The inheritance of mating type and growth rate in Choanephora cucurbitarum

When isolates of Choanephora cucurbitarum (Berk. & Rav.) Thaxt with similar growth rate and colony appearance were crossed, the mating-type distribution of zygospore progeny fit the ratio of 1(+):1(-):2(+,-). However, germsporangiospore progeny from the same pairs fit a 1(+):1(-) ratio but not a 1(+):1(-):2(+,-) ratio. When isolates with different growth type (F for fast and S for slow) were crossed, the resulting zygospore progenies fit a 1(+):1(-) ratio but not a 1(+):1(-):2(+,-) ratio. Their growth type distribution also fit a 1F:1S ratio. All the sporangiospores tested were multinucleate.