II. 37. Two new types of trisomics in barley.(1)
J. W. Shim (2)and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.
(1) Supported by USDA/SEA Competitive Research Grant No. 82-CRCR-1-1020
and CSU Hatch project.
(2) Visiting professor, leave of absence from College of Agriculture,
Seoul National University, Suewon, Korea.
In recent years the telocentric chromosomes and other fragment chromosomes, including acrocentric chromosomes, are recognized as important material for linkage mapping and the study of genetic architecture of barley chromosomes (Tsuchiya et al. 1983). In this report two additional cases of new trisomics will be described.
1. A trisomic for a centric fragment of chromosome 1 (SE82-38).
This trisomic was found in a trisomic stock, Triplo 1 (Bush). In the
somatic cells the trisomic showed a small submetacentric fragment. Although
the nature of this chromosome has not been cytologically or genetically
determined, the plant morphology indicated that the fragment was the segment
of chromosome 1. This trisomic plant and its progenies showed a typical
qualitative trait of Bush, the primary trisomic for chromosome 1. The trisomics
have narrow, a relatively short, dark blue-green leaves. Also the trisomics
showed some fused or onion leaves which are characteristics for trisomics
carrying whole or a part of the long arm of chromosome l. However, the
trisomic type differed from primary trisomic (Triplo 1) in that the new
trisomic had three completely developed anthers in all florets and much
more vigorous than primary and other trisomics carrying whole or a segment
of the long arm of chromosome 1.
The transmission rates of the extra fragment chromosome were 20.5% through female (8 of 39) and 24.4% (11 of 45) in the selfed progeny. One primary trisomic plant was obtained among the 45 plants in the selfed progeny.
Genetic analysis with some multiple genetic marker stocks will provide interesting information on the genetic architecture of this particular segment and also chromosome 1 as a whole.
2. Acrotrisomic 6S6L (?).
This apparently acrotrisomic 6S6L was found in an F2 population
(IItr83-7) of Triplo 6S x msg,, bk o. The extra chromosome seems
to consist of a complete short arm and a small segment of the long arm.
Detailed analysis is now underway. The genetic analysis with this new trisomic
and telotrisomic for 6S (Triplo 6S) will provide useful information on
the genetic architecture of not only the short arm but also probably the
proximal portion of the long arm of chromosome 6.
Reference:
Tsuchiya, T., R. J. Singh, A. Shahla and A. Hang. (1983) Acrotrisomic analysis in linkage mapping in barley. Can. J. Genet. Cytol. (Submitted).