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Abstract

The effects of in-row spacing (1.8, 3.0, and 4.3 m) and rootstock [seedling, Mailing Merton (MM) 111, MM 106, and Mailing (M) 7] on growth and yield of ‘Redspur Delicious’ (RS) and ‘Goldspur Golden Delicious’ (GS) apple (Malus domestica Borkh.) were studied over 14 years. Close in-row spacing generally reduced annual yield per tree of all scion-stock combinations. However, increased estimated yields per hectare resulted from close tree spacings, which compensated for the reduced yield per tree. RS/MM 106 generally had greater yield per tree than the others and exhibited greatest precocity. RS/seedling initially exhibited the lowest production per tree, although it eventually performed well. Of GS combinations, GS/M 7 generally performed best and GS/seedling poorest, although in early years the latter did well. Although a spacing × rootstock interaction on yield per tree or per hectare was not found in any year, significant spacing effects were first evident on clonal rootstocks (RS/MM 106, RS/M 7, GS/MM 111, GS/M 7). Cumulative production efficiency was affected by rootstock but not by spacing. RS and GS on MM 106 and M 7 were the most efficient, nearly twice that on seedling. Trunk cross-sectional area in 1984 was less on clonal than on seedling rootstocks. All combinations had smallest trunk size at the closest spacing.

Open Access

Bases of orchard productivity were evaluated in four 10-year-old apple orchard systems (`Empire' and `Redchief Delicious' Malus domestics Borkh. on slender spindle/M.9, Y-trellis/M.26, central leader/M.9/MM.111, and central leader/M.7a). Trunk cross-sectional areas (TCA), canopy dimension and volume, and light interception were measured. Canopy dimension and canopy volume were found to be relatively poor estimators of orchard light interception or yield, especially for the restricted canopy of the Y-trellis. TCA was correlated to both percentage of photosynthetically active radiation (PAR) intercepted and yields. Total light interception during the 7th to the 10th years showed the best correlation with yields of the different systems and explained most of the yield variations among systems. Average light interception was highest with the Y-trellis/M.26 system of both cultivars and approached 70% of available PAR with `Empire'. The higher light interception of this system was the result of canopy architecture that allowed the tree canopy to grow over the tractor alleys. The central leader/M.7a had the lowest light interception with both cultivars. The efficiency of converting light energy into fruit (conversion efficiency = fruit yield/light intercepted) was significantly higher for the Y-trellis/M.26 system than for the slender spindle/M.9 or central leader/M.9/MM.111 systems. The central leader/M.7a system bad the lowest conversion efficiency. An index of partitioning was calculated as the kilograms of fruit per square centimeter increase in TCA. The slender spindle/M.9 system had significantly higher partitioning index than the Y-trellis/M.26 or central leader/M.9/MM.111. The central leader/M.7a system had the lowest partitioning index. The higher conversion efficiency of the Y/M.26 system was not due to increased partitioning to the fruit; however, the basis for the greater efficiency is unknown. The poor conversion efficiency of the central leader/M.7a was mostly due to low partitioning to the fruit. The Y-trellis/M.26 system was found to be the most efficient in both intercepting PAR and converting that energy into fruit.

