Laboratory of Cytogenetics
Head L.B.Budashkina, Ph.D.
Sea-buckthorn variety Sibirskiy Rumianets, early ripening, high (to 30 mg/%) carotinoid content, very tasty
Wheat x rye substitution line 5R/5D
Long-standing research activity concerning karyotype reorganization pattern in the common wheat (Triticum aestivum L.) genome containing genetic material transferred from other plant species is continued at the Laboratory.
Studies were based mainly on two models: intergeneric (T. aestivum x S. cereale) and interspecific (T. aestivum x T. timopheevii) hybrids.
A variant of differential chromosome staining was developed by A.I.Shchapova at the Laboratory. The method allows to identify each rye (S. cereale) chromosome and many Agropyron and wheat chromosomes. It was demonstrated that karyotype stabilization in the interspecific and intergeneric hybrids is associated with intergenomic chromosome substitution.
The major factors determining the process are:
- genotypic environment,
- genomic structure,
- ploidy level of the hybrid.
Unique collections of introgressive forms of common wheat were established. The collection of wheat x rye lines serves as a model to study the role of individual chromosomes in the genetic control of economically valuable characters and to localize genes controlling important steps of meiosis.
It was shown that the Edu (Equational division of univalents) genes are located in the chromosomes of homoeologous group 5: the P(Edu) promoter is in rye chromosome 5R and the inhibitor of univalent equational division is in wheat chromosome 5A. The chromosomes of homoeologous groups 1 and 5 carry the genes for soil salinity resistance in hybrids.
The collection of disease resistant introgressive lines containing T. timopheevii genetic material was derived from 6 commercial varieties. In these lines, rust resistance is controlled by differently interacting one or two genes that are not allelic to the Lr-genes of the world collection. Using microsatellite markers, these genes that were transferred from the common wheat to the T. timopheevii genomes are being localized at the Laboratory in collaboration with the Section of Molecular Genetics of Plants. The developed lines are used in breeding of disease resistance donors.
Studies on sea-buckthorn (Hippophae rhamnoides L.), another plant of agricultural importance, have established for the first time that it contains sex chromosomes: heterogametic (XY), male, and homogametic (XX), female.
Sea-buckthorn populations were produced in experiments. Fruit weight was increased, on the average, by 25-30% in polyploids as compared with diploids, without reduction in fertility.
A set of sea-buckthorn varieties was developed in collaboration with the Novosibirsk Zonal Fruit-Berry Experimental Station. Their growth is delayed, they are thornless; the large fruit is easy to pluck, color is different and taste delicious. Of the developed varieties, Zyrianka and Drujina were zoned. Development and improvement of varieties lending to mechanical gathering are under way.