M Biruma, P. Okori, J. J. Mudingotto, R Edema, Geoffrey Tusiime, S.B. Mathur, E Adipala

Seed-borne fungi associated with farmer saved rice seed in Uganda and their effect on germination

Introduction

Seed-borne fungi associated with farmer saved rice seed in uganda and their effect on germination. Identifies 20 seed-borne fungi, including Bipolaris oryzae, impacting farmer-saved rice in Uganda. Research reveals their effect on germination and seedling abnormalities.

Abstract

Seventy seed samples from three districts of Uganda, namely, Bugiri, Pallisa, and Lira were examined by the blotter method for fungal infection at Makerere University. Twenty different seed-borne fungi were identified and their incidence and infection levels varied significantly (P<0.01) with respect to location and within districts. Bipolaris oryzae was the most prevalent pathogen with an infection range of 3-94%. Phoma oryzae, Pyricularia oryzae, Alternaria padwickii, Fusarium moniliforme, Curvularia lunnata, Nigrospora oryzae, Verticilium cinabarium and Alternaria alternata were also present in all the districts. However, some pathogens were localised. For example, Exserohilum rostratum, and Curvularia eragrostidis were only encountered in Lira and Bugiri districts, respectively. Pallisa district had the least number of fungal species while Bugiri registered the greatest diversity. Mean infections were also low in Pallisa as opposed to Bugiri and Lira districts. Nine categories of seedling abnormality were recorded. Seedlings with shoot and root decay were encountered frequently. B. oryzae, Phoma oryzae, Pyricularia oryzae, A. padwickii, F. moniliforme, C. lunnata, Melanospora zaminae and Alternaria alternata were found associated with 100%, 55.6%, 44.4%, 66.7%, 77.8%, 11.1% and 11.1% of the different abnormalities, respectively. Results of the present study have revealed the occurrence of a wide range of pathogenic fungi and their association with seedling abnormalities.

Review

This study provides a valuable examination of seed-borne fungal pathogens affecting farmer-saved rice seeds in Uganda, an area critical for food security. By analyzing seventy seed samples from three distinct districts (Bugiri, Pallisa, and Lira) using the blotter method, the researchers identified a diverse array of fungal species. The methodology employed appears sound for initial identification and quantification of fungal presence, setting a robust foundation for understanding the scope of seed health issues in these farming communities. The findings reveal a significant prevalence and diversity of seed-borne fungi, with twenty distinct species identified. A key observation is the substantial variation in fungal incidence and infection levels across and within the studied districts, highlighting potential localized ecological factors or farming practices influencing pathogen loads. *Bipolaris oryzae* stands out as the most dominant pathogen, exhibiting a high infection range, which is particularly concerning given its known pathogenicity in rice. Other commonly found pathogens like *Phoma oryzae*, *Pyricularia oryzae*, and *Fusarium moniliforme* further underscore the broad spectrum of threats. The association of these fungi with nine categories of seedling abnormalities, including frequent shoot and root decay, directly links the pathogen presence to detrimental effects on germination and early crop establishment, with specific pathogens strongly correlated with particular abnormalities. Overall, this research successfully elucidates the occurrence of a wide range of pathogenic fungi in farmer-saved rice seeds in Uganda and their direct impact on seedling health. The identification of prevalent and localized pathogens, coupled with the quantitative data on infection levels and their association with germination abnormalities, offers crucial insights. These findings are highly significant for developing targeted seed health management strategies, promoting informed seed selection practices among farmers, and potentially guiding future research into disease resistance or effective seed treatments to safeguard rice production and improve food security in the region.

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