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Purpose: The study seeks to determine the level of awareness and the highest amount consumers were willing to pay by positioning the novel product ready-to eat-cereals for breakfast Sorghum-pigeon pea processed from locally grown crop. Methodology: Contingent Valuation Method (CVM) to assess consumer willingness to pay (WTP) for sorghum-pigeon pea flakes, which are Ready-to-Eat Cereals (RTEC). Three-stage sampling technique was used in selection of the two counties, and from each county three market places was identified. Glen sample size formula was used to obtain the total number of respondents, whereby a well semi-structured dichotomous questionnaire was used on 223 consumers from Makueni and Busia counties in Kenya. Double bounded logit model was employed in determining consumers' willingness to pay (WTP) for SPPF. Findings: Results from the WTP assessment showed that consumers in both counties were willing to pay for the Sorghum-Pigeon Pea Flakes. The average WTP value in Busia and Makueni Counties was 140 and 136 Kenya Shillings, respectively. Further, nearly half of the respondents in both counties were aware of the ready-to-eat breakfast cereal SPPF for nutritional improvement. According to the findings of the double-bounded logit regression, being male, marital status, awareness of SPPF, and living in Busia County all positively influenced WTP for SPP. Having formal employment and household expenditure, on the other hand, had a negative impact on the WTP for SPPF. Recommendations: The study recommends nutritional training to raise awareness of the benefits of consuming SPP. Furthermore, policies should focus on raising awareness of the nutritional benefits of SPPF among families, particularly those in Makueni.

Robusta coffee yields higher than Arabica coffee. However, it is limited by the inferior cup quality. The biochemical compounds found in coffee interact and determines the final cup quality. The objective of the study was to characterize the biochemical compounds found in Arabusta coffee hybrids. Twenty coffee genotypes including the Arabusta hybrids, backcrosses, Robusta and Arabica coffee were established at KALRO-Alupe (Busia) and Siaya -ATC in the year 2015. Coffee cherry was harvested and processed in the year 2018 and the green beans were analysed for sucrose, oil, trigonelline, caffeine and chlorogenic acids using the HPLC and soxhlet method. There were significant differences amongst the genotypes for these biochemical compounds across the two different environments (Busia and Siaya counties). Robusta recorded higher levels of caffeine and chlorogenic acids while the Arabusta hybrids recorded intermediate levels of the biochemical compounds between the Robusta and Arabica coffee species. The Genotype by Environment (G x E) interaction effect was only significant for chlorogenic acids. Caffeine, sucrose, oil and trigonelline levels were significantly high for genotypes evaluated in Siaya when compared to Busia. Chlorogenic acid had a positive significant association with caffeine, but was negatively correlated with coffee oil and sucrose. Coffee oil indicated a positive significant association with sucrose and Trigonelline. The Principal Component Analysis (PCA) differentiated the genotypes based on the levels of biochemical compounds indicating high genetic variation amongst the genotypes. Arabusta hybrids exceeded Robusta coffee in performance of biochemical compounds which implies that there was a successful introgression of quality genes

Sorghum (Sorghum bicolor [L.] Moench) is the fifth most important cereal crop worldwide and second aftermaize (Zeamays L.) in Kenya. It is an important food security crop in arid and semi-arid lands, where its production potential is hampered by drought. Drought tolerance can be measured by a plant’s ability to resist premature senescence, often described as stay-green. This study was carried out with the objective of identifying novel stay-green trait among wild and landrace genotypes of sorghum. Forty-four sorghum genotypes that included 16 improved, nine landraces, and 17 wild relatives of sorghum alongside known stay-green sources, B35 and E36-1, were evaluated under well-watered and water-stressed conditions in an alpha-lattice design of three replications. Data was collected on plant height (PHT), flag leaf area (FLA), panicle weight (PWT), 100-seed weight (HSW), relative chlorophyll content (RCC), number of green leaves at maturity (GLAM), days to 50% flowering (DFL), and grain yield (YLD). Genetic diversity was determined using diversity arrays technology (DArT) sequencing and quality control (QC) markers were generated using a java script. Lodoka, a landrace, was the most drought-tolerant genotype, recorded the highest numbers of RCC and GLAM, and outperformed B35 and E36-1 in yield under water-stress and well-watered conditions. The RCC was highly correlated with GLAM (r = .71) and with yield-related traits, HSW (r = .85), PWT (r = .82), and YLD (r = .78). All traits revealed high heritability (broad-sense) ranging from 60.14 to 98.4% for RCC and DFL, respectively. These results confirm earlier reports that wild relatives and landraces are a good source of drought tolerance alleles.

Sorghum is an under-utilized crop and one of the most important cereal crops in semi-arid tropics. In Kenya, sorghum is grown in the often drought prone marginal agricultural areas of Eastern, Nyanza and Coast regions where there are many biotic and abiotic constraints that reduce its productivity. The aim of the present study was to assess the current utilization and processing practices by small holder farmers. Makueni County, a representative of drought prone areas situated in agro-ecological zone was selected since sorghum is a widely cultivated crop and the region has organized formally registered farmer groups. Key informant interviews (20), household survey questionnaires (300) and focus group discussions (12) with the farmers were conducted to gather data on sorghum production, challenges in production consumption and utilization, processing technology and market access. Key informant interviews (20), household survey questionnaires (300) and focus group discussions (12) with the farmers were conducted to gather data on sorghum production, challenges in production consumption and utilization, processing technology and market access. The main uses of sorghum include: Stiff porridge (ugali) (37.6%), thin porridge (uji) (35.2%), fried dough (mandazi) (3.1%), flat bread (chapatti) (2.6%),githeri(sorghum mixed with legumes) (8.0%), sorghum cake (1.2%), beverage (sorghum tea) (0.8%) and animal feed (8.5%). The greatest challenges that hinders utilization and limits processing of sorghum and value addition were lack of markets (12.3%), low volumes of production due to low productivity (3.5%), lack of capital (4.6%), pest and diseases (38.2%), lack of farm equipment (24.6%) and lack of processing knowledge (16.8%). This work recommended that more farmers training on sorghum value addition be conducted to create awareness on sorghum products utilization and to link the products to the markets.

