Question 15 Marks
A homozygous tall plant (TT) bearing red coloured $(R R)$ flowers is crossed with a homozygous dwarf plant (tt) bearing white flowers (rr) :
(i) Give the genotype and phenotype of the $F_1$ generation.
(ii) Give the possible combinations of the gametes that can be obtained from the $F_1$ hybrid.
(iii) Give the dihybrid ratio and the phenotype of the offspring of $F_2$ generation when two plants of above $F_1$ generation are crossed.
(i) Give the genotype and phenotype of the $F_1$ generation.
(ii) Give the possible combinations of the gametes that can be obtained from the $F_1$ hybrid.
(iii) Give the dihybrid ratio and the phenotype of the offspring of $F_2$ generation when two plants of above $F_1$ generation are crossed.
Answer
View full question & answer→Cross between homozygous tall plant (TT) bearing red coloured (RR) flowers with a homozygous dwarf plant
( tt ) bearing white flowers ( rr ) is as follows:
(i) Genotype of the $F _1$ generation is TtRr. Phenotype of the $F _1$ generation is tall plant with red flowers.
(ii) On self pollination of $F _1$ generation in the above cross, the possible combinations of the gametes that can be obtained from the $F_1$ hybrid are: $F _1$ generation is Tt Rr On selfing - Tt Rr $\times Tt Rr$, Gametes are TR, Tr, tR, tr.
(iii) From the above cross,
The dihybrid ratio of $F_2$ generation is $9: 3: 3: 1$
( tt ) bearing white flowers ( rr ) is as follows:
(i) Genotype of the $F _1$ generation is TtRr. Phenotype of the $F _1$ generation is tall plant with red flowers.
(ii) On self pollination of $F _1$ generation in the above cross, the possible combinations of the gametes that can be obtained from the $F_1$ hybrid are: $F _1$ generation is Tt Rr On selfing - Tt Rr $\times Tt Rr$, Gametes are TR, Tr, tR, tr.
(iii) From the above cross,
The dihybrid ratio of $F_2$ generation is $9: 3: 3: 1$