Breeding of short stalked alien translocation lines and their cytological identification: Among the named dwarf genes, none came from Th. ponticum (Yang 1993). Using common wheat crossing with Th. ponticum, a number of partial amphiploids and germplasms have been produced. But from these materials, no dwarf genes were reported. In the hybrids of Xiaoyan7631 and wheat cultivar Lumai No.5, two short stalked disomic addition lines named as Shannong31504 and Shannong31505 were selected. Their plant height were about 50 cm resistant to yellow rust and not semilism (Li 1995). In the F₂ progenies between Shannong315O4 and high wheat cultivars, plant height separated into three groups: the high plants, semi-high plants and short stalked plants, which their chromosome number were 2n=44, 43 and 42, respectively. This indicated that the dwarf gene was located on alien chromosomes, and has dosage effect (Li 1996). So we deemed that Th. ponticum contained a dwarf gene. Maybe, due to the compensating action, the gene effect was shielded in Th. ponticum and Xiaoyan763l. On the bases of Shannong315O4 and Shannong315O5, two short stalked individuals, which could be observed 21 bivalents in PMC MI, were selected from the selfed progenies of Shannong31504 and Shannong31505. Through two generations of selfed on the condition of covered of sacks, two strains Shannong31504-1(Fig. 1) and Shannong315O5-1(Fig. 2), which their chromosome numbers were stably 2n=42 and 21 bivalents can be observed in PMC MI, were obtained and their main agronomic characters were shown in Table 1. In the PMC MI of F₁ hybrid between Shannong31504-1 and Lumai No.5, quadrivalent can be observed, but 21 bivalents were observed in Shannong31505-1/Lumai No.5. In the PMC MI of F₁ hybrid between Shannong315O4-1 and Shannong31505-1, about two univalents and twenty bivalents can be observed. All of these data were shown in Table 2 and indicated that Shannong31504-1 and Shannong31505-1 may be two wheat-Th. ponticum translocation lines and they probably were permeated with different Th. ponhicum chromatins. Electrophoresis: the translocation lines Shannong31504-1 and Shannong31505-1, Th.ponticum, Xiaoyan763l and wheat cultivar Lumai No.5, as well as CS and Marquis, were used in the gliadin electrophoresis analysis. The electrophoreogram was presented in Fig. 3. Gliadin bands patterns of Shannong315O4-1 and Shannong315O5-1 clearly discriminated to Lumai No.5, two Th. ponticum specific bands coded by Gli-B1 (located on 1B), according to the nomenclature of Metakovsky(1991), presented in the two translocation lines and Xiaoyan7631, were absent in wheat cultivar Lumai No.5 (shown by the the arrow). So it is indicated that two translocation lines have Th. ponticum chromatins and chromosome structural recombination occurred on first chromosome group. In addition, one band shown by the arrowhead can be used to differentiate two tranalocation lines.
RAPD analysis: a total of 112 decamer primers (S₂₅swung dash S₃₇, S₄₁swung dash S₆₀, S₁₃₅swung dash S₁₆₀, S₁₉₆ and S₅₁₆ ) were studied among the translocation lines Shannong3l504-1, Shannong315O5-1, maternal parent Local No. 5, paternal parent Xiaoyan7631 and Th. ponticum. Three primers S36 (5'AGCCAGCGAA3'), S37 (5'GACCGCTTGT3') and S97 (5'ACGACCGACA3') could produce Th. ponticum specific amplification fragments in the translocation lines. With S36. Shannong315O4-1 and Shannong315O5-1 exhibited a fragment (about 18OObp, labeled as S36₁₈₀₀) that was present in Xiaoyan7631 and Th. ponticum but absent in Lumai No.5 (Fig. 4-a); in the amplification products of primer S37, a Th. ponticccm specific fragment (about 720bp, labeled as S37₇₂₀) was appeared (Fig. 4-b), the other primer S97 could also amplify a Th. ponticum specific product about 490bp (labeled as S97₄₉₀) (Fig. 4-c). So the presence of S36₁₈₀₀, S37₇₁₀ and S97₄₉₀ in the translocation line amplification profiles and their absence in Lumai No.5 amplification profiles suggested that S36₁₈₀₀, S37₇₂₀ and S97₄₉₀ were three makers to tag the Th. ponticum chromatin in the wheat-Th. ponticum translocation lines Shannoag31504-1 and Shannong31505-1.

Acknowledgments

The authors are thankful to National Natural Scientific Funds Committee for their financial supports, and grateful to Dr. Xing-Feng Li for his valuable guide during experiments.