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Wheat Information Service
December 79: 37 - 41 (1994)


Identification of translocated chromosomes in a Japanese common wheat variety Saitama 27

A. M. Ali, N. Nakata, M. Tomita and Y. Yasumuro

Faculty of Agriculture, Tottori University, Tottori 680, Japan


Summary

The Japanese common wheat variety Saitama 27 contributes significantly to the wheat breeding in Europe through its distinctive semi-dwarfing gene. Two independent reciprocal translocations were identified in Saitama 27 by means of the pairing configurations in its monotelodisomic hybrids with Chinese Spring ditelosomics. One was centromeric translocation between 3A and 7A which was possibily originated by centric breakage-fusion of univalents at meiosis, giving rise to T3AS/7AS and T3AL/7AL. The other translocation was of small segments between I A and one of the B genome chromosomes other than 1B, 2B and 5B. Thus, these translocations are not expected to be transmitted with the semi-dwarfing gene of Saitama 27 to the European wheat, unless they contain other breeding potentials.


Introduction

Saitama 27 carries a single gibberellic acid insensitive semi-dwarfing gene (Worland and Petrovic 19,88, Yamada 1990). This gene is allelic to the Rht1 and Rht3 on chromosome 4B, and was named as Rht1S (Worland and Petrovic 1988). The Rht1S gene of Saitama 27 was introduced into the Italian variety Orlandi, and has spread into many Southern European varieties. This gene has a selective advantages in these regions due to its less sensitivity to heat stress (Worland 1986, Worland and Petrovic 1988).

We reported that Saitama 27 contains two independent reciprocal translocations (A1i et al. 1992). However, the co-transmission of these translocations with the semi-dwarfing gene into the European wheat is not determined. This paper describes the identification of the translocated chromosomes by using Chinese Spring ditelosomics.


Materials and Methods

The variety Saitama 27 was crossed with 22 ditelosomic (DT) lines of the variety Chinese Spring (CS). F₁ monotelodisomic plants were grown in the field. Spikes at appropriate growth stage were collected and fixed in Carnoy's solution. Pairing configurations involving the telosome at the first metaphase (MI) were observed to determine the translocated chromosomes by acetocarmine squash method.

The breakpoints of translocations were estimated by comparing the C-banding patterns of the translocated chromosomes with those of the critical chromosomes of CS.

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