Is the slow-darkening gene another allele at P?

Citation

Bett, K.E., Stonehouse, R.G., Miklas, P.N., Dhaubhadel, S., Austin, R.S., and Marsolais, F. (2015). "Is the slow-darkening gene another allele at P?", Bean Improvement Cooperatives 2015, Niagara Falls, ON, Canada, November 1-4, 2015. (Abstract)