Biochemical quality indices of sorghum genotypes from east Africa for malting and brewing

There is a gradual shift to substitute barley with sorghum in brewing industry to reduce the cost of doing business and make beer products more competitive. This study evaluates the sorghum genotypes for desirable malting and brewing characteristics. Biochemical characteristics assayed for 131 sorghum [Sorghum bicolor (L) Moench] accessions included total starch, amylopectin, amylose, proteins, tannins contents, germination energy and germination capacity. Results indicate that starch contents ranged from 22.8 - 81.2%, amylose from 11.5 - 30.2% while the amylopectin content ranged from 6.6 - 59.8%. Generally, amylose contents of sorghum genotypes were lower than their amylopectin contents, with a ratio of 1:2. The mean protein content for the sorghum accessions was 9.4% with a range of 3 - 18%, while that of barley was from 7.7 - 9.8%. Germination energy and germination capacity for sorghum ranged from 82.9 - 99.8% and 74.0 to 99.5%, respectively. Barley varieties showed germination energy and capacity greater than 98%. Sorghum tannin contents ranged from 2.55 mg/100 ml to as high as 100 mg/100 ml while barley varieties had tannin contents of 8.9 to 10.3 mg/100 ml. Two genotypes, SDSA 1x ICSR 43 and SP 993520-1 were the most favorable for brewing.Keywords: Sorghum, starch, protein, tannin, germination energy, malting and brewingAfrican Journal of Biotechnology, Vol. 13(2), pp. 313-321, 8 January, 201

Cane Yield and Juice Volume Determine Ethanol Yield in Sweet Sorghum (Sorghum bicolor L. Moench)

Sweet sorghum (Sorghum bicolor L. Moench) contains fermentable sugars in the stem that can be converted to ethanol. The current study aimed at evaluating the performance of three sweet sorghum genotypes with five checks and contributes towards availing suitable sweet sorghum for industrial ethanol production. Field studies were carried out in Kenya at varied locations in a randomized complete block design with three replications. Sorghum was harvested at hard dough stage of grain development and evaluated for several stem juice production traits including plant height, cane yield, juice volume, degrees Brix, total, reducing, and non-reducing sugars, and ethanol yield via juice fermentation. Analyses of variance using SAS version 9.1 showed a significant effect of genotype for morphological characters and ethanol yield. Genotype EUSS10 produced the greatest cane (27.4 T/ha) and juice yield (7806.7 L/ha) whereas ACFC003/12 recorded the greatest ethanol yield (423.1 L/ha). At all sites, EUSS10 had the greatest plant height and days to 50% heading whereas SS04 had the greatest Brix and total sugar concentration. The greatest grain yield and non-reducing sugar concentration was produced by SS17 and SS21, respectively. Results of this study show that though Brix and total sugars are desirable for ethanol yield, cane yield, and juice volume of sweet sorghum determines the ultimate volume of ethanol produced

Adaptability and Stability Study of Selected Sweet Sorghum Genotypes for Ethanol Production under Different Environments Using AMMI Analysis and GGE Biplots

The genotype and environment interaction influences the selection criteria of sorghum (Sorghum bicolor) genotypes. Eight sweet sorghum genotypes were evaluated at five different locations in two growing seasons of 2014. The aim was to determine the interaction between genotype and environment on cane, juice, and ethanol yield and to identify best genotypes for bioethanol production in Kenya. The experiments were conducted in a randomized complete block design replicated three times. Sorghum canes were harvested at hard dough stage of grain development and passed through rollers to obtain juice that was then fermented to obtain ethanol. Cane, juice, and ethanol yield was analyzed using the additive main effect and multiplication interaction model (AMMI) and genotype plus genotype by environment (GGE) biplot. The combined analysis of variance of cane and juice yield of sorghum genotypes showed that sweet sorghum genotypes were significantly (P<0.05) affected by environments (E), genotypes (G) and genotype by environment interaction (GEI). GGE biplot showed high yielding genotypes EUSS10, ACFC003/12, SS14, and EUSS11 for cane yield; EUSS10, EUSS11, and SS14 for juice yield; and EUSS10, SS04, SS14, and ACFC003/12 for ethanol yield. Genotype SS14 showed high general adaptability for cane, juice, and ethanol yield

