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

Leveraging on germplasm acquisition for Arabica coffee improvement in Kenya

Abstract. The low genetic variability within Coffea arabica species is a major hindrance to its improvement. The emergence of new pathogen races, especially for the prevalent fungus Hemileia vastatrix causing Coffee Leaf Rust (CLR) is a challenge to coffee production worldwide. Two accessions, namely Selection 5A and Selection 6 were received in 2008 from India as part of germplasm exchange in a Coffee Leaf Rust collaborative project involving India and four African countries namely, Uganda, Zimbabwe, Rwanda and Kenya. Seedlings of two Kenyan commercial varieties SL 28 and Ruiru 11 representing susceptible and resistant varieties respectively were also raised alongside the Indian accessions. The seedlings of the four varieties were planted at Coffee Research Institute (CRI) sub-centre in Kisii country and Agricultural Training Centre in Machakos country for field evaluation. Data was recorded on growth and yield parameters before and after crop bearing. Field records were also taken for infection by Coffee Berry Disease (CBD) and Coffee Leaf Rust (CLR). Growth parameters related to crop bearing had stronger correlation with actual berry count and hence yield confirming that potential yield of a coffee variety can accurately be predicted by combining early measurements of growth parameters and yield records. The yield potential of the Indian accessions was found to be lower than the standard Kenyan varieties. However, the accessions were outstanding in resistance to CLR which was only comparable to the resistant Ruiru 11 variety. The study confirmed that CLR, if not controlled can erode the high yield potential of elite varieties if conditions are favorable. It was also concluded that the Indian accessions provides an opportunity upon which traditional Kenyan commercial cultivars can be improved to withstand existing and new races of the rust pathogen

Influence of Cultivars and Nitrogen Fertilizer Rates and Application Mode on Yields and Quality Parameters of Ratoon Sugarcane in Western Kenya

Productivity of sugarcane in Kenya has declined despite use of recommended production practices including introduction of elite high yielding and early maturing sugarcane varieties. Farmers continue to use recommended agronomic inputs for the old low yielding and late maturing varieties on these elite varieties. Nitrogen fertilizer rates in single or split doses for old varieties are still in use yet their appropriateness on new varieties remains untested culminating to decline in sugarcane productivity in Kenya. Currently, cane payment is based on delivered milling cane weight. The industry plans to change payment to a combination of quality and yields. Influence of agronomic inputs and timing of harvesting period on proposed mode of payment is unknown. Harvesting age in western Kenya remains 18-20 months after ratooning (MAR). However, optimal age that combines quality and yields is not documented. Influence of these agronomic practices on quality, yields and optimal harvesting age of ratoon crop of new (D8484) and old (CO421) varieties were evaluated in a 2x4x3 split-split-plot design replicated three times. Four rates of nitrogen as urea, all applied at 3 MAR, split once (50-50%) and applied at 3 and 6 MAR or split three times (40-30-30%) and applied at 3, 6 and 9 MAR were evaluated. Yields and quality parameters were monitored from 10th-24th MAR. Variety D8484 out-yielded (p≤0.05) CO421 throughout demonstrating its superiority. Yields reached maximum at 20 and 19 MAR for CO421 and D8484, respectively. Maximum pol and brix were attained at 18 and 15 MAR for CO421 and D8484, respectively, while commercial cane sugar (CCS) was maximum at 18 and 17 MAR for CO421 and D8484, respectively. Results demonstrated that for high returns, D8484 should be harvested between 15-18 MAR while CO421 between 17-19 MAR. The 60 kg N/ha, that produced higher (p≤0.05) output in both varieties, from 16th MAR is recommended for both varieties. Split fertilizer application did not affect productivity