If shape and color of radishes are both due to genes with incompletely dominant alleles, crossing two dihybrid

Question

heterozygotes will produce how many different phenotypes?

1. 2

2. 3

3. 4

4. 5

5. 9

Answer 1

Using Sophia J's lettering scheme, you would have the following 16 possible genotypes from the SsCc  x  SsCc  cross:

SSCC

SSCc

SSCc

SScc

SsCC

SsCc

SsCc

Sscc

SsCC

SsCc

SsCc

Sscc

ssCC

ssCc

ssCc

sscc

So, you would have the following nine unique genotypes (and thus unique phenotypes with incomplete dominance):

1 SSCC

2 SSCc

1 SScc

2 SsCC

4 SsCc

2 Sscc

1 ssCC

2 ssCc

1 sscc

16 possible genotypes, some are the same outcomes, giving 9 possible phenotypes.

Answer 2

Incomplete dominance means that heterozygotes exhibit a third, unique phenotype.  

So, if you cross a SsCc with another SsCc (by the way, in incomplete dominance, you don't use capital and lower case letters to designate alleles, but I can't do subscripts on here), each parent could produce four different gamete types:

SC

Sc

sC

sc

Doing the punnett square, you'll get 9 possible phenotypes.