coffea arabica, as cultivated, has little genetic diversity. plant breeders are
ID: 262168 • Letter: C
Question
coffea arabica, as cultivated, has little genetic diversity. plant breeders are searching wild relatives to hybridize and hopefully increase diversity in this most precious of crop plants. coffea canephore is superior in multiple ways: for example, c. canephora is less susceptible to disease and drought and has greater yields with greater caffeine content. a plant breeder decides to breed a hybrid between c. arabica and c. canephora. the breeder is not certain as to which traits are dominant for drought resistance and caffein content and so breeds two true- breeding parents. all the f1s had high drought resistance and medium caffeine content. the plant breeder then crosses two of the f2s that results in the following phenotypes: drought resistant and medium caffein content, drought resistant and high caffein content. drought resistant and lowcaffein content, not drought resistant and medium caffein content, not drought resistant and high caffein content, not drought resistant and low caffein content. create a punnette square for the parental cross, resulting in f1. give genotypic and phenotypic ratios.
Explanation / Answer
Coffea arabica X Coffea canephora
Drought resistance, Caffeine content X Drought resistance, Caffeine content
DrCc X DrCc
F1 – High drought resistance, medium caffeine content
Parents
Dr
Cc
Dr
Cc
Dr
DrDr
DrCc
DrDr
DrCc
Cc
DrCc
CcCc
DrCc
CcCc
Dr
DrDr
DrCc
DrDr
DrCc
Cc
DrCc
CcCc
DrCc
CcCc
DrDr – 4
DrCc – 8
CcCc – 4
The genotypic ratio is 1:2:1
The phenotypic ratio is 1:2:1 (drought resistance : drought resistance, caffeine content : caffeine content)
Parents
Dr
Cc
Dr
Cc
Dr
DrDr
DrCc
DrDr
DrCc
Cc
DrCc
CcCc
DrCc
CcCc
Dr
DrDr
DrCc
DrDr
DrCc
Cc
DrCc
CcCc
DrCc
CcCc
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.