A green stemmed rose plant denoted by GG and a brown stemmed rose
plant denoted by gg are allowed to undergo a cross with each other.
(a) List your observations regarding
(1) Colour of stem in their F, progeny
(ii) Percentage of brown stemmed plants in F, progeny if F, plants
are self pollinated.
(iii) Ratio of GG and Gg in the F, progeny.
(b) Based on the findings of this cross, what conclusion can be drawn?
DD
Answers
Answer:
1)F1- green
3) 2:8 ,2:8
Answer:
a)
- The stem color of the plant in F progeny is green color.
- The percentage of plants with green color stems in F’ progeny is 25%.
- The ratio of GG to Gg in F’ progeny is a 1:2 ratio.
b) The conclusion is that both the alleles (green and brown color) of stem color trait separate at the time of gamete formation. Hence, a green-colored stem plant was observed in the F’ progeny.
Explanation:
Genotype GG gg
Phenotype (Green stem rose plant) (Brown stem rose plant)
F generation Gg
(Green stem rose plant)
Self Pollination Gg Gg
♀♂ - G g G g
F’ generation GG, Gg, Gg, gg
a)
i) The color of the stem in F progeny is green because the green color stem is a dominant trait.
ii) The percentage of plants with brown stem color in F’ progeny, if F progeny is self-pollinated, is 25%.
- GG, Gg - Green color stem plant
- gg - Brown color stem plant
- Percentage of brown stem plant = (1/4) 100 =25%
iii) The ratio of GG to Gg in the F’ progeny is 1:2.
b) The monohybrid cross proves Mendel’s Law of Segregation, which states that the two alleles of a trait separate at the time of gamete formation. Hence, the conclusion of the above findings is that the two alleles (Green and Brown color) of stem color traits separate during gamete formation.
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