Climate change presents increasing challenges for tropical agriculture, especially for crops such as common bean (Phaseolus vulgaris L.), which are highly sensitive to thermal stress. This study evaluates the effects of moderate warming on the root system structure and symbioses of two local varieties, Matambú and Guaymí, grown under humid tropical conditions in Costa Rica. Field experiments were conducted using open-top chambers (OTCs) to simulate a passive temperature increase of approximately +2 °C above ambient conditions. The experimental setup comprised twelve plots (six OTCs and six controls), with destructive root sampling after harvesting the pods. Root biomass, depth, number of nodules, and arbuscular mycorrhizal (AM) colonization were quantified. Preliminary results indicated that Matambú exhibited a 28% increase in root biomass under OTC conditions (5.4 ± 0.3 g/plant) compared to controls (4.2 ± 0.2 g/plant), while Guaymí showed a smaller increase of 12%. Root depth in Matambú increased from 19.5 ± 1.1 cm (control) to 24.7 ± 1.3 cm (OTC), suggesting a heat-induced root elongation strategy. Additionally, Matambú plants under warming formed, on average, 38.2 ± 3.1 nodules per plant, versus 27.4 ± 2.8 in control, with AM colonization rates of 64 ± 5% vs. 51 ± 4%, respectively. In contrast, Guaymí displayed lower nodulation and mycorrhizal response. These findings suggest that Matambú may possess enhanced adaptive traits for coping with moderate thermal stress, particularly in terms of root architecture and beneficial microbial interactions. The results underscore the importance of conserving and promoting resilient local genotypes for sustainable agriculture under future climate scenarios.
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Related Effects of Climate Change on Root System Dynamics and Symbiotic Activity in Local Bean Varieties (Phaseolus vulgaris L.) in the Humid Tropics of Costa Rica
Published:
20 October 2025
by MDPI
in The 3rd International Online Conference on Agriculture
session Crop Production
Abstract:
Keywords: OTC, abiotic stress, nodules, induced passive heat
