In vitro selection and characterization of drought-tolerant plants of durum wheat (Triticum durum Desf)

Abstract

— Somaclonal variation has been used as a source of variability to improve the drought tolerance of durum wheat (Triticum durum Desf). Of the 6 varieties currently grown in Morocco, 3 were selected for their ability to produce calli and regenerate plants in vitro. Using polyethylene glycol 10000 in the in vitro culture medium, low external water potentials were applied during callus proliferation and plant regeneration phases to select plantlets that were tolerant to drought. Out of the 30 plants that survived the stress, 13 exhibited improved tolerance to drought compared with unselected controls, using chlorophyll fluorescence and electrolyte leakage of leaves subjected to water stress as criteria. Applying osmotic stress during the regeneration phase seemed to be the most efficient. durum wheat / in vitro selection / drought tolerance / PEG Rsum — Slection in vitro et caractrisation de plantes de bl dur (Triticum durum Desf) tolrantes la scheresse. La variation somaclonale a t utilise comme source de variation gntique pour l'am- lioration de la tolrance la scheresse chez le bl dur (Triticum durum Desf). Parmi 6 varits largement cultives au Maroc, 3 ont t choisies sur leur capacit dvelopper des cals et rgnrer des plantes in vitro. L'addition de polythylne glycol 10 000 aux milieux de culture a t utilise pour rduire le potentiel hydrique externe, pendant la croissance des cals ou durant la phase de rgnration, et slectionner des plantules tolrantes la scheresse. Sur les 30 plantules rgnres partir des cals survivants, 13 montrent une amlioration de la tolrance par rapport aux tmoins, sur la base des mesures de la fluo- rescence de la chlorophylle et des pertes d'lectrolytes effectues sur les feuilles en prsence d'un stress hydrique. La slection sur milieu de rgnration semble la plus efficace. bl dur / slection in vitro / tolrance la schesse / PEG * Correspondence and reprints. opment from germination up to grain filling, through vegetative and reproductive growth. Owing to the fact that this species, which is of great economic importance, has to endure drought conditions in numerous countries where it is cultivated, its future production will largely depend on studies devoted to a better understanding of this stress.