Response of germination capacity of local varieties of common bean (Phaseolus vulgaris L.) with different levels of heat stress

Abstract

objective: Common bean (Phaseolus vulgaris L.), a staple food crop in Mexico, faces increasing challenges due to shifting climatic patterns during its production cycle. This necessitates comprehensive studies and the integration of technological components to ensure its adaptability to emerging environmental conditions. The objective of this study was to evaluate the germination capacity of various local bean varieties both improved and traditional under different thermal treatments. Design/Methodology: The germination performance of bean varieties developed in the Guadiana Valley Pinto Saltillo, PID 1, NOD 1, and PID 2 was assessed at five temperature levels: 27, 30, 33, 36, and 39 °C. A randomized complete block design was employed, and statistical analysis included goodness-of-fit tests and post hoc comparisons for significance testing. Results: The NOD 1 variety exhibited the highest germination percentage (GP), consistently exceeding 96% between 27 °C and 36 °C. However, at 39 °C, its GP dropped below that of PID 2. Notably, PID 2 achieved the highest GP at 39 °C (60%) but showed the lowest values at the other temperature levels. Implications: It is advisable to explore germination responses at lower temperatures using the same varieties, as three of the four exhibited significantly reduced GP at 39 °C. This trend suggests limited viability for selection under extreme heat conditions. Conclusions: Within the optimal thermal range of 27–36 °C, the improved varieties PID 1 and NOD 1 outperformed Pinto Saltillo and PID 2 in germination percentage. However, PID 1 demonstrated superior germination under the highest tested temperature of 39 °C.