BGN 12: An unstable Balanced Tertiary Trisomic in barley BARLEY GENETICS NEWSLETTER, VOL. 12, II. RESEARCH NOTES
Shahla and Tsuchiya, pp. 33-34

II. 13. An unstable Balanced Tertiary Trisomic in barley. (1)

A. Shahla and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.

(1) Supported by USDA/SEA Competitive Research Grant 5901-0410-9-0334-0 and USDA/SEA Cooperative Research Grant 12-14-5001-265 and CSU Hatch project.

A Balanced Tertiary Trisomic (BTT) offers a good pollen source when working with lethal genes. One Balanced Tertiary Trisomic line which has been established for the lethal gene ac2 (Albino seedling) has an interchanged chromosome Tl-6a (Ramage and Tuleen, 1964). Ten seeds were germinated in this line as a male parent. The chromosome count was not made in the root tip cells, assuming all green plants had 2n = 15 chromosomes. One seedling showed white stripes on leaves at early seedling stage. Root tips were collected from this plant and chromosome numbers were studied. All 29 cells from 3 roots had 2n = 14 chromosomes. No cells with 2n = 15 chromosomes were observed. It was assumed that the extra interchanged chromosome which carried the dominant allele (Ac2) for green trait was eliminated in the somatic tissues. This indicates that the BTT line 1-6a-ac2 may be unstable in some plants.

Ramage, R. T. and N. A. Tuleen. 1964. Balanced tertiary trisomics in barley serve as a pollen source homogeneous for a recessive lethal gene. Crop Science 4:81-82.

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