EFFECT OF IRRIGATION ON JOJOBA PRODUCTION UNDER ARID CHACO CONDITIONS .2. SEED YIELDS AND WAX QUALITY

In the phytogeographic region of the Arid Chaco, in Las Oscuras, Province of Cordoba, Argentina, the production of jojoba seed under four levels of irrigation was evaluated during two years. The plants used were established by direct sowing with seeds from the Tucson Mountains, outside Tucson, Arizona, four years before the test started. The plants were not irrigated until the test began. The treatments were: T1 = 0; T2 = 300; T3 = 600; and T4 = 900 mm/ha/year, in twelve equal irrigations, applied every 30 d. The experimental design used was randomized complete blocks with two replications (30 plants in each replication). Each of the variables was compared by analysis of variance, and means were subjected to Duncan's New Multiple Range Test. For the conditions of this test, the results obtained suggest that: (i) seed production of jojoba plants increased significantly with high levels of water applied monthly (treatments T3 = 600 mm and T4 = 900 mm); (ii) The most efficient irrigation treatment was T3; (iii) Jojoba plants respond to high levels of irrigation (T4 = 900 mm) and produce the heaviest seeds under these conditions; (iv) an increase in water does not produce significant differences in fatty acid content, but it may change from year to year; and (v) increased jojoba yields can be achieved on dry-farm plantations by applying irrigation.