Question

Help!!!!!!
what would be the phenotypic ratio when a TtRR plant is self fertilized?
A.9:3:3:1
B.2:1
C.3:1
D.1:2:1
and plz explain in detail...
will fan and give a medal

Answer 1

@IrishBoy123

Answer 2

@Maddy1251

Answer 3

Draw a punnet square first.

Answer 4

Phenotypic ratio- 3:1
Genotypic ratio-1:2:1
Draw a punnet square....R is homozygous dominant ,;so it will show dominant phenotype in all cases.
T is heterozygous..it will show the ratio of 3:1 when self-fertilized for phenotype and 1:2:1 for genotype.

Answer 5

can u explain me a little more?actually how to take gametes of heterozygous individuals....i m stuck here...
@globalbiomaniac .........

Answer 6

See draw a punnet square.
Homozygous gene wl form only one kind of gamete and heterozygous sill form two: one small and other capital.
So 2 types of gametes are formed: one is TR another is tR. Both these gametes are formed by both the parents.
Now in the punnet square ; u would see that; 3 types of genotypes are formed: 2 TtRR, 1 TTRR, 1 ttRR;
And their ratios will be 1:2:1;
But both TTRR & TtRR will hv same phenotypes. So only 2 types of phenotypes will be there in the ratio 3:1

Answer 7

now it make sense...thanks a lot...