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S. Kaan Kurtural, Lydia F. Wessner, and Geoffrey Dervishian

at harvest, and production efficiency of a procumbent cultivar in a warm climate region. Materials and Methods Vineyard description and experimental layout This study was conducted from 2009 to 2011 at a commercial vineyard planted with ‘Syrah

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Mikel R. Stevens, C. Frank Williams, Ronald H. Walser, Tim D. Davis, Von D. Jolley, and Sheldon D. Nelson

Abstract

A 2-year study involving 15 garden vegetables and 5 different-sized gardens was conducted to assess land, labor, and production efficiency. As garden size increased, total production increased, but yield per unit area decreased. Relative labor inputs varied with garden size, but were greatest for harvesting (38%) followed by planting (23%), miscellaneous (22%), and weeding (17%). The highest production in relationship to labor and land use was obtained with beets, carrots, cucumbers, onions, tomatoes, and summer squash. The poorest yielding crops were pole and bush beans, sweet corn, peas, peppers, and radishes. Total vegetable yield for the 2-year study averaged 6.2 kg/m2.

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D.D. Archbold, G.R. Brown, and P.L. Cornelius

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.

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Terence L. Robinson and Alan N. Lakso

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.

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Terence L. Robinson, Alan N. Lakso, and Zhongbo Ren

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K. Rachelle Goldman and Cary A. Mitchell

The day-neutral, semidwarf rice (Oryza sativa L.) cultivar Ai-Nan-Tsao was grown in a greenhouse under summer conditions using high-pressure sodium lamps to extend the natural photoperiod. After allowing 2 weeks for germination, stand establishment, and thinning to a consistent planting density of 212 plants/m2, stands were maintained under continuous lighting for 35 or 49 days before shifting to 8- or 12-h photoperiods until harvest 76 days after planting. Non-shifted control treatments consisting of 8-, 12-, or 24-h photoperiods also were maintained throughout production. Tiller number increased as duration of exposure to continuous light increased before shifting to shorter photoperiods. However, shoot harvest index and yield efficiency rate were lower for all plants receiving continuous light than for those under the 8- or 12-h photoperiods. Stands receiving 12-h photoperiods throughout production had the highest grain yield per plant and equaled the 8-h-photoperiod control plants for the lowest tiller number per plant. As long as stands were exposed to continuous light, tiller formation continued. Shifting to shorter photoperiods late in the cropping cycle resulted in newly formed tillers that were either sterile or unable to mature grain before harvest. Late-forming tillers also suppressed yield of grain in early-forming tillers, presumably by competing for photosynthate or for remobilized assimilate during senescence. Stands receiving 12-h photoperiods throughout production not only produced the highest grain yield at harvest but had the highest shoot harvest index, which is important for resource-recovery strategies in advanced life-support systems proposed for space.

Open access

C. G. Forshey and M. Wayne McKee

Abstract

There were no differences between a large (29.0 ft branch spread) and a small (10.5 ft branch spread) ‘McIntosh’ apple tree in total dry matter accumulated per unit of occupied land. However, the small tree produced 80.6% more fruit on a unit area basis. In terms of leaf efficiency, the small tree produced 60.4% more dry matter per unit weight of leaves than the large tree.

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David C. Ferree, Richard C. Funt, and Bert L. Bishop

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.

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Edward F. Durner and Joseph C. Goffreda

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.

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Michael P. Harvey and Mark H. Brand

Hakonechloa macra Makino 'Aureola' is an ornamental, shade tolerant landscape grass that grows slowly and commands high prices. Hakonechloa plants grown from four initial division sizes, of 1-2, 4-6, 8-10, or 12-15 tiller buds, were evaluated following a complete growing season (105 days). Based on visual observation, we rated 100% of plants grown from the two larger division sizes to be salable compared with only 30% of those from divisions containing 4-6 growing points, and none from the smallest division size. However, divisions of 1-2 tiller buds produced twice as many new shoots and tiller buds per initial tiller bud as did larger division sizes. To produce salable plants in one growing season, results suggest the use of 8-10 tiller bud divisions, but for propagation and increase of stock material, where it is important to obtain the greatest number of new growing points per initial growing point, use of the smaller division sizes is indicated. Hakonechloa plants were grown under shading densities of 0%, 30%, 50%, or 70% provided by polypropylene shade cloth. Shading increased overall growth and improved the appearance and leaf color of Hakonechloa, but at 70% shade density, plants appeared languid and open. For this reason, 50% shading is recommended for nursery production of Hakonechloa macra 'Aureola'.