Questions and Problems 339 



7. In squash (see question 6), a yellow-fruited plant crossed with a 

 white-fruited one produced the following offspring: 46 white : 35 yellow : 

 13 green. What are the genotypes of the parents? 



8. In squash (see question 6), a WW yy and a ww YY plant were 

 crossed. By selfing the F2 plants, what would be the chance of producing 

 a pure-breeding white-fruited strain? 



9. A pure-bred White Leghorn fowl is crossed with a pure-bred 

 Plymouth Rock. Two Fi birds were mated. What are the phenotypes 

 and genotypes of the F2? 



10. What phenotypes are produced by crossing the Fi obtained in 

 question 9 with (1) a pure-bred White Leghorn and (2) a pure-bred 

 Plymouth Rock? 



11. Two purple-flowered Emily Henderson sweet peas, when crossed, 

 produced 94 purple- and 75 white-flowered plants. Statistically, could 

 this be considered a 1 : 1 ratio? If not, how would you interpret it, and 

 what would be the genotypes of the parents? 



12. What offspring are produced from the following crosses in the Emily 

 Henderson sweet pea? 



(a) CC pp X cc Pp (d) Cc Pp X Cc Pp 



(b) Cc Pp X cc pp (e) Cc pp X cc PP 



(c) Cc pp XccPp if) CC Pp X cc pp 



13. In poultry. Black Langshans have feathered shanks and Buff 

 Rocks have shanks without feathers. When crossed, these breeds pro- 

 duced a feathered Fi. Two Fi's were crossed, and the F2 segregated 

 into 15 feathered : 1 unfeathered. Explain. 



14. In poultry, feathered shanks are dominant over unfeathered and 

 are the result of the duplicate genes Fi and F2. What are the offspring 

 of the following crosses: 



(a) FJi F2/2 X /i/i /2/2 

 ib) 7^1/1/2/2 XFi/1/2/2 



(C) /l/l F2f2XFif 1/2/2 



15. In shepherd 's-purse, triangular capsule is dominant over round 

 and is due to the duplicate genes, C and D. What are the genotypes of 

 the parents that would produce the following results? 



