Analysis of indigenous production methods and farm-based biodiversity of amochi (<Emphasis Type="Italic">Arisaema schimperianum</Emphasis> Schott) in two sub-zones of Southern Ethiopia

For the first time we report that diverse types of Arisaema schimperianum Schott locally called amochi, are grown and managed as an off-season food crop in Southern Ethiopia. Participatory Rural Appraisal (PRA) and formal survey studies on 204 households were conducted over two consecutive years (2003–2004) in Chencha and Dita sub zones of Southern Ethiopia, to identify indigenous production methods and farm based biodiversity of amochi. Amochi is propagated from seed tubers and tuber parts left in the soil from the preceding harvest and grow during the dry season, February to June. Average share of proportion in the annual household consumption from amochi tubers was 9% and 4% for Chencha and Dita respectively. Uncooked amochi is irritating in contact to skin and mouth. Fifteen amochi types were identified in Dita and 12 in Chencha. They differ in the level of irritation, maturity and yield. Rich farmers with large family size as a working force, large farm size to support larger number of livestock that is source of farmyard manure, have farms with larger diversity of amochi than their poor counterparts, suggesting that its diversity is influenced by house hold characteristics and favoured under relatively fertile soil conditions. In both sub zones women had better experience in identifying amochi types than men. Further study is needed to identify chemical contents; and genetic variation using morphologic and molecular traits, in order to develop a strategy to assess and utilise the existing genetic diversity.     

Influence of phosphorus application on yield,yield components,and quality of linseed

Abstract

Soil fertility depletion coupled with improper fertilization is one of the major constraints limiting linseed production in Ethiopia. Experiment was conducted in 2014/2015 on Nitisol in southeastern Ethiopian highlands to study the effect of phosphorus (P) fertilizer rate on yield, yield components, and oil content of linseed. It comprised of six levels of P fertilizer (0, 5, 10, 15, 20, and 25?kg?P?ha^?1) arranged in randomized complete block design with three replications. Results revealed that P fertilization brought significant effect on biomass yield, harvest index, plant height, number of capsules per plant, and kernel size. However, it didn’t significantly increase seed yield and oil content on linseed. Considering its influence on increasing biomass yield and improving yield components, application of 5?kg?P?ha^?1 has been recommended for replenishing the extracted P, maintaining soil fertility and improving linseed production on Nitisols of southeastern Ethiopian highlands and other similar agro-ecologies.     

Effects of cryostabilizers, low temperature, and freezing on the kinetics of the pectin methylesterase-catalyzed de-esterification of pectin

The kinetics of the pectin methylesterase (PME)-catalyzed de-esterification of pectin was studied at 25 degrees C in the presence of sucrose, fructose, maltodextrin (DE = 16.5-19.5), and carboxymethylcellulose at different concentrations and in the presence of maltodextrin and sucrose at different concentrations in a temperature range between +25 and -4 degrees C in subcooled and frozen states. The objective was to determine whether the reaction is diffusion-controlled, to gain insight about the factors determining the diffusion of the reactants, and to determine the effect of the carbohydrates, low temperature, and freezing on the structural conformation of the enzyme. The results indicate that the PME-catalyzed de-esterification of pectin is diffusion-controlled. Nevertheless, the diffusion is not controlled by the macroviscosity of the reaction medium, but rather by the microviscosity experienced by the diffusants. Low temperature in the temperature range studied does not affect the structural conformation of the enzyme, while freezing seems to have some effect.