Diversity of Sorghum (Sorghum bicolor L. Moench) Germplasm from Tanzania

Sorghum (Sorghum bicolor L. Moench) is an important cereal crop cultivated in varied agro-ecological zones of Tanzania ranging from the southern highlands to coastal lowlands. Different cultivars and varieties of sorghum are needed for cultivation in such varied zones. Phenotypic properties of Tanzanian sorghums are not well-studied. Objective of this study was to phenotype some sorghum germplasm from Tanzania using morphological markers to establish their diversity for future use in breeding programs. Ninety-eight sorghum genotypes were evaluated at Bumala and Amagoro in Western Kenya during 2009 and 2010 seasons in a randomized complete block design. The International Plant Genetic Resource Centre descriptors of 1993 were used for data collection. Accession MCSR T29 was the earliest which took only 64 days while MCSR T80 was the latest taking 86 days to attain 50% flowering compared to the overall mean of 71 days. The MCSR T71 was the best yielder (114.6 g/ panicle) and MCSR T10 was the lowest (10.3 g/panicle) compared to overall mean of 92.4g/panicle. About 60% of the sorghums had brown and only 2.2% had black grains. MCSR T90 had bold grains with 1000 seed weight of 55.2g. Leaves per plant ranged from 7 in MCSR T69 to 17 in MCSR T25. Plant height ranged from 72.8 cm in MCSR T53 to 434.6 cm in MCSR T80. This study showed that, Tanzanian sorghums are diverse therefore could be used in future breeding programs for developing multipurpose and adapted cultivars. Keywords: Cultivars, Diversity, Phenotype, Varieties, SorghumSorghum (Sorghum bicolor L. Moench) is an important cereal crop cultivated in varied agro-ecological zones of Tanzania ranging from the southern highlands to coastal lowlands. Different cultivars and varieties of sorghum are needed for cultivation in such varied zones. Phenotypic properties of Tanzanian sorghums are not well-studied. Objective of this study was to phenotype some sorghum germplasm from Tanzania using morphological markers to establish their diversity for future use in breeding programs. Ninety-eight sorghum genotypes were evaluated at Bumala and Amagoro in Western Kenya during 2009 and 2010 seasons in a randomized complete block design. The International Plant Genetic Resource Centre descriptors of 1993 were used for data collection. Accession MCSR T29 was the earliest which took only 64 days while MCSR T80 was the latest taking 86 days to attain 50% flowering compared to the overall mean of 71 days. The MCSR T71 was the best yielder (114.6 g/ panicle) and MCSR T10 was the lowest (10.3 g/panicle) compared to overall mean of 92.4g/panicle. About 60% of the sorghums had brown and only 2.2% had black grains. MCSR T90 had bold grains with 1000 seed weight of 55.2g. Leaves per plant ranged from 7 in MCSR T69 to 17 in MCSR T25. Plant height ranged from 72.8 cm in MCSR T53 to 434.6 cm in MCSR T80. This study showed that, Tanzanian sorghums are diverse therefore could be used in future breeding programs for developing multipurpose and adapted cultivars. Keywords: Cultivars, Diversity, Phenotype, Varieties, Sorghu

Prevalence, virulence genes and Antimicrobial Resistance of Shiga-toxigenic E.coli in diarrhoea patients from Kitale, Kenya

