A cross was made between pure breeding pea plants having green and yellow pod. The off springs obtained were all yellow in color.

1. Between green and yellow which is a recessive trait.
2.  Using appropriate symbols, write the genotype and phenotype of the parents and F1 off springs.
3. What will be the ratio of yellow and green podded plants in F2 off springs  if F1 generation undergoes self-fertilization( Selfing ) . Work out the cross using Punnette square.

 

Dear student,

Here, YY= Green ,   yy= Yellow

Parent generation :    YY(Green)             yy(Yellow)
                                  
Gametes              :          Y                      y

F1 generation       :                   Yy(Green)   {Selfing}

​F2 generation       :          

Male/ Female	Y	y
Y	YY (Green)	Yy (Green)
y	Yy (Green)	yy (Yellow)

Ans1. Yellow is the recessive trait.
Ans2. The parents will have YY(Green) and yy(Yellow) phenotypes and genotypes respectively. In F1 generation, Yy(Green) gametes will undergo selfing with Yy.
Ans3. The above mentioned diagram shows the punnett square and the offsprings obtained in the F2 generation. 
         Phenotypic ratio = 3(Green) : 1(Yellow).
         Gentotypic ratio = 1 (YY): 2(Yy) : 1 (yy)

 Regards.