testcross
verbEtymology From test + cross.
testcross
noun/ˈtɛstˌkɹɒs/
Etymology From test + cross.
1
Biology, Genetics, Medicine, Natural sciences, Sciences 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.
- 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.1967, W. A. Russell, A. H. Teich, Selection in Zea Mays L. by Inbred Line Appearance and Testcross Performance in Low and High Plant Densities:
- 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.2012, Benjamin A. Pierce, Genetics: A Conceptual Approach, Macmillan, →ISBN, page 55: