Variability of nodulation traits in Andean and Mesoamerican common bean gene pools

Adriano Moreira Knupp,Enderson Petrônio De Brito Ferreira,Adelson Paulo Araújo

doi:10.1590/s0100-204x2017000400005

Adriano Moreira Knupp, Enderson Petrônio De Brito Ferreira + Show 1 more

Open Access

https://doi.org/10.1590/s0100-204x2017000400005

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Abstract

Abstract: The objective of this work was to evaluate the genotypic diversity for nodulation in common bean (Phaseolus vulgaris) genotypes of Andean and Mesoamerican gene pools present in the core collections of Embrapa, in Brazil. Evaluations were carried out in two stages: the first one with 879 genotypes, taking the cultivar 'Ouro Negro' as reference; and the second one with 116 genotypes with greater nodulation, to identify those showing stability in nodulation in the two stages. Rhizobium strains were inoculated in pre-germinated common bean seed. Plants received weekly a nutrient solution without N, and nodulation was evaluated 35 days after planting. The percentage of genotypes that exceeded the reference cultivar was 22% for number of nodules, 46% for nodule dry weight, and 33% for one nodule dry weight. The combined analysis of data from the two evaluation phases showed wide differences among genotypes, and significant interactions between genotypes and stages. By the orthogonal contrasts analysis, the Mesoamerican genotypes showed a greater nodulation than the Andean ones. In both stages, twenty-six more stable genotypes were identified, most of them belonging to the Mesoamerican gene pool. There is a large variability in nodulation traits among the common bean genotypes present in the core germplasm collections of Embrapa, which suggests that there are genotypes with improved nodulation.

Highlights

The genetic diversification of common bean (Phaseolus vulgaris L.) had two main centers of domestication, the Andean e Mesoamerican (Bitocchi et al, 2013) ones, which can be distinguished by plant morphology (Singh et al, 1991; Rana et al, 2015), as well as by molecular approaches (Bitocchi et al, 2013; Gaut, 2014)
The objective of this work was to evaluate the genotypic diversity for nodulation in common bean genotypes of the Andean and Mesoamerican gene pools present in the core collections of Embrapa, in Brazil
Differences between common bean genotypes for nodulation traits are often observed in greenhouse experiments, such as those reported by Akter et al (2014) and Farid & Navabi (2015), who reported a similar magnitude of variation to that observed in the present work

Summary

Introduction

The genetic diversification of common bean (Phaseolus vulgaris L.) had two main centers of domestication, the Andean e Mesoamerican (Bitocchi et al, 2013) ones, which can be distinguished by plant morphology (Singh et al, 1991; Rana et al, 2015), as well as by molecular approaches (Bitocchi et al, 2013; Gaut, 2014). The Mesoamerican gene pool consists of small seed, with 100-seed weight of less than 25 g, and. The access to the available diversity within each of these two gene pools is required for identification of the genotypes with desirable alleles to be introduced into breeding programs (Singh, 2001; Rana et al, 2015)

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