Robusta coffee is known to be high yielding than Arabica coffee, since it is more vigorous in growth. However, it is limited by the inferior cup quality. The aim of the study was to evaluate the performance of the Arabusta hybrids and its backcross derivatives for bean physical characteristics and organoleptic properties including their interrelationship. Nineteen coffee genotypes were evaluated at Siaya ATC and KALRO-Alupe, using randomized complete block design with three replications. Data on the bean grades and sensory traits was carried out on beans harvested in the year 2018. The results indicated that there was a significant variation on both the sensory and bean grade traits from the two locations. On average, Arabusta hybrids showed better performance on bean traits when compared to its backcrosses and Robusta. There was a highly significant positive correlation between the sensory traits which had highly significant positive association with aftertaste (r=0.96), aroma (r=0.84), balance (r=0.85), flavor (r=0.96) and overall standard (r=0.96). The positive significant correlation between the 100 bean weight and the AA bean size is an indication that weight of beans can be used in predicting the bean sizes. The interspecific hybridization enables the transfer of good cup quality attributes from Arabica coffee to Robusta coffee. Key words: Flavor, Arabica, bean grade, quality, Arabica, Robusta, environment, variation.

The biennial bearing and the long productive nature of coffee makes it difficult to release coffee variety within a short time span. This study aimed at evaluating the yield performance of the Arabusta hybrids and its backcrosses developed by Coffee Research Institute of the Kenya Agricultural and Livestock Research Organization (KALRO-CRI) using the morphological traits. Nineteen coffee genotypes were evaluated at Siaya ATC and KALRO-Alupe using randomized complete block design with three replications and the morphological data for growth and yield was recorded during the year 2018. The results indicated that there was significant difference in yield among the coffee genotypes and between the sites. Yield had positive significant associations with parentage berries per node (r= 0.61), berries on the longest primary (r= 0.58) and berries per node on the longest primary(r=0.60). The genotypic coefficient of variation (GCV) values for the morphological traits varied from 6.50 to 31.01%. Broad sense heritability ranged from 0.15 to 0.61 with bean yield recording heritability of 0.31. The number of berries on the longest primary had high broad sense heritability and high genetic advance indicating the presence of additive genes that can be used in coffee improvement through selection. Key words: Environment, Genetic advance, Robusta, Response, Selection, Variation

In Kenya, the key abiotic stress affecting rice production is drought stress which is experienced mainly during reproductive phase of the crop. This study evaluated the performance of Kenyan rice populations including 19 generation of crosses, 6 parental and 5 checks under well-watered and drought stressed environment with the aim of identifying the phenotypic traits that confer drought tolerance in rice. The 19 generation of crosses were in F3 when they were evaluated in the short rains season and later advanced to F4 in the long rains season. Nineteen generation of crosses rice (Oryza sativa L.) lines, six parental and five check lines were evaluated for response to drought under drought stressed and well-watered environment. The study was conducted over two seasons in the year 2016/2017 at Kenya Agricultural Livestock Research Organization (KALRO) -Mwea Centre. The experiment was set up in an alpha lattice design with three replications. Drought stress was imposed at panicle initiation by withholding irrigation till physiological maturity meanwhile the well-watered environment continued to enjoy the recommended irrigation regime from planting to physiological maturity. Yield data were scored for drought tolerance. AMMI analysis of variance for grain yield showed that genotypes from crosses of crosses of SARO5XNERICA11, NERICA2XSARO5 and NERICA15XSARO5 expressed high grain yield. AMMI stability Variance (ASV) showed genotypes NERICA15, Duorado Precoce and progenies from crosses of NERICA11XNERICA2, SARO5XKomboka and NERICA2XNERICA11 expressed high stability in both well-watered and drought-stressed environment. GGE analysis showed that Principal Components (PC1) and PC2 accounted for 96.46% and 3.54%, respectively. GGE biplots showed that genotypes from crosses SARO5XNERICA11 and NERICA15XSARO5 were the most stable and high yielding. GGE biplots ranked the rice lines as follows: those above average in performance, the stable ones, unstable and those below average in performance. SARO5XNERICA11 is worth of selection due to its high mean yield value and is stable across the mega-environments.

