In: Biology
A true-breeding strain of peas with round seeds and a true-breeding strain of peas with wrinkled seeds are crossed.
Their offspring (F1) are allowed to self-fertilize and produce an F2 generation.
Round pea seeds (F2) were planted and produced mature plants with flowers.
The pollen from these plants was collected and used to fertilize plants from the true-breeding wrinkled strain.
a) what proportion of these progeny is expected to have wrinkled seeds?
b) what proportion of these progeny are expected to be heterozygous?
a) The correct answer is 1/2. Half of these progeny is expected to have wrinkled seeds.
b) The correct answer is 1/2. Half of these progeny is expected to be heterozygous.
When a true breeding strain of peas with round seeds (RR) was crossed with wrinkled seeds (rr), it will produce heterozygous strain with round seeds (Rr) in F1 generation. Whene these (Rr) are self fertilized they will produce RR, Rr, Rr and rr genotypic plants in F2 generation. Among F2 individuals, RR, Rr and Rr are round pea plants.
When these round pea F2 plants were crossed with true breeding wrinkled strain (rr) the following progenies will be obtained.
The RR genotype plant will produce all four heterozygous round pea plants (Rr),
the Rr genotype plants will produce two heterozygous round pea plants and two wrinkled strains, and
the rr genotype plant will produce all four wrinkled strains.
Among 16 progenies, 8 were heterozygous round pea plants (1/2) and 8 were wrinkled strains (1/2).