Larger Trunk Cross-sectional Area Research Articles

Branch Configuration Impacts on Production, Fruit Quality, and Leaf Minerals of ‘Aztec Fuji’ Apple Trees in an Upright Single Row High-Density Orchard System Over Five Years

Tree architectures play a critical role in the productivity of high-density orchards, but limited information is available in this subject. We studied effects of three branch configurations on tree growth, yield components, fruit quality and leaf mineral nutrients in ‘Aztec Fuji’ apple (Malus domestica Bork.) in a single row upright high-density system under southwest Idaho, USA conditions over 2012-2016. This study revealed that trees trained into a Tall Spindle (TS) had larger trunk cross sectional area (TCSA) than those with an Overlapped Arm (OA) system. Trees trained into a TS had higher number of fruit and yield per tree, three years after planting in 2012, than those with a Tipping Arm (TA) or OA system. However, in 2013, trees with a TA system had higher yield than those with a TS or OA configuration due to trees’ biennial bearing habit and higher spur formation in trees with a TA system. Trees receiving a TA training had lower biennial bearing index between all consecutive years. Trees with an OA training had smaller fruit than those with either a TA or TS training in all years between 2012-2016. Training systems did not have any effect on fruit color, soluble solids concentration, or starch degradation pattern at harvest. However, fruit from trees with an OA training had higher firmness and lower water core than those from trees with a TS or TA training. Leaves from trees receiving a TA training had greater leaf area, fresh weight, and potassium (K) and magnesium (Mn) concentrations than those with other trainings. Leaves from trees receiving an OA training had higher leaf iron (Fe), zinc (Zn), and copper (Cu) than those with a TS training. In this study, we concluded that training trees into a TA configuration rather than an OA system is recommended if the management and operation of apple production mandate the use of an “upright wall” structure to facilitate mechanical harvesting.

Interaction of Irrigation and Soil Management on Sweet Cherry Productivity and Fruit Quality at Different Crop Loads that Simulate Those Occurring by Environmental Extremes

‘Cristalina’ and ‘Skeena’ sweet cherry cultivars (Prunus avium L.) on Gisela 6 (Prunus cerasus × Prunus canescens) rootstock planted in 2005 were maintained since 2006 in a randomly blocked split-split plot experimental design with six blocks of two irrigation frequency main plot treatments within which two cultivar subplots and three soil management sub-subplots were randomly applied. The focus of this study was the growth, yield, and fruit quality response of sweet cherry to water and soil management over three successive fruiting seasons, 2009–11, in a cold climate production area. The final 2 years of the study period were characterized by cool, wet springs resulting in low yield and yield efficiency across all treatments. Soil moisture content (0- to 20-cm depth) during the growing season was often higher in soils that received high-frequency irrigation (HFI) compared with low-frequency irrigation (LFI). HFI and LFI received the same amount of water, but water was applied four times daily in the HFI treatment but every other day in the LFI treatment. Consequently, larger trunk cross-sectional area (TCSA) and higher yield were found on HFI compared with LFI trees. Soil management strategies involving annual bloom time phosphorus (P) fertigation and wood waste mulching did not affect tree vigor and yield. Increased soluble solids concentration (SSC) occurred with LFI. Decreased SSC occurred with delayed harvest maturity in trees receiving P fertigation at bloom. The largest fruit size was correlated for both cultivars with low crop loads ranging from 100 to 200 g fruit/cm2 TCSA. Overall cool, wet spring weather strongly affected annual yield and fruit quality, often overriding cultivar and soil and water management effects.

Postharvest Fruit Quality and Growth of ‘Pacific Gala’ Apple Trees at Different Ages as Influenced by Irrigation and Rootstock