Introduction: Shiga toxin-producing Escherichia coli (STEC) are among the most important causes of food-borne diseases. They cause illnesses ranging from mild diarrhea to more severe conditions that may progress to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). The burden of STEC in patients with diarrheal illness in Kitale county referral hospital, Trans-Nzoia County had not been established.Objectives: To determine the prevalence of STEC, its associated virulence genes and antimicrobial resistance among patients seeking treatment for diarrhoeal illness at Kitale County Referral Hospital.Methods: Stool samples from patients seeking treatment for diarrheal illness and had consented to participate in the study were collected and cultured for enteric bacteria. Suspect E.coli isolates were further identified using conventional biochemical methods. Conventional multiplex PCR targeting Shiga toxins (stx1, stx2, hlyA and attaching and effacing mechanisms (eaeA) were used to detect STEC virulence markers responsible for the Pathogenicity of STEC infection among other E.coli pathotypes.Results: A total of 295 participants were enrolled; median age 120 months (IQR: 36-312). 39 %( 115) were children aged <5yearsof whom 54% (160) were females. The prevalence of pathogenic E.coli was 19%56/295 and STEC was the most prevalent among E.coli pathotypes at5.4%16/295. The Stx2 gene and the Stx1/Stx2/hlyAcombination were the most prevalent in the STEC strains. The virulence genes (Stx1, Stx2, eaeA* and HlyA*)were observed in 13, 19, 9 and 14 in STEC isolates respectively.The most common gene was Stx2 and combinations of (Stx1+Stx2+hlyA)genes. Antimicrobial resistance to commonly prescribed antibiotics: chloramphenicol, ampicillin 10μg, erythromycin15μg, gentamicin10μg, ciprofloxacin 5μg, tetracycline 30μg, Trimethoprim/Sulfamethoxazole 25 μg, Cefotaxime 30 μg, furazolidine (8μg) and nalidixic acid 30 μg. were observed for all E.coli isolates except one (1.8%; 95% CI=0.1-9.6%). No isolates among STEC showed resistance to Furazolidine drug. However, Trimethoprim / Sulphurmethoxazole) was the drug which exhibited the highest resistance at (94%, 95% CI 70 to 99%).Conclusion and recommendation: Prevalence of STEC was 5.4%, (Stx1/Stx2/hlyA) virulence genes combination was the most common. High resistance to commonly prescribed antibiotics were observed in E.coli isolates and may be an existing problem that needs to be further research investigation.Keywords: Shiga-Toxigenic Escherichia coli (STEC), antimicrobial resistance, Kitale County referral hospitalAfr J Health Sci. 2017; 30(2):105-11

Tolerance to aluminium toxicity in Tanzanian sorghum genotypes

Aluminium (Al) toxicity is a major abiotic constraint on grain sorghum (Sorghum bicolor L. Moench) production on acid soils in East Africa. Aluminium in acidic soil inhibits water and mineral uptake from and consequently, reduces plant vigour and yield. A study was done to determine genetic diversity of Tanzania's sorghum for response to Al toxicity. Five day old seedlings of 98 sorghum genotypes were subjected to 0, 148 or 222.25 moles of Al3+ supplied as Al2 (SO4)3.16H2O in Hoagland's nutrient solution. Seedlings were raised in a growth chamber for five days, after which root lengths were recorded. Net root growth was used to discriminate the germplasm into phenotypic groups. The genotype MCSR T33 exhibited highest net root length and was classified as tolerant. Wahi, MCSR T69 and MCSR T11 were moderately tolerant, while the rest were susceptible.La toxicit\ue9 aluminique est une contrainte majeur \ue0 la production du sorhgo (Sorghum bicolor L. Moench) sur les sols acides en Afrique de l'est. L'aluminium (Al) des sols acides inhibe l'assimilation d'eau et de min\ue9raux du sol, et r\ue9duit par cons\ue9quent la vigueur des plantes et le rendement.Une \ue9tude \ue9tait faite pour d\ue9terminer la diversit\ue9 g\ue9n\ue9tique du sorgho de la Tanzanie en r\ue9ponse \ue0 la toxicit\ue9 aluminique. Les plants ag\ue9s de 5 jours issus de 98 g\ue9notypes de sorgho \ue9taient soumis \ue0 0, 148 ou 222.25 moles de Al3+ fournis sous forme de Al2 (SO4)3.16H2O dans une solution de nutriment de Hoagland. Les plantules \ue9taient plant\ue9es dans la chambre de croissance pendant 5 jours apr\ue8s lesquels la longueur des racines \ue9tait mesur\ue9e. La croissance nette des racines \ue9tait utilis\ue9e pour s\ue9parer les racines en groupes ph\ue9notypiques. Le g\ue9notype MCSR T33 avait exhib\ue9 une longueur nette plus \ue9lev\ue9e des racines et \ue9tait classifi\ue9 comme tol\ue9rant. Wahi, MCSR T69 et MCSR T11 \ue9taient mod\ue9r\ue9ment tol\ue9rant, alors que les restes \ue9taient susceptibles

