testcross


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Related to testcross: incomplete dominance

test·cross

(test'kros),
Crossing of an unknown genotype to a recessive homozygote so that the phenotype of the progeny corresponds directly to the chromosomes carried by the parents of unknown genotype.
Synonym(s): backcross (2)

testcross

(tĕst′krôs′, -krŏs′)
n.
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·crossing, test·crosses
To subject to a testcross.
Testcrossclick for a larger image
Fig. 295 Testcross. A testcross to find the genotype of the unknown parent.

testcross

a cross in which one partner is homozygous (see HOMOZYGOTE for the recessive alleles of the genes being investigated. The testcross progeny will indicate the GENOTYPE of the unknown parent. See Fig. 295 . Test crosses are used extensively in experiments to establish GENETIC LINKAGE. See also BACKCROSS.
References in periodicals archive ?
Estimates of testcross means and testcross genetic variances ([V.sub.TC]) were obtained within each level of N.
Segregation of TMV resistance in testcross families involving NC1125-2 and the 12 accessions from the U.S.
Both testcross generation means analysis and ordinary generation means analysis estimate only net effects of genes or gene combinations summed over loci.
In the present study, we developed a testcross population by crossing 204 RILs derived from two elite restorer lines with a male sterile line that was commonly used in hybrid rice breeding [27].
A total of 441 treatments, comprising the 426 testcross hybrids and 15 checks, were evaluated in nine trials in 7x7 lattices with two replications.
The F1 {[w.sup.1] [cv.sup.+]/[w.sup.+] [cv.sup.18]} virgin females are then crossed to [w.sup.1] [cv.sup.18] / Y males to produce the testcross diagrammed in Figure 2B.
Thus, a testcross would be a green-seeded plant (yy) x a yellow-seeded plant (either YY or Yy).
The other one half of the F2 progeny is the product of the se e/male gamete and is effectively the result of a testcross gamete.
In order to determine if this method is appropriate and approximates the results obtained when a test-cross is carried out, the class also performed a testcross on the F1 generated from the same starting cross.
where [G.sub.k] was the testcross genotypic value of the kth individual; [E.sub.ik] was the activity of the ith enzyme in the kth individual; and c was a constant which did not affect the relative values of [G.sub.k].
If this was correct, then some of the testcross progeny with 7DL should have acquired Dn5 through crossover and would have segregated for resistance.
In addition, this study reports analysis of testcross progenies and of protein and starch data not reported in the study of Laurie et al.