title: Utilization of flow cytometry for festulolium breeding (Lolium multiflorum (2x) × Festuca arundinacea (6x)).
abstract: Festulolium is a hybrid between Festuca and Lolium species that has valuable agronomic traits from both grass species. The purpose of our breeding program is to produce hexaploid festulolium that introduces tolerance to summer depression into Italian ryegrass (Lolium multiflorum) by crossing it with tall fescue (Festuca arundinacea). However, we found the DNA ploidy of hexaploids was not stable and was reduced in successive generations. We aimed to find out how to obtain stable high-ploidy festulolium. F1 hybrids of L. multiflorum and F. arundinacea were produced. The F3 generation was produced from putative hexaploid F2 individuals by open pollination. The F4 to F6 generations were obtained by polycrossing. The DNA ploidy levels of F2 to F6 individuals were estimated by flow cytometry. Cytological characteristics of the F5 and F6 individuals were investigated by FISH and GISH. The DNA ploidy level of hexaploid festulolium was reduced and stabilized at almost the same level as a tetraploid. Seed fertility was inversely correlated with an increase in ploidy level. GISH revealed no preferential Lolium transmission. FISH with a telomere probe revealed that counting the exact number of chromosomes in festulolium was difficult. DNA ploidy level was strongly correlated with the number of chromosomes.
authors.affiliation: National Research and Development Agency, National Agriculture and Food Research Organization (NARO), Tohoku Agricultural Research Center, 4 Akahira, Shimokuriyagawa, Morioka, Iwate 020-0198, Japan; The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Akiyama
authors.affiliation: National Research and Development Agency, National Agriculture and Food Research Organization (NARO), Institute of Livestock and Grassland Science (NILGS) , 768 Senbonmatsu, Nasushiobara, Tochigi 329-2793 , Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Ueyama
authors.affiliation: Department of BioEngineering, Nagaoka University of Technology , 1603-1 Kamitomioka-cho, Nagaoka, Niigata 940-2188 , Japan.
authors.forename: Seiya
authors.initials: S
authors.lastname: Hamada
authors.affiliation: National Research and Development Agency, National Agriculture and Food Research Organization (NARO), Tohoku Agricultural Research Center , 4 Akahira, Shimokuriyagawa, Morioka, Iwate 020-0198 , Japan.
authors.forename: Akito
authors.initials: A
authors.lastname: Kubota
authors.affiliation: National Research and Development Agency, National Agriculture and Food Research Organization (NARO), Tohoku Agricultural Research Center , 4 Akahira, Shimokuriyagawa, Morioka, Iwate 020-0198 , Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kato
authors.affiliation: Faculty of Agriculture, Iwate University , 3-18-8 Ueda, Morioka, Iwate 020-8550 , Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Yamada-Akiyama
authors.affiliation: Department of BioEngineering, Nagaoka University of Technology , 1603-1 Kamitomioka-cho, Nagaoka, Niigata 940-2188 , Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takahara
authors.affiliation: National Research and Development Agency, National Agriculture and Food Research Organization (NARO), Tohoku Agricultural Research Center, 4 Akahira, Shimokuriyagawa, Morioka, Iwate 020-0198, Japan; The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujimori
keywords: DNA ploidy; Festuca arundinacea; Lolium multiflorum; festulolium; flow cytometry (FCM); fluorescence in situ hybridization (FISH); genomic in situ hybridization (GISH)