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Wening S.,Bah Lias Research Station | Croxford A.E.,Aberystwyth University | Croxford A.E.,University of Adelaide | Ford C.S.,Aberystwyth University | And 9 more authors.
Annals of Applied Biology | Year: 2012

Plant breeders constantly need to introduce desirable new alleles to refresh breeding stocks. This first requires an assessment of potential new sources of material and then identification of genotypes most able to augment existing stocks. Genetic distance analysis is widely used for both purposes, although it measures both haplotype diversity and novel allele abundance. Here, we present a more tailored approach to address these problems. Using oil palm as an exemplar, simple metrics of allelic and genetic richness, graphical genotyping and multivariate analysis were deployed to determine the overall value of Ghanaian germplasm to supplement Sumatra Bioscience (SumBio) breeding material. We next compared three methods to rank individuals. The first was based on multivariate genetic distance. However, we also developed two new systems: Global Allelic Divergence (GAD), based on novel allele abundance, and Genome Scan Allelic (GSA) divergence, which additionally considers genome context. Ghanaian material exhibited increased allelic richness, higher heterozygosity and a higher proportion of private alleles than extant SumBio breeding stocks. Graphical genotyping revealed Ghanaian material as allele-rich in genomic regions that were allele-poor in SumBio breeding stocks. Multivariate analysis showed a collective distinctness and increased variability of Ghanaian plants. Ranks of individuals varied between GSA, GAD and genetic distance. The GAD and GSA ranks correlated strongly with each other but only poorly with the genetic distance-based ranks. We conclude that GSA and GAD are superior ranking systems to identify individuals most likely to introduce valuable new alleles, whilst genetic distance analysis identifies individuals likely to require least backcrossing. © 2012 Association of Applied Biologists.

Larbi E.,CSIR Oil Palm Research Institute | Anim-Okyere S.,CSIR Oil Palm Research Institute | Danso F.,CSIR Oil Palm Research Institute | Danso I.,CSIR Oil Palm Research Institute | Marfo-Ahenkora E.,CSIR Animal Research Institute
Research Journal of Applied Sciences, Engineering and Technology | Year: 2014

The study examines the seasonal reproductive performance of sheep reared under oil palm plantation and the subsequent survival of lambs up to weaning age. On-station studies were carried out from 2007 to 2010 at CSIR-Oil Palm Research Institute, Kusi (001.45 W, 0600 N and 150 m above sea level). The average total rainfall is about 1600 mm/annum with average daily maximum temperature of 32±2oC. Sheep productivity (% lambing, litter size per ewe, survival rate, monthly birth and death rates) were the variables measured. An annual average of 58 ewes and 4 lambs were used. Results show that while lambing rate was 98%, lamb survival was 63.84%. This implies that almost two-fifth of yearly reproduction was lost to mortality with significantly large number of lambs dying in August. Though there was high percentage of lambing, this was offset by high mortality of lambs. © Maxwell Scientific Organization, 2014.

Logah V.,Kwame Nkrumah University Of Science And Technology | Safo E.Y.,Kwame Nkrumah University Of Science And Technology | Quansah C.,Kwame Nkrumah University Of Science And Technology | Danso I.,CSIR Oil Palm Research Institute
West African Journal of Applied Ecology | Year: 2010

A field experiment to monitor the dynamics of microbial biomass carbon, nitrogen and phosphorus under amendments and cropping systems were conducted in 2006 and 2007 at the Central Agricultural Station, Kwadaso Kumasi, Ghana. The field experiment was a split plot with three replications. Three different amendments (poultry manure, poultry manure + chemical fertilizer, chemical fertilizer) and a control (no amendment) constituted the sub-plots whereas cropping systems (continuous maize, maize/soybean intercrop and maize/cowpea rotation) were assigned to the main plots. Soil samples under each amendment and cropping system were taken at 3 weeks interval within each cropping season and analysed. The results of the study revealed a general buildup of microbial biomass over the seasons. Microbial biomass carbon ranged from 25 to 248 mg/kg soil in 2006 (major season) to 87 to 713 and 546 to 770 mg/kg soil in 2006 (minor) and 2007 (major seasons), respectively. Biomass carbon showed positive correlations with soil organic carbon with r 2 values of 0.71, 0.40 and 0.64 in 2006 (major) 2006 (minor) and 2007 (major seasons), respectively. Biomass nitrogen showed more temporal fluctuations than biomass carbon. Negative values (-47.7 to -7.40 mg/kg soil) for microbial biomass phosphorus were observed at 42 and 63 days after amendments application (DAAA), signifying immobilization of phosphorus at the peak of crop growth. The immobilized phosphorus was, however, released 84 DAAA, thus, adding to the available phosphorus content of the soil. The study has shown that microbial biomass could be influenced positively by amendments and cropping systems overtime, and that phosphorus could be immobilized at the peak of crop growth; its release not concurring with peak nutrient demands of crops, hence, the need for synchronization.

Logah V.,Kwame Nkrumah University Of Science And Technology | Ewusi-Mensah N.,Kwame Nkrumah University Of Science And Technology | Tetteh E.N.,CSIR Crops Research Institute | Quansah C.,Kwame Nkrumah University Of Science And Technology | Danso I.,CSIR Oil Palm Research Institute
Journal of Tropical Agriculture | Year: 2013

A study was conducted for three consecutive cropping seasons at the Central Agricultural Station, Kwadaso, Kumasi in the semi - deciduous forest zone of Ghana to investigate the seasonal variations of soil microbial biomass carbon, nitrogen and phosphorus under different nutrient management and cropping systems. The field experiment was a split - plot in a randomized complete block design replicated thrice. Continuous maize cropping (CM), maize/cowpea rotation (M/C) and maize/soybean intercropping (M/S) systems were considered as main plot factors. Poultry manure (PM) at a rate of 4 Mg ha-1, chemical fertilizer (CF) (NPK 15- 15- 15) at a rate of 90 - 60 - 60 kg ha-1, complementary application of poultry manure and chemical fertilizer (PM + CF) at 2 Mg ha-1 PM + 45- 30 -30 kg ha-1 CF and a control (no amendment) constituted the sub-plot factors. Biomass C showed increases over the seasons under nutrient management systems (amendments) and cropping systems. Values recorded in 2006- major rainy season differed significantly (P ≤ 0.05) from values recorded in the subsequent seasons. Unlike biomass C, biomass N recorded highest values in 2006 - minor rainy season. The lowest microbial P values were recorded in 2006 - minor rainy season which was characterized by P immobilization under all the amendments. Phosphorus was immobilized under cropping systems except in M/S system in the minor rainy season. Biomass carbon to nitrogen ratios (Cmic: Nmic) showed significant differences among amendments during all seasons of cropping and ranged from 3.9 - 35.0. Generally, cropping systems did not have siginificant effect on Cmic: Nmic ratios except in 2006- minor season when CM recorded the highest value of 15.2 with M/S system recording the least (11.9). Soil pH showed positive correlations with Cmic: Nmic ratios in the major rainy seasons but not in the minor season. The study has indicated that efficient seasonal nutrient management under cropping systems could result in buildup of microbial biomass C but may not necessarily lead to corresponding build up in biomass N and P.

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