New Zealand Journal of Crop and Horticultural Science, Sep 1, 1995
Eighteen‐year‐old, top‐dominant central leader trees of ‘Granny Smith’ apple (Malus domestica Bor... more Eighteen‐year‐old, top‐dominant central leader trees of ‘Granny Smith’ apple (Malus domestica Borkh.) were restructured during the 1987 and 1988 dormant seasons into either palmette central leader (initially) or pyramid central leader forms. In the palmette form, pruning was restricted to the total removal of the uppermost east‐ and west‐facing fruiting scaffolds in 1987, and the shortening of all middle scaffolds
Spurs were collected periodically throughout three growing seasons from the 1-year-old section of... more Spurs were collected periodically throughout three growing seasons from the 1-year-old section of wood of `Royal Gala' trees growing in New Zealand. Three classes of spurs were sampled: purely vegetative spurs, those that flowered but did not carry fruit, and spurs on which a single fruit was borne. The bourse bud, in which flowers may form for the following year's crop, was dissected and bud appendages classified and counted. In addition, axillary buds from current-season shoots were sampled and dissected. Over the period 50–200 days after full bloom, the number of appendages in buds on vegetative spurs increased from ≈14 to 22, whereas the increase in buds on fruiting spurs was 14 to 20. In contrast, axillary bud appendage numbers increased from ≈11 to 14 over this period. By the end of the growing season, flowers were evident in a high proportion of buds of all classes. The critical appendage number at which the change from a vegetative to floral status became visible was...
Fruit growth and development are physiological processes controlled by several internal and exter... more Fruit growth and development are physiological processes controlled by several internal and external factors. This complex regulatory mechanism comprises a series of events occurring in a chronological order over a growing season. Understanding the underlying mechanism of fruit development events, however, requires consideration of the events occurring prior to fruit development such as flowering, pollination, fertilization, and fruit set. Such events are interrelated and occur in a sequential order. Recent advances in high-throughput sequencing technology in conjunction with improved statistical and computational methods have empowered science to identify some of the major molecular components and mechanisms involved in the regulation of fruit growth and have supplied encouraging successes in associating genotypic differentiation with phenotypic observations. As a result, multiple approaches have been developed to dissect such complex regulatory machinery and understand the genetic...
Pollination is an important factor in growing fruits and nuts, since for most of these crops poll... more Pollination is an important factor in growing fruits and nuts, since for most of these crops pollination is a prerequisite for fruit production. Pollination is the transfer of pollen from the stamen, or male part of a flower, to the pistil, or female part of a flower. Pollen is transferred by wind, splashing rain, moths, butterflies, birds, or honey-bees, depending on the plant species. Most fruit trees are pollinated primarily by bees, while most nut trees are pollinated primarily by wind. The agent of pollen transfer (for example, a bee) is called the "pollinator" whereas the "pollinizer" is the source of pollen. After pollination occurs, the pollen grain must germinate and grow into the ovary of the flower where the male pollen cell unites with the female egg cell in a process called fertilization. The success of pollination and fertilization depends upon the favorable environmental conditions as well as the right pollen grain reaching the pistil of the right ...
Plantings State/Province Cooperators 2 1995 1999 AL H AR Curt Rom* Donn Johnson Ron McNew Pat Fen... more Plantings State/Province Cooperators 2 1995 1999 AL H AR Curt Rom* Donn Johnson Ron McNew Pat Fenn CT-NH Victoria L. Smith* P P GA Dan Horton* Kathryn Taylor H,P ID Esmaeil Fallahi* Krishna Mohan P IN Peter Hirst* Rick Foster Paul Pecknold H KY Joseph Masabni MA Duane Greene* Wes Autio Jon Clements Dan Cooley H H,P ME Renae Moran* H MI George Sundin* Phil Schwallier R. Beaudry Greg Lang H,P H,P,P MO W. Hal Schaffer* M. Warmund H H NC Dick Unrath* J. Obermiller M. Parker H NH William Lord* H H NJ Win Cowgill* Bob Belding Bill Tietjen Joe Goffreda Dean Polk H
It is believed that gibberellins (GA) produced in apple seeds act as an inhibitory signal to flow... more It is believed that gibberellins (GA) produced in apple seeds act as an inhibitory signal to flower induction in the neighboring buds. The alternate bearing behavior of an apple cultivar is therefore likely to be associated with the activity of endogenous GAs in the seeds of that cultivar. To elucidate the impact of GAs on the flowering of biennial and non-biennial apple cultivars, fruits were sampled from `Fuji' (biennial, on-year) and `Gala' (non-biennial) trees periodically during the early part of the growing season. Seeds were removed from fruits immediately, frozen in liquid Nitrogen and freeze dried. Full scan analysis for GAs using GC-MS identified 16 GAs: GA1, GA3, GA4, GA7, GA20, GA31, GA34, GA35, GA44, GA50, GA54, GA61, GA63, GA68, GA80, and GA88. In addition, we also traced a number of GA-like mass spectra that do not match any published GA mass spectrum reference. The possible structures of these GA-like compounds were also proposed. More types of GAs were found...
