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ARS Home » Southeast Area » Mayaguez, Puerto Rico » Tropical Crops and Germplasm Research » Research » Publications at this Location » Publication #341720

Research Project: Genetic Enhancement of Common Bean Using Exotic Germplasm for Biotic and Abiotic Stress Tolerance

Location: Tropical Crops and Germplasm Research

Title: A differential nursery for testing nodulation effectiveness of rhizobium strains in common beans

Author
item Rosas, Juan - Zamorano, Panamerican School Of Agriculture
item Estevez De Jensen, Consuelo - University Of Puerto Rico
item Beaver, James - University Of Puerto Rico
item Porch, Timothy - Tim

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Most common beans in Central America are produced on soils having low nitrogen (N) and phosphorous content. The small-scale farmers do not have resources to use fertilizers or implement soil management practices. Strategies to improve the adaptation of beans to low N soils include the enhancement of nodulation and biological nitrogen fixation (BNF) and the use of effective Rhizobium inoculants that in turn fix nitrogen. The objective of this research was to develop and validate the BNF efficiency of Andean and Mesoamerican bean lines and develop a differential nursery to evaluate the performance of Rhizobium isolates as strains for nodulation and BNF studies and for use as commercial inoculant production. In 2013-14 a group of 32 Andean and Mesoamerican bean accessions were evaluated in a screen-house. The set of six Andean and six Mesoamerican differential lines were identified from those having the best response to inoculation with the strains CIAT 632 and CIAT 899. In 2015-16, the differential nursery was used to characterize Rhizobium isolates from nodules collected in farmer fields under screen-house conditions. In addition, sets of differential nurseries were also evaluated in farmer fields and at Zamorano University. Nodulation and plant biomass were determined at flowering and seed yield was measured at maturity. The results suggest that the differential nursery would be useful to evaluate the effectiveness of Rhizobium isolates and their identification as strains, and to estimate the nodulation effectiveness and BNF contributions of Rhizobium resident populations present in small farms.

Technical Abstract: Most common beans (Phaseolus vulgaris L.) in Central America are produced on soils having low nitrogen (N) and phosphorous content. The small-scale farmers do not have resources to use fertilizers or implement soil management practices. Strategies to improve the adaptation of beans to low N soils include the enhancement of nodulation and biological nitrogen fixation (BNF) and the use of effective Rhizobium inoculants. The objective of this research was to develop and validate the BNF efficiency of Andean and Mesoamerican bean lines and develop a differential nursery to evaluate the performance of Rhizobium isolates as strains for nodulation and BNF studies and for use as commercial inoculant production. In 2013-14 a group of 32 Andean and Mesoamerican bean accessions were evaluated in a screen-house. The set of six Andean and six Mesoamerican differential lines were identified from those having the best response to inoculation with the strains CIAT 632 (R. etli) and CIAT 899 (R. tropici). In 2015-16 the differential nursery was used to characterize Rhizobium isolates from nodules collected in farmer fields under screen-house conditions. In addition, sets of differential nurseries were also evaluated in farmer fields and at Zamorano University. Nodulation and plant biomass were determined at flowering and seed yield was measured at maturity. The results suggest that the differential nursery would be useful to evaluate the effectiveness of Rhizobium isolates and their identification as strains, and to estimate the nodulation effectiveness and BNF contributions of Rhizobium resident populations present in small farms.