Background: the problem with weeds is that they are very similar to crops, often they are close relatives, meaning that there is gene flow from crop to weed. Those alleles that are important for humans to distinguish crop and weed, can thus escape into the weed. This helps the weed to become very similar to the crop and thus to escape human selection. However, for other genes, the weed maintains the (often "wild") version of alleles that are the reason for yield loss.
Task: The task consists in modelling the introgression of weedy traits from Weedy Red Rice into Rice based on a simple monogenic dominant-recessive inheritance of the trait. The weedy allele (which is the original "wild" allele or a phenocopy of it) is dominant. For simplicity we just consider one cycle. The seeds, contaminated with the weed, are sown and harvested. These harvested seeds are then resown the next year. How many of them will give rise to individuals with a "weedy phenotype"?