Genotypic variation of Kenyan tomato (Lycopersicon esculentum L.) germplasm

Systematic genotypic analysis of Kenyan tomato germplasm was carried out in order to delineate potential variability based on various morphological, agronomic and biochemical traits. Both landraces and market cultivars were examined with a view to facilitating tomato improvement. In an experiment conducted in 1993 in a glasshouse at the Federal Agriculture Research Centre (FAL), Germany, 26 tomato landraces and nine market cultivars were investigated using block design. Analysis of variance clearly illustrated a large variation for all the quantitative traits. Landraces on average produced more fruit per plant (90) but of a smaller size than the market cultivars (19). However, market cultivars had a superior average fresh fruit weight of 56.5g while the landraces registered on average 40.6 g. Multiple correlation analysis confirmed the superiority of landraces for trait of fruit quality and a strong negative association between fruit weight. Limited structure groupings were detected on the basis of a principal components analysis. Using this method, processing and fresh tomato cultivars within the germplasm could be clearly separated on the basis of fruit characters. Furthermore, this analysis distinguished a few landraces from the market cultivars, although closer phylogeny through introgression was highly suspected. Within the landraces, the yellow-cherry types were distinct from all the others, On the basis of this study, the use of more prolific landraces, in terms of number of fruit as well as actual fruit yield, would be desirable for intensive and continuous production of tomatoes. The Journal of Food Technology in Africa Volume 6 Number 1 (January-March 2001), pp. 13-17 KEY WORDS: Genetic diversity, landraces, Lycopersicon esculentum, phylogenic relationaships, principal components analysis, Tomat

Genotypic variation of Kenyan tomato (Lycopersicon esculentum L.) germplasm

Genotypic variation of Kenyan tomato (Lycopersicon esculentum L.) germplasm Systematic genotypic analysis of Kenyan tomato germplasm was carried out in order to delineate potential variability based on various morphological, agronomic and biochemical traits. Both landraces and market cultivars were examined with a view to facilitating tomato improvement. In an experiment conducted in 1993 in a glasshouse at the Federal Agriculture Research Centre (FAL), Germany, 26 tomato landraces and nine market cultivars were investigated using block design. Analysis of variance clearly illustrated a large variation for all the quantitative traits. Landraces on average produced more fruit per plant (90) but of a smaller size than the market cultivars (19). However, market cultivars had a superior average fresh fruit weight of 56.5g while the landraces registered on average 40.6 g. Multiple correlation analysis confirmed the superiority of landraces for trait of fruit quality and a strong negative association between fruit weight. Limited structure groupings were detected on the basis of a principal components analysis. Using this method, processing and fresh tomato cultivars within the germplasm could be clearly separated on the basis of fruit characters. Furthermore, this analysis distinguished a few landraces from the market cultivars, although closer phylogeny through introgression was highly suspected. Within the landraces, the yellow-cherry types were distinct from all the others, On the basis of this study, the use of more prolific landraces, in terms of number of fruit as well as actual fruit yield, would be desirable for intensive and continuous production of tomatoes

Response of tomato genotypes to induced salt stress

Thirteen tomato (Lycopersicon esculentum   L.) genotypes were subjected to salt treatment under hydroponics and their responses monitored in a set of two experiments with the objective of advancing them as potential salt tolerant tomato scion and/or rootstocks. Salt applications ranged from 0 to 2% NaCl, with the resultant EC values of 1.4 to 37 dS m-1, respectively. Genotypes were cultured in the experimental solutions for up to four weeks in the greenhouse. Significant genotypic and/or salt treatment effects were registered on plant height, leaf green meter value and area, dry matter yield, Na+ and Cl- accumulation in tomato tissues. Salt treatment at 2% NaCl stimulated chlorophyll production, but caused severe depression on dry matter yield and leaf area. Some tomato genotypes consistently showed superior biological activity at higher salinity and others exhibited greater shift in the shoot:root ratio (from 8:1 to 5:1 for 'First'), based on dry matter biomass production thus displaying relatively greater adaptation to salt stress. Two tomato genotypes ('Siozawa' and 'Gambaru Ne-3') displayed superior performance

Comparison between embryoid and shoot primordia methods of plantlet production for Asiatic hybrid lily and Oriental hybrid lily

Growth and development from shoot primordia and embryoids obtained from the Asiatic Hybrid Lily and the Oriental Hybrid Lily were studied. Shoot primordium and embryoid formation of the Asiatic Hybrid Lily was more successful than the Oriental Hybrid Lily. The highest shoot primordium formation medium of the Asiatic Hybrid Lily from apical meristem was achieved at 0.5 BA (6-benzylaminopurin) without NAA (nafthalen acetic acid), and that of the Oriental Hybrid Lily required 0.01 mg/l NAA and 0.5 mg/l BA. Embryogenic calli from the shoot apex for embryoid germination gave rise to numerous embryoids, which regenerated rapidly in the medium with the same concentrations of NAA and BA in the medium for shoot primordium formation. Concentrations of NAA and BA in the medium for regeneration from shoot primordium and embrioids were similar to treatment for shoot primordium and embryoids formation but differed between the Asiatic Hybrid Lily and the Oriental Hybrid Lily. Young plants regenerated in vitro from shoot primordium and embryoids acclimatised with the maintenance of humidity. Only a few cases of somaclonal mutation were noted in the regenerated plants from shoot primordium and embryoids. Thus, our results suggest that plantlets produced by these methods are stable and commercial production via this protocol is feasible for lily propagation. Key Words: Asiatic Lily, mutation, propagation, shoot primordial (African Crop Science Journal: 2000, 8(2): 117-128

Exploiting the Genetic Diversity of Vegetable African Nightshades

African nightshades (Solanum section Solanum) are an important source of daily nutrients and income for small-scale farmers in sub-Saharan Africa and are a delicacy for urban inhabitants. The section is one of the most ubiquitous, largest and most diverse species groups of the genus Solanum, with more than 30 reported species. Complete profiling of the species in this section has been hampered by several morphological, cytological and taxonomic complexities. There is great diversity within the section that could be exploited to improve African nightshade for greater productivity, income generation and nutritional benefits. This paper outlines some factors responsible for the diversity and emphasizes the need for conservation, improvement and utilization of the agrobiodiversity within this sectio