Phenotypical, physiological and biochemical traits of the vegetative growth of wild tepary bean (Phaseolus acutifolius) under restricted water conditions

Abstract

Tepary bean (Phaseolus acutifolius A. Gray) is distributed in arid and semi-arid regions from Arizona to the northern areas of Mexico. The objective of this study was to quantify the effects of water deficit on vegetative growth in four accessions of wild tepary bean from Chihuahua (10020), Durango (10006 and 10017) and Nayarit (10011) in Mexico. For analysis, 30-day-old plants were placed in pots containing 1.5 L of soil. One group of plants was watered to field capacity (FC), and in the two other groups watering was withheld to maintain soil at 25% and 50% FC. Plant water potential (ΨW) and chlorophyll a fluorescence (Fv/Fm) were indicators of plant stress and there was a significant difference in plant growth. The data obtained with phenotyping platform showed a biomass reduction of 20% in 10020, 10006 and 10011 and approximately a 30% biomass increase in 10017. The 25% and 50% FC groups showed decreased glucose and fructose concentrations (50%). In contrast, sucrose concentrations increased in the 10006, 10011 and 10020 accessions but not in 10017. Surprisingly, sucrose content under water deficit in accession 10020 increased by twice the amount of well-watered plants.