Enhancing Soybean Rust resistance through Rpp2, Rpp3 and Rpp4 pair wise Gene Pyramiding
Loading...
Date
2012-08-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Agricultural Research
Abstract
The threat posed by soybean rust (Phakopsora pachyrhizi) on soybean production is worsened by
resistance breakdown associated with single gene resistance present in most cultivars. Few studies
have however been undertaken to use mapped simple sequence markers for gene pyramiding to
enhance rust resistance. This study validated use of identified simple sequence repeat markers for
gene pyramiding, and determined the most effective pairwise gene combination for three independent
soybean rust resistance genes, Rpp2, Rpp3 and Rpp4. Markers Satt460 and AF162283 were
polymorphic for the three resistance genes among the parents and were therefore used in selections
made in the F2 and F3 families. In the F2 generation, soybean plants (homozygous dominant or
heterozygous at both loci) with two gene combinations had relatively lower disease severity and
sporulation than the parents, suggesting complementary epistatic gene action for resistance. Similarly,
homozygous F3 families showed lower severity, lesion density and sporulation. Gene Rpp3 contributed
positively to resistance with various genetic backgrounds for most parameters measured, compared to
Rpp2 and Rpp4 resistance genes. Overall, the results suggest that marker gene pyramiding is feasible
and can substantially increase resistance to soybean rust through reduced severity and reduced
sporulating lesions.
Description
Keywords
Citation
Maphosa, M., Talwana, H., & Tukamuhabwa, P. (2012). Enhancing soybean rust resistance through Rpp2, Rpp3 and Rpp4 pair wise gene pyramiding.