Abstract

A pioneer collaboration between the breeding

programs in Honduras, Mexico and Michigan State

University (MSU) was designed to identify commercial black

bean cultivars exhibiting drought resistance adapted for

Central America and regions in Mexico. Two recombinant

inbred line (RIL) populations were developed from crosses

between a drought resistant line, B98311 from MSU, with

TLP 19 and VAX 5, two lines from CIAT with improved

disease resistance and adapted to the growing conditions in

Latin America. Both populations were tested (in Zamorano,

Honduras and Veracruz, Mexico) under drought stress and

non-stress conditions. Yields were reduced by drought stress

and Macrophomina phaseolina, the causal fungal pathogen of

charcoal rot. Drought stress, disease pressure and low yields

contributed to the high variation coefficients (VC), which

hindered the identification and selection for superior lines.

Selection was based on rank of the geometric mean (GM)

yield, calculated from the yield of each line in the stress and

non-stress treatments. The RIL, L88-63 ranked first in GM

yield at both locations. Subsequent testing in Honduras and

Michigan supported the high yield potential and broad

adaptation of L88-63. Breeding for drought resistance in

lowland tropical environments will require that additional

resistance to M. phaseolina be incorporated into potential

new bean lines being considered for release in this region.