Rice is the third most important staple food in Kenya after maize and wheat and it is mostly grown by small scale farmers both for food and cash under irrigated and rainfed production systems. In this study, fourteen F 2.3 segregating populations together with their parental lines, were evaluated during the long and short rainy seasons of 2016/2017 at the Mwea Research Station (KALRO) in a randomized complete block design of three replications for grain yield, quality and agronomic traits. There were significant differences among genotypes for all the traits studied. Genotypes, Nerica 1, Nerica 2 and Basmati-370 matured earliest, whereas genotype, Basmati-370 gave the highest grain yields in both seasons. The F1 generations of crosses of Dourado x Nerica 3 and Mwur 4 x Nerica 3 had the highest positive Specific Combining Ability (SCA) gene effects for panicle length, days to flowering and grain yield. However in the F 2.3 generations, the progenies of Nerica 2 x Basmati-370 and Nerica 3 x Basmati-370 had the highest grain yields. Generations of Nerica 10 x Mwur 4 crosses, had the longest grains whereas the Basmati-370 genotype had the strongest aroma. Generations of NERICA 3 x Basmati 370 and NERICA 2 x Basmati 370 crosses were of mild aroma, but those of K1-99 x KOMBOKA and NERCA 10 were non aromatic. Grain yield was positively significantly correlated with number of productive tillers, number of filled grains and 1000 grain weight indicating that these traits could serve as secondary selection indices for yield. It is inferred that breeding rice cultivars with improved traits for grain yield, long grain and strong aroma would benefit from the utilization of parental and population germplasm identified in this study, in the pursuit of filling the current rice production deficit in the Kenyan consumer markets.

Climate change is hastening the genetic degradation of numerous crops in Kenya's semi-arid regions, jeopardising the food security of resource-poor farmers. Using simple sequence repeat (SSR) markers, this study evaluated the genetic diversity of available Sorghum bicolor L. germplasm with the goal of discovering varieties that can be chosen to suit the food security demands of these marginal areas. 39 SSR markers were genotyped on accessions from four agro-ecological areas based on their location in the genome and the high repeat sizes they represented. The alleles were called using the Gene Mapper software (version 3.7), sizes assigned with the allelobin software and the subsequent data analyzed with the Power Marker software (version 3.25). The diversity indices and intra-population structure were calculated using the Arlequin programme (version 2.0). Rogers modified distance was used to compute genetic distances, and principal component analysis was used to cluster the accessions (PCA). The average polymorphic information content (PIC) value was 0.536, suggesting moderate polymorphism levels. The variability within accessions among the populations was 56.37%, within individual accessions was 38.85% and among geographical origins was 4.78%. A low level of genetic differentiation (FST = 0.048) and a high inbreeding level (FIS = 0.59) showed an increased degree of allele fixation. The findings revealed that, despite the fact that most of the accessions were identical, there was enough genetic variety within and within Kenyan sorghum landraces to aid in the increase of sorghum yield.

Striga hermonthica is the most important parasitic weed in sub-Saharan Africa and remains one of the most devastating biotic factors affecting sorghum production in the western regions of Kenya. Farmers have traditionally managed Striga using cultural methods, but the most effective and practical solution to poor smallholder farmers is to develop Striga-resistant varieties. This study was undertaken with the aim of identifying new sources of resistance to Striga in comparison with the conventional sources as standard checks. We evaluated 64 sorghum genotypes consisting of wild relatives, landraces, improved varieties, and fourth filial generation (F4) progenies in both a field trial and a pot trial. Data were collected for days to 50% flowering (DTF), dry panicle weight (DPW, g), plant height (PH, cm), yield (YLD, t ha−1), 100-grain weight (HGW, g), overall disease score (ODS), overall pest score (OPS), area under Striga number progress curve (ASNPC), maximum above-ground Striga (NSmax), and number of Striga-forming capsules (NSFC) at relevant stages. Genetic diversity and hybridity confirmation was determined using Diversity Arrays Technology sequencing (DArT-seq). Residual heterosis for HGW and NSmax was calculated as the percent increase or decrease in performance of F4 crossover midparent (MP). The top 10 best yielding genotypes were predominantly F4 crosses in both experiments, all of which yielded better than resistant checks, except FRAMIDA in the field trial and HAKIKA in the pot trial. Five F4 progenies (ICSVIII IN × E36-1, LANDIWHITE × B35, B35 × E36-1, F6YQ212 × B35, and ICSVIII IN × LODOKA) recorded some of the highest HGW in both trials revealing their stability in good performance. Three genotypes (F6YQ212, GBK045827, and F6YQ212xB35) and one check (SRN39) were among the most resistant to Striga in both trials. SNPs generated from DArT-seq grouped the genotypes into three major clusters, with all resistant checks grouping in the same cluster except N13. We identified more resistant and high-yielding genotypes than the conventional checks, especially among the F4 crosses, which should be promoted for adoption by farmers. Future studies will need to look for more diverse sources of Striga resistance and pyramid different mechanisms of resistance into farmer-preferred varieties to enhance the durability of Striga resistance in the fields of farmers.

Coffee as a cash crop, reduces food insecurity by providing regular incomes and is a major foreign exchange earner in more than fifty tropical countries where it is grown either as Arabica (Coffea arabica) or Robust (Coffea canepora). In Kenya which grow some Robusta but mostly Arabica coffee, the production has been declining, mainly because world coffee prices have plummeted to about 5 USD for a 650Kg of un-hulled beans per acre. The only way world prices are likely to increase and benefit the small-scale farmers, is by improving the cup quality and enabling these countries to sell their coffee in specialty markets. This review, underscores the importance of analyzing and estimating organoleptic, sensory and biochemical compounds diversity in Arabica coffee, since these are the factors that determine cup quality. In an attempt to do so, the chapter presents experimental data that analyzed various sensory and organoleptic traits of Arabica coffee and their Arabusta hybrids that proves that tremendous genetic diversity exists in coffee genotypes grown in Kenya and it is possible to utilize this genetic variation to improve cup quality.

