Fenton E. Larsen

Comparative gas exchange characteristics of potted, glasshouse-grown almond, apple, fig, grape, olive, peach and Asian pear

Abstract Net photosynthesis (Pn), dark respiration (Rd), transpirational flux density (TFD) and leaf conductance (kl) on glasshouse-grown plants of almond, apple, fig, grape, olive, peach and Asian pear were examined under various laboratory environmental conditions. Grape and almond had the highest light-saturated photosynthetic rates, greater than 20 μmol CO2 m−2 s−1. Apple had the lowest temperature optimum for Pn, 20°C. Almond had the highest Rd rate between 10 and 50°C, but grape had the highest Q10 for respiration, a value of 2.5. Apple, olive and grape stomata were most sensitive to the leaf-to-air vapor pressure difference. Apple had the greatest sensitivity of Pn to the vapor pressure difference.

Diurnal water relations of apple, apricot, grape, olive and peach in an arid environment (Jordan)☆

Abstract Selected water-relations parameters were examined on a diurnal basis for apple, apricot, grape, olive and peach grown under common conditions in Amman, Jordan. The study objective was to determine if there were differences in water-relations characteristics that could be useful for the prediction of water use by these crop plants at various sites in Jordan or in similar arid areas with limited water. Transpiration was greatest in apple, followed by peach. Apricot, olive and grape had similar transpiration rates, and these species lost less water per unit leaf area than peach or apple. Apple and olive reached maximum leaf conductance in the afternoon, while peach and apricot had maxima at mid-day; grape had the earliest maximum leaf conductance. Grape had the highest midday xylem pressure potential and olive the lowest, with apple, apricot and peach being intermediate. Apple and olive appeared to have the most rapid return to pre-dawn xylem pressure potential. Estimates of the liquid pathway resistance to water flow were lowest in apple and highest in olive. Results suggest that these species represent alternative plant strategies in response to a common moisture regime.

Rootstock influence over 25 years on yield, yield efficiency and tree growth of cultivars ‘delicious’ and ‘golden delicious’ apple (Malus domestica Borkh.)☆

Abstract The influence of nine rootstocks on growth and production of cultivars ‘Goldspur’ (GS) and ‘Wellspur Delicious’ (WS) and of three rootstocks on growth and production of cultivars ‘Red King Delicious’ (RK) and ‘Golden Delicious’ (GD) apple was evaluated. With spurred scions (WS and GS), the largest trees were on seedling (sdlg), Malling Merton (MM) 104 and MM 109 roots, and the smallest were on Malling (M) 26. Annual yields of most combinations had reached a plateau but none showed significant signs of decline after 25 years. WS cumulative yields were not significantly greater than RK (non-spur). GD produced greater cumulative yields than GS. When cumulative yields among nine stocks within spurred scions were compared, GS/MM 106 and MM 104 and WS/MM 109 and MM 106 ranked highest. Yield efficiencies were superior with M 26, spurred growth habit and clonal stocks.

Protein and isozyme electrophoresis and isoelectric focusing for the characterization of apple clones

Abstract To identify apple (Malus domestica Borkh.) clones, electrophoretic and isoelectric focusing of protein and isozyme pattern differences were investigated. Existing electrophoretic methods were adapted to obtain satisfactory separation and reproducibility of patterns. Several protein extraction buffers and procedures were evaluated to optimize protein recovery and enzyme activity from shoot bark tissue and other organs and to counteract the interference of other cell components. Sodium dodecyl sulfate—polyacrylamide gel electrophoresis (SDS-PAGE) did not reveal useful differences among cultivars, nor did total native protein patterns (non-denaturing PAGE). Peroxidase, esterase, acid phosphatase and indoleacetic acid oxidase extracted from shoot bark tissue did, however, show isozymic differences useful for identification. These enzymes expressed constant isozyme patterns at different times of the year and from trees growing under different conditions, and patterns were independent of wood age and rootstock influence.

Scion/interstock/rootstock effect on sweet cherry yield, tree size and yield efficiency

Abstract Yield and trunk cross-sectional area of ‘Bing’ and ‘Chinook’ cherries were measured on four tart cherry interstocks, ‘Kansas Sweet’, ‘Northstar’, ‘Montmorency’ and ‘Redrich’, and on four rootstocks, Mahaleb 4, Mahaleb 900, F 12-1 Mazzard and New York Mazzard, over a 20-year period. Additional treatments included both scions on either mahaleb or mazzard rootstocks without interstocks. Fifty-seven percent of total mortality was associated with ‘Redrich’ interstock, with no other single treatment showing disproportionately high mortality. After 20 years, cumulative yield was highest on Mahaleb rootstocks, but there were no significant differences in cumulative yield among interstocks. Trees lacking interstocks had significantly lower cumulative yield than trees with interstocks. Trunk cross-sectional area of ‘Bing’ was smaller than ‘Chinook’, and ‘Northstar’ produced smaller trunks than other interstocks tested. However, trees without interstocks tended to have smaller trunks than those with interstocks, although not significantly smaller than those with ‘Northstar’ interstocks. Trunk cross-sectional area was not affected by rootstock. Yield efficiency of ‘Bing’/‘Northstar’/Mahaleb 4 was the highest of the combinations tested.

