Abstract
Common bean (Phaseolus vulgaris L.) is sensitive to different types of abiotic stresses (drought, high temperature, low soil fertility, and acid soil), and this may limit its adaptation and consequently to its yield under stress. Because of this, a sister species, tepary bean (Phaseolus acutifolius A. Gray), has recently gained attention in breeding for improved abiotic stress tolerance in common bean. In this study, we evaluated the adaptation of 302 accessions of tepary bean (Phaseolus acutifolius A. Gray) and its wild relatives (grouped in four types of tepary bean genetic resource: cultivated, acutifolius regressive, acutifolius wild, tenuifolius wild) when grown under high temperature and acid soil conditions with aluminum toxicity in the Amazon region of Colombia. Our objective was to determine differences among four types of tepary bean genetic resource in their morpho-phenological, agronomic, and physiological responses to combined high temperature and acid soil stress conditions. We found that cultivated P. acutifolius var acutifolius presented a greater number of pods per plant, as well as larger seeds and a greater number of seeds per pod. Some traits, such as root biomass, days to flowering and physiological maturity, specific leaf area, and stomatal density, showed significant differences between types of tepary bean genetic resource, probably contributing to difference in adaptation to combined stress conditions of high temperature and acid soil conditions. The photochemical quenching (qP) was higher in cultivated P. acutifolius var. acutifolius, while energy dissipation by non-photochemical quenching (NPQ) in the form of heat and the coefficient of non-photochemical dissipation (qN) were higher in acutifolius regressive and tenuifolius wild accessions. We have identified 6 accessions of cultivated and 19 accessions of tenuifolius wild that exhibited grain yields above 1800 kg ha−1. These accessions could be suitable to use as parents to improve dry seed production of tepary bean under combined stress conditions of high temperature and acid soil.
Highlights
The effects of climate change are rapidly impacting ecosystems around the world [1]by generating alterations related to increased global average temperatures, changes in precipitation patterns [2], and increased CO2 levels [3]
Our results indicate that the combination of phenological attributes, such as flowering and early maturity, with agronomic attributes, such as higher number of pods per plant and grain yield, shown by the accessions of P. acutifolius var. acutifolius cultivated type (25 accessions), makes these tepary bean accessions as valuable genetic resources with potential to boost production in the Amazon region
Results from the present study indicate that selection based on morpho-agronomic and physiological attributes could contribute toward improving yield gains in P. acutifolius breeding programs, and the identified, stress adapted accessions could serve as a valuable genetic resource for improving common bean yield under the combined stress conditions of high temperature and acid soil
Summary
The effects of climate change are rapidly impacting ecosystems around the world [1]by generating alterations related to increased global average temperatures, changes in precipitation patterns [2], and increased CO2 levels [3]. It has been estimated that agriculture by 2050 will need to produce 60% to 100% more food than is currently produced [1], becoming a major challenge to address food security in the coming decades [4] Likewise, these dramatic near-term climate change scenarios give rise to predictions of yield reduction in crops, especially those with greater abiotic stress sensitivity, such as common bean [5]. These dramatic near-term climate change scenarios give rise to predictions of yield reduction in crops, especially those with greater abiotic stress sensitivity, such as common bean [5] This has led to the identification and characterization of new sources of abiotic stress tolerance as one of the most urgent requirements to cope with the effects of climate change on crop production [6]. A sister species, such as tepary bean (Phaseolus acutifolius A Gray.), has recently gained attention in breeding efforts for improving abiotic stress tolerance in common bean [12,13,14]
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