Deployment of gene specific marker in development of kunitz trypsin inhibitor free soybean genotypes

Genetic elimination of kunitz trypsin inhibitor in soybean seed would obviate the need for boiling required to inactivate the antinutritional factor and therefore economize the soy processing. PI542044, the source of null variant of kunitz trypsin inhibitor gene is being used in the development of kunitz trypsin inhibitor free soybean genotypes in India. Gene specific marker can expedite the genetic elimination of this undesirable trait from popular soybean genotypes. In the present study, we tested the DNA amplification of soybean genotype PI542044 and kunitz trypsin inhibitor null lines derived from this genotype with a gene specific primer developed from the null variant of PI157740. The amplicons so obtained corresponded to the absence of kunitz trypsin inhibitor protein band on 10% polyacrylamide gel. The gene specific marker also amplified the null allele of template DNA of F1, BC1F1 and BC2F1 plants developed during marker assisted introgression of null allele of kunitz trypsin inhibitor into elite soybean cultivar JS97-52. The results presented show the utility of this gene specific marker developed from null allele of kunitz trypsin inhibitor for identification of kunitz trypsin inhibitor free genotypes developed from PI542044, the only source of null variant available in India.