Isolation and Identification of Fungal Pathogens Associated with Cold Storage Type of (Coffee Arabica.) Seed, at Jimma Agricultural Research Center, Western Ethiopia

Abstract

Coffee is the most important commercial crop in the national economy of Ethiopia. Coffee seed are subject to various operations of contamination by microorganisms during growth (while the beans are on trees), after harvesting (when the beans are de-hulled, washed and stored) and during storing. The aim of this research is to isolate and identify the fungal pathogens associated with cold storage type of coffee (coffee arabica L.) seed. Different fungi were associated with coffee seed under cold storage condition. These different fungal species was isolated and identified both in blotter and agar plate method. In blotter test method the identified fungi were; Aspergillus sp.; Pencillium sp.; Fusarium sp., and another some unidentified species were isolated and identified at genesis level from the two month coffee seeds storage. Among these, Aspergillus spp. had the highest (49.375%) frequency of occurrence, followed by Penicillium spp. (11.875%), Fusarium spp. (5.625%) and unidentified species (0.626%). In addition, in blotter test method the obtained result indicated that the infection mean percentage in blotting methods W0V74-1 (without parchment) followed by W0V74-110 (without parchment) were highly infected mean percentage 80% and 97.5% respectively. However the lowest fungal infestation was noted on both W1V74-1 and W1V74-110 (45 %) with parchment of coffee seed was verified. The results of germination test obtained in blotter plate method showed that the germination mean percentage of W0V74-110 (without parchment) were highly germinated with mean percentage of (98%). However the lowest germination mean percentage was noted on W1V74-1 (27.5%) with parchment of coffee seed. In agar plate method also the identified fungi were; Fusarium sp. Aspergillus sp. Pencillium sp. and another some unidentified species. Among these, Aspergillus spp. had the highest (31.25%) frequency of occurrence, followed by Penicillium spp. (10.625%) and Fusarium spp. (11.875%) and unidentified spp. (9.375%). Moreover, in agar plate method the maximum coffee seeds mean infection percentage were recorded 82.5% and the mean minimum infection percentage were (52.5%) in the treatment W1V74_110 (with parchment) and W0V74_110 (without parchment) respectively. From total four treatments (62.5%) maximum fungal contaminations were recorded. The result of present study, storage fungi chiefly comprise several "group species" of the genera Aspergillus spp, Penicillium spp, Fusarium spp. and another unidentified species. The species identified in this study are among the most common species of fungi present in storage environments at high moisture. They can tolerate growth in different substrates and environmental conditions, and their complete elimination is difficult. However, the use of good hygiene practices and using optimum moisture of coffee seeds in storage management and can minimize mycroflora association of coffee seeds. Although the present study was carried out in one location in Jimma University College of Agriculture and Veterinary Medicine (JUCAVM)/Jimma Agricultural Research Center for three month in 2013 and, it has clearly indicated that different fungi were associated with coffee seed under storage condition, especially Aspergillus species. In general, further research is needed to identify all recovered fungal pathogens and evaluation of promising treatments for use in integrated disease management strategy to manage not only fungal but also other coffee seed diseases and also further investigation of storage temperature, relative humidity, periods of storage and storage types in wide range across the location that suitable for good supply of health coffee seeds. Keywords: Coffee, seed, cold storage, mycoflora.