Flowering margins support natural enemies between cropping seasons

Here we investigated how agricultural landscapes support natural pest regulating insects between cropping seasons; an important challenge in Pest Management by Small-Holder Farmers so aligns with this special issue. Smallholders in East Africa clear margins to provide fodder for cattle or livestock or simply to reduce the ingression of weeds into crop fields. We show that there was a significant seasonal variation in plant species richness and diversity around crops and the abundance of margin plants was strongly linked to abundance of natural enemies in the off season. The time since harvesting was also a significant factor influencing the overall abundance of natural enemies. Our paper reinforces our understanding of the importance flowering plants in agricultural systems as a refuge for natural enemies and other beneficial insects but uniquely emphasising the time between cropping seasons. Improving agricultural landscapes between crops to better support invertebrates will lead to more effective natural pest regulation early in the following crop with positive outcomes for the farmers and their families

Flowering margins support natural enemies between cropping seasons

IntroductionPopulations of natural enemies of insect pests are declining owing to agricultural intensification and indiscriminate use of pesticides, and this may be exacerbated in agricultural systems that clear all margin plants after the cropping season for other uses such as fodder. Retaining a diversity of non-crop flowering vegetation outside the cropping season may support more resilient and effective natural pest regulation.MethodsWe tested the potential for non-crop vegetation to support natural enemies in fields across two locations after harvesting the primary crops of lablab and maize.ResultsA total of 54 plant species were recorded across the sites in Kenya with 59% of them being annuals and 41% perennials. There was a significant seasonal variation in plant species richness (ANOVA: F1, 16 = 33. 45; P&lt; 0.0001) and diversity (ANOVA: F1, 16 = 7.20; P = 0.0511). While time since harvesting was a significant factor influencing the overall abundance of natural enemies (ANOVA: F2, 1,133 = 8.11; P&lt; 0.0001), they were generally higher in abundance in locations with margin plants or where a diversity of margin plants was observed.DiscussionThese findings demonstrate that flowering plants in agricultural systems offer refuge and alternative food for natural enemies and potentially other beneficial insects between cropping seasons. The conservation of natural enemies between crops may lead to more effective natural pest regulation early in the following crop, thus reducing reliance on insecticides application

Modeling Infant Mortality Risk Factors using Logistic Regression Model and Spatial Analysis in Kenya

Globally, infant mortality is used as an important indicator for healthcare status hence an important tool for evaluation and planning of public health strategies. Despite of numerous interventions by governments aimed at reducing infant mortality, high rates are still reported in Kenya. A lot of resources are channeled towards its control leading to low productivity hence impacting the household economic welfare and national GD. The specific objective was to establish risk factors and the spatial variation of infantmortality in Kenya by analyzing the 2014 Kenya Demographic Health Survey data. A fully Bayesian paradigm and logistic regression model were used to determine infant mortality risk factors and spatial variation in Kenya.Demographic, socioeconomic and environmental factors were found to have significant effect on infant mortality. Counties from the northern parts of Kenya, Rift Valley, Central, Eastern, Nyanza, Coastal and Western parts of Kenya showed a high level of infant deaths. Infant mortality is highin arid and semi-arid areas and coastal areas due to high prevalence of infectious diseases and inadequate water supply, health facilities and low education levels. Infant mortality varies significantly across regions in Kenya due to cultural activities, and weather patterns hence exists spatial autocorrelation among neighboring regions

Leaf Gas Exchange and Root Nodulation Respond to Planting Density in Soybean [Glycine max (L) Merrill]

Planting density influences structural characteristics and affects mineral nutrient acquisition, irradiance and photosynthesis amongst plants. An experiment was conducted to determine the effect of planting density on leaf gas exchange and nodulation of soybean (Glycine max (L) Merrill). The experiment was conducted as a randomized complete block design (RCBD) in a 5 by 2 factorial treatment arrangement and was replicated three times. Planting density (10, 12, 20, 40, and 80 plants m−2) and soybean varieties (EAI 3600 and DPSB 19) were first and second factors, respectively. Collected data were subjected to analysis of variance in GENSTAT. Significantly different treatment means were separated using Tukey’s honestly significant difference test at 0.05 significance level. Higher planting density significantly increased (p<0.001) interception of photosynthetically active radiation. Increasing number of plants per unit area significantly (p<0.001) reduced root nodulation, stomata conductance, sub-stomatal CO2 concentration, photosynthetic and transpiration rates. Total chlorophyll content was not responsive to planting density though concentration of chlorophyll “a” content was significantly (p<0.005) higher at lower plant density than at higher plant density. Soil moisture status increased with reduction in plant density. Indeterminate variety DPSB 19 had higher rates of stomata conductance, photosynthesis and sub-stomatal CO2 concentration compared to determinate variety EAI 3600

