testcross

plural testcrosses · alternative test cross

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

   2 more 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.

   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

present singular third person testcrosses · participle present testcrossing · participle past testcrossed · past testcrossed · alternative test cross

1. biologyTo breed an individual in this manner.