West Africa Centre for Crop Improvement
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Item Assessment of the Quality of Marketed Certified Vegetable Seeds in Original Package and those Repackaged at Retailers’ End in the Ashanti Region of Ghana(University Of Ghana, 2019-07) Johnson, A.A.The use of quality seed is a prerequisite for high vegetable productivity. The Ghana Seed Inspection Division conducts seed quality assessment to ensure that seeds meet minimum quality standards before they are certified to be sold to farmers. Poor seed storage practices and repackaging of certified seeds at retailers’ end could adversely affect seed quality before farmers purchase these for planting. Post-certification surveillance was undertaken to assess the quality of certified vegetable seeds in their original package and those that were repackaged at commercial retailers’ end in the Ashanti Region to ascertain the quality of vegetable seeds that would eventually end up with farmers for planting. Structured questionnaires were administered to 25 commercial vegetable seed retailers who constituted the main vegetable seed delivery channels to farmers across the Ashanti Region of Ghana. Survey data was analysed to ascertain vegetable seed retailers’ knowledge and practices on the handling of certified vegetable seeds and to determine marketing challenges retailers faced in their operations. Survey results indicated that retailers were educated, and had adequate knowledge and experience in the handling of certified seeds. Retailers’ major marketing challenges were seed pricing in relation to farmers’ dissatisfaction with the cost of seeds, lack of cold storage facilities, farmers’ dissatisfaction with seed package sizes being too small or too large, and poor access to credit facilities. Thirty vegetable seed samples, out of which 15 were in their original containers and 15 had been repackaged into transparent plastic bags were initially sampled from 22 retail shops for seed quality tests at the National Seed Testing Laboratory of the Ghana Seed Inspection Division. Following the first sampling, 3 specific vegetable seeds, each in original container and repackaged form, common to 3 retail shops were sampled for another evaluation. Both laboratory evaluations were arranged in a Completely Randomized Design with 4 replications and evaluated for percentage purity, moisture content, percentage germination, seedling vigour, and seed health. Data collected from both laboratory tests were analysed using Genstat statistical package 12th Edition. Fishers’ Protected LSD was used to separate treatment means at 5% significance level. Results from the laboratory analysis indicated that with the exception of 6 out of the 30 seed samples, both seeds in original package and those repackaged had germination percentages and vigour indices that were within minimum quality standards. All but 5 seed samples also had purity percentages that were within minimum quality standards. Twenty (20) of the 30 seed samples had moisture contents above the acceptable maximum moisture content of 8%. High seed moisture content and decline in seed viability of some samples were attributed to the poor storage conditions witnessed at retail shops such as high temperature (29.0 0C – 36.9 0C) and high relative humidity (40% - 64%). Two storage fungi, Aspergillus niger and Aspergillus flavus, were found to be associated with 13 out the 30 seed samples. Seeds in original package had mean percentage purity, mean moisture content, mean germination percentage, mean vigour index, and fungal prevalence to be 98.43%, 8.82%, 83.20%, 10.23 and 33.3% respectively whilst those repackaged had mean percentage purity, mean moisture content, mean germination percentage, mean vigour index, and fungal prevalence to be 95.78%, 8.91%, 77.70%, 9.28 and 53.33% respectively. These findings indicated that seed repackaging had adverse effect on vegetable seed quality.Item Effects of Low Dose Gamma Radiation on Quality and Storability of Groundnut Seed (Arachis hypogaea L.)(University Of Ghana, 2019-07) Kadri, O.M.The effect of selected low gamma radiation doses on the quality and storability of groundnut seeds cv. Chinese was studied for five months under ambient storage conditions. Six radiation doses (0,1,2,3,4 and 5 Gy), two groundnut seed forms (shelled and unshelled) and eight tri-weekly intervals were combined using Completely Randomised Design with three replications. Physiological parameters (germination percentage, speed and peak value of germination; seedling, root and shoot lengths; seedling vigour index, moisture content), sanitary seed quality parameters (pathogen infectivity and insect infestation percentages) and genetic quality parameters (emergence percentage, days to emergence, days to 50% flowering, leaf and