(go to KOMUGI Home) (go to WIS List) (go to NO.86 Contents)

Wheat Information Service
Number 86: 39-40 (1998)
Research information

Genomic constitution of a partial Triticum aestivum x Thinopyrum intermedium amphiploid

Gao Zhi, Han Fangpu * and Li Jilin

Department of Biology, Harbin Normal University, Harbin, 150080, China


Zhong 2 is a partial amphiploid (2n=56) between Triticum aestivum and Thinoyrum intermedium. Meiotic metaphase I in the hybrids between Triticum aestivum Chinese Spring and Zhang 2 usually has 21 bivalents and 7 univalents (Table 1), suggesting that Zhong 2 may carry all the chromosomes of common wheat and seven pairs of chromosomes from Th. intermedium. Th. intermedium is a hexaploid species, its genome constitution is revised as E1E1E2E2XX(Dewey 1984; Friebe et al. 1992). In order to determine which set of Th. intermedium chromosomes Zhong 2 contains, we made crossing between F1 hybrids from T. durum x Th. intermedium and Zhong 2, and crossing between Zhong 2 and T. durum. Chromosome pairing of the hybrids was studied in this paper.

In all the combinations, the PMCs of the hybrids exhibited trivalents and quadrivalents. A high level of trivalents was observed in hybrids between (T. durum x Th. intermedium)F1 and Zhong 2, five trivalents were observed in some cells. Quadrivalent and pentavalent can also be observed in some cells, these mutivalents may be due to chromosome translocation or chromosome structural variation in Zhong 2.

The genomic constitution of the partial amphiploids of T. aestivum x Th. intermedium should be AABBDDE1 E1 or AABBDDE2 E2 and AABBDDXX. The genomic constitution of hybrids of (T. durum x Th. intermedium) x Zhong 2 (2n=63) is AABBDXE1 E2 C (the C represents one genome in Zhong 2 that comes from Th. intermedium). If C=X, the genomic constitution of the hybrids (2n=63) is AABBDXE1 E2 X, they should have 28 bivalents and 7 univalents at meiotic metaphase I. If C=E1 or E2 , the genomic constitution of the hybrids (2n=63) is AABBDXE1 E1 E2 or AABBDXE1 E2 E2 , they should show 14 bivalents, 7 trivalents and 14 univalents in the PMC. From the actual observed results, chromosome pairing averaged 17.2I+17.9II+2.4III+0.41V+O.1V in the hybrids (2n=63), but the average of trivalents per cell in Zhong 2 x T. durum and C S x Zhong 2 hybrids were 0.9 and 0.4, respectively. These results indicated that the genomic constitution of Zhong 2 maybe AABBDDE1 E1 or AABBDDE2 E2 . A slightly low frequency of trivalents in the hybrids (2n=63) might be due to a tendency of chromosome pairing towards bivalentization. This result is similar to the frequency of trivalents in the triploid hybrids between diploid Th. elongatum (EE) and tetraploid. Th. elongatum (E1 E1 E2 E2 ). Chromosome pairing averaged 5.6II+2.2III and 4.2II+2.8III in the triploid hybrids as reported by Dvorak( 1981 )and Charpentier et al. (1986), respectively.

*Corresponding author, e-mail: ycsuo@ivy.nenu.edu.cn


Reference

Charpentier A, Feldman M and Cauderon Y (1986) Genetic control of meiotic chromosome pairing in tetraploid Agropyron elongatum. I. Pattern of pairing in natural and induced tetraploid and in F1 tetraploid hybrids. Can J Genet Cytol 28: 783-788.

Dewey D R (1984) The genomic system of classification as a guide to intergeneric hybridization within the perennial Triticeae. In: Gustafson J P (ed) Gene manipulation in plant improvement. Plenum Publishing, New York, PP 209- 279.

Dvorak J (1981) Genome relationships among Elytrigia (=Agropyron) elongata, E. stipifolia, "E. elongata 4x", E. caespitosa, E. intermedium, and "E. elongata 10x" . Can J Genet Cytol 23: 481-492.

Friebe B, Mukai Y, Gill BS and Cauderon Y (1992) C-banding and in situ hybridization analyses of Agropyron intermedium, a partial wheat x Ag. intermedium amphiploid, six derived chromosome addition lines. Theor Apll Genet 84: 899-905.

　

(go to KOMUGI Home) (go to WIS List) (go to NO.86 Contents)