The effects of four rootstocks and two irrigation systems on tree growth, and fruit quality after storage in ‘Pacific Gala’ apple [(Malus × domestica) Borkh] were examined. Trees on ‘Budagovsky 9’ (‘B.9’) had a smaller trunk cross sectional area (TCA) and higher yield efficiency, while those on ‘Supporter4’ (‘Sup.4’) had larger TCA and lower yield efficiency than those on other rootstocks. Trees on ‘Nic.29’ (‘RN29’) had higher yield per tree as compared to those on other rootstocks. Trees on ‘RN29’ often had higher fruit weight, while trees on ‘B.9’ had lower fruit weight than did those on other rootstocks. Trees on ‘Sup.4’had lower yields and smaller fruits than those on ‘RN29’ every year. Fruits from trees on ‘B.9’ and ‘Cornell-Geneva30’ (‘CG.30’) often had higher soluble solids concentration (SSC) than other rootstocks at harvest and after storage. Fruits from trees on ‘CG.30’ also had higher fruit spoilage after storage. Trees with full sprinkler (FS) irrigation had higher TCA than those with the full drip (FD) system. ‘Gala’ fruit from trees with FS consistently had better color than those with the FD system every year.

Irrigation and Rootstock Influence on Water Use, Tree Growth, Yield, and Fruit Quality at Harvest at Different Ages of Trees in ‘Pacific Gala’ Apple

During various ages of tree between 2002 and 2007, the effects of four rootstocks and two irrigation systems using a crop evapotranspiration-based (ETc) water scheduling on water use, tree growth, yield, and fruit quality at harvest in ‘Pacific Gala’ apple [(Malus ×domestica) Borkh] were studied. The use of ETc when a precise crop coefficient value (Kc), modified by percentage of ground shade (GS) and tree canopy maturity (M) was used, provided a reliable tool for irrigation scheduling of ‘Pacific Gala’ apple. Young trees with a full sprinkler (FS) system received an average of 872.3 mm (5616.8 L/tree), whereas those with full drip (FD) received 448.9 mm (2921.1 L/tree). However, when trees were mature, trees with a FS system received an average of 994 mm (6461.7 L/tree), whereas trees with a FD received 614.1 mm (3996 L/tree) of irrigation water per growing season. Trees on ‘Budagovsky 9’ (‘B.9’) had smaller trunk cross-sectional area (TCA) and higher yield efficiency, whereas those on ‘Supporter4’ (‘Sup.4’) had larger TCA and lower yield efficiency than those on other rootstocks in all years of the study. Trees on ‘Nic.9’ (‘RN29’) always had higher yield per tree as compared with those on other rootstocks. Trees on ‘RN29’ often had higher but trees on ‘B.9’ had lower fruit weight than did those on other rootstocks. Trees on ‘Sup.4’, despite their lower yields, had smaller fruits than those on ‘RN29’ every year and thus were not suitable for planting. Fruit from trees on ‘B.9’ and ‘Cornell-Geneva30’ (‘G.30’) often had higher soluble solids concentration (SSC) and starch degradation pattern (SDP) than those other rootstocks. Fruits from trees on ‘G.30’ also had lower firmness and higher stem-end cracking, suggesting that this rootstock advances maturity in ‘Pacific Gala’ apple. Trees with FS irrigation had higher TCA than those with the FD system. Trees with the FD system were more precocious and had higher yield per tree, yield efficiency, and fruit weight than trees with the FS system when they were young. However, these differences were not significant when trees matured. ‘Pacific Gala’ fruit from trees with FS consistently had better color than those with the FD system every year. Fruits from young trees with the FD system often had higher SDP and lower firmness than those from FS irrigation.

Factors Affecting Establishment of Sweet Cherry on Gisela 6 Rootstock

Cristalina and Skeena sweet cherry cultivars (Prunus avium L.) on Gisela 6 (Prunus cerasus × Prunus canescens) rootstock were maintained for the first four growing seasons in a randomized, replicated split-split plot experimental design with two main plot irrigation frequency treatments, the two cultivars as subplots and three soil management subsubplot treatments. The same amount of irrigation water was applied through four drip emitters per tree at either high (I1, four times daily) or low frequency (I2, once every second day) beginning in the second year. Three different soil management treatments were established the year of planting and included: 1) NK fertigation with a herbicide strip (control), or additionally; 2) maintenance of a 10-cm thick bark mulch over the herbicide strip; and 3) annual fertigation of 20 g phosphorus (P) per tree per year immediately after bloom. I1 irrigation increased soil moisture (0- to 20-cm depth) throughout each growing season. The I1 irrigation resulted in higher leaf and fruit concentrations of the immobile nutrients P and potassium (K) and larger trunk cross-sectional area than I2 trees. I1 irrigation, in general, did not affect initial yield or fruit size. Fruit from I2 irrigation had higher soluble solids concentration (SSC), color, and total phenolic concentration at harvest in 2008 and lower titratable acidity (TA), firmness, and stem pull force suggesting an acceleration of fruit maturity. When compared with the control soil management treatment, P fertigation resulted in leaves and fruit with higher P concentrations, a higher 2008 crop yield, and a delay in 2008 crop maturity as indicated by lower harvest color and SSC and higher stem pull force. Mulch application, relative to control treatments, resulted in trees with higher vigor (but only with I1 irrigation) and leaf K concentration and had few effects on initial fruit yield or quality. There were important differences in cultivar responses to treatments. ‘Cristalina’ vigor was lower than ‘Skeena’ whose fruit had lower firmness and pedicel retention than ‘Cristalina’.

