Steven A. Weinbaum

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Effects of irrigation deprivation during the harvest period on yield determinants in mature almond (Prunus dulcis (Mill.) D.A. Webb cv. Nonpareil) trees were investigated during a 3-year field experiment. Return bloom and fruit set were measured on 2185 individually tagged spurs. Water stress resulting from irrigation deprivation during the harvest period,(More)
Nitrogen (N) derived from both the soil during current-year uptake, and the withintree pool of storage N was distinguished in two groups of “Serr” walnut trees using labeled fertilizer (15N-depleted ammonium sulfate) applied in different years. Mass spectrometric analysis of N in xylem sap collected periodically in spring allowed quantification of the(More)
Effect of irrigation deprivation during the harvest period on the nonstructural carbohydrate (NC) content of dormant, mature, field-grown almond (Prunus dulcis (Mill.) D.A. Webb cv. Nonpareil) trees was studied. Roots, trunk, branches, spurs and stems of 12 trees were subsampled in February 1997, across a gradient of irrigation treatments (FI = fully(More)
The influence of alternate bearing on nutrient utilization and total tree nutrient content was investigated in mature pistachio (Pistacia vera L. cv Kerman trees). Removal of N, P and Zn in fruit and abscised leaves of cropping (‘on’) trees averaged 5, 6, and 2 times, respectively, the removal in abscised leaflets of the non-fruiting, ‘off’ year trees. One(More)
Two treatments were employed to influence the amount of amino nitrogen (N) transport in phloem. In walnut trees (Juglans regia L.), developing fruit significantly reduced the efflux of foliar-applied 15N-enriched urea from treated spurs over a 33-day period in comparison with similarly-treated defruited spurs. Those data suggest that local aboveground(More)
In nut tree orchards in California, irrigation is typically withheld during the harvest period to reduce the likelihood of bark damage during mechanical shaking of the trees. The ensuing water stress, however, may result in premature defoliation and subsequent yield declines. Our objective was to establish and quantify the water stress resulting from(More)
Pollen grains from selected cutivars of almond [Prunus dulcis (Mill.) D. A. Webb] and peach (Prunus persica Batsch L.) were exposed to a range of temperatures between 1°C and 34°C on a thermogradient plate. Pollen germination at temperatures below 9°C was conspicuously greater in almond than peach. Miximal germination percentages were attained at about 16°C(More)
Retention of pollen grains following natural self-pollination was evaluated in 15 cultivars (cvs.) of almond, 4 peach and 2 nectarine cvs., and 37 interspecific peach × almond hybrids compared to 7 almond seedlings. The level of pollen retention was presumed to reflect and integrate the degree of homogamy, the amount of pollen produced by the flower, the(More)
G.A. Picchioni, Dep. of Agronomy and Horticulture, New Mexico State Univ., Las Cruces, NM 88003; S.A. Weinbaum, Dep. of Pomology, Univ. of California, Davis, CA 95616; D.L. Daniel, Dep. of Economics/International Business and Univ. Statistics Center, New Mexico State Univ., Las Cruces, NM 88003; and H. Karaca, Soil Science Dep., Mustafa Kemal Univ.,(More)