Genetic variability in the physiological responses of Andean lupin to drought stress
Abstract
Drought is one of the most important abiotic stresses that causes significant reductions in crop yield, and thus
hinders the food security of the growing world population. In consequence, it is urgent to select crops able to
resist drought, maintain high yield and have a good nutritive content. The purpose of this project was to
evaluate the responses of different accessions of Andean lupin to drought stress, and identify if there are
significant differences in their physiological responses.
To identify germplasm for further investigation, thirty accessions of Lupinus mutabilis Sweet. and one
accession of L. albococcineus Hort. were screened in two sets, A of 15 and B of 16 accessions. From these
sets, four lines were chosen on the basis of extreme values in the measurements, and this set of four was
investigated 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, water
potential, ion membrane leakage, and shoot dry weight were measured and transpiration efficiency was
calculated. In addition, carbon isotope discrimination, root length, root dry matter, proline content and
soluble 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 considered
as being drought resistant and PI 510572 was considered as drought sensitive. However, the results from set
C showed that accession PI 510572 is able to adapt its cell membrane to the drought stress so that its ion
leakage is less than in the other accessions, and in addition it has the ability to accumulate higher
concentrations of osmoprotectants.
Thus, this survey identified that some accessions of Andean lupin were able to avoid drought stress through
stomatal traits and root traits, and others that were able to tolerate drought through the accumulation of
osmotically active substances. Consequently, there are good prospects for breeding of Andean lupin to
improve its drought resistance.