In order to select camu-camu superior genotypes, a comparative of clones from natural populations, farmer plantations and an experimental field of the National Institute of Agrarian Innovation (INIA), was established in 2004 in varzea, at the Peruvian Amazon Research Institute (IIAP). Nine harvests between 2006 and 2016 have been evaluated, including variables in vegetative and reproductive development states. Statistical analysis was performed using the SPSS program for analysis of variance and SELEGEN REML/BLUP for repetitivity analysis of “fruit yield” (FY) and “fruit weight” (FW) with 5 and 4 measurements (years) respectively. For FY, a repetitivity index r = 0.117±0.07 was obtained with a selective precision of 0.63 and efficiency of 1.84 where clones 69, 48, 58, 50, 61, 13, 18, 29, 49 and 32, were selected in descending order of merit. For FW, r = 0.690±0.294 was obtained with selective precision of 0.948, efficiency of 1.14 and selection of clones 44, 13, 26, 23, 69, 64 22, 52, 27 and 8. As for the content in ascorbic acid, clones 48, 32 and 35 occupied the first places with more than 2000 mg of ascorbic acid/100 g. The selections achieved strengthened the pre-improvement work by conferring vigour y fiavility of a long term research.

Organoleptic and biochemical attributes in the coffee bean determine the final cup quality of coffee which is a critical factor in the price determination of coffee in the market. The study aimed at determining the genetic variability of the green coffee bean. The trial sites were located at Siaya and Busia counties in Kenya. Nineteen different genotypes were established and included Arabusta coffee hybrids, backcrosses of Arabica to tetraploid Robusta, Arabica coffee, Robusta coffee, and Arabusta coffee. Randomized Complete Block Design with three replications in each site was used in conducting the experiment. The coffee beans were harvested in the year 2018 and extraction and calculation of sucrose, trigonelline, caffeine, and chlorogenic acids was carried using the recommended methods. The cupping procedure involved the use of five judges in assessing the flavor, aroma, balance, overall standard, acidity, body, and aftertaste of the roasted coffee beans. The sensory evaluation used the Specialty Coffee Association (SCA) method. There were significant variations recorded for the traits that were measured. All the traits were highly heritable registering values of > 50% for heritability whereby, caffeine and oil were highly heritable traits with 90.8% and 88.9% respectively. Oil had a high phenotypic coefficient of variation, genotypic variation, and response values when compared to the other traits. All the organoleptic traits were positively correlated with sucrose, trigonelline, and oil but the correlation with caffeine and chlorogenic acids was negative. The genotypic effects contributed largely to the high heritability recorded with a low influence from the environmental factors.

Tree morphological characters have a direct relationship with bean physical qualities that ultimately determine the market and price of coffee. This work assessed tree and roast bean phenotypic variability in the Robusta coffee so as to be able to inform markets the appropriate selection criteria for these two traits. Two hundred and six C. canephora genotypes from 21 traditional growing districts and three on station germplasm collections were evaluated using nine quantitative coffee descriptors for morphological traits and four roasted bean physical characteristics. Girth diameter increased with age, vigor was closely associated with production capacity and all the leaf characters with the exception of number of stems were also closely associated. Hybrids with a significant Mahalanobis distance (D2) were distantly unrelated to nganda and erecta whereas, commercial types, nganda and erecta types with insignificant D2 values were closely related to each other. About 80% of the beans were of screen size 15 (>) while 61% were of the average size, 15. Denser beans of screen sizes 15, 15(>), and 18 had longer roast time but lesser weight decrease. The Robusta local landraces in Uganda are endowed with tremendous, genetic variability, and present opportunities for selection of yield, abiotic, and biotic stresses and cup quality.

Ready to Eat (RTE) sorghum cookies were prepared by incorporating green gram flour at 10%, 20%, 30%, dried mango powder at 10% and evaluated for their physico-chemical and nutritional properties. Protein, fat, fiber and ash increased with increase in green gram flour substitution as carbohydrate content decreased significantly. Significant differences (p ≤ 0.05) in protein content were seen in cookies ranging from 9.52% to 13.60%. Fiber increased significantly from 9.40% to 10.90%. In vitro protein digestibility ranged from 67.75 ± 0.01% to 90.05 ± 0.10 %. Vitamins analysed increased with addition of green gram flour. Thiamine content ranged from 0.22±0.02 to 0.61±0.02 mg/100g, riboflavin from 0.09±0.00 to 1.39±0.04 mg/100g and ascorbic acid from 13.87±0.79 to 19.31±0.94 mg/100g. Value addition of under-utilized crops like sorghum and green grams can play a vital role in development of high nutritional quality RTE products.

