Monohybrid Cross

Monohybrid Cross
Hypothesis - Kernel cobs with different traits were counted. e.g in this experiment coloured and colourless. If the results obtained is close enough to the expected ratio to be acceptable as a significant result. (Observed results fit the expected results)
Alternative hypothesis - If the observed data does not fit the expected data the results obtained were not significant. (Ratio observed are so far off the ratios expected)
Genetic diagram
A = Coloured allele. a = Colourless allele.
Parents’ phenotype Coloured X Colourless
(Kernel phenotype)

Kernel genotype A A X aa

Gametes A A X a a

Possible genotypes of
F1 generation Aa Aa Aa Aa (All Coloured)

Parents phenotype Coloured X Coloured

Parents genotype Aa X Aa

Gametes A a X A a

Possible genotypes of
F2 offspring AA Aa Aa aa

Phenotypes of the F2
Offspring Coloured Colourless

Ratio 3 : 1

Kernel phenotype
Observed frequency(O)
Expected frequency(E) (O-E)
(O-E)2
(O-E)2 E
Coloured
87
88.5
1.5
2.25
(2.25/88.5) = 0.025
Colourless
31
29.5
1.5
2.25
(2.25/29.5) = 0.763 Calculation –

Expected frequency for Coloured Kernel – Total of the Observed frequency 4 = 118 4