Root-zone temperatures affect phenology of bud break, flower cluster development, shoot extension growth and gas exchange of 'Braeburn' (Malus domestica) apple trees

The effects of NAA, BA, or Accel on CO2 assimilation of shoot leaves of mature bearing Redchief `Delicious' and `Empire' apple (Malus ×domestica Borkh.) trees were evaluated over two seasons. BA at 50 mg·L-1 did not significantly affect any of the gas-exchange parameters measured. NAA (15 mg·L-1) consistently suppressed CO2 assimilation rate (from ≈10% to 24% below that of the control). This suppression was NAA-concentration dependent, continued for >15 days after treatment, and was completely overcome in `Empire', but only partially or not at all in `Delicious' when BA was combined with NAA. These results are discussed in relation to fruit thinning and NAA-induced inhibition of fruit growth in spur-type `Delicious'. Chemical names used: 2-(1-napthyl) acetic acid (NAA); N-(phenyl)-1H-purine-6-amine (BA); BA + gibberellin A (GA)4+7 (Accel).

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Mature `Starkrimson Delicious' Apple Tree Response to Paclobutrazol Application Method

HortScience ◽

10.21273/hortsci.25.4.429 ◽

1990 ◽

Vol 25 (4) ◽

pp. 429-430 ◽

Cited By ~ 1

Author(s):

Laura J. Lehman ◽

C.R. Unrath ◽

Eric Young

Keyword(s):

Malus Domestica ◽

Soil Cover ◽

Apple Tree ◽

Root Zone ◽

Fruit Weight ◽

Shoot Length ◽

Apple Trees ◽

Foliar Sprays ◽

Pedicel Length ◽

Shoot Number

Mature spur-type `Delicious'/seedling apple trees (Malus domestica Borkh.) were examined for 2 years after paclobutrazol (PB) foliar sprays with or without a soil cover to direct spray runoff away from the root zone, soil sprays, or a trunk drench. Foliar sprays with runoff reduced shoot number and fruit pedicel length in the year of treatment, but had no effect on shoot length. Trees that received foliar sprays with no runoff had fewer and shorter shoots and shorter pedicels the year after treatment. Soil sprays or a trunk drench reduced shoot number and pedicel length for 2 years after application, while only soil sprays reduced fruit weight, diameter, and length. Chemical name used: β- [(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)-1 H -1,2,4,-triazol-1-ethanol (paclobutrazol).

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Water-Related Variables for Predicting Yield of Apple under Deficit Irrigation

Horticulturae ◽

10.3390/horticulturae5010008 ◽

2019 ◽

Vol 5 (1) ◽

pp. 8 ◽

Cited By ~ 2

Author(s):

Riccardo Lo Bianco

Keyword(s):

Gas Exchange ◽

Linear Combination ◽

Water Use ◽

Deficit Irrigation ◽

Root Zone ◽

Water Status ◽

Transpiration Efficiency ◽

Apple Trees ◽

Tree Water Use ◽

Model Variability

Predicting apple yield in relation to tree water use is important for irrigation planning and evaluation. The aim of the present study was to identify measurable variables related to tree water use that could predict final fruit yield of apple trees under different strategies of deficit irrigation. Adult ‘Gala’ and ‘Fuji’ apple trees were exposed to conventional irrigation (CI), delivering 100% of crop evapotranspiration; partial root zone drying (PRD), delivering 50% of CI water only on one alternated side of the root-zone; and continuous deficit irrigation (CDI), delivering 50% of CI water on both sides of the root-zone. Integrals of soil (SWDint) and leaf (LWSDint) water deficit along with growth and stomatal conductance (Gsint) were calculated across each season and used to estimate total conductance (GStree) and transpiration (Trtree) per tree, transpiration efficiency on a fruit (GRfruit/Tr) or tree (GRtrunk/Tr) growth basis, and transpiration productivity (Yield/Trtree). ‘Fuji’ trees had higher Yield/Trtree, but had lower GRtrunk/Tr and similar GRfruit/Tr compared to ‘Gala’ trees. In ‘Fuji’, CDI reduced yield, trunk growth, leaf hydration, and gas exchange, while in ‘Gala’, it did not reduce yield and gas exchange. In ‘Fuji’, a linear combination of GRtrunk/Tr, GRfruit/Tr, and Gstree contributed to predicting yield, with GRfruit/Tr explaining nearly 78% of the model variability. In ‘Gala’, a linear combination of LWSDint and Gstree contributed to predicting yield, with Gstree explaining over 79% of the model variability. These results indicate that measuring tree water status or water use may help predict final apple yields only in those cultivars like ‘Gala’ that cannot limit dehydration by closing stomates because of carbon starvation. In more vigorous cultivars like ‘Fuji’, transpiration efficiency based on fruit growth can be a powerful predictor of final yields.

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Effects of dormancy factors on the growth of vegetative buds of young apple trees

Australian Journal of Agricultural Research ◽

10.1071/ar9750989 ◽

1975 ◽

Vol 26 (6) ◽

pp. 989 ◽

Cited By ~ 17

Author(s):

WK Thompson ◽

DL Jones ◽

DG Nichols

Keyword(s):

High Temperature ◽

Temperature Effects ◽

Extension Growth ◽

Bud Break ◽

Chilling Temperature ◽

Subsequent Growth ◽

Apple Trees ◽

Dormant Period ◽

Vegetative Buds ◽

Young Apple

Controlled temperature conditions were used to investigate the chilling requirements of potted 1-year-old apple trees cv. Jonathan. The rate of bud break, the number of buds growing and extension growth were increased by prior chilling. Temperature effects over the range 2–10°C were greatest at the lower end of the range. Chilling early in the dormant period was less effective than later chilling, and interruption of chilling with periods of high temperature reduced subsequent growth.

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Hybridisation of Malus sylvestris (L.) Mill. with Malus × domestica Borkh. and Implications for the Production of Forest Reproductive Material

Forests ◽

10.3390/f12030367 ◽

2021 ◽

Vol 12 (3) ◽

pp. 367

Author(s):

Mateja Kišek ◽

Kristjan Jarni ◽

Robert Brus

Keyword(s):

Malus Domestica ◽

Natural Populations ◽

Morphological Characteristics ◽

Apple Trees ◽

Genetic Characteristics ◽

Malus Domestica Borkh ◽

Malus Sylvestris ◽

Forest Reproductive Material ◽

Reproductive Material ◽

Crab Apple

This study focuses on the morphological and genetic characteristics of European crab apple (Malus sylvestris (L.) Mill.) and the occurrence of hybrids in its populations. We analyzed a total of 107 putative European crab apple trees in Slovenia: 92 from nine natural populations, five from a seed stand and 10 from a stand of unnatural origin. We also included 18 domesticated apple trees (Malus × domestica Borkh.) and two Japanese flowering crab apple trees (Malusfloribunda van Houtte) as outliers. The trees were classified into groups of European crab apples, hybrids and domesticated apples according to their morphological and genetic characteristics. Classification based on morphological traits produced different results (58.75% European crab apple, 37.11% hybrids and 4.14% domesticated apple) compared to those based on genetic analysis (70.10% European crab apple, 21.64% hybrids and 8.26% domesticated apple). When genetic and morphological characteristics were combined, only 40.20% of the trees were classified as European crab apple, and an additional group of feral cultivars of domesticated apples (6.18%) was identified. The analysis revealed that hybridization with domesticated apple is taking place in all studied natural European crab apple populations; however, hybrids and feral cultivars only occur to a limited extent. When introducing European crab apple into forests in the future, only genetically verified forest reproductive material obtained exclusively from suitable seed stands should be used.

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