petiole colour) were observed during the storage period. Results showed significant differences between irradiated and non-irradiated seeds, and also among radiation doses for physiological parameters except moisture content. There was significant difference between the seed forms in their response to effect of radiation doses (for root and shoot lengths, and speed of germination) and storage periods (germination percentage, speed and peak of germination, and moisture content), with unshelled outperforming shelled seeds. Storage period had a negative effect on all physiological and sanitary parameters with pathogen infectivity increasing from 22 to 79.9% as storage period advanced for both seed forms and in all doses. Interaction effects between dose, form and storage period were significant (p<0.05) for all parameters except pathogen infectivity. A dose range of 2-4 Gy was found to impact stimulatory effects on germination and seedling parameters irrespective of the seed forms. However, these low doses had no influence of any sort on the sanitary and genetic quality of the seeds irrespective of the seed forms. Therefore, the irradiation of 2-4 Gy on unshelled groundnut cv. Chinese could significantly enhance quality and storability of the seeds.Item Production of Potato (Solanum Tuberosum L) Pre-Basic Seed through Tissue Culture in Katibougou, Mali(University of Ghana, 2018-07) Abdoulaye, M.In Mali, the main problems limiting the productivity and production of potatoes is the non-availability of quality seeds in adequate quantities and at affordable prices for the farmers. To meet quantity and quality requirements for potato seeds in Mali, this study proposes to undertake two experiments to improve the techniques adopted in the IPR/IFRA plant biotechnology laboratory in Mali. The evaluation of the effects of three (3) concentrations of coconut water and two (2) concentrations of potassium nitrate on potato plantlets growth in vitro and the effects of two physiological ages and three substrates on potato in vitro plants’ establishment, post in vitro growth and mini tubers production in vivo. The first experiment was laid out in a Completely Randomized Design (CRD) with twelve (12) treatments replicated 4 times. The second experiment was a factorial experiment with 2 factors (physiological ages: 2 levels and substrate: 3 levels) laid out in a Randomized Complete Block Design (RCBD) with 6 treatments replicated 4 times. The results in the first experiment showed that the culture medium M7 (MS+40 ml/l of coconut water +250 mg of potassium nitrate) had promoted all plant growth parameters (shoot emergence, plant height, number of nodes, leaves and roots and plant fresh and dry weight) after 30 days of in vitro culture. The lower concentrations of coconut water (40 ml) and potassium nitrate (250 mg) per liter of MS medium had significant and positive effects on all the in vitro growth parameters after 30 days of culturing. The results in the second experiment showed that the plantlet weaning age of 25 days and the post-flask culture substrate S1 (only soil) provided the best plant survival percentage at 20 days after transplanting in vivo. The substrate S2 (soil and cow dung 2:1) positively affects plant stem length, stem diameter, plant fresh and dry biomass formation, tuber yield, tuber numbers per plant and tuber grading size B (tubers with a diameter of less than 28 mm). The substrate compositions S1(only soil) has significantly affected the weight loss (12.50%) of tubers stored within 8 weeks. The weaning age 45 days and the substrates S2 (soil and cow dung 2:1) and S3 (soil and cow dung 1:1) conditions significantly reduced the number of sprouts per tuber and sprouts number per eye on tubers. In addition, the results indicate that for better and more rapid growth of potato plantlets in vitro culture, the coconut water concentration used as supplement to MS medium should be 40ml per liter of medium. The proportion of cow dung used in substrate composition should not exceed the soil and cow dung 2:1 mixture for maximum post transplanting plant re-establishment rate in vivo and for rapid maturity of mini-tubers.Item Post-Certification Surveillance of Marketed Vegetable Seeds in the Greater Accra Region for Seed Quality Maintenance(University of Ghana, 2018-07) Radiant, A.K.A.Quality seeds constitute one of the basic and the most important inputs in any vegetable crop production endeavour. A post-certification surveillance was undertaken to evaluate the quality of certified imported and local vegetable seeds at commercial retailers’ end in the distribution and marketing chains in the Greater Accra Region of Ghana. Structured questionnaires were administered to 18 commercial vegetable seed retailers who constituted the main vegetable seed delivery channels