Genetic variability in the physiological responses of Andean lupin to drought stress

Drought is one of the most important abiotic stresses that causes significant reductions in crop yield, and thushinders the food security of the growing world population. In consequence, it is urgent to select crops able toresist drought, maintain high yield and have a good nutritive content. The purpose of this project was toevaluate the responses of different accessions of Andean lupin to drought stress, and identify if there aresignificant differences in their physiological responses.To identify germplasm for further investigation, thirty accessions of Lupinus mutabilis Sweet. and oneaccession of L. albococcineus Hort. were screened in two sets, A of 15 and B of 16 accessions. From thesesets, four lines were chosen on the basis of extreme values in the measurements, and this set of four wasinvestigated in depth (set C). Water stress consisted of controlled water loss from the soil (at 2% per day).The screening techniques used were: leaf temperature, stomatal conductance, relative water content, waterpotential, ion membrane leakage, and shoot dry weight were measured and transpiration efficiency wascalculated. In addition, carbon isotope discrimination, root length, root dry matter, proline content andsoluble sugar content were included in only set C.Based on the results from set A and set B, accessions PI 457981, PI 457972, and AC 2792 were consideredas being drought resistant and PI 510572 was considered as drought sensitive. However, the results from setC showed that accession PI 510572 is able to adapt its cell membrane to the drought stress so that its ionleakage is less than in the other accessions, and in addition it has the ability to accumulate higherconcentrations of osmoprotectants.Thus, this survey identified that some accessions of Andean lupin were able to avoid drought stress throughstomatal traits and root traits, and others that were able to tolerate drought through the accumulation ofosmotically active substances. Consequently, there are good prospects for breeding of Andean lupin toimprove its drought resistance.