Sorghum (Sorghum bicolour (L.) Moench), the second most important staple crop in Sub-Saharan Africa (SSA) after maize, is well adapted to marginal environments of drought stress and high temperatures. But besides drought stress, the obligate root-parasitic flowering plant Striga hermonthica is an equally economically important biotic stress in agro-ecological zones where soils are marginal. Notwithstanding widespread and intense Striga infestation, genetic variations in defence mechanisms against the parasite have been reported. Sorghum variants, producing low levels of chemical stimulants such as sorgolactones that deter the advance of Striga seed germination and are therefore deemed resistant to the parasite, have been also reported in a few studies. But the existence of sorghum genetic variation for this resistance especially among farmers’ landraces is yet to be demonstrated. The objective of this study was therefore to determine the levels of Striga germination stimulants in response to each of the 111 collected sorghum landraces and their progenies from Eritrea. The ability of a sorghum genotype to cause germination of a Striga seed as a measure of the amount of the germination stimulant produced was used to assess the resistance of these accessions. The data were recorded as Striga germination percentage by counting the number of germinated Striga seeds. Landraces EG47, EG1261, EG830, EG1076, EG54 and EG746 with 14.68%, 15.32%, 11.85%, 13.05%, 15.74% and 16.5% germination percentages respectively were found to stimulate low levels of Striga germination percentage compared to commercial checks, IS9830, SRN39, Framida, with 22.46%, 22.67%, 23.27% germination respectively. While these variants did not show complete resistance against Striga seed germination, the low level production of stimulant indicated their high level of resistance to Striga . These results implied that these accessions are likely potential sources of resistance against Striga infestation in SSA sorghum breeding programs.

The parasitic weed Striga hermonthica hampers the production of sorghum, the most important cereal crop in Eritrea. This weed has a complex mode of infestation that adapts to many hosts and environments, complicating conventional breeding for resistance, which is the only form of crop improvement available to Eritrean breeders, but has failed. This study aimed at improving resistance against this parasite by transferring 5 Striga resistant Quantitative Trait Loci (QTLs) from resistance donor N13 to Striga susceptible Farmer-Preferred Sorghum Variety (FPSV) Hugurtay from Eritrea. The method involved backcrossing using marker-assisted selection (MAS) and evaluation of the best introgressed lines for Striga resistance in artificially infested fields. Foreground selection was performed with up to 11 polymorphic simple sequence repeat (SSR) markers linked to Striga resistance QTLs, while background selection was conducted in the BC 3 F 2 generation with 27 polymorphic unlinked SSR markers to identify the best recovery of the recurrent parent (RP) genetic background. Out of 84 BC 3 F 3 lines, L2P3-B, L1P5-A and L2P5P35 performed best with respect to both grain yield and reduced Striga infestation. These lines were more resistant to Striga than Hugurtay, but less resistant than N13. The three lines yielded twice as much as N13, with Area Under Striga Number Progression Curve (AUSNPC) values on average 18% higher than that of N13 and 38% lower than that of Hugurtay. This suggests that the introgressed QTLs conferred significant Striga resistance and yield advantage to these BC 3 F 3 backcross progenies under Striga pressure. These lines have good potential for future release and demonstrate that when MAS is available to conventional breeders, even in countries with no genotyping facilities, it is a useful tool for enhancement, expediency and precision in crop improvement.

In the semi-arid areas of Kenya, the effects of climate change are accelerating the genetic erosion of many crops and threatening food security of resource-poor farmers. This study analyzed the genetic diversity of the available Sorghum bicolor L. germplasm using simple sequence repeat (SSR) markers with the aim of identifying varieties that can be selected to meet food security needs of these marginal environments. Accessions from four agro-ecological regions were genotyped with 39 SSR markers chosen on the basis of their position in the genome and the large repeat sizes they represented. The alleles were called using the Gene Mapper software (version 3.7), sizes assigned with the allelobin software and the subsequent data analyzed with the Power Marker software (version 3.25). The Arlequin software (version 2.0) was used to calculate the diversity indices and the intra-population structure. Genetic distances were calculated according to Rogers modified distance and the accessions were clustered using principal component analysis (PCA). A mean polymorphic information content (PIC) value of 0.536 was observed, indicating moderate levels of polymorphism. The variability within accessions among the populations was 56.37%, within individual accessions was 38.85% and among geographical origins was 4.78%. A low level of genetic differentiation (FST = 0.048) and a high inbreeding level (FIS = 0.59) showed an increased degree of allele fixation. The results showed that though most of the accessions were similar, there was sufficient genetic diversity among and within sorghum landraces in Kenya, which would be useful in the improvement of sorghum productivity.

Drought stress is a major constraint to sorghum production in Kenya, especially during flowering stage. This study aimed at developing drought tolerant sorghum varieties by transferring the stay green trait that confers drought tolerance in sorghum from a mapped and characterized donor source into an adapted farmer preferred variety. The drought tolerance donor source, E36-1 originally from Ethiopia was backcrossed into a Kenyan farmer-preferred variety, Ochuti until BC2F1 generation and the stay-green Quantitative Trait Loci (QTL) were transferred through Marker Assisted Breeding (MAB) strategy. Five polymorphic Simple Sequence Repeat (SSR) markers were used to select the 3 stay green QTL of E36-1 found in SBI-01, SBI- 07 and SBI-10 linkage groups. In the F1 generation, two of these QTL, were transferred into three genotypes. In the BC1F1 generation, 32 genotypes had at least one QTL incorporated. From a population of 157 BC2F1 progenies, 45 genotypes had incorporated either one or two of the stay-green QTL. Despite a few number of genotypes obtained through the backcrosses, the results showed that stay-green QTL and consequently drought tolerance can be transferred successfully into farmer preferred sorghum varieties through MAB.

Background: The aim of this research was to estimate the genetic divergence among 49 genotypes of Jatropha curcas L. and to identify potential parental lines needed for breeding high oil and seed yielding cultivars. Methodology: The genotypes were studied for several agronomic traits including: plant height, days to flowering (50%), male:female flower ratio, number of fruits, seed yield, 100-seed weight and oil content. Genetic divergence was measured using Mahalanobis’ D2 statistics and Tocher cluster methods. Results & conclusion: The most diverse genotypes were those from different geographical origins, suggesting a relationship between genetic and geographical diversity. Hybridization of genotypes from East Africa with those from Madagascar and Mexico would generate high-level genetic divergence.

