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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #69946
Title: CYTOLOGICAL AND MOLECULAR CHARACTERIZATION OF OAT X MAIZE PARTIAL HYBRIDS

Author
item RIERA-LIZARAZU, OSCAR - UNIVERSITY OF MINNESOTA
item Rines, Howard
item PHILLIPS, RONALD - UNIVERSITY OF MINNESOTA

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Transferring useful characteristics from one crop species into an unrelated crop species has long been seen as a potential way to improve plants. Fertile, stable combinations between crop species to date has been limited to natural hybridizations between related species, such as wheat and rye to form triticale, or to specific gene introductions made by modern recombinant DNA introduction procedures. We have now developed a method t produce partial hybrids between two highly unrelated cereals, oat and corn. This is the first report of such a wide partial hybrid in crop plants. The plants were produced by "rescuing" embryos formed after fertilization of oat flowers with corn pollen. The rescue procedure involved removing developing embryos about 14 days after pollination and putting them onto an artificial growth medium. The nutrients in the medium nursed the embryos' growth into a plant. The recovered plants contained a full set of oat genetic material (which comes physically packaged in a set of 21 chromosomes) plus one to four corn chromosomes. Corn has a basic chromosome number of 10. Self-fertilization of a portion of these plants resulted in the recovery of stable, fertile oat plants that carry an added chromosome pair from corn. Among 11 plants thus recovered, we found single chromosome pair addition lines for six of the corn chromosomes and one line carrying two corn chromosome pairs. These novel partial oat-corn hybrids provide a possible means to introduce useful traits such as heat tolerance, disease resistance, and unique grain composition into oat.

Technical Abstract: We have crossed hexaploid oat (2n=6x=42, Avena sativa L.) and maize (2n=2x=20, Zea mays L.) and recovered 90 progenies through embryo rescue. Fifty-two plants (58%) produced from oat x maize hybridization were oat haploids (2n=3x=21) following maize chromosome elimination. Twenty-eight plants (31%) were found to be karyotypically stable partial hybrids with one to four maize chromosomes in addition to a haploid set of 21 oat chromosomes (2n=21+1 to 2n=21+4). DNA restriction fragment length polymorphisms (RFLPs) were used to identify the maize chromosome(s) present in the various oat-maize progenies. Maize chromosomes 2, 3, 4, 5, 6, 7, 8, and 9 were detected in partial hybrids and chromosomal chimeras. Upon selfing, partial hybrids with one or two maize chromosomes showed nearly complete transmission of the maize chromosome to give self-fertile maize chromosome addition oat plants. Fertile lines were recovered that contained an added maize chromosome or chromosome pair representing six of the ten maize chromosomes. Four independently derived disomic maize chromosome addition lines contained chromosome 4, one line carried chromosome 7, two lines had chromosome 9, one had chromosome 2, and one had chromosome 3. One maize chromosome 8 monosomic addition line was also identified. This constitutes the first report of the production of karyotypically stable partial hybrids involving highly unrelated species from two subfamilies of the Gramineae (Pooideae - oat and Panicoideae - maize) and the subsequent recovery of fertile oat-maize chromosome addition lines. These represent novel materials for gene/marker mapping, maize chromosome manipulation, study of maize gene expression in oat, and transfer of maize DNA, genes, or active transposons to oat.