Rootstock effects on responses of potted ‘Smoothee Golden Delicious’ apple to soil-applied triazole growth inhibitors. I: Shoot and root growth

Abstract Emulsions containing 0, 1, 10 or 100 mg paclobutrazol, uniconazole or triapenthenol in 100 ml water were applied to the soil of potted cultivar ‘Smoothee Golden Delicious’ apple ( Malus domestica , Borkh.) on M 9, M 7a or MM 111 rootstocks (M = Malling, MM = Malling-Merton). Percentage reductions in shoot length were greatest for trees on MM 111 and M 7a, and least for M 9. Mean shoot lengths of treated trees compared to controls were 64% for MM 111, 69% for M 7a and 75% for M 9. Within rootstocks, triapenthenol caused the greatest and uniconazole the least reduction in shoot growth and stem cross-sectional area per unit increase in dosage. The marginal effectiveness for reduction in shoot length and cross-sectional area was greatest for triapenthenol and least for uniconazole, but the reverse was true for a reduction in shoot dry weight. Rootstock effect on root dry weight at the end of the experiment depended on the chemical used and the dosage applied. Total root growth was small in all treatments.

Growth and fruit production of young micropropagated apple (Malus domestica Borkh.) trees

Abstract Tree size, cumulative yield, yield efficiency and anchorage of six micropropagated (MP) apple ( Malus domestica Borkh.) cultivars were determined in 1991 after 5 years of fruit production, as compared with trees budded on domestic seedling (sdlg) or Malling (M) 7a roots. Trees were planted in 1984, with crops harvested from 1987 through 1991. Trees of all scions except cultivar ‘Rome’ were smaller (as determined by trunk cross-sectional area) on M 7a than for MP trees. MP trees of cultivar ‘Delicious’, cultivar ‘Jonathan’, cultivar ‘Rome’ and cultivar ‘Spartan’ were larger than trees on sdlg, while the opposite occurred with ‘Golden Delicious’ (GD). Cumulative yield was affected by a scion × rootstock interaction, with few consistent trends in scion or rootstock effects. Yield efficiency was also affected by a scion × rootstock interaction. In 1991, cumulative yield efficiency on M 7a was superior to other rootstocks with all scions except GD, while the efficiency of sdlg and MP trees was statistically similar with all scions. In general, cumulative yield efficiency for M 7a was twice that for sdlg and MP trees. Nearly all trees leaned in response to prevailing westerly winds, with trees on sdlg generally more upright than MP or M 7a trees.

Mt. St. Helens volcanic ash: effect of incorporated and unincorporated ash of two particle sizes on runoff and erosion

Abstract The effect of ash from the 1980 Mt. St. Helens eruption on runoff and rill erosion of cultivated land was studied in 1981 and 1982. Ash from the Pullman (fine particles) and Yakima, WA (coarse particles), areas was applied to a silt loam soil, and water was applied. Treatments were: bare soil (fine-silty, mixed, Mesic Pachic Ultic Haploxerolls); ash incorporated with soil; and unincorporated ash on the soil surface. Sediment concentration in runoff first increased with time to a maximum, then decreased to an approximate steady state. Sediment concentrations were higher for unincorporated ash as compared to ash incorporated with the underlying soil, and were even lower for bare soil. Sediment concentration was higher with Yakima ash as compared to Pullman ash or bare soil because of the less cohesive nature of Yakima ash. Rills became wide and shallow with Yakima ash, as compared to deeper and narrower rills for Pullman ash, because of the relatively more cohesive nature and finer particle size of Pullman ash. The finer Pullman ash caused formation of a surface seal, thus restricting the infiltration rate and producing a higher runoff rate than from rills with Yakima ash or bare soil.

Induction of lateral branches in tree fruit nursery stock with propyl 3-t-butylphenoxy acetate (MB 25, 105) and Promalin (GA4+7 + 6-benzyladenine)

Abstract Sprays with 250–2000 mg l−1 propyl 3-t-butylphenoxy acetate (MB 25,105) and 250 and 500 mg l−1 GA4+7 + 6-benzyladenine (Promalin) were applied to scion growth of first nursery trees of ‘Bartlett’ pear (Pyrus communis L.), ‘Bing’ cherry (Prunus avium L.) and ‘Oregon Spur II Delicious’ apple (Malus domestica Borkh.) to stimulate lateral branching in the nursery. Most treatments significantly increased branching compared to untreated controls. Combination sprays of the two chemicals were usually better than either used alone. Chemical treatment usually produced greater branching and wider branch angles than mechanical heading. Both chemical and mechanical treatments reduced tree height and caliper, but the decrease was not always statistically significant.

Rootstock effects on responses of potted Smoothee Golden Delicious apple to soil-applied triazole growth inhibitors. II, Mineral nutrition and carbohydrate status

Abstract Emulsions containing 0 or 10 mg paclobutrazol, uniconazole or triapenthenol were applied to the soil of potted cultivar ‘Smoothee Golden Delicious’ apple (Malus domestica, Borkh.) on M 9, M 7a or MM 111 rootstocks (M = Malling, MM = Malling-Merton). Significant differences in mineral concentrations occurred, depending on rootstock, tissue and plant growth regulator (PGR), but few consistent trends emerged. PGR had no effect on carbohydrates in plants on MM 111. The carbohydrate concentrations in plants on M 7a were most sensitive to PGR, although differences in relative carbohydrate concentrations were also evident in trees on M 9.