Free access

Abstract

Trees of ‘Golden Delicious’, ‘Topred Delicious’, ‘Millersturdeespur Delicious’, and ‘Sundale Golden Delicious’ apple (Malus domestica Borkh.) were grown in two or more of the following orchard management systems established in 1973: slender spindle (SS), 2151 trees/ha, ‘Golden Delicious’ and ‘Sundale Golden Delicious’; trellis (TR), 1121 trees/ha, all cultivars; interstem hedgerow (IH), 795 trees/ha, all cultivars; and pyramid hedgerow (PH), 425 trees/ha, ‘Golden Delicious’ and ‘Topred Delicious’. Yields of ‘Golden Delicious’ in the SS and TR were similar during the first 7 years and these systems generally produced higher yields than the less-intensive systems (IH and PH) during this period. Except for a drop in yield in the TR system in year 10, ‘Golden Delicious’ trees ≥8 years old in all systems produced >50 t·ha−1. ‘Topred’ in the TR system outyielded IH and PH every year, while IH had higher yields than PH in three out of the eight cropping years. The spur-type cultivars Sundale and Millersturdeespur had lower yields per hectare than the standard-habit cultivars because they were spaced too widely. Yields of the systems with ‘Sundale’ generally followed plant density, with the SS being highest, IH lowest, and TR in between and often not significantly different from the other two systems. Orchard management systems had no consistent effects on fruit size. The cumulative yield per hectare of ‘Golden Delicious’ over 11 years grown as SS outproduced the IH and PH systems, with the TR yields intermediate. ‘Sundale’ managed as SS outproduced both the TR and IH systems. ‘Topred’ in the TR had higher cumulative yields per hectare than the PH system. An economic comparison of the ‘Golden Delicious’ systems indicated that PH provided the highest rate of return and the SS the lowest, with the IH and TR systems intermediate.

Open Access

Three peach [Prunus persica (L.) Batsch] rootstock plantings were monitored for date and rate of bloom during Spring 1989 and 1990 to determine if the time of scion bloom on different rootstocks is determined by the date of initiation of bud growth in the spring or by the duration of a particular bud stage. Included were a 1984 planting of `Redhaven' on eight rootstocks, a 1984 planting of `Rio-Oso-Gem' and `Loring', each on 11 rootstocks, and a 1986 planting of `Encore' on 18 rootstocks. The effect of rootstock on bud phenology was consistent within scion cultivar over two extremely different spring temperature profiles. In `Redhaven' and `Rio-Oso-Gem', rootstocks affected the dates but not the rates of bud development. Rootstocks affected both the dates and rates of `Loring' and `Encore' bud development. No consistent effect of rootstock on yield could be associated with delayed bud development in `Rio-Oso-Gem', `Redhaven', or `Loring'; however, delayed bud development of `Encore' on `Okinawa' x `Cardinal' and 62325 resulted in enhanced yield following spring frosts.

Free access

which cacao beans were dried until water content was ≈8%. The percentage of healthy pods (no disease observed), total dry weight (grams), yield potential (calculation of hypothetical total yield equivalent to sum of healthy and diseased pods), production

Free access

extended shelf life that reduce postharvest losses could increase production efficiency by reducing the frequency of product replacement in the marketplace. This is often difficult to achieve because there are few reports on the genetics of postharvest

Free access

Interploid hybridization was conducted using `Key' lime [Citrus aurantifolia (Cristm.) Swing.], `Lakeland' limequat hybrid [C. aurantifolia × Fortunella japonica (Thumb.) Swing.], Palestine sweet lime (C. limettioides Tan.), `Etrog' citron (C. medica L.), and seven lemon [C. limon (L.) Burm. F.] varieties as female progenitors and five allotetraploid somatic hybrids {`Hamlin' sweet orange [C. sinensis (L.) Osbeck] × `Femminello' lemon (C. limon)]; `Key' lime × `Valencia' sweet orange (C. sinensis); `Valencia' sweet orange × rough lemon (C. jambhiri Lush); Milam lemon (purported C. jambhiri hybrid) × `Femminello' lemon (C. limon); and `Valencia' sweet orange × `Femminello' lemon} and two autotetraploids [`Giant Key' lime (C. aurantifolia) and `Femminello' lemon] as pollen progenitors. A few tetraploid × diploid crosses were also performed. Thirty-five parental cross combinations were accomplished in 2000, 2001, and 2002. The breeding targets were seedlessness, cold-tolerance, and disease resistance. Triploid hybrids were recovered through embryo culture. Generation of triploid citrus hybrids was affected by several factors including sexual compatibility, cross direction, embryo developmental stage, pollen viability, as well as horticultural practices and climatic conditions. Efficiency of triploid hybrid production was higher in diploid × tetraploid crosses than the reciprocal. Many more triploid hybrids were generated from lemon seed progenitors compared to the other acid citrus fruit progenitors. `Todo el Año', `Lisbon', and `Limonero Fino 49' showed the highest sexual compatibility. Embryo germination rate and normal plant recovery were also higher in lemons as compared to the other seed progenitors. Low winter temperatures might have affected the hybrid production efficiency from tropical acid fruit progenitors. A total of 650 hybrids (mostly triploid) were transferred to soil. The novel genetic combinations of these progenies should be valuable for the genetic improvement of acid citrus fruit (lemons and limes).

