| Autor: |
Margarido GR; Departamento de Genética, Escola Superior de Agricultura 'Luiz de Queiroz' (ESALQ), Universidade de São Paulo (USP), CP 83, Piracicaba, SP 13418-900 Brazil., Pastina MM; Embrapa Milho e Sorgo, CP 285, Sete Lagoas, MG 35701-970 Brazil., Souza AP; Centro de Biologia Molecular e Engenharia Genética (CBMEG), Departamento de Genética e Evolução, Universidade Estadual de Campinas (UNICAMP), Cidade Universitária Zeferino Vaz, CP6010, Campinas, SP 13083-875 Brazil., Garcia AA; Departamento de Genética, Escola Superior de Agricultura 'Luiz de Queiroz' (ESALQ), Universidade de São Paulo (USP), CP 83, Piracicaba, SP 13418-900 Brazil. |
| Abstrakt: |
Breeding trials typically consist of phenotypic observations for various traits evaluated in multiple environments. For sugarcane in particular, repeated measures are obtained for plant crop and one or more ratoons, such that joint analysis through mixed models for modeling heterogeneous genetic (co)variances between traits, locations and harvests is appropriate. This modeling approach also enables us to include molecular marker information, aiding in understanding the genetic architecture of quantitative traits. Our work aims at detecting QTL and QTL by environment interactions by fitting mixed models with multiple QTLs, with appropriate modeling of multi-trait multi-environment data for outcrossing species. We evaluated 100 individuals from a biparental cross at two locations and three years for fiber content, sugar content (POL) and tonnes of cane per hectare (TCH). We detected 13 QTLs exhibiting QTL by location, QTL by harvest or the three-way interaction. Overall, 11 of the 13 effects presented some degree of pleiotropy, affecting at least two traits. Furthermore, these QTLs always affected fiber and TCH in the same direction, whereas POL was affected in the opposite way. There was no evidence in favor of the linked QTL over the pleiotropic QTL hypothesis for any detected genome position. These results provide valuable insights into the genetic basis of quantitative variation in sugarcane and the genetic relation between traits. |
