Genetic characterization of the cytoplasms of tetra ploid aegilops species
Memoirs of Osaka Kyoiku University Series III Natural Science and Applied Science 31(1): 13-34
Nuclei of 12 common wheats (genome constitution AABBDD), i.e., Triticum aestivum var. erythrospermum (Tve), strain P168 (P168), cv. Chinese Spring (CS), cv. Norin 26 (N26), strain Salmon (Slm), cv. Jones Fife (JF), cv. Selkirk (Sk), and cv. S-615 (S615), T. sphaerococcum var. rotundatum (Sphr), T. compactum cv. No. 44 (Cmp), T. spelta var. duhamelianum (Splt), and T. macha var. subletschumicum (Mch), were placed into the cytoplasms of 7 tetraploid Aegilops spp., i.e., A. biuncialis (CuCuMbMb), A. columnaris (CuCuMcMc), A. ovata (CuCuMoMo), A. triaristata (CuCuMtMt), A. kotschyi (CuCuSvSv), A. variabilis (CuCuSvSv) and A. ventricosa (DDMvMv) by repeated backcrosses. Using these nucleus-cytoplasm (NC) hybrids, the genetic differences between the cytoplasms of these species were investigated. The cytoplasms of A. biuncialis, A. columnaris and A. triaristata delayed heading, reduced plant growth, and induced variegation in almost all common wheats. JF had some restorer gene(s) against growth retardation caused by these cytoplasms. Seven common wheats (Tve, N26, Slm, Sk, Sphr, Splt and Mch with these cytoplasms showed complete or almost complete sterility, while 5 other wheats restored some male fertility. These cytoplasms also caused formation of germless grains in Tve, Slm, and Mch, and production of haploids and twin seedlings in Slm and Mch. The cytoplasm of A. columnaris, however, slightly differed from those of A. biuncialis and A. triaristata, because the former cytoplasm induced anther malformation with abnormal tetrads. Although A. ovata has the same basic genome constitution with abnormal tetrads. Although A. ovata has the same basic genome constitution as the above-mentioned species, genetic characteristics of the A. ovata cytoplasm considerably differed from those of the latter 3 cytoplasms. This cytoplasm delayed heading, gave almost normal growth vigor, and caused complete male sterility, except P168 and CS which restored fertility. No variegation nor formation of germless grains and haploids was observed, but the anther was partially malformed. The cytoplasms of A. kotschyi and A. variabilis did not affect heading date and any other characters relating to plant growth except a few characters. Male sterility was caused by these cytoplasms only in Slm, Splt and Mch. These cytoplasms induced germless grains in Tve and Slm, and haploids and twin seedlings in Slm. The cytoplasm of A. ventricosa had no particular effects on all characters of all common wheats tested.