IV.6. The genetic male sterile barley collection.
E. A. Hockett. Western Region, ARS, U.S.D.A. and Plant and Soil Science Department, Montana State University, Bozeman, Montana 59715, U.S.A.
In accordance with the rules for symbolization adopted by the Eighth American Barley Research Worker's Conference at Tucson, Arizona on January 27, 1972 it is proposed to change the symbol for genetic male sterility from ms to msg. The male sterile stocks listed in Table 1 conform to this adopted system. The new genetic symbols assigned since last year's coordinator's report in BGN 2(2) are given in Table 1. Ten new mutational events are listed along with a new letter symbolization for the already numbered loci (msg 1 cr through msg 19 cr) which did not have a letter symbol for the mutational event. It is realized that most investigators will use only the msg 1, msg 2, etc. symbolization in their publications unless they are studying such things as complementation tests to delineate cistrons. Three of the new mutants, for which data are available, fit the hypothesis of a single recessive gene for male sterility, except for msg,,bw where an excess of sterile plants was present.
Table 1. Ratios of fertile to sterile plants in F2 and selfing behavior of sterile plants.
In last year's report Msg,,bt msg,,bt segregation did not fit a 3:1 ratio of fertile to sterile plants. Additional data in 1972 giving 36 fertile: 14 male sterile plants from heterozygous plants supports a single gene hypothesis since p = .7 - .6 for fit to a 3:1 ratio.
Table 2 gives the results of testing for allelism where the mutant lines were found to be allelic with previously designated lines. The msg,,ar and msg,,bp mutants are allelic with msg 1 ca.
Table 2. Ratios of fertile to male sterile F1 plants from crosses of genes determined to be allelic.
No new numbered loci were assigned although five or six are nearing the completion of allelism tests.
A method for production of hybrid barley has recently been proposed utilizing a cytoplasmic-genetic system (3). It should be pointed out that all the "genetic male steriles" we have in the collection can be thought of as having a "sterile" cytoplasm. They must all have a "sterile" cytoplasm since otherwise the msg msg genotype would produce a fertile plant.
Therefore, one may cross the msg gene into anything except the donor variety by using Msg msg plant as the male parent. If no segregation for male sterility takes place in the new variety (foreign cytoplasm) you have discovered the "restorer or fertile" cytoplasm for your msg gene.
References:
1. Hockett, E. A. 1968. Genetic male sterility in barley. I. Nonallelic genes. Crop Sci. 8:218-220.
2. Hockett, E. A. 1972. Coordinator's report on the genetic male sterile barley collection. Barley Genetics Newsletter 2:139-144.
3. Pfeifer, R. P. 1972. A method to produce hybrid barley. Agron. Abstr. 64 Annu. Meeting: 17.
