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Question : 5
Total: 7
A green stemmed tomato plant denoted by (GG) is crossed with a tomato plant with purple stem denoted by (gg).
(i) What colour of the stem would you expect in their F1 progeny?
(ii) In what ratio would you find the green and purple coloured stem in plants of F2 progeny?
(iii) What conclusion can be drawn for the above observations?
(i) What colour of the stem would you expect in their F1 progeny?
(ii) In what ratio would you find the green and purple coloured stem in plants of F2 progeny?
(iii) What conclusion can be drawn for the above observations?
Solution:
(i) F1 will have all green stemmed plants.
(ii) Green : Purple= 3 : 1
(iii) The above observation shows that green stem is dominant trait over purple stem. Hence, as per law of dominance, only dominant trait appeared in F1. However, occurrence of purple stem in F2 shows that alleles for purple stem were inherited but not expressed in F1. They got expressed only in F2 under homozygous conditions.
(ii) Green : Purple
(iii) The above observation shows that green stem is dominant trait over purple stem. Hence, as per law of dominance, only dominant trait appeared in F1. However, occurrence of purple stem in F2 shows that alleles for purple stem were inherited but not expressed in F1. They got expressed only in F2 under homozygous conditions.
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