Answer:
(a) 90
(b) 30
(c) 30
(d) 10
F2 data for stem length (tall:dwarf) is consistent with Mendel's law of segregation.
F2 data for stem length (tall:dwarf) and flower color (violet:white) is consistent with Mendel's law of independent assortment
Explanation:
The F2 phenotypes are supposed to be in 9:3:3:1 according to Mendelian law. The total number of F2 progeny is: 80 + 36 + 39 + 5 = 160
(a) Hence, the expected number of tall, violet plants will be:
9/16 x 160 = 90
(b) Expected number of tall, white plants will be:
3/16 x 160 = 30
(c) Expected number of dwarf, violet plants will be:
3/16 x 160 = 30
(d) Expected number of dwarf, white plants will be:
1/16 x 160 = 10.
Total number of tall F2 plants = 80 + 36 = 116
Total number of dwarf F2 plants = 39 + 5 = 44
Expected ratio of tall:dwarf plants according to Mendel = 3:1
Expected number of tall plants = 3/4 x 160 = 120
Expected number of dwarf plants = 1/4 x 160 = 40
Chi square
=
for tall =
= 0.1333
for dwarf =
= 0.40
Total = 0.1333 + 0.4
0.5333
Degree of freedom = n - 1
2 - 1 = 1
Tabulated (α = 0.05) = 3.841
Since the tabulated is more than the calculated
, the hypothesis that the F2 data for stem length (tall:dwarf) is consistent with Mendel's law of segregation is accepted.
Observed Expected
tall, violet flowers 80 90
tall, white flowers 36 30
dwarf, violet flowers 39 30
dwarf, white flowers 5 10
Total 160 160 7.51
Degree of freedom = 4 - 1 = 3
Tabulated (α = 0.05) = 7.815
The tabulated value is more than the calculated
value. Hence, F2 data for stem length (tall:dwarf) and flower color (violet:white) is consistent with Mendel's law of independent assortment.