The plant will form all the gametes with alleles Gk.
The genotype of the given plant is GGkk. Since the plant is homozygous for both the genes, it will form all same type of gametes. Gametes have only one allele for each gene. The plant with genotype GGkk will form the gametes with one copy of "G" and one copy of "k" alleles. Hence, all the gametes formed by the plant with gentoype GGkk will have genotype "Gk".