Genetic control of iron concentration in Mesoamerican and Andean common bean seeds

Abstract

-The objective of this work was to evaluate the main differences in the genetic control of the iron concentration in Mesoamerican and Andean common bean seeds, in early generations, and to select recombinants with a high iron concentration in the seeds. F 1 , F 1 reciprocal, F 2 , F 2 reciprocal, and backcross (BC 11 and BC 12 ) generations were produced by crosses between Mesoamerican (CNFP 10104 x CHC 01-175) and Andean (Cal 96 x Hooter) inbred lines. The expression of significant maternal effect was observed for the Mesoamerican gene pool. Iron concentration was higher in the seed coat of Mesoamerican common bean seeds (54.61 to 67.92%) and in the embryo of Andean common bean seeds (69.40 to 73.44%). High broad-sense heritability was obtained for iron concentration in Mesoamerican and Andean common bean seeds. Gains with the selection of higher magnitude, from 20.39 to 24.58%, are expected in Mesoamerican common bean seeds. Iron concentration in common bean seeds showed a continuous distribution in F 2 , which is characteristic of quantitative inheritance in Mesoamerican and Andean common bean seeds. Recombinants with high iron concentration in seeds can be selected in both Mesoamerican and Andean common bean hybrids.

<b>Genetic parameters of iron and zinc concentrations in Andean common bean seeds

“…This result indicates the absence of a maternal effect and that the seeds of the F 1 generation represent fertilization between the parents in both hybrid combinations. Our results agree with those of Possobom et al (2015) and Rosa et al (2010), who reported non-significant maternal effects for iron and zinc concentrations, respectively, in hybrid seeds of common bean.…”

“…For the iron concentration in seeds, the P 1 × P 2 contrast was not significant for any of the hybrid combinations, indicating no genetic variability between the parents, in contrast with the observations of Ribeiro et al (2014a) for the IAC Boreal, Light Red Kidney and Ouro Branco cultivars. In this case, the differences in the soil pH, soil iron content and amount of precipitation during the growing season explain the variation that was observed in the iron concentrations of common bean seeds (Moraghan, Padilha, Etchevers, Grafton, & Acosta-Gallegos, 2002;Silva, Abreu, Ramalho, & Corrêa, 2012b;Petry, Boy, Wirth, & Hurrell, 2015;Possobom et al, 2015). Because the parents that were used in the controlled crosses were contrasting regarding the zinc concentration in their seeds, it was possible to obtain recombinants with genetic variability, with zinc concentrations ranging from 10.73 to 37.50 mg kg -1 DM ( Figure 1C and D).…”

“…Iron and zinc are minerals that, depending on the cultivar, can be concentrated in higher quantities in the seed coat or embryo in common bean seeds and can even occur in similar proportions in the seed fractions (Moraghan et al, 2002;Ribeiro et al, 2012;Possobom et al, 2015). Possobom et al (2015) observed that the parents CNFP 10104 and CHC 01-175 accumulated from 54.61 to 67.92% of the total iron in the seed coat of common bean seeds and observed a significant maternal effect of this mineral in the hybrids. In the other evaluated hybrid combination (Cal 96 × Hooter), the authors did not find any maternal effect expression, which was verified by the greater accumulation of iron, from 69.40 to 73.44%, in the seed embryo.…”

“…In the other evaluated hybrid combination (Cal 96 × Hooter), the authors did not find any maternal effect expression, which was verified by the greater accumulation of iron, from 69.40 to 73.44%, in the seed embryo. Therefore, the selection of superior common bean recombinants for iron concentration should begin in seeds of the F 3 generation if iron accumulates more in the seed coat or in seeds of the F 2 generation if iron is more concentrated in the seed embryo (Jost et al, 2009;Possobom et al, 2015).…”

“…The expression of a maternal effect of iron and zinc concentrations in common bean seeds depends on the evaluated gene pool and the tested hybrid combination (Jost, Ribeiro, Cerutti, Poersch, & Maziero, 2009;Rosa et al, 2010;Silva, Abreu, & Ramalho, 2013;Mukamuhirwa, Tusiime, & Mukankusi, 2015;Possobom, Ribeiro, Domingues, & Casagrande, 2015). Similarly, there is a wide range of variation for narrow-sense heritability and predicted gain with selection estimates for iron and zinc concentrations in Middle American and Andean common bean seeds (Cichy, Forster, Grafton, & Hosfield, 2005;Jost et al, 2009;Rosa et al, 2010;Mukamuhirwa et al, 2015;Possobom et al, 2015).…”