EFFECT OF RIDGING AND INTERCROPPING ON SORGHUM PRODUCTIVITY IN ARID AND SEMI-ARID LANDS OF EASTERN KENYA

Soil moisture deficit is a key constraint to sorghum ( Sorghum bicolor ) productivity in arid and semi-arid lands globally. The objective of this study was to determine the effect of ridging and sorghum-bean intercropping (additive system) on soil moisture conservation and sorghum productivity. Sorghum (gadam) was grown either as a sole crop or intercropped with two bean ( Phaseolus vulgaris L.) varieties (KATx56 and KAT B1), under two types of ridging (open ridges and tied ridges), and a control without ridges for two years. The study was set up in split plot arrangement, in a randomised complete block design, at the Kenya Agricultural and Livestock Research Organization, Kiboko, in 2019 and 2020. There was no significant interaction between ridging and intercropping. Soil moisture content increased by 11-26% due to ridging; and decreased by -11 and -7% due to sorghum-KAT B1 and Sorghum-KAT X56 intercropping, respectively. Higher moisture content due to ridging was attributed to formation of basin-like structures, which increased water harvesting and infiltration compared to the no ridges where surface run-off was predominant. The highest moisture content was attained on sole bean, followed by sole sorghum and then sorghum/bean intercropping. The decrease in moisture content in intercrops of sorghum/bean relative to their specific sole crops was attributed to higher crop density, which reduced crop spacing, thus triggering competition for available soil moisture. The highest sorghum grain and equivalent yields were obtained in the ridged plots. Intercropping resulted into decrease in sorghum grain yield, but led to increase in sorghum equivalent yield (SEY) and Land Equivalent Ratio (LER). The results show that both ridging and intercropping are suitable for higher water use efficiency and land productivity in ASALs of Kenya.Le d\ue9ficit d\u2019humidit\ue9 du sol est une contrainte majeure \ue0 la productivit\ue9 du sorgho (Sorghum bicolor) dans les terres arides et semi-arides \ue0 l\u2019\ue9chelle mondiale. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer l\u2019effet du billonnage et de la culture intercalaire sorgho-haricot (syst\ue8me additif) sur la conservation de l\u2019humidit\ue9 du sol et la productivit\ue9 du sorgho. Le sorgho (gadam) \ue9tait cultiv\ue9 soit en monoculture, soit en association avec deux vari\ue9t\ue9s de haricot (Phaseolus vulgaris L.) (KATx56 et KAT B1), sous deux types de billons (billons ouverts et billons li\ue9s), et un t\ue9moin sans billons pendant deux ann\ue9es. L\u2019\ue9tude a \ue9t\ue9 mise en place en parcelles divis\ue9es, dans une conception en blocs complets randomis\ue9s, \ue0 l\u2019Organisation de recherche sur l\u2019agriculture et l\u2019\ue9levage du Kenya, Kiboko, en 2019 et 2020. L\u2019\ue9tude n\u2019a montr\ue9 aucune interaction significative entre le billonnage et la culture intercalaire. La teneur en humidit\ue9 du sol a augment\ue9 de 11 \ue0 26 % en raison du billonnage ; et diminu\ue9 de -11 et -7% en raison des cultures intercalaires sorgho-KAT B1 et Sorgho-KAT X56, respectivement. La teneur en humidit\ue9 plus \ue9lev\ue9e due aux cr\ueates a \ue9t\ue9 attribu\ue9e \ue0 la formation de structures de type bassin, ce qui a augment\ue9 la collecte et l\u2019infiltration de l\u2019eau par rapport \ue0 l\u2019absence de cr\ueates o\uf9 le ruissellement de surface \ue9tait pr\ue9dominant. La teneur en humidit\ue9 la plus \ue9lev\ue9e \ue9tait sur le haricot unique, suivi du sorgho unique, puis de la culture intercalaire sorgho/haricot. La diminution de la teneur en humidit\ue9 dans les cultures intercalaires de sorgho/haricot par rapport \ue0 leurs cultures uniques sp\ue9cifiques a \ue9t\ue9 attribu\ue9e \ue0 une densit\ue9 de culture plus \ue9lev\ue9e, qui a r\ue9duit l\u2019espacement des cultures, d\ue9clenchant une comp\ue9tition pour l\u2019humidit\ue9 disponible du sol. Les rendements les plus \ue9lev\ue9s en grain de sorgho et en \ue9quivalent ont \ue9t\ue9 obtenus dans les parcelles butt\ue9es. La culture intercalaire a entra\ueen\ue9 une diminution du rendement en grains de sorgho, mais a entra\ueen\ue9 une augmentation du rendement \ue9quivalent en sorgho (SEY) et du rapport d\u2019\ue9quivalent en terres (LER). Les r\ue9sultats montrent que le billonnage et la culture intercalaire conviennent \ue0 une plus grande efficacit\ue9 de l\u2019utilisation de l\u2019eau et \ue0 la productivit\ue9 des terres dans les TASA du Kenya

