Appendix E 



439 



1. What gametes will be formed by an J^i hybrid individual 

 from the cross between tall, green and dwarf, yellow ? 



2. How many offspring will it be necessary to grow in order 

 to allow every combination to appear in the second generation ? 



3. How many genotypes will there be ? 



4. How many pheno types will appear ? 



5. In what ratio will the pheno types appear? 



6. How many pure dominant individuals? 



7. How many pure recessive individuals ? 



8. If the combination T X t gave plants of medium height 

 when a tall plant with yellow seeds is crossed with a dwarf plant 

 with green seeds, how many genotypes will appear in F^ How 

 many pheno types ? In what ratio ? 



Illustrative problems. The following problems may be studied 

 by way of illustration. These are taken from actual cases with 

 the tomato, but will apply in principle to other plants, by sub- 

 stituting other unit characters : 

 Problem 1. 



Tall, homozygous (T) X dwarf, homozygous (t) = Tt ; FI 



FI gametes = T ; t 



F! self ed = 



POLLEN-GRAINS 



T 



TT 



tT 



EGG-CELLS 



Tt 



