II. 12. Telotrisomic analysis of the gene ac2 (albino seedling) in Triplo 1S in barley. (1)
Azizeh Shahla and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.
(1)Partly supported by USDA/SEA Competitive Research Grant No. 5901-04109-0334-0 and 82-CRCR-1-1020, and CSU Hatch Project.
In a previous study, telotrisomic analysis of Triplo 1L with marker gene ac2 (albino seedling) (Robertson, 1937) did not show a clear disomic segregation ratio. The presence of two homozygous trisomics suggested that the gene is not located on the long arm of chromosome 1 (Shahla and Tsuchiya, 1982) which was in conflict with the results from a three point test by Søgaard (1977).
To find the accurate arm location of the marker gene, a balanced tertiary trisomic line with the lethal gene ac2 (Ramage and Tuleen, 1964) was used in crosses with the telotrisomic plant with 2n=14+1 telo 1S (Triplo 1S). The segregation ratios were observed in the F2 generation (Table 1).
The F2 segregation ratios did not fit a disomic (3:1) ratio and no homozygous recessive plants were observed in the trisomic portion. Thus, results clearly indicate that the mutant gene ac2 is located on the short arm of chromosome 1 (1S) near the centromere.
References:
Ramage, R. T. and N. A. Tuleen. 1964. Balanced tertiary trisomics in barley serve as pollen source homogeneous for a recessive lethal gene. Crop Sci. 4:81-82.
Robertson, D. W. 1937. Inheritance in barly. II. Genetics 22:443-451.
Shahla, A. and T. Tsuchiya. 1982. Telotrisomic analysis of the gene ac2 (albino seedling) in Triplo 1L in barley. BGN 12:32-33.
Søgaard, B. 1977. The location of eceriferum loci in barley. V. Three point tests of genes on chromosome 1 and 3 in barley. Carlsberg Res. Commun. 42:67-75.
Tsuchiya, T. and R. J. Singh. 1973. Further information on telotrisomic analysis in barley. BGN 3:75-78.
