the effect of irrigation regime and sowing depth on yield and yield components of persian shallot (allium altissimum regel.) in mashhad climatic conditions

shallot (allium altissimum regel.) is a medicinal, industrial and perennial plant that has underground tubers. it is one of the most important allium species in iran, which normally grows in semi-cold to very cold highlands. because of being a wild plant, shallot is encounter with water deficit during its growth season. therefore evaluation of water requirement of shallot is important. in order to assess the effects of different irrigation regimes and planting depth, a factorial experiment based on randomized complete block design with three replications was conducted at agricultural research station ferdowsi university of mashhad, faculty of agriculture. treatments were five irrigation levels: no irrigation (i1), irrigation after 80±5 mm evaporation from pan evaporation (i2), irrigation after 60±5 mm evaporation from pan evaporation (i3), irrigation after 40±5 mm evaporation from pan evaporation (i4) and irrigation after 20±5 mm evaporation from pan evaporation (i5, control) and two levels of sowing depth of 5 cm (d1) and 10 cm (d2). results showed that dry bulb yield, biological yield, harvest index and plant height were reduced by increasing irrigation intervals. sowing depth had no significant effect on the parameters studied. also the interaction between irrigation levels and sowing depth reduced plant height, dry bulb yield and harvest index. the interaction between irrigation and sowing depth was significant in leaf area index and crop growth rate. shallot reacts to the amount of available water positively, but sowing depth of 10 cm has no effect on the bulb.