Background: Jatropha curcas L. has the potential for becoming an important feedstock for biodiesel and bioenergy in Kenya. The objective of this study was to evaluate the effects of genotype × environment interaction and to determine the stability of performance of the currently grown genotypes. Methodology: A field trial consisting of 49 genotypes was laid out in a lattice design of two replications in two contrasting agroecological environments, namely Thika and Kibwezi, for 2 years. The Eberhart and Russell stability method was used to measure the performance of yield components of the 49 genotypes. Results: Environmental variance influenced the performance of genotypes for all the traits measured and genotype × environment interactions were important in determining their performance.

The aim of this study was to estimate the extent of the genetic diversity present in sorghum germplasm grown in Kenya using simple sequence repeat markers. A total of 139 accessions were genotyped using 11 microsatellite markers or simple sequence repeats (SSRs) and the genetic diversity was estimated. The markers showed a wide range of differences in quality index from 0.005 to 0.39. The average Polymorphic Information Content value observed was 0.6241 indicating a high level of diversity. The gene diversity index ranged between 0.2419 and 0.9313 with a mean of 0.6627 per locus. A total of 105 alleles were observed with an average of 10.4 alleles per locus. The average heterozygosity level per locus was low at 0.1717. The variability within accessions among the populations was 74.85% and within individual accessions was 18.67%. The results showed that genetic diversity within Kenyan sorghum germplasm accessions is higher than that between the different populations. It is implied that such genetic diversity can be exploited as such or in hybridization programs to improve sorghum varieties currently grown by subsistence farmers in Kenya.

Cassava mosaic disease (CMD) caused by Bemisia tabaci is among the major contributors to low cassava yield in Africa and therefore requires instituting control measures. Due to genetic diversity in cassava, only clones with superior agronomic traits, disease resistance and high yield are selected and released to farmers or deployed in breeding program. This study was conducted to evaluate the resistance of cassava half-sib families to CMD. Field trials were conducted at Kenya Agricultural and Livestock Research Organization (KALRO), at Kakamega and Alupe research stations in western Kenya from June 2016 to June 2017. Sixty progenies were compared to that of their five parents by planting cuttings in 4 × 2 meters plots. Data were collected on plant height, number of roots per plant, harvest index, root yield, dry matter content, cassava mosaic disease and whiteflies infestation. Twenty three genotypes had a mean score of 1.0 to CMD, implying that they are resistant. Cassava grown at Alupe was observed to have high number of susceptible genotypes compared to cassava grown at Kakamega, indicating the effect of the environment on the genotypes. Parental genotypes, Kaleso and MM96/4271 presented high number of progenies showing CMD resistance. Genotypes, P4G1 and P2G3 with mean root yield of 31.6 t ha-1 and 30.0 t ha-1 were the highest yielding in term of root yield. A number of half-sib families generated from MM96/4271, Kaleso and MM96/0686 performed well with respect to yield recorded on their respective parents. Evaluation of new cassava varieties under local disease conditions would most likely improve the productivity of cassava through selection of resistant clones.

Sweet potato is one of the most important staple crops in Sub-Sahara Africa because of its supply of carbohydrates, vitamin A and C, fiber, iron, potassium and protein.The objective of this study was to determine phenotypic variation in diverse sweetpotato varieties for marketable roots, fresh root yield, fresh biomass weight, harvest index, beta carotene content and root dry matter content. Twenty five sweet potato genotypes were evaluated at two sites in two seasons in Kenya using a randomized complete block design of three replications. The results indicated that there were highly significantly variations for genotypes and sites for all the traits studied. There were no significant differences for genotype x site x season effects for the traits except for the number of marketable roots and fresh root yield. The mean fresh root was 32.19 t/ha,with the genotype Ininda expressing the highest fresh root yield of 54.79 t/ha. Genotypes, Naspot 13, Ejumula, Kabode, Vitaa and Tio-Joe gave the highest beta carotene content ranging between 11.830 and 10.040 mg/100g; with a mean of 5.384 mg/100g. The mean root dry matter content was 24.84 % with clones Amelia and Melinda showing the highest and lowest root dry matter content of 30.62 and 16.52 % respectively. Ten genotypes including Ininda, Erica, Jane, Naspot 13, Ejumula, Kabode, Vitaa, Tio-Joe, Amelia and Mayai were recommended as potential parents for sweet potato breeding program in Kenya.

Analysis of the gene action exhibited by an agronomic trait in crop plants is useful in the planning of an effective plant breeding program. This study sought to establish the inheritance variance of root yield components and beta carotene content present in sweet potato clones commonly grown in Kenya. Ten contrasting parents were selected based on their beta carotene content, dry matter content and yield potential. They were planted in pots in the green house at KEPHIS-Muguga, Kenya, where they were grafted into Ipomoea setosa to boost their ability to flower. Five parents were further selected based on their ability to flower under local environmental conditions and crossed in a 5 × 5 half diallel manner. Five parents and ten F1 clones arising from this hybridization were evaluated at KALRO-Kiboko, Kenya during two rainy seasons. The field trials were laid out in a randomized complete block design of three replications. The data were scored for root yield characteristics, beta carotene and root dry matter content. Griffing Method II, Model 1 diallel was used to estimate the general and specific combining ability. Genetic variability for beta carotene and root dry matter content indicated that the two traits were controlled mostly by both additive and dominant gene actions. Heterosis gene effects were found for beta carotene and root dry matter content which would be useful in the improvement of sweet potato productivity.

