GrainGenes
A Database for Triticeae and Avena
Hang and Tsuchiya, pp. 41-42
II. 22. New telocentric chromosome in chromosome 4 in barley (1)
A. Hang and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.
(1) Supported partly by USDA/SEA Competitive Research Grant 82-CRCR-1-1020 and CSU Hatch project.
A telotrisomic plant was found in the progenies of an F2 population from a cross between Triplo 7 X C.S.U. B8-9 (Zebra Colorado, zbc). The telotrisomic was first described as telotrisomic 4LB. A complete pedigree and origin of the new telotrisomic (Triplo 4) was reported by Furst and Tsuchiya (1983). Giemsa staining showed that the extra telocentric chromosome seems to consist of a complete short arm of chromosome 4 and a proximal heterochromatic portion of the long arm. Since the heterochromatic segment of the new telocentric 4 is almost the same as the entire heterochromatic segment of chromosome 4 in the Giemsa N-banding technique, it is assumed that a pericentric inversion may have occurred at the proximal heterochromatic region. The total length of the new telo 4 is also longer than either arm of chromosome 4. However, the banding pattern of the euchromatic distal segment suggests that the new telo 4 consists of the entire arm of 4S and a proximal heterochromatic segment with a pericentric inversion. It is therefore designated tentatively telocentric 4SL (inv).
Morphological characteristics of telotrisomic 4SL (inv.) is similar to that of the primary trisomic for chromosome 4 (Triplo 4) with robust character and dark green leaves. Seed fertility of telotrisomic 4SL (inv.) was relatively high with 75.8% in selfing and almost 100% in 2x + 4SL (inv.) x 2x.
The transmission rate of the telocentric chromosome was 28.1% in the selfed progenies.
Several telotrisomics and acrotrisomics for chromosome 4 were reported (Tsuchiya, 1971) and most of them resulted from two breakages: one break at the tip of the short arm, the other break was close to the centromere of the long arm. Since the new telocentric chromosome seems to have a complete short arm, it may be used to physically locate some genes such as the K group which were considered to be located at the proximal portion of chromosome 4L. Genetic marker stocks for chromosome 4 have been crossed with the new telotrisomic 4SL (inv.). Seed stock is not available at present.
References:
Furst, E. and T. Tsuchiya. 1983. New telosomic and acrosomic trisomics in barley. Barley Genet. Newsl. 13:47-48.
Tsuchiya, T. 1971. Characteristics of telotrisomics and other aneuploids in barley. Barley Genet. Newsl. 1:58-60.