Pollen production and pollen viability in male jojoba plants

Jojoba (Simmondsia chinensis (Link) Schneider) is a dioecious wind pollinated shrub native to the Sonora desert of the southwestern USA and Northern Mexico. A comprehensive program for the selection of female cultivars was conducted in Israel for many years. However, selection for male cultivars as pollen sources has largely been neglected. The current use of male seedlings with their large variation in bloom period, amount of pollen produced, and pollen viability, could result in insufficient pollination and reduced yields. The study was conducted at Hazerim plantation, Israel (northern Negev desert), on 8-9-year-old male jojoba plants. Pollen production was investigated 24 and 48 h after removal from the plants. Pollen viability was tested both in vitro and in vivo. Pollen production, in percent pollen from inflorescence fresh weight, was the highest during peak male bloom. The greatest amount of pollen having the best germinability was collected 24 h after the inflorescences were removed from the plants. In vitro germinability of jojoba pollen was affected by pollen source, and by sucrose concentration of the germination solution. Jojoba pollen from all pollen sources germinated intensively on the stigmas of the female flowers, but the percentage fruit set was different for various pollen donors. Several male plants from our study showed promising traits as potential male cultivars in terms of pollen production and viability. (C) 2003 Elsevier Science B.V. All rights reserved.