Meaning of testcross | Babel Free

Definitions

The breeding of an individual with a phenotypically recessive individual, in order to determine the zygosity of the former by analysing proportions of offspring phenotypes.

Examples

“The inbreds of groups 3 and 4 have⟳ a distinct difference in plant⟳ height, except for a few selections, presumably because of some difference in selection pressure at low- and high-stand densities. Group means for testcross performance showed more progress⟳ in group 4 than in group 3 because of a difference in the number⟳ of low-yielding genotypes in the two groups.”

“You could determine⟳ its genotype by performing a testcross. If the plant⟳ were homozygous (TT), a testcross would produce⟳ all tall progeny (TT × tt → all Tt); if the plant⟳ were heterozygous (Tt), half of the progeny would be tall and half would be short (Tt × tt → 1/2 Tt and 1/2 tt). When a testcross is performed, any recessive allele in the unknown genotype is expressed in the progeny, because it will be paired with a recessive allele from the homozygous recessive parent.”

CEFR level