Read the given passage and answer any of the four questions from (a) to (e) given below:
Seema crossed pure breed pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were crossbreed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.
(a) What are A-B type of seeds?
(i) Round -yellow
(ii) Round- green
(iii) Wrinkled- yellow
(iv) Wrinkled- green
Answer:
All the seeds in the F 1 progeny were round and yellow.
So, the correct answer is (i) Round - yellow
(b) A and B are _____________ traits.
(i) dominant
(ii) recessive
Answer:
The traits that express themselves in the F 1 progeny are called dominant traits.
So, A and B are dominant traits.
So, the correct answer is (i) dominant traits
(c) A-D are __________ and C-B are _______ type of seeds.
(i) Round green and wrinkled yellow respectively
(ii) Round yellow and wrinkled green respectively
(iii) Wrinkled green and round green respectively
(iv) Wrinkled green and round yellow respectively
Answer:
When F 1 generation pea plants having A-B type of seeds were crossbreed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties of seed were obtained ie., round green and wrinkled yellow seeds.
So, the correct answer is (i) Round green and wrinkled yellow respectively.
(d) Which one of these will be produced in minimum and maximum number in the F2 generation?
(i) A-B
(ii) A-D
Answer:
In the F 2 generation, 9/16 seed were of type A-B ie., round and yellow and 3/16 seeds were of type A-D ie., round and green.
So, A-B i s produced in maximum number while A-D will be produced in minimum number.
(e) The above cross is known as
(i) Monohybrid cross
(ii) Dihybrid cross
(iii) Test cross
(iv) Back cross
Answer:
When we breed two plants having two contrasting characteristics each to obtain new plants, it is called dihybrid cross.
So, the correct answer is (ii) Dihybrid cross.
