Identificação de marcadores moleculares relacionados à severidade de sintomas da ferrugem marrom em painel associativo de cana-de-açúcar (Saccharum spp.)
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Data
2012-07-03
Autores
Gonçalves, Bruna Sousa [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Associações entre marcadores moleculares e caracteres agronômicos importantes constituem uma ferramenta valiosa em programas de melhoramento, uma vez que podem identificar indivíduos superiores, ainda em fases juvenis, e, consequentemente, acelerar o processo de desenvolvimento de cultivares. Neste contexto, este trabalho teve por finalidade estabelecer associações entre marcadores moleculares (AFLP e SSR) e resistência e/ou suscetibilidade à ferrugem marrom (Puccinia melanocephala) da cana-de-açúcar, por meio da abordagem de mapeamento associativo. Os dados fenotípicos foram obtidos de experimentos conduzidos em Ribeirão Preto, durante março de 2010 e janeiro de 2012, em delineamento de blocos casualizados completos, DBC, com três repetições. Oitenta e três genótipos de cana-de-açúcar, incluindo cultivares comerciais e clones IAC, foram avaliados quanto a resistência à ferrugem marrom, sob condições de infecção natural. As plantas foram fenotipadas aos 10 meses após o plantio e 7 meses após o primeiro corte. A maioria dos genótipos avaliados (>71%) apresentou reação de resistência à ferrugem marrom; sendo o ciclo de cana-planta mais suscetível ao ataque do fungo do que a soqueira. A resistência à ferrugem marrom apresentou elevada herdabilidade, superior a 0,7. O painel associativo foi caracterizado com 79 pares de primer SSR e 20 combinações de AFLP, os quais detectaram 1015 marcas polimórficas. Os marcadores SCC60.8, SCA31.3, M56/E35 e M56/E37 foram correlacionados à suscetibilidade, enquanto SCB14.9 e M56/E33, ligados à resistência à ferrugem marrom. O efeito individual das marcas oscilou entre -0.37 (R2 = 0.05) e 0.24 (R2 = 0.08). Os marcadores moleculares associados à severidade à ferrugem marrom serão validados, visando explorá-los dentro do programa de melhoramento genético para identificar materiais resistentes ou mesmo eliminar alelos desfavoráveis, e, assim, acelerar os ganhos genéticos
Associations between markers and agriculturally important traits are a valuable tool for breeding programs, since they can identify superior individuals still in the initial developmental stages, and thus accelerate the cultivars development. In this context, the work aimed to establish associations between molecular markers (AFLP and SSR) and resistance and/or susceptibility to brown rust (Puccinia melanocephala) in sugarcane, using association mapping approach. The phenotypic data were obtained from field trials in Ribeirão Preto, during March 2010 and January 2012 in a randomized complete block design, DBC, with three replications. Eighty-three sugarcane genotypes, including commercial cultivars and IAC clones, were evaluated for resistance to brown rust under natural infection. The plants were phenotyped at 10 months after planting and 7 months after the first cut. Most of the evaluated genotypes (>71%) presented rust resistance reaction, with the plant cane crop cycle more susceptible to the fungus attack than the rattoon cane. Brown rust resistance showed high heritability, greater than 0,7. The whole panel was genotyped with 79 SSR primer pairs and 20 AFLP primer combinations, resulting in 1015 polymorphic markers. Markers SCC60.8, SCA31.3, M56/E35 and M56/E37 were correlated with susceptibility, while SCB14.9 and M56/E33 were associated to brown rust resistance. The individual marker effect ranged from -0.37 (R2 = 0.05) to 0.24 (R2 = 0.08). The molecular markers associated with the severity of brown rust should be validated, to be exploited in the breeding program to identify resistant materials or even eliminate unfavorable alleles, and thus accelerate the genetic gain
Associations between markers and agriculturally important traits are a valuable tool for breeding programs, since they can identify superior individuals still in the initial developmental stages, and thus accelerate the cultivars development. In this context, the work aimed to establish associations between molecular markers (AFLP and SSR) and resistance and/or susceptibility to brown rust (Puccinia melanocephala) in sugarcane, using association mapping approach. The phenotypic data were obtained from field trials in Ribeirão Preto, during March 2010 and January 2012 in a randomized complete block design, DBC, with three replications. Eighty-three sugarcane genotypes, including commercial cultivars and IAC clones, were evaluated for resistance to brown rust under natural infection. The plants were phenotyped at 10 months after planting and 7 months after the first cut. Most of the evaluated genotypes (>71%) presented rust resistance reaction, with the plant cane crop cycle more susceptible to the fungus attack than the rattoon cane. Brown rust resistance showed high heritability, greater than 0,7. The whole panel was genotyped with 79 SSR primer pairs and 20 AFLP primer combinations, resulting in 1015 polymorphic markers. Markers SCC60.8, SCA31.3, M56/E35 and M56/E37 were correlated with susceptibility, while SCB14.9 and M56/E33 were associated to brown rust resistance. The individual marker effect ranged from -0.37 (R2 = 0.05) to 0.24 (R2 = 0.08). The molecular markers associated with the severity of brown rust should be validated, to be exploited in the breeding program to identify resistant materials or even eliminate unfavorable alleles, and thus accelerate the genetic gain
Descrição
Palavras-chave
Cana-de-açúcar - Cultivares, Cana-de-açúcar - Doenças e pragas, Fungos fitopatogenicos, Marcadores biologicos, Puccinia, Fungi
Como citar
GONÇALVES, Bruna Sousa. Identificação de marcadores moleculares relacionados à severidade de sintomas da ferrugem marrom em painel associativo de cana-de-açúcar (Saccharum spp.). 2012. v, 68 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, 2012.