Confirmation of root-knot nematode resistant gene Rmi1 using SSR markers

Background: The Root Knot Nematode (RKN) is a serious economic threat to various cultivated crops worldwide. It is a devastating pest of soybean and responsible to cause severe yield loss in Pakistan. The cultivation of resistant soybean varieties against this pest is the sustainable strategy to manage the heavy loss and increase yield. There is an utmost need to identify RKN resistant varieties of soybean against cultivated in Pakistan. The presented study is an attempt to identify and confirm the presence of resistant gene Rmi1 in soybean.  Method: Molecular studies have been done using Simple Sequence Repeat (SSR) marker system to identify resistant soybean varieties against Root Knot Nematode (RKN) using fifteen (15) indigenous cultivars and four (4) US cultivars. DNA was isolated, purified, quantified and then used to employ various SSR markers. The amplified product is observed using gel documentation system after electrophoresis.   Results: Diagnostic SSR markers Satt-358 and Satt-492 have shown the presence of Rmi1 gene in all resistance carrying genotypes. Satt-358 amplified the fragment of 200 bp and Satt-492 generated 232 bp bands in all resistant genotypes. This study confirmed the Rmi gene locus (G248A-1) in all internationally confirmed resistant including six (6) native varieties. Conclusion: These investigations have identified six (6) resistant cultivars revealing the effective and informative sources that can be utilized in breeding programs for the selection of RKN resistance soybean genotypes in Pakistan.