to farmers across the Greater Accra Region of Ghana. Survey data was analysed using SPSS to ascertain vegetable seed retailers’ knowledge and experience on certified vegetable seeds and to determine marketing challenges they face in their operations. The results of the survey indicated that, certified vegetable seed retailers were experienced, well-educated and had adequate knowledge on standard procedures and practices related to the seed retailing business. The major problems faced by seed retailers were the lack of proper storage facilities which made them resort to storing seeds at temperatures ranging from 29 to 37 0C, lack of access to good communication network between them and farmers and complaints about high cost of vegetable seeds due to high import duties. Twenty vegetable seeds were initially sampled from fifteen out of the eighteen retail shops for initial seed quality evaluation at the Seed Testing Laboratory of the Ghana Seed Inspection Division (GSID) of the Plant Protection and Regulatory Services Directorate (PPRSD). Following the first sampling, a second informed selection of eight specific vegetable seeds common to nine retail shops were sampled for another evaluation. Both laboratory evaluations were arranged in a CRD with 4 replications and evaluated for percentage germination, percentage purity, moisture content, seed health and seedling vigour. Data collected from both laboratory evaluations were analysed using Genstat statistical package 12th Edition. Fishers’ Protected LSD was used to separate treatment means at 5 % significance level. Results from the laboratory analysis showed that vegetable seed quality were up to the labelled recommended standards for most of the imported vegetable seeds except for eggplant and onion but quality of some locally produced vegetable seeds such as okra and hot pepper were below the labelled recommended values. Poor storage practices and re-packaging of seeds into smaller retail packs were identified to be responsible for the loss in seed quality. The study highlights the need for investments in infrastructure and equipment for maintenance of quality in the marketing and distribution value chain for vegetable seeds. Increase in the production of high quality locally produced vegetable seeds (hot pepper and okra) would ensure availability of these vegetable seeds for end users.Item Effect of Soil Amendment and Seed Extraction Techniques on Seed Yield and Quality of Pepper (Capsicum Chinensis) in Southern Senegal(University of Ghana, 2019-06) Bassene, S.Vegetable production in general and pepper production in particular are of paramount importance in the economic life of rural and peri-urban farmers in Senegal. However, high input costs such as seeds and chemical fertilizers are a limitation to the sector's growth. In order to find technologies capable of producing quality seeds with cheaper inputs, this study was conducted at the Djibelor Agricultural Research Centre in the southern region of Senegal. Six treatments T1 (NPK 300 kg/ha and urea 200 kg/ha), T2 (NPK 150 kg/ha, urea 200 kg/ha and compost 10 tons/ha), T3 (NPK 100 kg/ha, urea 200 kg/ha and compost 15 kg/ha), T4 (NPK 50 kg/ha, urea 200 kg/ha and compost 20 tons/ha), T5 (compost 25 tons/ha) and T6 (control) made from the combination of compost and chemical fertilizer were tested in a randomized complete block with four replicates. The results of this study revealed a positive effect of the combined fertilizer at different rates on pepper growth and reproduction parameters. The height of the plants, the number of branches, the thickness of the stems, the size of the fruits and the biomass were significantly increased with the mixture of compost and chemical fertilizers. In addition, these fertilizers had the effect of shortening days of the reproductive stages (50% flowering, 50% fruiting and 50% ripening) of the Big Sun pepper variety (Capsicum chinensis) used for this study. Also, after harvest two seed extraction techniques were used (Fresh fruit extraction and dry fruit extraction). With the two extraction techniques used, fruit drying prior to seed extraction played an important role in seed quality. The seeds from the dried fruits showed germination rates and germination vigour well above that of seeds from fresh fruits. These results suggest that the mixt of compost and low rate of chemical fertilizers in the south region of Senegal should be encouraged for use as a substitute to the high level cost of chemical fertilizers for optimum pepper fruits production. Furthermore, dried pepper berries prior to seed extraction is the best technique that maintains seed quality. Keywords: Capsicum chinensis, compost, chemical fertilizer, growth, yield, seed extraction and qualityItem Detection, Identification and Management of Seed-Borne Fungal