The potential of jojoba (Simmondsia chinensis) in New South Wales. 1. Growth and yield

Abstract

Jojoba (Simmondsia chinensis [Link] Schneider) was tested at several sites and on various soil types to assess its production potential under rainfed conditions in semi-arid areas of New South Wales. Stands were established using either plants grown from seed or cuttings taken from selected plants. With good nutrition and weed control, plant height increased at a similar rate over the experiment at all but the most sandy site, where growth was consistently poorer despite similar climatic conditions and management. Stands established from seed had extremely variable yields. Some plants failed to produce seed after 8 years while other plants consistently produced fruit after year 4, with yields as high as 1 kg clean seed per bush by year 8. The average yield was well under 200 g plant-1 except at Trangie in 1986-87 (590 g plant-1). At year 3, 50-100% of female plants were unproductive and by year 8, between 8 and 26% of plants remained unproductive. The variation in yield of the sampled population was consistently high irrespective of seasonal conditions, and usually the upper quartile yield was only marginally higher than the mean. However, the maximum yielding plant produced up to 10 times the mean yield. By contrast, the variation in yield of individuals within a clone was low regardless of the yield potential of that clone and the maximum yielding plant rarely exceeded twice the mean yield. Some clones (A, B and F) show promise as agricultural lines as they are relatively consistent yielders and show early yield development. The highest yield obtained extrapolates to 1.1 t ha-1 at year 7 at a site which averages 417 mm rainfall per year. Further research is needed to identify the reasons for the high variability and fluctuations in yield.