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 (tĕst′krôs′, -krŏs′)
A cross between an individual exhibiting the dominant phenotype of a trait and an individual that is homozygous recessive for that trait in order to determine the genotype of the dominant individual.
tr.v. test·crossed, test·cross·ing, test·cross·es
To subject to a testcross.


(ˈtɛstˌkrɒs) genetics
(Genetics) a genetic test for ascertaining whether an individual is homozygous or heterozygous
vb (tr)
(Genetics) to subject to a testcross


(ˈtɛstˌkrɔs, -ˌkrɒs)

a genetic test for heterozygosity in which an organism of dominant phenotype, but unknown genotype, is crossed with an organism recessive for all markers in question.
test′-cross`, v.t.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.testcross - a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring
hybridisation, hybridization, hybridizing, interbreeding, crossbreeding, crossing, cross - (genetics) the act of mixing different species or varieties of animals or plants and thus to produce hybrids
References in periodicals archive ?
These results indicated that heterosis in grain yield was presented in the testcrosses which was mainly ascribed to grain weight and grain number.
High genetic correlations coefficients among testcrosses at early and later inbreed generations were reported by Bernardo [30].
The second group included 70 testcrosses hybrids with averages between 6 369 and 8 536kg [ha.sup.-1], while the third group was formed by 30 testcross hybrids showing the worst performance in terms of grain yield, ranging from 1 535 to 6 193kg [ha.sup.-1].
Four possible exercises are presented: two dihybrid testcrosses (Figure 2A,B) and two trihybrid testcrosses (Figure 2 C,D).
The [s.sub.4] lines per se and the testcrosses were evaluated at Sinematialli under Striga-free conditions and at Ferkessedougou under artificial infestation with S.
At the [S.sub.4] stage of inbreeding, 450 to 500 lines derived from each population were evaluated for general combining ability in testcrosses and for performance per se in replicated trials at Ferkessedougou (9[degrees]30'N, 5[degrees]10'W), and Sinematialli (9[degrees]37' N, 3[degrees]04' W) both in Cote d'Ivoire which are hereafter referred to as Ferke and Sine, respectively.
The random nongenetic effects had a normal distribution with a mean of zero and were scaled so that broad-sense heritability among testcrosses was H = 0.20, 0.50, or 0.80 in the initial [F.sub.2] population.
Thus two types of progeny were developed: the lines per se (represented by a mating structure of [F.sub.1]R[M.sub.10][S.sub.2]) and their corresponding testcrosses with Monsanto 7051.
In the testcrosses, metaphase I chromosome pairing configurations of 13" + t1" + t' indicated that a spontaneous homoeologous translocation had occurred in the double-monosomic B[C.sub.1][F.sub.1] plant.
[S.sub.2] testcrosses with Iowa Stiff-Stalk Synthetic (BSSS) related single-cross tester B73/B94 were produced in 1993 and evaluated in trials at one site with conventional-tillage and one with minimum-tillage, near Wooster, and at an additional site near South Charleston, OH, in 1994.