Chromosome Genetic Analysis Of Nobilization Of Saccharum Spontaneum

Interspecific hybridization of sugarcane is an important approach of germplasm innovation, and nobilization is the breeding theory with development and utilization of wild germplasm. As an important wild species, S. spontaneum is the main donor of resistance and adaptive gene in the nobilization breeding process. The chromosome transfer of sugarcane is more complicated, and the research of different inheritance patterns can provide guidance for sugarcane breeding. The identification of 10 sugarcane germplasms commonly used in production was carried out by two different methods in chromosome counting and genomic in situ hybridization. Then, the 5 clear pedigree noble Fi chromosome constitution were analyzed by dual-color fluorescence in situ hybridization to investigate the patterns of chromosome inheritance. Chromosome inheritance patterns of the first noble cane Fi were investigated and their parents S. officinarum also discussed in this study, these findings may provide the theoretical basis to the rational use and germplasm innovation of sugarcane resources. The main findings are as follows:(1) Identificating authenticity of 10 S. officinarum by counting chromosomes in this study, chromosome number is 80 in Badila, Loethers, Crystallina, Luohanzhe, Yuenanniuzhe and Nanjianguozhe, while chromosome number in 50uahapele, Muckche, Canablanca and Baimeizhe is more than 80. Comparative genomic in situ hybridization was applied in above materials, with the double probes labeled by Biotin (S. officinarum) and Digoxigenin (S. spontaneum). The fluorescence signals of dual probes are presented over the entire genome chromosomes. However, among Badila, Loethers, Crystallina, Luohanzhe, Yuenanniuzhe and Nanjianguozhe, there were the strong red signal on chromosomes, such signal dominated in the whole cells, it showed that they were really ture S. officinarum species. There was the distinct green fluorescent signal on chromosomes of 50uahapele, Muckche, Baimeizhe and Canablanca, demonstrated that they were not S. officinarum clones.(2) Results of GISH showed that 5 F1 clones of S. officinarum × S. spontaneum, YC58-43, YC75-409 and YC75-419 shared a total of 120 chromosomes, of which 80 were derived from S. officinarum, and 40 from S. spontaneum; YC82-108 showed a total of 112 chromosomes, the chromosomes reported in female parent S. officinarum was the same as 80, the difference was 32 from Yunnan75-2-11 (S. spontaneum). Above all, the 4 F1 clones were product of a 2n+n transmission. However, YC 75-408 showed a total of 80 chromosomes, of which 40 from S. officinarum and the other 40 chromosomes were inheritance of male parent S. spontaneum, this F1 clone was product of a n+n transmission. Hence, the chromosome inheritance of progeny in noble Fi mostly exhibits 2n+n transmission, and a few clones were product of a n +n transmission.(3) YC75-408 and YC75-409 are the sibling lines of the different F1 progeny with the same parents, there was a large difference in chromosome number, leading to different patterns of chromosome inheritance.