Tolerance to Aluminium toxicity in Tanzanian sorghum genotypes

Aluminium (Al) toxicity is a major abiotic constraint on grain sorghum (Sorghum bicolor L. Moench) production on acid soils in East Africa. Aluminium in acidic soil inhibits water and mineral uptake from and consequently, reduces plant vigour and yield. A study was done to determine genetic diversity of Tanzania's sorghum for response to Al toxicity. Five day old seedlings of 98 sorghum genotypes were subjected to 0, 148 or 222.25 moles of Al3+ supplied as Al2 (SO4)3.16H2O in Hoagland's nutrient solution. Seedlings were raised in a growth chamber for five days, after which root lengths were recorded. Net root growth was used to discriminate the germplasm into phenotypic groups. The genotype MCSR T33 exhibited highest net root length and was classified as tolerant. Wahi, MCSR T69 and MCSR T11 were moderately tolerant, while the rest were susceptible.La toxicité aluminique est une contrainte majeur à la production du sorhgo (Sorghum bicolor L. Moench) sur les sols acides en Afrique de l'est. L'aluminium (Al) des sols acides inhibe l'assimilation d'eau et de minéraux du sol, et réduit par conséquent la vigueur des plantes et le rendement.Une étude était faite pour déterminer la diversité génétique du sorgho de la Tanzanie en réponse à la toxicité aluminique. Les plants agés de 5 jours issus de 98 génotypes de sorgho étaient soumis à 0, 148 ou 222.25 moles de Al3+ fournis sous forme de Al2 (SO4)3.16H2O dans une solution de nutriment de Hoagland. Les plantules étaient plantées dans la chambre de croissance pendant 5 jours après lesquels la longueur des racines était mesurée. La croissance nette des racines était utilisée pour séparer les racines en groupes phénotypiques. Le génotype MCSR T33 avait exhibé une longueur nette plus élevée des racines et était classifié comme tolérant. Wahi, MCSR T69 et MCSR T11 étaient modérément tolérant, alors que les restes étaient susceptibles

