LONG-TERM EFFECT OF IRRIGATION WITH SALINE WATER ON THE DEVELOPMENT AND PRODUCTIVITY OF JOJOBA CLONES

Three commercial clones of jojoba (Simmondsia chinensis) (64, Q-106 an d 879-154) were planted in June 1991 at the Ramat Negev Experimental S tation (Israel) and fertigated with water at three salinity levels, 1. 2, 3.4 or 6.2 dS m(-1). The effects of salinity over three and a half years on key metabolic activities, on plant growth and development, on flowering characteristics, and on yield were studied. Salinity barely inhibited the rate of net photosynthesis, although it did reduce stom atal conductivity by about 50%. Salinity also affected the water statu s of the plants by reducing water potential. Growth of the plants was not greatly affected by salinity. It was found that jojoba plants accu mulate sodium and chloride ions in their leaves and use a strategy typ ical of many halophytes to cope with the salinity. The effect of salin ity on flower development was also studied, since the vitality of flow ers is a key factor in obtaining seeds. Salinity did not affect the ti ming of the breaking of flower bud dormancy in the 1992-93 season, alt hough it did delay flower bud growth in clones Q-106 and 64. Salinity brought forward the flowering of clone 879-154 by about a fortnight in the 1993-94 season, but did not affect the flowering pattern of the o ther clones. Fruit set was not inhibited by salinity in the 1994 or 19 95 season, and no significant effects were found on yield and wax cont ent in 1994 season, but yield was reduced by salinity in the 1995 seas on.