Using Hardy-Weinberg equation of genetic variation being constant when disturbing factors such has mutation and others are removed.
p² + pq + q² = 1 and p + q = 1
where p² is the frequency of the homozygous dominant genotype (RR) and q² is the frequency of the homozygous recessive genotype (rr) and 2pq is the frequency of heterozygous genotype (Rr). p represent the frequency of "R" and q represent "g". since the coefficient against the green/green homozygote is 0.30 then
the fitness of the green/green homozygote = 1 - 0.3 = 0.7
