A COMPENDIUM OF RECIPROCAL TRANSLOCATIONS IN WHEAT
by Rolf Schlegel
Wheat varieties and wheat species are frequently differentiated by reciprocal translocations of inhomologous chromosomes. Therefore, for several studies the knowledge about interchanges is required. A list was compiled summarizing available data on the presence and number of translocations, on configurations observed and their frequencies of occurrence and on involved chromosomes from 466 wheat combinations. The modified chromosomes are usually identified after common chromosome studies, intercrossing and meiotic analysis in F1 hybrids. Among the wheat accessions listed 20.4 % show a non-translocated karyotype, while the remaining show multivalent configurations of the type:
14 (51.3 %), 24 (20.4 %), 34 (3.4 %), 44 (0.6 %), 16 (1.7 %), 18 (0.4 %), 14+16 (1.7 %) and 24+16 (1.6 %).
The chromosomes 1A, 7B and 2D are most frequently associated with translocations. Between the genomes the B genome exhibits the most interchanges (A = 12.3 %, B = 61.4 %, D = 26.3 %). However, no close correlations were evident between individual chromosome length (Ám), 4C DNA content per chromosome (pg) and the frequency of chromosomes involved in translocations (r= < 0.4**).