release of metals as a result of oxidation of metal-bearing sulphides in the mine dumps and pits at the selected sampling sites. The study showed that addition of lime as a treatment option has not been effective. Hence new conventional methods such as Aerobic wetland, Compost or Anaerobic Wetland, Open Limestone Channels, Diversion wells, Anoxic Limestone Drains (ALD) etc. should be considered in the treatment of acidic water (AMD) in the mining area.

Aim: The experiment was conducted in the Kintampo North Municipality during the 2017 cropping season from August to November to evaluate the response of cabbage to different soil amendments. Methods: It was a single factor experiment laid out in a Randomized Complete Block design with three replications. The five treatments which includes NPK 15-15-15, poultry manure, cow dung and goat manure and a control. Results: Parameters measured were plant height, number of leaves, leave length, canopy diameter, head diameter and head weight. Generally, all treatments performed better than the control used in the study. Conclusions: Poultry manure performed similar to NPK 15-15-15, and were superior to all other treatments in all parameters measured. Cow dung and goat manure performed fairly well in the parameters measured. Recommendation: The study therefore recommends the application of poultry manure for improved growth, yield maximization and sustainable cabbage production.  Application of cow dung and goat manure can also be adopted for appreciable yields of cabbage.

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