بررسي اثر تنش كم آبي بر روي عملكرد علوفه خشك و كارايي مصرف آب ارقام يونجه (Medicago sativa L .)

The effects of water ucflcit stress on hay alfa lfa (Medicago sativa) yield and water use efficiency cultivars

A field experiment was conducted during 2005 - 2006 in Agriculture Research Centre of Jiroft and Kahnouj to determine the effect of wate r stress on water u. efficiency (WliE) alfalfa cultivars. Using a split plot design based on Randomized Complete Block Des ign (ReBD) with three replications. The three levels of water stre ss (a, = severely stressed , a~ =moderately stressed and a, =least stressed) was main the plot factor and five cultiv ars of alfalfa (b , =Yazdi , b1 =Nicshahri, bJ =Rangar, b, =Bami and b,=Baghdad i) were cul lect ede in the sub plots fac tor. The results showed that decre ased water use efficiency, alfa lfa hay forage by increasi ng water stress . Comparison of corr elation coclficie nts show ed that there were significant positi ve correlation between alfalfa hay, forage and water use efficiency. Alfalfa water usc effic i ncy averaged (6 cut tings) 1.14 kgnr-haʹ alfa lfa hay in the most stres; eel and 1.64 kgrn J alfalfa hay in the lea t stressed treatment. Water use effic iency was highest (1.8 7 cgm ") in Nicshahri cultivar, There were no si nifi cant diff fences betwee n Bami (1.84 kgmʹ) and Nicshahri. .\ 1 alfa water usc efficiency -as highest at the pring 2.0 kgm-ʹhaʹ! and lowest at the summer 0018 kgrrr-haʹ) al falfa hay.