Identification of physiological traits and genotypes combined to high achene yield in sunflower (Helianthus annuus L.) under contrasting water regimes

Field experiments were conducted to determine the effect of different leaf hydraulic traits on achene yield in sunflower under irrigated and drought regimes. Among leaf hydraulics, stomatal conductance (gs) showed highest relationship with achene yield (ay) under irrigated regime while in drought; osmotic adjustment (OA) showed highest positive relationship with ay. Presence of highly strong relationship between OA and relative water contents (RWC) indicated that RWC contents may be utilized as physiological marker of OA when source material comprises of different genotypes. Further more RWC contents also showed highly significant relationship with ay. OA also showed significant relationship with turgor pressure (TP) suggesting its role in maintenance of turgor. Genotype AMES-10107 showed highest ay which was accompanied by the higher gs in non stress regime. However under drought stress, AMES-10103 showed highest ay. This genotype also showed highest OA, RWC and TP.