Pathogens on Farmer Saved Soybean (Glycine Max (L.) Merrill) Seeds(University of Ghana, 2018-07) Ansaah, F.A.Soybean is afected by a wide range of diseases, many of which are seed-borne. Infection by seed-borne pathogens leads to seed rot, low seedling vigour and reduction in plant growth. Seed-borne fungal pathogens on farmer-saved seeds of soybeans were investigated by examining a total of eleven (11) seed samples from two districts (Saboba and Yendi) in the Northern region and one from CSIR-Savanna Agricultural Research Institute (CSIR-SARI). Appearance quality of farmer-saved soybean seed samples revealed the main categories of damaged seeds as shrivelled (ranging from 6% to 10.5%), discolored (8.3% to 12.5%), broken and cracked (5.5% to 12.5%). Four hundred seeds (400) from each seed sample were used. Seed sample obtained from Sunsong-Gbung in the Yendi district were found to have the highest proportion of discolored seeds (12.5%). Seed samples obtained from Zang district were observed to have the highest proportion (12.5%) of broken and cracked seeds. The blotter and agar plate incubation methods as described by International Seed Testing Association (ISTA) were used to identify fungi associated with the seed samples. A Completely Randomized Design with four replications was used. Two hundred (200) seeds from each seed sample were used with fifty (50) seeds per replication. A total of nine fungi were found to be associated with the soybean seeds evaluated using blotter and agar plate methods. Out of this number, four of them were identified as pathogenic on soybean and had high prevalence level before seed treatment applications as follows: Alternaria spp. (ranging from 9.0% to 14.2%), Cercospora spp. (9.0% to 11.9%), Fusarium spp. (9.8% to 15.2%) and Macrophomina phaseolina (7.8% to 13.4%). The other five fungi species were identified to be saprophytic. They had a high prevalence levels as well in the seed tested before seed treatment as follows: Aspergillus flavus (9.0% to 12.9%), Aspergillus niger (7.0% to 13.5%), Curvularia spp. (9.0% to 13.2%), Penicillium spp. (9.0% to 14.1%) and Rhizopus stolonifer (16.9% to 21.5%). Pathogenicity tests conducted on the four fungal isolates; Alternaria spp., Cercospora spp., Fusarium spp. and Macrophomina phaseolina to fulfil Koch’s postulate proved to be positive. A Completely Randomized Design with three replications was used. Nine potted plants were used for each treatment. All soybean plants inoculated with fungal isolates developed disease symptoms one week after inoculation. Re-isolation of fungal pathogens from diseased plants confirmed they were the causal organism of the symptoms that were observed. The use of Insector T 45 (Imidacloprid 350g/kg and Thiram 100g/kg), Monceren GT 390 FS (20% Imidaclopride) and 20% Pencycuron), Garlic extract (Allicin) and Neem (Azadirachtin) seed extract as seed treatments over a period of 90 days, led to a decrease in prevalence of fungal as well as an increase in seed germination and seedling vigour compared with the untreated seeds. Seeds treated with Monceren GT 390 FS over a period of 90 days had the highest reduction in fungal as well as high germination (85.0%) and seedling vigour (1360.1). Further studies should be conducted to determine bio-efficacy of the neem seed and garlic extract which have been proved to have some degree of antifungal effect in the study. Farmers should be educated on seed treatment measures before storage to prevent the build-up of seed-borne fungi which results in higher prevalence of fungi and poor seed germination.Item Assessment of Four Plant Extracts as Maize Seed Storage Protectants against Sitophilus Zeamais and Prostephanus Truncatus in Ghana.(University of Ghana, 2018-07) Gariba, Y.S.Sitophilus zeamais and Prostephanus truncatus are two most important storage insect pests of maize in Ghana and Africa as a whole. These insects cause weight loss of about 20 to 90 % of the untreated stored maize seeds. The control of post-harvest pests largely depends on the use of pesticides. Because of the adverse effects of insecticides on humans and the environment, attempts are being made to discover remedies pest management. This study was to assess four plants (Lantana camara, Moringa oleifera, Citrus sinensis and Hyptis suaveolens) extracts as maize seed storage protectants against Sitophilus zeamais and Prostephanus truncatus in Ghana. The study was laid out in a Completely Randomized Design (CRD) with three replications. Dried powders at (5 and 10%) and aqueous extracts (0.05 and 0.1 g/mL) of botanicals were prepared and evaluated for their insecticidal activity against P. truncatus and S. zeamais in treated maize seed. Untreated control and seed maize grains treated with Actellic were included as checks. There was decrease in oviposition