Smut disease of sugarcane, caused by the fungus Ustilago scitaminea Sydow, can cause considerable yield losses and reductions in cane quality. To investigate the reactions of the seedlings to smut, three different inoculation methods were employed. Data on number of smut whips per stool, disease incidents per population and number of tillers per plot were recorded and analysed. Results showed that screening for smut resistance at the first stage of selection to assess seedling reaction to smut is possible. The wound paste method of inoculation gave better results than the other techniques evaluated.

Cloned DNA-A and DNA-B components of Kenyan isolates of East African cassava mosaic virus (EACMV, EACMV-UG and EACMV-KE2), East African cassava mosaic Kenya virus (EACMKV) and East African cassava mosaic Zanzibar virus (EACMZV) are shown to be infectious in cassava. EACMV and EACMKV genomic components have the same iteron sequence (GGGGG) and can form viable pseudorecombinants, while EACMZV components have a different sequence (GGAGA) and are incompatible with EACMV and EACMKV. Mutagenesis of EACMZV has demonstrated that open reading frames (ORFs) AV1 (encoding the coat protein), AV2 and AC4 are not essential for a symptomatic infection of cassava, although mutants of both ORF AV1 and AV2 produce attenuated symptoms in this host. Furthermore, ORF AV1 and AV2 mutants were compromised for coat protein production, suggesting a close structural and/or functional relationship between these coding regions or their protein products.

Cassava is a major factor in food security across sub-Saharan Africa. However, the crop is susceptible to losses due to biotic stresses, in particular to viruses of the genus Begomovirus (family Geminiviridae) that cause cassava mosaic disease (CMD). During the 1990s, an epidemic of CMD severely hindered cassava production across eastern and central Africa. A significant influence on the appearance of virus epidemics is virus diversity. Here, a survey of the genetic diversity of CMD-associated begomoviruses across the major cassava-growing areas of Kenya is described. Because an initial PCR-restriction fragment-length polymorphism analysis identified a much greater diversity of viruses than assumed previously, representative members of the population were characterized by sequence analysis. The full-length sequences of 109 components (68 DNA-A and 41 DNA-B) were determined, representing isolates of East African cassava mosaic virus and East African cassava mosaic Zanzibar virus, as well as a novel begomovirus species for which the name East African cassava mosaic Kenya virus is proposed. The DNA-B components were much less diverse than their corresponding DNA-A components, but nonetheless segregated into western and eastern (coastal) groups. All virus species and strains encountered showed distinct geographical distributions, highlighting the importance of preventing both the movement of viruses between these regions and the importation of the disease from adjacent countries and islands in the Indian Ocean that would undoubtedly encourage further diversification.

Sorghum (Sorghum bicolour (L.) Moench), the most important cereal crop in Eritrea, is grown in more than 210,000 ha annually but its productivity is hampered by many factors including: farmer perception, lack of appropriate varieties, undeveloped seed systems, drought stress and Striga infestation. This study was aimed at understanding the sorghum smallholder livelihoods, farming systems, Striga incidence and infestation levels, and types of varieties grown in Striga infested sorghum growing areas. A semi structured questionnaire and focused group discussions were used to gather information from a total of 136 randomly selected farmers from three Striga endemic sub-regions of Eritrea namely, Hamelmalo, Goluj, and Tesseney. The results indicated that the most important cereal crops in the study area were sorghum, pear millet, ground nut and sesame. The most important constraint to sorghum production was identified as drought stress followed by Striga infestation. The majority of the respondents (81.6%) reported that their sorghum was affected by Striga and the level of infestation varied from mild (10%) to severe (70% and above). Small-holder farmers also indicated that high grain yield, drought tolerance/resistance and Striga resistance were their most important criteria when selecting sorghum varieties. Up to 31 different landraces were listed as the most popular in the study area. The dominant source of seed for cultivation was the local varieties retained by farmers from previous harvests. The information documented from this study may be used in future as a basis for a participatory farmer-oriented sorghum breeding program.

The Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA) through its Agrobiodiversity and Biotechnology Programme is enhancing the utilization of biotechnology research and development innovations in Eastern and Central Africa (ECA). We present successes in the application of biotechnology to enhance the productivity of cassava, sweet potato, banana, maize and sorghum in ECA. These products—drought tolerant maize, sorghum resistant to striga, as well as the technology for producing and distributing disease free planting materials of cassava, sweet potato and banana to farmers—are central for the agro-ecological intensification of farming systems in the central African highlands.

