FLOWER BUD DORMANCY, ABA CONCENTRATION, AND SURVIVAL DURING FROST OF JOJOBA GENOTYPES UNDER WATER-STRESS

Flower bud dormancy and anthesis patterns, ABA concentration, and bud survival following frost were studied in eight jojoba [Simmondsia shinensis (Link) Schneider] clones grown under two irrigation regimes (water stress and well irrigated). Several clones broke dormancy in the autumn. Anthesis in the field before winter occurred only in one clone (a male) in the well-irrigated treatment. Buds on water-stressed plants broke dormancy earlier than those on well-watered plants, but anthesis in the field occurred later in the year. Buds on water-stressed plants were less affected by a severe frost than those on control plants (43% vs. 10% survival). There were large differences among clones in the amount of frost damage. ABA levels did not correlate with dormancy patterns or with the amount of frost damage. Chemical name used: S-(Z,E)-5-(1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid (ABA).