Seleção de famílias de feijoeiro baseada na produtividade, no tipo de grãos e informações de QTLs

Abstract

RESUMOObjetivou-se neste trabalho, selecionar famílias de feijoeiro promissoras para a produtividade de grãos com tipo de grãos ideal utilizando informações fenotípicas e de marcadores moleculares ligados a QTLs. Foram utilizadas 100 famílias F 3:7 , avaliadas em três safras, com dois experimentos/safra, totalizando seis experimentos. A primeira safra foi a da seca/2007, na qual conduziu-se um experimento em Lavras-MG e o outro em Ijaci-MG. Nas safras de inverno/2007 e águas 2007/2008, foram conduzidos, em cada uma, um experimento em Lavras-MG e outro em Lambari-MG. Em todos eles foi utilizado o delineamento látice triplo 10x10, com parcelas de duas linhas de dois metros. As famílias foram avaliadas pela sua produtividade de grãos. Em apenas um dos experimentos de cada safra foi avaliado o tipo de grão. Os dados foram submetidos à análise de variância individual e conjunta, por local e por safra. 480 marcadores microssatélites foram testados para identificar polimorfismo entre os genitores. Os oito marcadores polimórficos identificados foram utilizados para a genotipagem das famílias. Entre esses, cinco explicaram parte da variação da produtividade de grãos. Os marcadores explicaram pequena porcentagem da variação fenotípica e apresentaram alta interação QTLs x ambientes. O ganho com a seleção fenotípica para produtividade de grãos foi de 7,4%, e de 9,6% para tipo de grãos, adotando a intensidade de seleção de 5%. A seleção assistida por marcadores foi equivalente à fenotípica para produtividade de grãos, porque apenas um marcador mais estável contribuiu para a seleção com base na média dos ambientes. Termos para indexação:Phaseolus vulgaris, linhagens,seleção assistida por marcadores, seleção fenotípica, microssatélites. ABSTRACTThe objectives of this research were to select com mon bean families with high grain yield and ideal grain type using phenotypical information and molecular markers linked to the QTLs. One hundred F 3:7 families were evaluated in three seasons, in two field experiments per season. Two experiments were set up in the counties of Lavras and Ijaci in the dry season/2007, other four experiments were set up in Lavras and Lambari, two in the winter season/2007 and two in the 2007/2008 rainy season. A 10x10 lattice design was used in all experiments, using 2m-long plots and rows 50cm apart. The families were evaluated based on grain yield in all experiments, and based on grain type in one experiment per season. Moreover, 480 microsatellite markers were tested in the parents. Eight markers were polymorphic and used for genotyping the families. Among them five explained part of the grain yield variability and presented high interaction by environments. Selecting 5% of the families the genetic gain was of 7,4% for grain yield and 9,6% for grain type. The marker-assisted selection gave a similar result to the phenotypic selection because only one more stable marker of the along with average grain yield was used in the selection.

Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

“…Although low experimental precision was obtained for grain yield, the higher number of evaluated lines allowed for better exploration of the genetic variability produced by the crosses. Similar variation coefficient values were observed for segregating populations of common bean evaluated in experiments conducted with a 14 x 14 simple lattice design (Aguiar et al, 2000) and a 10 x 10 triple lattice design (Torga et al, 2010). Preliminary evaluations of a large number of lines, normally use smaller plots, it is interesting that higherintensity selection is generally applied because it contributes to increasing the genetic gain (Aguiar et al, 2000).…”

“…Torga et al (2010) observed heritability estimates from 27% to 79.70% for grain yield when 100 F 3:7 common bean lines were evaluated. The authors explained the high amplitude of variation by the occurrence of interactions between lines and environments.…”

“…Pedigree and SingleSeed Descent (SSD) methods have been used in the genetic breeding of common bean. These methods were effective in the selection of a greater number of lines with high grain yield, early cycle, anthracnose resistance and better grain type (Costa et al, 2002, Torga et al, 2010. However, the application of these methods in the selection for high mineral concentration in common bean grains is unknown.…”

Methods of selecting common bean lines having high yield, early cycle and erect growth

“…The result is that average genetic gains ranging from 0.88 to 1.07% have been observed for grain yield in the common bean (CHIORATO et al, 2010;RIBEIRO;POSSEBON;STORCK, 2003). Genetic variability has allowed both the selection in different breeding programs of those lines with phenotypic superiority (COSTA; RAVA; ZIMMERMANN, 2002;TORGA et al, 2010) and the registration of new cultivars in the National Register of Cultivars of the Ministry of Agriculture, Livestock and Supply.…”

“…Progression of segregating populations in the common bean using the Pedigree method has been effective in the selection of lines with higher grain yield (MORETO et al, 2007;TORGA et al, 2010). However, it contributed to the production of less erect plants (MORETO et al, 2007) and was not associated with the types of grain having a greater acceptance for consumption (TORGA et al, 2010).…”