Coffea canephora organoleptic cup attributes are the most important factors that define its price in world markets. Determining the components that contribute to the diversity of organoleptic characters will help in the improvement of these qualities in order to obtain favourable markets. Two hundred and six genotypes from twenty one districts and two research institutes were analyzed by a three member expert panel from Uganda Coffee Development Authority using a 10 point descriptive scale and protocols from, The Coffee Quality Institute of America (CQIA). The results revealed that the evaluators’ organoleptic cup trait ratings were significantly different (p< 0.05) for all attributes, reflecting a diversity of cup interests. Four multivariate groups that were significantly different for fragrance, aroma and flavour were formed offering diverse cup tests to different markets. A variety of fine and commercial flavours were detected in ripe cherry and green roasted beans. Cup balance contributed the highest regression coefficient (R2=0.90) to overall assessment while fragrance/aroma had the least (R2=0.22). The above average rating of 75% for cup balance, flavour, mouth feel, aftertaste, fragrance and aroma revealed that Ugandan Robusta coffees were of high quality with a mild taste. The higher cup acidity among land races,‘nganda’ and ‘erecta’ genotypes revealed that genotypes with high sugars and cup acidity could be selected for from local germ-plasm. Coffee types and environmental factors such as soil texture, altitude and location influenced the content and level of organoleptic cup attributes. A diversity of flavours that exist among Uganda Robusta coffee and has so far remained unexploited, would provide new marketing channels, enhance quality and earn the country the much desired foreign exchange capital.

Characterisation of the available Kenyan sorghum genetic diversity is important for understanding the dynamics of the genetic resources and for improving and sustaining sorghum productivity. The aim of this study was to assess the extent and structure of diversity in sorghum landraces from Kenya. Phenotypic data were used to assess diversity in 148 sorghum accessions collected from Western, Turkana, Coast and Eastern regions of Kenya. The accessions were phenotyped using qualitative and quantitative morphological characters. Most of the accessions were high yielding as revealed by the means of panicle branches (43), panicle length (21cm), and grain weight (1.5g). Majority of the sorghums were late maturing and tall as shown by the mean number of days to 50% flowering (88 days), number of leaves and nodes. Turkana and coast sorghums had similarities in maturity, height and panicle length. The number of panicle branches had the highest Broad-sense heritability (0.957). Majority of the sorghums had dull green midrib (49.55%), no basal tillers (83%), had waxy bloom (39.64%) and produced prop roots (87%). Loose and semi-loose erect panicles dominated (69%) while 83% of the accessions had slightly exerted peduncles. The two Eigen values in PCA explained 67% of the total variance. Phenotypic cluster analysis gave two major groups subdivided into four sub clusters.

Backcross breeding enables breeders to transfer a desired trait from a Genetic Improvement of Kenyan sorghum variety for drought resistance donor parent, into the favoured genetic background of a recurrent parent. This study utilised back-cross breeding to transfer stay green quantitative trait locus (QTLs) from the donor parental line E36-1 into a Kenyan farmer-preferred variety, Ochuti as the recurrent parental line. The parental lines E36-1 has 3 stay green QTLs, SBI-01, SBI-07 and SBI-10 located at various chromosomes. The transfer of these QTLs was confirmed with the help of Simple Sequence Repeats (SSRs) molecular markers. Five foreground markers that were polymorphic among the two parental genotypes were used to identify individuals of F1 generation that had stay green QTLs transferred into Ochuti. A maximum of two QTLs, namely, SBI-07 and SBI-10 were identified as having been transferred into three individual genotypes. Two other F1 genotypes had only one QTL (SBI-10) transferred into Ochuti. The heterozygous F1 genotypes were used as the female parents in the generation of BC1F1. About 25% of the BC1F1 progenies that were genotyped had at least One QTL introgressed. As is the case in all marker-assisted back-cross breeding, the rate of success in introgressing QTL from donor to recurrent parental lines depends on the number of plants screened.

Drought stress is the major abiotic factor that limits cassava productivity in many agro-ecological regions of sub-saharan Africa. In this study, stay-green trait in two transgenic cassava genotypes (transformed with isopentenyl transferase (ipt) gene for improved drought tolerance) and six non-transgenic cassava genotypes were evaluated under green-house condi- tions. Leaf abscission (for leaf retention), elongation of the last internodes, photosynthetic rates, and stomatal conductance were determined in these cassava genotypes subjected to three levels of water stress treatments (0, 30, and 60 %) and a positive control or fully irrigated plants. Two non transgenic genotypes (98-0002 and 98-2226) and one transgenic line (529-48) that expressed relatively high level of stay green or leaf retention, also exhibited significantly higher photosynthetic rates, internode elongation and relatively low stomatal conductance compared to other genotypes. Non transgenic genotypes 91-02322 and TME-3 and transgenic line 529-28, expressed moderate levels of stay green and non transgenic genotype 95-0306 and wild type TMS 60444 (for the transgenic lines) were highly susceptible to the water stress treatments. The results reported here showed there was a positive correlation between leaf retention, photosynthetic rates, internode elongation and stomatal conductance.

Sorghum is the world’s fifth most important cereal, in terms of both production and area planted. Striga hermonthica is one of the major constraints of sorghum production globally and particularly so in Eastern Africa. This study aimed at transferring five Striga resistances Quantitative Trait Loci (QTL) located on linkage groups SBI-01, SBI-02, SBI-05 and SBI-06 from a genetically mapped donor source line N13 into a locally adapted farmer preferred variety, IS8193 using Simple Sequence Repeats (SSRs). Nine polymorphic SSR markers were used to identify F1 generations and the subsequent BC1F1 progenies carrying Striga resistance QTL. Sixteen F1 progenies and twelve BC1F1 were found to have incorporated one to three Striga resistances QTL. The twelve BC1F1 lines with Striga resistance QTL were subsequently backcrossed to IS8193 to produce BC2F1 generation for further fore-ground and back-ground selection in the future. This work was conducted during March 2010 to August 2011 at University of Nairobi and at Biosciences eastern and central Africa (BecA)-Nairobi Kenya.