Effect of a Synthetic Fabric Row Cover on Soil Moisture Content, Growth and Fruiting of Young Sweet Cherry Trees (Prunus avium L. cv. `Regina'/Gisela 6)

A `Regina'/Gisela 6 sweet cherry orchard was planted in April 2001 to evaluate a row cover (RC) made of black, woven polypropylene fabric, in water conservation. Trees were trained to a central leader and planted at 3 m x 5.4 m. Soil water content and tree growth variables were compared for trees growing with or without a 2.4 m-wide RC. Irrigation of all trees replenished approximately 80% of weekly evaporation rate. Trees with RC maintained consistently higher (30% to 40%) soil moisture content at 30 cm depth than non-RC trees. In Spring 2003, trees in RC had significantly larger trunk cross sectional area (34%), height (7%), total wood length (65%), total number of branches (20%) and number of 1-year-old-shoots (45%) compared to trees with no row cover. Length of 1-year-old wood for trees in RC was two-fold that of non-covered trees. In Summer 2003, RC had no clear effect on bloom time, intensity or duration. Fruit yields were light and not affected by RC, but fruit size was slightly larger for trees in RC. Although trees were not fertilized, foliar nitrogen content was significantly higher and leaf green color was notably darker green for trees with RC. During Spring and Summer 2003, soil temperatures under RC at 5-cm and-10 cm depths were generally 1 °C to 2 °C warmer than in non-covered ground. The RC did not affect air temperature at 10 cm and 30 cm above ground. It is speculated that RC promoted tree growth by a combined increased available soil moisture and warmer root temperatures, which favor root development and nutrient uptake, particularly in the absence of competing weeds. Increased branching in trees with RC is unclear. It is possible that light quality above RC triggers developmental changes resulting in increased vegetative budbreak.

USE OF ORGANIC APPLICATIONS TO INCREASE PRODUCTIVITY OF HIGH DENSITY APPLE ORCHARDS

USE OF ORGANIC APPLICATIONS TO INCREASE PRODUCTIVITY OF HIGH DENSITY APPLE ORCHARDS

Tree Form and Heading Height at Planting Affect Peach Tree Yield and Crop Value

`Sweet Sue' peach (Prunus persica L. Batsch) trees were subjected to a factorial arrangement of treatments. At planting, trees were headed at 10 or 70 cm above the bud union and trees were trained to an open-vase or central-leader form. For the first 4 years, high-headed trees were larger than low-headed trees. After 7 years, open-vase trees had larger trunk cross-sectional area, tree spread, and canopy volume than central-leader trees. Open-vase trees had higher yield and crop value per tree, but lower yield and crop value per unit of land area or unit of canopy volume than central-leader trees. Crop density and yield efficiency were similar for all treatments.

Early Performance of Four Apple Cultivars on Mark and M.26 Rootstocks

To evaluate the interactions between cultivar and rootstock, four apple (Malus domestica Borkh.) cultivars, `Pioneer Mac', `Marshall McIntosh', `Ginger Gold', and `Empire' on two rootstocks, M.26 and Mark, were planted in a split-plot design. After 5 years, `Pioneer Mac' and `Ginger Gold' had larger trunk cross-sectional area (TCSA) on M.26 than on Mark. `Marshall McIntosh' and `Empire' had larger TCSA on Mark than on M.26. Precocity, expressed as both number of flower clusters and yield, was greater for trees on Mark for all cultivars except `Ginger Gold', which had greater flower cluster numbers and yield on M.26. Fruit size was variable from year to year, depending on crop load; however, `Pioneer Mac' and `Ginger Gold' usually produced the largest fruit, while `Empire' consistently produced the smallest fruit—'Ginger Gold' appears to be incompatible on Mark. The results of this study demonstrate that cultivar × rootstock interactions can be significant and need to be considered when rootstock and planting density recommendations are made.

