In a curly pumpkin, the white color of fruits A dominates over yellow a, and the disc-shaped form B over the spherical form b. Homozygous plants are crossed, one of which has white globular fruits, and the other has yellow disc-shaped fruits. Determine the genotype and phenotype: 1) F1 hybrids; 2) F2 hybrids; 3) offspring from backcrossing F1 hybrids with the mother plant; 4) offspring from backcrossing F1 hybrids with the parent plant.
1) Genotype F1 – AaBb, phenotype – plants with white disc-shaped fruits;
2) genotypes F2 – AABB: AABb: Aabb: AaBB: AaBb: Aabb: aaBB: aaBb: aabb in the ratio 1: 2: 1: 2: 4: 2: 1: 2: 1; phenotypes – plants with white disc-shaped, white spherical, yellow disc-shaped and yellow spherical fruits in a ratio of 9: 3: 3: 1;
3) genotypes of offspring from backcrossing of F1 hybrids with the mother plant – AaBB, AAbb, AaBb, Aabb in a ratio of 1: 1: 1: 1; phenotypes – plants with white disc-shaped fruits and white globular fruits in a ratio of 1: 1;
4) genotypes of offspring from backcrossing F1 hybrids with the parent plant – AaBB, AaBb, aaBB, aaBb in a ratio of 1: 1: 1: 1; phenotypes – plants with white disc-shaped fruits and yellow disc-shaped fruits in a 1: 1 ratio.
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