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Field experiments were conducted in 1996 and 1997 to examine the effects of plant density on yield and quality of fruit and seeds of muskmelons (Cucumis melo L.). Two open-pollinated cultivars, Noy Yizre'el (Ha'Ogen type) and TopMark (western U.S. shipper type), were grown at plant densities ranging from 0.5 to 16.0 plants/m2 under commercial conditions. The highest marketable fruit yields were achieved with plant densities of 2 to 4 plants/m2. In contrast, the highest seed yields were obtained at 8 to 12 plants/m2. Seed yield index [seed yield (g)/fruit yield (kg)] was used as a parameter to define seed production efficiency. High seed yield was closely related to high value of the seed yield index. High seed yield indexes resulted from high plant densities (up to 12 plants/m2), at which the crops produced many, but relatively small fruit. In all cases, the seed yield per fruit (seed number and seed size) increased with increasing fruit weight. However, the sum of the seed yield of two small fruit was always greater than the seed yield of one, double-sized fruit. There was a clear exception with extremely small fruit (<500 g), which produced both low seed yields and poor seed quality. A positive relationship was found between fruit size and seed size in both cultivars. Nevertheless, relatively small seeds (25 to 30 mg) extracted from relatively small fruit (500 to 1000 g) showed the best performance in terms of germination and emergence percentages and rates, and in the vegetative development vigor of the seedlings.

Free access

Abstract

A planting was established in 1964 and 1965 to evaluate the following ‘Delicious’ strains: ‘Red Prince’, ‘Jardine Red’, ‘Royal Red’, ‘Turner Red’, ‘Richared’, ‘Rogers Red’, ‘Gardner Red’, ‘Sturdeespur’, and ‘Starkrimson’, the last 2 being spur types. The strains have been evaluated through 1979. Leaf N, K, Ca and Mg levels varied among the strains but none was consistently different from another. The cumulative yield per tree from 1970 to 1979 was higher for all standard strains except ‘Red Prince’ than for the spur strains. Theoretical cumulative yield per hectare was highest for ‘Sturdeespur’ and significantly higher than all other cultivars with the exception of ‘Turner Red’. ‘Sturdeespur’ had the highest production efficiency. Watercore severity at harvest was inconsistent among the strains, but in 3 of 4 years fewer ‘Starkrimson’ fruits were affected.

Open Access

Abstract

The performance of ‘Marsh’ grapefruit (Citrus paradisi Macf.) and ‘Valencia’ sweet orange [C. sinensis (L.) Osb.] on 18 rootstocks was evaluated with trees spaced 3.1 × 4.6 m and planted in 1968 in a deep, sandy soil. Rootstocks had significant effects on tree size, yield, production efficiency (kg of fruit/m3 of canopy), fruit quality and the quantity of soluble solids/tree. The largest, most productive trees were generally those on rough lemon (C. jambhiri Lush.) in contrast to the smallest trees on the hybrid C. sunki Hort. ex Tanaka × Swingle trifoliate orange (Poncirus trifoliata Raf.). Rootstocks that showed promise for use in close-spaced plantings were Rubidoux trifoliate orange, Rusk citrange (P. trifoliata × C. sinensis) Koethen sweet orange × Rubidoux, Rangpur lime (C. limonia Osb.) × Troyer citrange, and a mandarin.

Open Access