Evaluation of new hybrids of citrus for resistance to citrus variegated chlorosis
| Grant number: | 12/25236-4 |
| Support type: | Scholarships in Brazil - Doctorate |
| Effective date (Start): | May 01, 2013 |
| Effective date (End): | February 28, 2015 |
| Field of knowledge: | Agronomical Sciences - Agronomy |
| Principal Investigator: | Antonio Augusto Franco Garcia |
| Grantee: | Guilherme da Silva Pereira |
| Home Institution: | Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil |
Abstract Sweet sorghum and sugarcane are two important grasses for bioenergy purposes. However, despite their known evolutionary relationship, the genomes of these species differ in complexity and size. Sorghum bicolor is a diploid species, with basic chromosome number equal to ten, which has about 740 Mb completely sequenced, whereas Saccharum x officinarum has a autopolyploid genome with frequent aneuploidy, and the monoploid size is estimated at 1 Gb. Therefore, genetic studies and breeding in sugarcane is challenging. In this context, the possibility of integrating mapping studies between sorghum and sugarcane becomes feasible given the employment of appropriate methodologies. In this work, we propose to map and to compare QTLs for agronomic traits in both species. We will use two mapping populations. The population of sorghum consists of 272 RILs densely genotyped by SNP markers, which are physically mapped against the genome of the species. The population of sugarcane is an F1 segregating progeny with 154 individuals, being genotyped by SSR and SNP markers. SNP markers in sugarcane allow estimation of alleles dosages as well as the construction of informative genetic maps through methodologies being developed by our research group. The populations, already established in experimental areas, are being evaluated for agronomic and disease resistance phenotypes. Adjusted means for individuals in each population will be obtained by using a mixed models approach. QTL mapping in sorghum population involves the use of multiple interval mapping model, and in sugarcane population we will use multiple QTL mapping model extended to maps based on multiple dosages. Comparison of the genomes will be based on the original marker sequences from sugarcane, which will be aligned against the complete genome of sorghum. The putative QTL associated with syntenic regions will allow inferences about the evolutionary conserved control of traits between the species. Furthermore, the discovery of markers significantly linked to QTLs may suggest applications in gene cloning and marker assisted selection. | |