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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 %), 4(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**).

Figure 1. The relationship between the relative amount of translocated chromosomes of the different wheat genomes and the relative genome size

translo-diagram1

© by R. Schlegel 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2014 2015 2014 2015 2016

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Wheat x Aegilops ovata hybrid and parental spikes

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Wheat x Aegilops caudata hybrid, F1 meiosis

Aegilops_neglecta

Aegilops neglecta

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Wheat x Aegilops sharonense hybrid and parental spikes