[The production and multi-color genomic in situ hybridization identification of maize-Z. perennis substituted material].

Genus Zea. L was composed of two sections: sect. Luxuriantes Doebley & Iltis including Z. dipperennis, Z. luxurians and Z. perennis, and sect. Zea. mays consisting only one species, annual Z. mays. To improve the biodiversity of germ-plasm in maize breeding, the study of transferring maize relatives gene into common maize were performed. Firstly, interspecific hybrids between maize (Zea. L) (2n = 20) and Z. perennis (2n = 40) were produced with the aim of transferring desirable horticultural traits from Z. perennis to maize. The F1 of maize x Z. perennis (2n = 30) plant had the most frequent configuration of 5 III + 5 II + 5 I, which were sterile and difficult to produce progeny because of genomic affinities. However,few F2 individuals of maize x Z. perennis could be obtained by some specially treatments, and one maize-like F2 plant were obtained, which were used as a female parent in backcrossing with maize parent. Twelve F2 x P1 ( BC1 F2 ) plants were obtained and then self-crossed to produce self-crossing generation of F2 x P1 (2n = 20) ( BC1 F3). The phenotypic characters of parents, F1 (2n = 30) hybrids, F2 and F2 x P1 were investigated, such as plant height, flowering, leaf shape and tillers. To further verify the genomic organization of maize-Z. perennis material, maize (inbred line 48-2) and BC1 F3 chromosomes, the root tip cells were analyzed by Multi-color GISH. We probed maize and BC1 F3 chromosomes with the probe mixture containing biotin-labeled Z. perennis genomic DNA and digoxigenin-labeled maize genomic DNA, the maize spread exhibited 10 chromosomes with yellow signals and the other 10 chromosomes carried green fluorescing bands. However, although the BC1 F3 was 2n = 20 in all cases. Multi-color GISH images revealed that 17 chromosomes had uniform signals similar to maize chromosomes, but dispersed red signals over the remaining three chromosomes were observed, which indicated that the 3 chromosomes originated from Z. perennis, and they were smaller than maize chromosomes. Data obtained from multi-color GISH images indicated that BC1 F3 was probably a substituted material from maize-Z. perennis.