Supplemental pollination-increasing jojoba (Simmondsia chinensis L. [schneider]) seed yields in the Arid Chaco environment

Jojoba (Simmondsia chinensis L. Schneider]) is a wind-pollinated perennial shrub native to the Sonoran Desert. In recent years commercial plantations in Arizona and Catamarca, Argentina have dramatically decreased in size and number, going from 13,000 ha in the early 1980s to about 2,300 ha today. The main reason for this decrease is yields being lower than expected, with low pollination percentages considered the main source of the problem, although use of inferior genetic material has contributed to the problem. Artificial or supplemental pollination has been used successfully in other crops to increase yields, and it was thought that this could also be used for jojoba. A trial was carried out over two seasons in which pollen collected in Arizona, was mechanically applied to commercial fields in Catamarca. The first year yields were significantly (P < 0.05) greater in the fields in which pollen had been applied, than in the controls. The second year yields were not measured. Rather the number of capsules with fruit, aborts, and empty capsules were counted on a number of randomly selected branches. This technique gives a good estimate of yield, and the results showed that pollen application significantly (P < 0.05) increased expected yields. In conclusion, application of supplemental pollen increases jojoba yields and hence should be considered a viable option for commercial plantations. Additional work is required, however, to determine the correct application rate so as to minimize collection costs, and determine when application should take place to optimize efficacy.