ASSESSMENT OF POST-HARVEST MYCOFLORA AND IN-VITRO MANAGEMENT TO MAINTAIN QUALITY OF COMMON BEAN (Phaseolus vulgaris L.) SEED IN EAST HARARGHE, ETHIOPIA

Abstract

Different mycoflora are contaminate common bean seed under storage conditions and leads to quantity and quality deteriorations and contribute to reduction of thesubsequent seasons crop performances and yield which affects the growers’ welfares. Thus, the present study determined the associated mycoflora of common bean seed regardless of different cultivars and in-vitro managements using botanical plant-based compounds for seed quality maintenance. Thus, total common bean seed samples (N=60) were collected from 2021/2022 cropping season from four districts (n=48) and two seed companies (n=12) at post-harvest stage from storage conditions. All samples were subjected for moisture test on laboratory arrival and proceed to further activities and isolations and identifications of mycoflora were done. Physiological quality parameters were considered and associated with the levels of mycoflora incidences in each sample. It was used completely randomized experimental design as 4 x 2 x 3 in factorial combination. Nine fungal genera were isolated. The highest mean infection (%) of seed sample was recorded in Meta (7.84 %), and Haramaya (6.74 %) districts. Among fungal species, Aspergillus niger (89.58 %), A. flavus (87.50 %), Rhizopusspecies(56.25 %), and Fusariumspecies (54.17%), had the highest mean frequency in order. In-vitro test against non-improved seeds treated with thymol (80, 400, and 1600 μg/mL) and cinnamaldehyde (80 and 400 μg/mL), revealed a significant different at p < 0.05, compared to other treatment groups against germination and Vigor-II in sample obtained from Goro Gutu district. Regarding the cultivars, white seeded was significantly affected in both Vigor I and II. The combinations of in-vitro treatment, cultivars, and seed sources indicated that, germination and root length were influenced only by treatments and source of seeds (p < 0.05). The effects of treatments against germination and root length showed, cinnamaldehyde (80, and 400 μg/mL) and thymol (80, 400, 1600 μg/mL) resulted significant differences (p < 0.05) of the maximum means compared to other treatments. The speed of germination was impacted by thymol (80 μg/mL) and cultivars (p < 0.05) while the source was non-significant (p > 0.05). The seeds treated with cinnamaldehyde and thymol at concentration of 80, 400, and 1600 µg/mL against shoot length, Vigorosity Index I and II showed significant difference (p < 0.05) as they were also affected by the inclusions of both cultivars and source of seeds (p < 0.05). Moreover, these contaminants are affected the most important parts of the seedling. Thus, maintaining the quality of common bean seed under storage condition using eco-friendly plant-based compound was crucial to reduce the seed borne mycoflora. These offer new windows to know the ecological niches of mycoflora, insights that we use to uncover the treatment options to improve the quality of common bean seed and initiate a further study to be carried out to increase our existing knowledge of mycoflora related common bean seeds and quality managements.