and survivorship of insects was lowest when grains were treated with plant extracts at egg stage compared to the control. There was reduction in the number of adult insects that emerged at all developmental stages of the insects in treated maize seeds with methanol extracts of botanicals. All plant extracts at 0.1 g/ mL showed significant (P<0.001) difference in repellency compared to the control; however, H. suaveolens recorded the highest repellent activity to P. truncatus and S. zeamais at 93.3 and 96.7% respectively. Maize seeds treated with L. camara and M. oleifera recorded a percentage germination of 94.0 each followed by Actellic (93.0%), C. sinensis and H. suaveolens (86.0%) and the control (82.0 %). Maize seeds treated with methanol extracts of the botanicals after 10 weeks in cribs, recorded a reduction in percentage seeds damaged and weight loss caused by the two insects as compared to the untreated seeds which recorded higher number of damaged seeds and percentage weight loss. The phytochemical analysis revealed that compounds such as alkaloids, saponins, tannins and phenolic, steroids, flavonoids, anthroquinones, phlobatinins, cardiac glycosides and terpenoids were recorded in all the four plant extracts. These compounds may have caused lower progeny emergence, inhibitory effect, repellent action and antifeedant effect to S. zeamais and P. truncatus in grains treated with the botanicals.The study proposes that the botanicals tested have the potential in the growth of the seed industry to enhance quality seed production. It is therefore recommended to be used by farmers to control P. truncatus and S. zeamais in stored maize seed.Item Effect of Seed Priming on Germination and Seedling Development of Pepper under Salinity Stress(University of Ghana, 2018-07) Akrasi, E.J.Salinity stress affects crop production in various stages of plant growth with germination and seed development being the most sensitive to this stress. The need to raise uniform seedlings with better crop establishment is of utmost importance. Various seed priming methods have been employed in many crops to alleviate the effect of saline, drought and temperature stress. The objective of this study was to evaluate NaCl and PEG priming for enhanced germination and improved seedling establishment in pepper under salinity stress. A study to select a priming protocol using three concentrations (25, 50 and 100 mM) of each priming agent were applied on ‘Legon 18’ pepper seeds at three different durations of 12, 24 and 36 hours. Results indicated that 25 mM NaCl applied to ‘Legon 18’ seeds for 36 hours and 25 mM PEG for 24 hours, had the highest germination percentages, germination index, and rate of germination with lowered mean germination time after seeds were sown in seed trays. Further studies using best primed treatments of NaCl and PEG were used to assess their response to germination under salinity stress. Primed and unprimed seeds were sown in transparent plastic cups at different saline levels (0, 4.46 and 8.95 dS/m). The results revealed that NaCl and PEG priming improved germination percentage, germination index, seedling length, mean germination time and seedling vigour than control though there were no significant interaction between salinity and priming among the studied traits. Primed and unprimed seeds were transplanted after 30 days of being irrigated with tap water. Saline treatments (0, 4.46 and 8.95 dS/m) were imposed after transplanting for another 30 days. Priming treatments improved plant height, number of leaves, chlorophyll content, stem diameter and total leaf area although they were reduced by increase salinity. Also, priming treatments generally increased K+/Na+ and Ca+2/Na+ ratios in leaves, stems and roots of pepper seedling plants than in control at all saline levels. From the results, seed priming with NaCl and PEG can be employed to increase germination and seedling performance of Legon 18 pepper under salinity stress.Item Effect of Various Combinations of Organic Fertilizers on Yield and Its Components and Evaluation of Three Extraction Methods on Seed Quality of Tomato (Lycopersicon Esculentum) in Ghana(University Of Ghana, 2018-07) Darboe, M.L.Tomato is one of the most important vegetable crops in the world which is either consumed fresh or as a paste. The high cost of chemical fertilizers has led to farmers turning to alternative methods of cultivation like the use of organic manure. Most organic waste can be turned into fertilizer at low cost for crop production. Information on the effects of different extraction duration methods on seed quality and the costs involved have not been documented under production conditions in Ghana. The objectives of this study were to 1) determine optimal combinations of organic manure for maximum yield in