II.18 Primary trisomics in Ingrid barley.
Sharon L. Morgan and R. T. Ramage. Department of Agronomy and Plant Genetics, University of Arizona, Tucson, Arizona 85721, USA.
Primary trisomics have been isolated from progenies of partially sterile plants selected from several different cultivars. Trisomics in the different cultivars show marked differences in vigor and fertility when grown in different environments. Those in the cultivar Betzes have been the most useful in our program as they exhibit reasonable vigor and fertility when grown in the greenhouse and field in Arizona and in the field in Montana (Barley Newsletter 12: 17).
For certain of our studies, it would be desirable to have a set of primary trisomics in a cultivar other than Betzes. A set of primary trisomics has been obtained in the cultivar Klages (BGN 4: 23). They have acceptable vigor and fertility when grown in the field in Montana but are not as vigorous or fertile as Betzes trisomics when grown in the field in Arizona. Some of the Klages trisomics are too weak and sterile to be of much use when grown in the greenhouse in Arizona during the winter months.
Because we need a set of primary trisomics in a cultivar that is adapted to the greenhouse and field in both Arizona and Montana, we have grown aneuploids obtained from several different cultivars. Based on a few aneuploids grown in the greenhouse in Arizona, the cultivar Ingrid appeared to be a source of acceptable trisomics.
In 1971, 16 partially sterile plants were selected from an Ingrid field grown near Creston, Montana. Of these 16 plants, 5 produced progenies containing aneuploids, 5 produced progenies which segregated for male sterility, 3 produced progenies containing no observable cytological abnormalities, 2 produced desynaptic progenies, and one did not produce progeny. The aneuploids obtained did not contain a complete set of primary trisomics.
In the summer of 1974, 105 partially sterile plants were selected from an Ingrid field grown near Creston, Montana. Root-tips of the progenies of 39 of these plants have been examined cytologically. Thirty-two of the progenies contained aneuploids, about 47 percent of which were primary trisomics. From these, a complete set of primary trisomics has been isolated. Determination of which chromosome was extra was made by comparing the morphological characteristics of the Ingrid trisomics to a set of known primary trisomics in Betzes. The morphological characteristics of the Ingrid trisomics are very similar to those of the Betzes trisomics. Also, trisomics for chromosomes 5, 6 and 7 were identified by root-tip karyotypes.
The primary trisomics in Ingrid are being increased in the greenhouse. Seed will be sent to Dr. Tsuchiya to be added to the World Collection of trisomics and aneuploids.