Developing Lowland Rice Germplasm with Resistance to Multiple Biotic Stresses through Anther Culture in Uganda
Kofi Ayirebi, Dartey Paul
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The lowland rice genotypes grown in Uganda were introduced in the 1970s. These genotypes (now landraces) are threatened by multiple biotic stresses namely; Rice Yellow Mottle Virus (RYMV) disease, Bacterial Leaf Streak(BLS). Bacterial Leaf Blight (BLB), and Rice Blast (BL). There are currently no rice lines with multiple resistance to these stresses although attempts have been made to develop them through hybridization involving cultivated, local and introduced lines and four varieties with tolerance to RYMV have been released. The use of potential resistance donor such as the traditional African cultivated rice, Oryza glaberrima, could be an alternative approach to furnish multiple resistance to the cultivated rice. The rice germplasm developed from a cross of an Oryza glaberrima from Niger Delta and Milyang23, a high-yielding Korean rice variety were evaluated for multiple resistance in Uganda as a Korea-Africa Food & Agriculture Cooperation Initiative (KAFACI)-Alliance for a Green Revolution in Africa (AGRA) joint cooperative project, “Enhancement of High Yielding Rice Germplasm in African Countries through Anther Culture Breeding”. Milyang23 was back crossed 4 times with Oryza. glaberrima and fixed through anther culture in Korea. An evaluation of 50 lines generated showed that up to 98%, 92%, 88% and 88% of the test plants showed resistance to the RYMV, BLS, BLB and BL diseases, respectively. There was no symptoms of the four diseases in 74% of the genotypes tested. The plants that showed symptoms of the three diseases had scores of not more than 3 on a 1 to 9 scale. This preliminary finding demonstrates that these generations of rice lines could help solving the current problem of susceptibility to multiple diseases.