Organoleptic, Sensory and Biochemical Traits of Arabica Coffee and Their Arabusta Hybrids

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

Novel sources of drought tolerance from landraces and wild sorghum relatives

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

Tailoring the Thermoelectric Performance of the Layered Topological Insulator SnSb₂Te₄ through Bi Positional Doping at the Sn and Sb Cation Sites

Ongoing research and development focus on emerging thermoelectric materials with enhanced performance, continually making the possibility of waste heat recovery a reality. In this work, we engineer the thermoelectric properties of the layered SnSb2Te4 topological insulators. To date, there is little research reporting on these materials as potential state-of-the-art thermoelectric materials. Thus, there is a need to formulate effective strategies to realize this potential. Since these materials are known to have intrinsically low lattice thermal conductivity, we shift our attention to improving the electrical transport properties. For the first time, positional Bi doping at both the Sn and Sb cation sites is adopted. The aliovalent and isovalent nature of Bi at these sites, respectively, is shown to cause significant improvements in the performance of these layered materials. The electronic band structure of the pure and doped samples, where we considered various occupancies, is studied whereby we reveal the occurrence of band convergence and resonant levels resulting in a high power factor of ∼10.8 μW cm–1 K–2 at 623 K. Overall, a high ZT of ∼0.46 at a relatively lower temperature of 673 K is recorded. The potential of these materials for thermoelectric applications is shown, especially in the case of Bi doping at the Sn cation site. Continued efforts to enhance the thermoelectric performance of these topological insulators are needed for them to gain a substantial competitive edge in comparison to other state-of-the-art thermoelectric materials

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

With the ever-growing demand for eco-friendly energy sources to mitigate the global rising temperatures, the universal insatiable need for sustainable and efficient energy sources are earnestly being intensively sought after. The ubiquitous heat within, if successfully tapped, is an utterly promising source of energy. To achieve this, a thermoelectric device (TED) is needed. To enhance the conversion efficiency from heat to useful electrical power, we developed a strategy to improve the thermoelectric performance of the materials involved. In this work, equimolar multication alloying (EMMCA) is proposed for the first time and employed to enhance the performance of SnTe-based thermoelectric materials. Beyond the cation’s solubility limit, in situ compositing is observed with an increasing doping ratio, whereby distinct CuInTe2 ternary second phases are dispersed within the SnTe matrix. The electronic properties of the ensuing alloy are significantly enhanced by the resulting carrier concentration modulation and the unique electronic band engineering. A decrease in the thermal transport properties is likewise reported, benefiting from enhanced phonon scattering and diminished electronic contribution. The mechanical properties are also shown to increase with increased alloying. As a result, single-leg TED performance shows substantial output power in comparison with the pristine sample. The outcomes stemming from EMMCA are documented as significantly impactful, contributing to superior overall thermoelectric performance