A translocation difference between wheat variety HY-11 and Triticale strain ST-69-1

P. K. GUPTA, P. K. YASHVIR and R. V. SINGH

Cytogenetics Laboratory, Division of Plant Sciences, Meerut University, Institute of Advanced Studies, Meerut, India

A Triticale improvement programme was initiated in this laboratory in the year 1971. For this purpose and for some other fundamental projects, crosses were made between wheat variety HY-11 and the Triticale strain ST-69-1. The seed of wheat variety HY-11 was obtained from the wheat specialist, J.N.K.V.V., Power-koeda, and that of Triticale strain ST-69-1 from I.A.R.I. New Delhi. The F₁ individuals were raised in 1972 and these were meiotically analysed. F₁ hybrids showed the formation of a quadrivalent in a large number of pollen mother cells besides variable number of univalents and bivalents in each pollen mother cell. Of the 28 pollen mother cells examined in one F₁ hybrid, 18 cells showed, the presence of a distinct quadrivalent (Fig.1) in each of them. The F₁ hybrids were selfed. Due to high degree of sterility only few seeds were available. These were raised into plants in 1972-73 and quadrivalent could be observed in some of these F₂ plants also. This confirmed that two nonhomologous chromosomes of A and/or B genomes of wheat variety HY-11 are involved in translocation relative to the A and/or B genomes of Triticale strain ST-69-1.

Structural changes in chromosomes of polyploid wheat seem to have played some role in evolution of this group (BAKER & MCINTOSH 1966). There are other reports where reciprocal translocations were reported between different cultivated varieties of wheat. SEARS (1953) described three varieties of wheat which differed from the variety Chinese Spring by a single reciprocal translocation. SEARS (1954) also suggested that Chinese Spring is the primitive variety and that the other varieties were derived due to mutational or structural changes in the chromosomes. Reciprocal translocations between wheat varieties were also described by RILEY and KIMBER (1961) and by BAKER and MCINTOSH (1966).

The present report is perhaps the first where a translocation difference between a wheat variety and a Triticale strain is demonstrated. Since the A and B genome of Triticale come from tetraploid wheat, the translocation difference reported here, is actually a difference between A and B genomes of a tetraploid wheat and hexaploid wheat variety. The sources of the tetraploid wheat and hexaploid wheat variety are not available. It is also difficult to find out whether the translocation difference already existed at the tetraploid level or it resulted after its incroporation into the hexaploid Triticale.

Literature cited

BAKER, E. P. and R. A. MCINTOSH 1966. Chromosome translocations identified in varieties of common wheat. Can. J. Genet. Cytol. 8: 592-599.

RILEY, R. and G. KIMBER 1961. Annual Report. 1959-60, Plants Breeding Institute, Cambridge, Pages, 60.

SEARS, E. R.1953. Nullisomic analysis in common wheat. Amer. Nat. 87: 245-252.

SEARS, E. R. 1954. The aneuploids of common wheat. Missouri Agr. Expt. Sta. Research Bull. 572: 59.

(Received July 17, 1973)