The Development of deficient aneuploids in durum wheat
Atkinson, Thomas Grisedale
Deficient1 aneuploids are proving of great value in the systematic genetic analysis of Triticum aestiyum L. emend. Fiori et Paoletti (=T.vulgare) (2n = 42). More and more wheat breeders and geneticists are utilizing the monosomic (20" + 1') and nullisomic (20") lines developed by Dr. E.R. Sears in the variety Chinese Spring. These aneuploids, by providing a means of associating genes with cerrain chromosomes, have simplified inheritance studies in the hexaploid wheats. Moreover they make possible the controlled synthesis of new varieties since specific chromosomes from other varieties, species or even genera may be substituted for the deficient one. The development of a monosomic or nullisomic series in the emmer wheats would aid greatly in the genetic study of that group. A program is underway at the University of Saskatchewan to develop such a series in T. durum Desf. var. Golden Ball (2n = 28). this program involves the use of deficient Chinese Spring lines as well as irradiation methods. The material for the present paper was obtained from the aforementioned program. Information is presented showing that it may be very difficult, if not impossible, to obtain deficient lines in Golden Ball. 1Monosomic and nullisomic plants having respectively one or both members of a single chromosome pair missing are referred to as deficient aneuploids. In contrast, plants having a certain chromosome represented more than twice (trisomes and tetrasomes) are referred to as duplicated aneuploids.