Final answer:
The deviation in the observed genotype frequencies from the expected frequencies in the sunflower population can be explained by genetic drift.
Step-by-step explanation:
The Hardy-Weinberg equilibrium principle states that allele frequencies in a population will remain constant in the absence of certain factors, which include natural selection, genetic drift, mutation, and migration. In the given sunflower population, the observed genotype frequencies deviate from the expected frequencies, indicating that the population is evolving and not in Hardy-Weinberg equilibrium. In this case, a plausible explanation for the deviation would be genetic drift.