II.8. Isolation of a set of primary trisomics in Klages barley.
Christine E. Fastnaught and R. T. Ramage, Department of Agronomy and Plant Genetics, University of Arizona, Tucson, Arizona 85721, USA.
We are isolating a set of primary trisomics in the cultivar 'Klages', C.I. 15478. Klages is a two-rowed spring barley released by the U.S. Department of Agriculture and the Idaho Agricultural Experiment Station as an acceptable malting and brewing variety.
The trisomics are being obtained from progenies of partially sterile plants selected from seed increase fields. The partially sterile plants were probably triploids, or near-triploids, as their progenies were similar in kinds and frequencies of aneuploids to progenies of known autotriploids. At the present time we cannot explain the spontaneous occurrence of the "triploid" plants. Similar plants have been selected from several different cultivars grown in Idaho and Montana and are excellent sources of trisomics and other aneuploids.
Trisomic plants are being obtained by cytological examination of root-tips of germinating seed produced by the selected partially sterile plants or their progenies. After trisomic plants have been isolated, they are transplanted to the greenhouse where they are grown to maturity. During their growth, they are compared morphologically to a set of known primary trisomics in the cultivar 'Betzes', C.I. 6398.
Plants trisomic for chromosomes 1, 2, 3, 4, 5 and 6 have been obtained. Plants trisomic for chromosomes 5 and 6 were identified by both their roottip karyotypes and their resemblance to known trisomic plants in Betzes. Plants trisomic for chromosomes 1, 2, 3 and 4 were identified by their resemblance to known trisomic plants in Betzes. Plants trisomic for chromosome 7 have not yet been positively identified. Progenies of trisomic plants that probably have an extra chromosome 7 are being grown for cytological identification.
Within the next year we expect to have a seed increase of all 7 of the primary trisomics in Klages to send to Dr. Tsuchiya to add to the World Collection of trisomics and aneuploids.