In Summer Squash, a cross between two pure spherical fruit types may yield a progeny having disc shaped fruits due to
In Summer Squash, a cross between two pure spherical fruit types may yield a progeny having disc shaped fruits due to
The correct option is B Additive genes
There are three types of fruit shape in Summer
squash, viz., disc, spherical and long. The disc shape is controlled by two
dominant genes (A and B), the spherical shape is produced by either dominant
allele (A or B) and long shaped fruits develop in double recessive (aabb)
plants. A cross between disc shape (AABB) and long shape (aabb) strains
produced disc shape fruits in F1. Inter-mating of F1 plants produced
plants with disc, spherical and long shape fruits in 9 : 6 : 1 ratio in F2. Here plants with A—B—(9/16)
genotypes produce disc shape fruits, those with A-bb-(3/16) and aaB-(3/16)
genotypes produce spherical fruits, and plants with aabb (1/16) genotype
produce long fruits. Thus in F2, normal dihybrid segregation ratio 9:3:3: 1 is modified to 9
: 6 : 1 ratio.
So,
the correct option is ‘Additive genes’.
There are three types of fruit shape in Summer squash, viz., disc, spherical and long. The disc shape is controlled by two dominant genes (A and B), the spherical shape is produced by either dominant allele (A or B) and long shaped fruits develop in double recessive (aabb) plants. A cross between disc shape (AABB) and long shape (aabb) strains produced disc shape fruits in F1. Inter-mating of F1 plants produced plants with disc, spherical and long shape fruits in 9 : 6 : 1 ratio in F2. Here plants with A—B—(9/16) genotypes produce disc shape fruits, those with A-bb-(3/16) and aaB-(3/16) genotypes produce spherical fruits, and plants with aabb (1/16) genotype produce long fruits. Thus in F2, normal dihybrid segregation ratio 9:3:3: 1 is modified to 9 : 6 : 1 ratio.
So, the correct option is ‘Additive genes’.