Genetic diversity of African sorghum (Sorghum bicolor L. Moench) accessions based on microsatellite markers

Abstract Genetic diversity plays an important role in selection of parental stocks in plant breeding. Sorghum [Sorghum bicolor (L.) Moench] breeding initiatives have been constrained by lack of information on genetic diversity of cultivated accessions which would otherwise guide in the choice of heterotic parents for hybridization. This study was carried out to determine genetic diversity of sorghum accessions collected from Africa and ICRISAT using simple sequence repeats (SSR) of microsatellite marker. Thirty sorghum SSR markers were used to assess the genetic diversity of 134 sorghum accessions. The number of alleles per microsatellite locus in the 134 sorghum accessions ranged between 2 to 22, with a total of 259 different alleles having been amplified. The greatest number of alleles was found at the locus 3590e705f67911e0b58c0010185a4b14 with 22 alleles. The average Polymorphism Information Content (PIC) for all the assayed sorghum accessions was 0.55. Expected heterozygosity of population ranged between 2.91 for Sudan and 1.58 for Central Africa. Pairwise population comparisons for genetic identity were derived based on Nei&apos;s. Genetic identity of the populations ranged from 0.36 for Central Africa and Northern Africa to 0.93 between Eastern Africa and Rwanda. Analysis of Molecular Variance (AMOVA) revealed that 75% of the molecular variation in sorghum accessions was due to within individual populations while 25% of the total variation was partitioned among populations. There was low population differentiation due to either continuous exchange of genes between sorghum populations largely by germplasm exchange or no intense selection processes. The diversity observed within sorghum accession from Sudan and East African region could be useful in improvement of sorghum for various traits

Effect of Harvesting Stage on Sweet Sorghum ( Sorghum bicolor

Harvesting stage of sweet sorghum (Sorghum bicolor L. Moench) cane is an important aspect in the content of sugar for production of industrial alcohol. Four sweet sorghum genotypes were evaluated for harvesting stage in a randomized complete block design. In order to determine sorghum harvest growth stage for bioethanol production, sorghum canes were harvested at intervals of seven days after anthesis. The genotypes were evaluated at different stages of development for maximum production of bioethanol from flowering to physiological maturity. The canes were crushed and juice fermented to produce ethanol. Measurements of chlorophyll were taken at various stages as well as panicles from the harvested canes. Dried kernels at 14% moisture content were also weighed at various stages. Chlorophyll, grain weight, absolute ethanol volume, juice volume, cane yield, and brix showed significant (p=0.05) differences for genotypes as well as the stages of harvesting. Results from this study showed that harvesting sweet sorghum at stages IV and V (104 to 117 days after planting) would be appropriate for production of kernels and ethanol. EUSS10 has the highest ethanol potential (1062.78 l ha−1) due to excellent juice volume (22976.9 l ha−1) and EUSS11 (985.26 l ha−1) due to its high brix (16.21)

Field margins and cropping system influence diversity and abundance of aphid natural enemies in Lablab purpureus

Field margin plants around crops are postulated to increase natural enemy abundance to enhance pest management. A trial was conducted to determine the contribution of field margin vegetation and cropping systems to natural enemies of bean aphids (Aphis fabae) on Lablab purpureus, an orphan crop legume. Natural enemy populations were surveyed in plots with cross combination of lablab monocrop or maize-lablab intercrop and with or without planted field margins comprising four plant species (Chenopodium album, Bidens pilosa, Galinsoga parviflora and Tagetes minuta), arranged in randomized complete block design with four replicates. A cage experiment was also conducted to understand the extent to which these field margin plants supported the parasitoid wasp, Aphidius colemani, to parasitize bean aphids. A total of 2029 insects from 10 families were collected using sticky cards and pan traps. In comparison to plots with no field margin plants, the presence of plant-rich field margins increased abundance of natural enemies by (9.5 %) and supported higher populations of Braconidae (parasitoids) and damsel bugs (predators). The maize-lablab intercrop had 15.5% lower abundance of natural enemies than the lablab monocrop. Higher grain yield was recorded in plots with a field margin vegetation (300 kg ha-1) compared to plots without field margin vegetation (210 kg ha-1). The presence of a companion plant did not significantly affect the performance of parasitoids, in the cage experiment, indicating that parasitoids were not limited by access to food. In supporting aphid parasitization, B. pilosa was associated with the highest number of mummies (8.28). The lowest number of mummies were observed in cages with T. minuta (3.44). These results demonstrate the potential of plant-rich field margins to augment natural enemy populations and enhance conservation biocontrol of aphids