Yield parameters in young jojoba plants and their relation to actual yield in later years

A total of 30 jojoba clones, among them six already commercial clones and 24 newly selected ones were characterized in terms of yield parameters, chilling requirements and morphological traits. The aim was to supply farmers (from Israel and abroad) better yielding clones. Considerable variability was found among the clones in all the parameters. Some clones exhibited excellent vegetative traits related to yield potential, such as a high survival rate: rapid growth, extensive branching, high node density, while others exhibited outstanding reproductive traits, such as earliness, high flower density, high percentage of fruit set, high seed weight, and high wax content in the seed. The clones also differed in their wax composition. Plants began to yield 2 years after planting in the field, some having commercial yields as early as their third year. The best clones with respect to wax yield were Hazerim, Negev, BGU, Forti, and Gvati, all new clones not yet planted in commercial plantations. An attempt to relate yield parameters at the third year to wax yield at their sixth year was made. The height in the third year and the flower index, relative fruit set and seed weight were related to yield. The flowering pattern of all clones was followed up during the season 1993/94, which was characterized by a combination of cool night temperatures with warm days. This weather enabled the clones that broke dormancy to flower during the winter instead of spring. We were thus able to identify clones with different chilling requirement. In conclusion some very promising clones with high yields can be added to our commercial clones. Owing to the new information gathered on depth of dormancy and flowering pattern, clones can also be allocated to environments differing in climatic conditions. (C) 1999 Elsevier Science B.V. All rights reserved.