INTRODUCTION TO PLANT BREEDING

AGRONOMY 815 / COURSE NOTES

P. STEPHEN BAENZIGER, 338 Keim Hall, 472-1538

DEPARTMENT OF AGRONOMY / UNIVERSITY OF NEBRASKA

POPULATION GENETICS EXAMPLE


You have a population of random mating corn plants. In the population there are 481 tall plants (T_) and 263 dwarf plants (tt). What is the frequency of the T and t alleles?

q2=263 / (481 + 263)=263/744=.353

q =.594

p =1 - q=1 - .594=.406

p2=(.406)2=.165,2pq=2(.594)(.406)


If you select 150 tall plants, how many of the tall plants will carry the dwarf allele?


(150)x(2(.594) / (1 + .594))=150 x .745=112 plants

or150x(.482) / (.482 + .165)= 112 =


What is the effective population size of a population in which 50 female plants were selected from a population of 300 which was pollinated by 350 males?


Ne=4(50)(350) / (50 + 350)=70,000 / 400=175

What is the change in the inbreeding level?


1/(2Ne)=1 / (2(175))=1 / 350=0.00285