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- Author or Editor: David A. Palzkill x
Abstract
Double eye (DE) and single eye (SE) nodal semihardwood cuttings of jojoba [Simmondsia chinensis (Link) Schneider] treated with 2000 ppm indolebutyric acid were rooted successfully under intermittent mist in a mixture of 1 perlite : 1 vermiculite. Differences in rooting percentages between 5-node, single node DE, and single node SE cuttings were not significant. The root systems of 5-node cuttings were much larger than those of nodal cuttings, and DE cuttings produced significantly more roots than SE cuttings. Clonal differences for rooting capability were evident among 12 clones tested; percentage of rooting varied from 30 to 97 for DE cuttings and from 43 to 95 for SE cuttings. Significantly more cuttings rooted in the 1 perlite: 1 vermiculite rooting mix than in Oasis Root Cubes.
The `Desert Museum' hybrid between the Blue, Foothills, and Mexican palo verdes has been well received by the public. However, it has remained unavailable due to difficulties in asexual propagation. Studies were conducted on effects of IBA cone. (0 to 10,000 ppm), cutting position along the stem, size of cutting, season, and temperature of the medium.
For `Desert Museum', basal cuttings of slightly hardened new stem growth rooted much better than apical cuttings. Best rooting for apical cuttings was 79% using IBA from 2,500-5,000 ppm. Basal cuttings averaged 95% rooting and showed no response to IBA. Rooting of cuttings taken in September declined to 10% for apical and 2170 for basal cuttings averaged over all IBA levels. Six other species or hybrids of Cercidium and Parkinsonia and five of Prosopis were also rooted.
Woody legumes used for landscape plants in the desert southwest are extremely variable when propagated from seed. Three Prosopis chilensis trees were air layered in early April, 1989. Stems diameters of 0,5 and 1.0 cm and IBA levels of 5,000 and 15,000 ppm IBA were compared. Except when mechanical damage occurred during the wounding stage or from wind, 100% of the layers at both 5,000 and 15,000 ppm IBA rooted. The 0.5 cm branches were more susceptible to mechanical damage from wounding than the 1.0 cm branches.
A second study begun in mid-August, 1989, compared 0 and 5,000 ppm IBA on the same three genotypes. After eight weeks, IBA treated layers had 83% and untreated layers only 13% rooting. Layers with IBA had thicker and more numerous roots.
Air layers of Cercidium, Parkinsonia, and other species of Prosopis were also successfully rooted.
The `Desert Museum' hybrid between the Blue, Foothills, and Mexican palo verdes has been well received by the public. However, it has remained unavailable due to difficulties in asexual propagation. Studies were conducted on effects of IBA cone. (0 to 10,000 ppm), cutting position along the stem, size of cutting, season, and temperature of the medium.
For `Desert Museum', basal cuttings of slightly hardened new stem growth rooted much better than apical cuttings. Best rooting for apical cuttings was 79% using IBA from 2,500-5,000 ppm. Basal cuttings averaged 95% rooting and showed no response to IBA. Rooting of cuttings taken in September declined to 10% for apical and 2170 for basal cuttings averaged over all IBA levels. Six other species or hybrids of Cercidium and Parkinsonia and five of Prosopis were also rooted.
Total nonstructural carbohydrates (TNC), starch, total soluble sugars, sucrose, and proline concentrations were monitored for 18 months in leaf tissue of two jojoba [Simmondsia chinensis (Link) Schneider] clones that differ in frost susceptibility. Seasonal changes in TNC and starch concentrations, with maxima in the winter and minima in summer, were significant. Sugar levels decreased from fall to spring and increased during early summer. The more frost-resistant clone (C-1) had significantly higher sugar concentrations during most of the study than the less frost-resistant clone (C-2). Proline concentrations largely followed the trends found for TNC. The C-1 clone had the higher levels of proline, except when C-2 was frost-injured. Growth trends were similiar between C-1 and C-2, with a major growth flush from March to May. Relatively high levels of starch preceded growth flushes.
Abstract
Fruit and seed development of seven jojoba [Simmondsia chinensis (Link) C. Schneid.] clones were monitored over two seasons. Pollination occurred in late February and early March. However, most of the seed dry matter and wax accumulated after 15 June in both years. Fruit weight rapidly increased during May, followed by a leveling off in June and a 70% drop in weight in July as fruit matured and water was lost. While all seven clones exhibited similar fruit and seed developmental patterns, there were large differences between clones in the actual values observed over the two seasons. Differences in final seed weight between clones were due to differences in both rate and length of time of filling.
Abstract
Cultivars or germplasm with published performance records are presently unavailable for jojoba. Only one cultivar, Mirov, is widely recognized in the industry, and it is not widely planted. Unfortunately, published performance records do not exist for this cultivar. Most existing commercial acreage has been planted with seed or seedlings collected from many different locations, or with cuttings collected from selected female plants growing in seedling plantings. There is a need for cultivars of known performance to both increase seed production of commercial plantings and to provide standards with which to compare other clones. The purpose of this report is to briefly describe three jojoba clones that have been studied for 8 years and have performed well in a field planting and to announce their release.
Flower bud injury resulting from freezing temperatures has been a major problem in jojoba [Simmondsia chinensis (Link) C. Schneid.] production. A 3-year field study, which began with 4-year-old plants, evaluated the effect of three irrigation treatments on growth, flower bud survival, seed yield, seed weight, and seed wax concentration of six clones. After 3 years, irrigation cut-off dates of late May (dry treatment) and early September (medium treatment) resulted in reduced plant height and width compared to irrigating through November (wet treatment). Flower bud survival and seed yields were very low in the first year for all treatments. In the second and third years, bud survival for most clones, even at -8C, was greatly improved by withholding water in the fall. In December of the second and third years, plants in the medium and dry plots had lower leaf water potential than those in the wet plot. In the second year, plants in the medium and dry plots had seed yields that were 3.5 times higher and wax yields that were were 2.3 times higher than plants in the wet plot. In the third year, the medium treatment had the highest seed and wax yields. Average seed weight and seed wax concentration were generally highest for plants in the wet plot where seed yields were low. Withholding irrigation from jojoba in the fall appears to improve flower bud survival and seed and wax yields following cold winters.
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).