New Aneuploids of Common Wheat

Abstract

Chromosomal structural changes can be induced by the addition of specifi c alien chromosomes called 'gametocidal (Gc) chromosomes'. In the monosomic addition of the Gc chromosome to common wheat, chromosomal breaks occur in gametes receiving no Gc chromosome, and the broken ends heal and stabilize in the subsequent generations. Thus, by the so-called Gc system, defi ciencies and translocations can be induced in common wheat and also in alien chromosome addition and substitution lines of common wheat. Defi ciencies of wheat and alien chromosomes were cytologically identifi ed by the chromosome banding and in situ hybridization techniques. The plants carrying deletions or wheat-alien translocations were established as new aneuploid lines of common wheat with sub-arm aneuploidy. Those for wheat chromosomes are called deletion stocks and those for alien chromosomes are called dissection lines. The new aneuploids have been used for cytological chromosome mapping and have corrected some mistakes in genetic mapping. Aneuploids of Common WheatThe hexaploid nature of common wheat ( Triticum aestivum L., 2n = 6x = 42) enables us to produce aneuploids rather easily. Almost 60 year ago Sears ( 1954 ) fi rst reported the systematic production of aneuploid lines in common wheat. These socalled conventional aneuploids comprise different series of aneuploid lines of Chinese Spring wheat, such as monosomics, nullisomic, nullisomic-tetrasomics and ditelosomics (Sears 1954 ;Sears and Sears 1978 ), which have been used extensively for the genetic and genomic studies of wheat. He allowed everybody to use those aneuploids freely. I believe that his generosity stimulated the subsequent development of not only genetic and cytogenetic studies but also molecular and genomics studies of wheat. Common wheat can also tolerate the addition of alien

Discovery of a susceptibility factor for Fusarium head blight on chromosome 7A of wheat

“…Polyploid nature of wheat offers it with a unique feature of genome buffering, due to which wheat can tolerate addition, substitution or deletion of different sets of chromosomes and still be fertile (Sears, 1954;Endo, 2015). A number of aneuploid stocks have been developed in bread wheat by wheat cytogeneticists using this feature that have served as a very important genetic resource for the wheat community (Sears, 1954;Sears, 1966;Endo and Gill, 1996; for review see Gupta & Vasistha, 2018).…”