Research on Striga spp. in rice shows genetic variation and host–parasite specificity of resistance and tolerance, underpinning the need for predictive breeding…
In a new publication in New Phytologist, scientists of AfricaRice, the University of Sheffield and a host of students and co-workers show that Striga virulence varies across species (S. asiatica and S. hermonthica; see Photo 1) and ecotypes and that the extent of damage these parasitic weeds cause to rice is a function of the interaction between parasite virulence and genetically determined levels of host–plant resistance and tolerance.
Photo 1: Parasitic weeds in rice: Striga asiatica (top) and Striga hermonthica (bottom)
Photo 2 (copyright New Phytologist) shows root systems of different rice genotypes (IAC165, IR38547 and WAB928), grown in rhizotron systems. The rice roots are infested by germinated seeds of either Striga asiatica from Kyela, Tanzania (Sa-Ky), S. hermonthica from Mbita, Kenya (Sh-Mb) or S. hermonthica from Namutumba, Uganda (Sh-Na). The green seedlings attached to these rice roots are the successful Striga infections. Rice genotypes IR38547 and WAB928 showed susceptibility against S. asiatica (Kyela), but high (post-attachment) resistance against both S. hermonthica ecotypes (Mbita and Namutumba). Genotype IAC165 is the overall susceptible check.
Photo 2: Roots of different rice genotypes infected by Striga in rhizotron systems
Rodenburg, J., Cissoko, M., Kayongo, N., Dieng, I., Bisikwa, J., Irakiza, R., Masoka, I., Midega, C. A. O. and Scholes, J. D. (2017), Genetic variation and host–parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding. New Phytol. doi:10.1111/nph.14451
The article is published Open Access: http://onlinelibrary.wiley.com/doi/10.1111/nph.14451/abstract?campaign=wolearlyview