tomato cultivation, 2) to determine the effects of seed extraction techniques on quality seed production as well as 3) cost benefit analysis for seed extraction and fruit production. The tomato variety used in the study was Pectomech, the most common tomato variety grown in Ghana due to its high yielding and tolerant to the environment. The research consist of seven treatments namely: cow dung 20 tons/ha, poultry manure 20 tons/ha, cow dung 10 tons/ha + poultry manure 10 tons/ha, cow dung 15 tons/ha + poultry manure 5 tons/ha, cow dung 5 tons/ha + poultry manure 15 tons/ha, NPK 150 kg/ha + urea 100 kg/ha and a control without application of organic manure no chemical fertilizer. The organic manures were applied on plots and incorporated into the soil. The experimental design used was a randomized complete block design with four replicates. Data collected included, chlorophyll content of leaves, number of branches per plant, number of leaves per plant, plant height, stem diameter, days to 50% flowering, day to 50% fruiting, days to 50% ripening, marketable fruit number and its weight, unmarketable fruit number and its weight, and yield per hectare in kilograms. Subsequently the following data was collected on extracted seeds (weight germination, and seedling height. The treatment effects produced significant differences (P = 0.05) in, days to 50% flowering, fruiting, and fruit ripening. The seeds obtained by extraction methods revealed cow dung manure at 20 tons/ha produced the maximum seed weight per hectare (55.8 kg/ha) whilst the control produced the least (20.6 kg/ha). Tomato seeds extracted and fermented for two days resulted in good quality seed (98.7% germination - blotter method; 86.5% germination - seed tray method) and seedlings (height 9.6 cm). Fermenting of seeds for two days was the most profitable extraction method.Item Empirical Validation of Genetic Gains of Genomic Selection In Cassava (Manihot Esculenta Crantz) Breeding(University of Ghana, 2017-12) Alabi, O.AThe success of a genetic breeding program can be assessed by the genetic gain obtained and successful varieties released. The validation of genomic selection (GS) efficacy in cassava (Manihot esculenta Crantz) breeding was the core objective of this study. A population of three cycles of genomic selection was evaluated to assess the genetic gains made in root yield, dry matter content and mosaic disease resistance in cassava. In the combined analysis, medium prediction accuracy was obtained for the dry matter content (r = 0.58), root weight (r = 0.49) and cassava mosaic disease resistance (r = 0.49) while lower accuracy was obtained for the root number. The expected gain and the realized selection gain for each of the traits are discussed here. Positive genetic gain (3.03%) was obtained in cycle two (C2) relative to and cycle one (C1), after an initial genetic loss (-1.62%) from cycle zero (C0) to C1 in the root weight. The translation of these genetic gains to actual root yield performance reflected in the top clones in the cycles of selection compared to the standard checks. The dry matter gain was highest (4.97%) in the C1 relative to C0; however, there was a decline in genetic gain in the subsequent cycles of selection. In a separate genomic prediction study, an assessment of prediction accuracy was conducted in a clonal evaluation trial, and this was compared with the accuracy of the prediction phase with genome-wide single nucleotide polymorphic markers, and the genomic estimated breeding values that were used for selecting the clones that were evaluated on the field. It was observed that prediction accuracy with genome-wide SNP markers has a direct relation to the field performance for all the root weight, dry matter content, harvest index and mosaic disease resistance. However, the cross- validation from the field trial was lower than the cross-validation from the prediction with the molecular markers. It is imperative to continually find ways of improving the accuracy of genomic prediction models for traits of interest especially for a complex trait like root yield which has significant additive and non-additive gene actions in cassava if GS is to be fully University of Ghana http://ugspace.ug.edu.gh iv implemented in cassava. A high prediction accuracy was obtained for the plant types and architecture traits which gives the flexibility of selecting good plant types even before the actual phenotyping. These findings suggest that genomic selection is a feasible complementary breeding scheme to conventional breeding especially in population improvement in cassava, hence the integration of GS with the existing conventional breeding programmes would greatly enhance genetic improvement of traits with greater efficiency and timely development of cassava varieties for the end-users.