Impact of soil moisture on common bean (Phaseolus vulgaris L.) phytochemicals

Water scarcity is detrimental for agricultural productivity and modifies food quality. Common bean is an important foodstuff mainly produced in regions prone to drought. Therefore, it is important to grow cultivars adapted to restricted irrigation whose grain is high in health related phytochemicals without compromising seed yield. The aim was to determine the effect of restricted irrigation (RI), terminal drought (TD) and irrigation during the whole cycle (IWC) treatments upon seed yield, and seed's phytochemicals and functional properties of two pinto bean cultivars, Rar ' amuri and Pinto Saltillo (PS). Compared to IWC, TD decreased seed yield, 13 % for Rar ' amuri and 20 % for PS, whereas RI increased yield by 33 % for Rar ' amuri and 5% for PS. A principal component analysis demonstrated that phytochemicals such as oligosaccharides, some phenolics, protein and resistant starch, differentiated the RI treatment from the TD and IWC. Moreover, a partial least squarediscriminant analysis indicated that some compounds were associated to the inhibitory capacity against digestive enzymes, like alpha-amylase, -glucosidase and pancreatic lipase. These results indicate that RI can be used to improve bean seed phytochemicals and functional quality without penalizing seed yield.