Picture of wheat head infected with Fusarium scab

Recent Advances in Wheat Head Scab Research in China

Li-Feng Chen, Gui-Hua Bai, and Anne E. Desjardins


USDA, Agricultural Research Service




Pathogen Biology





Disease Control




Other Resources





Wheat Synonymy Table Project



DOE Primer of Molecular Genetics



Raupp et al.,
Suggested Nomenclature for Genetic Stocks



Phillip McClean
Definitions of Chromosome Variations







































Additive gene One of a group of non-allelic genes affecting the same phenotypic characteristics and each enhancing the effect of the other.

Alien addition A genome that contains one or more chromosomes from another species in addition to the normal complement of chromosomes.

Anastomosis The joining of two or more cell processes to form a branching system.

Basic population A population established through multiple-parent crossing, which has wide genetic diversity and genetic variation. It is the base of recurrent selection to improve the population.

Booting stage The wheat growth stage at which the head has formed but has not emerged from the leaf sheath.

Bridge parent A parent that is sexually compatible with two reproductively isolated species and can be used to transfer genes between them.

Callus The cluster of cells that results from tissue culturing a single plant cell.

Carbendazim 2-(methoxycarbonylamino)-benzimidazole, a systemic fungicide.

C-banding A method for producing stained regions around chromosomal centromeres.

Chlorogenic acid 1,3,4,5-tetrahydroxycyclohexanecarboxylic acid 3-(3,4-dihydroxycinnamte), a plant metabolite.

Combining ability Average performance of a strain in a series of crosses.

Deoxynivalenol 12,13-epoxy-3,7,15-trihydroxytrichothec-9-en-8-one, one of a large family of sesquiterpene epoxide toxins known as trichothecenes.

Diniconazole 1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-lyl)-1-penten-3-ol, a systemic fungicide.

Disomic Having one or more chromosomes duplicated but not an entire genome duplicated.

Dominance Referring to alleles that fully manifest their phenotype when present in the heterozygous state.

Epidermis An outer layer of primary plant tissue that is usually one cell thick and provides protection to underlying tissues.

Gametocidal gene A gene encoding a product that destroys cells that divide to produce the gametes.

Glume One of the two empty bracts at the base of the spikelet in grasses.

Hypha A filament of a fungal thallus.

Jointing stage Wheat growth stage at which the first stem node is visible above ground.

Land race A locally developed line of wheat.

Long-term Gene Pool A population established for long-term breeding goals, with wide genetic variability. Lower selection pressure is applied when it is improved through recurrent selection. It can provide genetic variability to other gene pools.

Monosomic The condition in which one chromosome of one pair is missing.

Necrosis Localized death of plant tissue often characterized by discoloration.

Ovary The ovule-containing region of the pistil of a flower.

Ph gene A chromosome pairing controlling gene. When dominant, it inhibits pairing of homoeologous chromosomes; when recessive, the control of homoeologous chromosome pairing is relaxed.

Polymorphism The existence of two or more genetically different classes in the same interbreeding population.

Rachis The elongated axis of an inflorescence.

Random amplified polymorphic DNA Randomly generated oligodeoxyribonucleotides that serve as primers in reactions involving reverse transcriptase and annealing to complementary sequences in the template nucleic acid.

Recurrent selection Crossing an offspring and one of its parents or an individual genetically identical to one of its parents.

Resistance Resource Gene Pool A population rich in genetic variability of head scab resistance. The pool is kept to improve the resistance with a stronger selection and accumulate the resistance genes through recurrent selection.

Sclerenchyma A supporting tissue in higher plants composed of cells with walls that are thickened, lignified, or mineralized.
Sector A part of a fungal culture with a visibly changed form of growth.

Short-Term Gene Pool A population established for short-term breeding goals, with better agronomic performance and lower genetic variability. Stronger selection is adopted, simultaneously, for head scab resistance and agronomic traits, such as yield potential characters, plant height, maturity and so on.

Somaclonal variation The appearance of new traits in plants that regenerate from a callus in tissue culture.

Spikelet One of the small bracteate spikes that make up the compound inflorescence of grasses.

Substitution line A line in which one or more chromosomes have been replaced by chromosomes from a different species.

Thiophanate methyl Dimethyl4,4-O-phenylenebis (30thioallophanate), a systemic fungicide.

Thiram Tetramethylthiuram disulfide, a protective foliar fungicide.
Transgressive segregation Progeny phenotypes outside the range that occurs in the parents, usually attributed to polygene segregation.

Triadimefon 1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-2-butanone, a systemic fungicide.


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