Early Performance of Four Apple Cultivars on Mark and M.26 Rootstocks

To evaluate the interactions between cultivar and rootstock, four apple (Malus domestica Borkh.) cultivars, `Pioneer Mac', `Marshall McIntosh', `Ginger Gold', and `Empire' on two rootstocks, M.26 and Mark, were planted in a split-plot design. After 5 years, `Pioneer Mac' and `Ginger Gold' had larger trunk cross-sectional area (TCSA) on M.26 than on Mark. `Marshall McIntosh' and `Empire' had larger TCSA on Mark than on M.26. Precocity, expressed as both number of flower clusters and yield, was greater for trees on Mark for all cultivars except `Ginger Gold', which had greater flower cluster numbers and yield on M.26. Fruit size was variable from year to year, depending on crop load; however, `Pioneer Mac' and `Ginger Gold' usually produced the largest fruit, while `Empire' consistently produced the smallest fruit—'Ginger Gold' appears to be incompatible on Mark. The results of this study demonstrate that cultivar × rootstock interactions can be significant and need to be considered when rootstock and planting density recommendations are made.

Tree Growth and Productivity and Postharvest Fruit Quality in Various Strains of `Delicious' Apple

Twenty-six strains of `Delicious' apple (Malus domestica Borkh.) were evaluated over several years for growth, yield, and fruit quality at harvest and after 6 months of storage. `August Red', `Rose Red', and `Sharp Red' had larger trunk cross-sectional area (TCSA) 3 and 18 years after planting compared to most other strains. `August Red' and `Starking' had larger TCSA and cumulative yield. `Apex,' `Improved Ryan Spur', `Silverspur', `Starkrimson', and `Wellspur' were also among strains with high cumulative yields and yield efficiencies. `Hardi-Brite Spur' and `Red King Oregon Spur' had moderately high yields and small TCSAs, thus, high yield efficiencies. `Atwood', `Hardispur', `Imperial', `Improved Ryanred', `Starkspur Supreme', and `Topred' had low cumulative yields. `Ace' and `Improved Ryanred' had low yield efficiencies. `Ace', `Imperial', `Red King Oregon Spur', `Rose Red', `Starking', and `Wellspur' had heavier fruit, while fruit weight in `August Red', `Hardispur', and `Starkrimson' was lighter than that in most other strains. `Redspur' and `Starkspur Supreme' had the largest length to diameter (L/D) ratios. `Early Red One' had a similar red skin color rating as `Rose Red.' The red skin color rating of `Early Red One' was significantly higher than that of all other strains. `Hi-Early', `Improved Ryanred', `Redspur', and `Starking' had the poorest skin color ratings. `Hardispur', `Nured Royal', `Silverspur', and `Starkrimson' had high soluble solids concentrations (SSCs) at harvest and after storage. `Early Red One', `Imperial', `Improved Ryan Spur', and `Red King Oregon Spur' had lower SSCs at harvest and after storage. Fruit of `Apex' and `Redspur' had relatively high firmness at harvest, while `Hardispur', `Silverspur', `Starkrimson', and `Starkspur Supreme' had firm fruit at harvest and after storage. `Hardi-Brite Spur' had the softest fruit after storage, and fruit from `Rose Red' had a lower firmness than most other strains at harvest and after storage. Considering cumulative yield, yield efficiency, or some quality parameters, `Apex', `Classic Red', `Improved Ryan Spur', `Red King Oregon Spur', `Silverspur', and `Wellspur' had satisfactory overall performance. Strains are also suggested for planting depending on the market situation and the demand for a particular quality factor. `Hardispur' and `Sturdeespur' (Miller) are not recommended for planting under climatic conditions similar to those of this experiment.