Tolerance to aluminium toxicity in Tanzanian sorghum genotypes

Aluminium (Al) toxicity is a major abiotic constraint on grain sorghum (Sorghum bicolor L. Moench) production on acid soils in East Africa. Aluminium in acidic soil inhibits water and mineral uptake from and consequently, reduces plant vigour and yield. A study was done to determine genetic diversity of Tanzania's sorghum for response to Al toxicity. Five day old seedlings of 98 sorghum genotypes were subjected to 0, 148 or 222.25 moles of Al3+ supplied as Al2 (SO4)3.16H2O in Hoagland's nutrient solution. Seedlings were raised in a growth chamber for five days, after which root lengths were recorded. Net root growth was used to discriminate the germplasm into phenotypic groups. The genotype MCSR T33 exhibited highest net root length and was classified as tolerant. Wahi, MCSR T69 and MCSR T11 were moderately tolerant, while the rest were susceptible.La toxicité aluminique est une contrainte majeur à la production du sorhgo (Sorghum bicolor L. Moench) sur les sols acides en Afrique de l'est. L'aluminium (Al) des sols acides inhibe l'assimilation d'eau et de minéraux du sol, et réduit par conséquent la vigueur des plantes et le rendement.Une étude était faite pour déterminer la diversité génétique du sorgho de la Tanzanie en réponse à la toxicité aluminique. Les plants agés de 5 jours issus de 98 génotypes de sorgho étaient soumis à 0, 148 ou 222.25 moles de Al3+ fournis sous forme de Al2 (SO4)3.16H2O dans une solution de nutriment de Hoagland. Les plantules étaient plantées dans la chambre de croissance pendant 5 jours après lesquels la longueur des racines était mesurée. La croissance nette des racines était utilisée pour séparer les racines en groupes phénotypiques. Le génotype MCSR T33 avait exhibé une longueur nette plus élevée des racines et était classifié comme tolérant. Wahi, MCSR T69 et MCSR T11 étaient modérément tolérant, alors que les restes étaient susceptibles

Immediate and residual effects of lime and phosphorus fertilizer on soil acidity and maize production in western Kenya

Soil acidity and phosphorus (P) deficiency are some of the major causes of low maize yields in Kenya. This study determined the immediate and residual effects of lime and P fertilizer on soil pH, exchangeable aluminium (Al), available P, maize grain yield, agronomic P use and P fertilizer recovery efficiencies on a western Kenya acid soil. The treatments were: P fertilizer (0, 26 and 52 kg P ha−1 as triple super phosphate) and lime (0, 2, 4 and 6 tons lime ha−1 ) applied once at the beginning of the study. A burnt liming material with 92.5% calcium carbonate equivalent was used. Soil samples were analysed prior to and after treatment application. The site had low soil pH–H2 O (4.9), available P (2.3 mg kg−1 ), total N (0.17%), high Al (2.0 cmol kg−1 exchangeable Al and 29% Al saturation). Lime reduced soil pH and exchangeable Al, leading to increased soil available P. Lime at 2, 4 and 6 tons ha−1 maintained soil pH ≥ 5.5 for 2, 3 and 4 years, respectively. The study observed that the recommended P fertilizer rate (26 kg P ha−1 ) for maize production in Kenya was inadequate to raise soil available P to the critical level (≥10 mg P kg−1 soil bicarbonate extractable P) required for healthy maize growth. To maintain soil available P at the critical level where 52 kg P ha−1 and combined 52 kg P ha−1 + 4 tons lime ha−1 were applied, it would be necessary to reapply the same P fertilizer rate after every one and two cropping seasons, respectively. The 4-year mean grain yield increments were 0.17, 0.34, 0.50, 0.58 and 1.17 tons ha−1 due to 2, 4, 6 tons lime ha−1 , 26 kg P and 52 kg P ha−1 , respectively. Both agronomic P use and P fertilizer recovery efficiencies increased with increasing rates of lime and decreased with increasing rates of P fertilizer. Therefore, combined applications of both lime and P fertilizer are important for enhancing maize production on P-deficient acid soils in western Kenya