In freesias (a type of lily), a cross was made between a red-flowered male with
ID: 187842 • Letter: I
Question
In freesias (a type of lily), a cross was made between a red-flowered male with smooth leaves and a yellow-flowered female with rough leaves. The F1 generation consisted of male and female plants with red flowers and smooth leaves. When the F1 males and females are crossed, the F2 offspring consisted of 16 red-flowered females with rough leaves, 48 red-flowered females with smooth leaves, 15 yellow-flowered females with rough leaves, 49 yellow-flowered females with smooth leaves, 31 red-flowered males with rough leaves and 97 red-flowered males with smooth leaves.
1.What is the best explanation for the genetic basis of red flower color?
2.What is the best explanation for the genetic basis of rough leaves?
3. If you cross an F2 female red flowers and smooth leaves to an F1 male, what type of offspring are you unlikely to see?
Explanation / Answer
From the given data,
Total progenies in F2= 16+48+15+49+31+97=256
Let allele for red be R, yellow be r.
Allele for smooth leaf be S and for rough be s .
Parents 1: RRSS×rrss
Ans 1:
Outof 256 in F2, 192 have red leaves and 64 have yellow ones.
Their ratio is 3:1.
Thus allele for red color is dominant over allele for yellow colour.
Ans 2:
Out of 256 progenies in F2 , 62 have rough leaves and 190 have smooth leaves.
Thus, allele for smooth leaves is dominant over allele for rough leaves.
Ans- 3:
F2 female: RrSs
F1 male: RRSS
if we cross them, we will find that all progenies will be Red, smooth.
Yellow or rough phenotype will be unlikely.