Buds were sampled from nonflowering spurs on 1-year-old wood of 10 apple cultivars during the 200... more Buds were sampled from nonflowering spurs on 1-year-old wood of 10 apple cultivars during the 2004 growing season and dissected to determine floral commitment and morphogenesis. Dissected buds were classified into five stages based on floral bud morphogenesis. The 10 cultivars differed in their patterns of floral commitment and morphogenesis. At the end of the growing season, the proportion of floral buds was 30% to 100% depending on cultivar. The probability of observing doming, indicating floral commitment, was from 5% to 50% depending on cultivar, with `NJ90' (50%), `Zestar' (30%), and `CQR10T17' (30%) rated among the highest. The lowest probability (5%) was with `Ambrosia', `Pinova', and `Silken'. The time of a peak of floral commitment was earliest in `Delblush' and `CQR10T17' and latest in `Sundance'™ and `Pinova'. Most cultivars exhibited a single peak of floral commitment, except for `Pink Lady' in which two peaks were present. The...
Journal of the American Society for Horticultural Science
Irregular flowering and biennial bearing are challenging in many apple (Malus ×domestica) cultiva... more Irregular flowering and biennial bearing are challenging in many apple (Malus ×domestica) cultivars such as Honeycrisp. Apple flowering is influenced by many factors including crop load, fruit weight, seed number, and bourse shoot length. However, it is unclear how these factors exert their control. We investigated flowering in ‘Honeycrisp’ and whether flower formation is regulated locally within the spur or if it is under the control of the whole tree system. Treatments consisting of 30 to 240 fruit per tree with one or two fruit per spur were applied, and seed number, fruit weight, bourse shoot length, bourse number, and resulting flower formation measured. In 2013, flowering was affected by fruit number per tree, fruit number per spur and their interaction, and with lower total tree crop loads, spurs bearing two fruit had fewer flowers than those with a single fruit. In 2014, few spurs formed flowers regardless of treatment. In 2013, flowering was unaffected by seed number on sin...
Pollination is an essential prerequisite for the production of many fruit and seed crops, includi... more Pollination is an essential prerequisite for the production of many fruit and seed crops, including apple. In apple, successful fertilization requires pollen transfer to the stigma, pollen germination, and successful pollen tube growth resulting in fruit set. Precise selection of the most effective pollinizers for commercial orchards is not possible however, until these processes are more fully understood. The present study was undertaken to compare pollinizers in terms of pollen tube growth and fruit set. On trees of ‘Honeycrisp’, ‘Fuji’, and ‘Gala’ from which bees were excluded, flowers were hand-pollinated using pollen collected from crabapple (‘Ralph Shay’ or Malus floribunda), ‘Delicious’ and ‘Golden Delicious’. Flowers were harvested at one, two, three, and four days after pollination (DAP). Pollen source had a significant influence on pollen germination on the stigmatic surface, number of pollen tubes penetrating the stigma, distance of pollen tube growth down the style, and ...
One way in which rootstocks may influence production efficiency is by altering the number of spur... more One way in which rootstocks may influence production efficiency is by altering the number of spurs, and in particular reproductive spurs. However, rootstock influences on the morpholgy of shoots have not been quantified. Measurements were made on `Starkspur Supreme Delicious' trees growing on 17 rootstocks and planted in 1984 as part of the NC-140 regional rootstock trial. In each of the 6 years from 1988-1993, the length of the 2-year old section of wood of selected branches was measured and the number of spurs, flowers and shoots counted. For all rootstocks, trunk cross-sectional area was closely related to shoot length. Trees on P.22 (the most dwarfing rootstock in the planting) had shoot lengths 40-50% of those of trees on seedling rootstocks. For each rootstock, there was a strong negative relationship between shoot length and spur density, but there was not a common relationship among rootstocks. Similarly, flower number per shoot was also related to shoot length with diff...
Journal of the American Society for Horticultural Science, 1995
In each of 3 years, vegetative spurs were sampled from l-year-old wood of `Starkspur Supreme Deli... more In each of 3 years, vegetative spurs were sampled from l-year-old wood of `Starkspur Supreme Delicious' apple trees (Malus domestica Borkh.) growing on B.9, M.26 EMLA, M.7 EMLA, P.18, and seedling rootstocks. Mineral concentrations of spur leaves and bud apical meristems were determined, and related to spur bud development. The spur leaf P concentration decreased during the growing season each year, hut was unaffected by rootstock. Spur leaves of trees on B.9 rootstock had 30% higher Ca concentrations than trees on M.26 EMLA or seedling rootstocks. In each year, trees growing on M.26 EMLA rootstocks had the highest leaf Mg concentrations. Mineral concentrations were generally unrelated to spur leaf number, leaf area, leaf dry weight, or specific leaf weight. Phosphorus concentrations in spur bud apical meristems declined during two of the three growing seasons of the study and were unaffected by rootstock. Bud P concentration was weakly negatively related to bud diameter and bud...
Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the pop... more Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the population level. Seed samples were collected from four provenances in China and examined for variations in morphometric traits, chemical components, and seedling growth in the nursery stage. There were significant differences in the seed length, width, dry weight, 1000-seed weight, oil concentration, Mg and Cu concentrations, root biomass, and root–stem biomass ratio. The largest seed in terms of size and weight was from Ongniud Banner, Inner Mongolia (OB), but these seeds also had the lowest seed oil concentration. At the end of the first growing season in the nursery, seedlings stopped growing one month earlier in height than in diameter. The provenance difference in height was significant at the first 2 months after sowing but disappeared later. Genotypic variance (Vg) was found to be higher than corresponding environmental (Ve) variance for seed length, seed width, seed dry weight, 100...
Journal of the American Society for Horticultural Science
Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major ch... more Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major challenge for apple industries around the world. ‘Honeycrisp’ is a high value apple cultivar, but consistent flowering is difficult to achieve. Apple flower formation is affected by factors including defoliation, girdling, and gibberellin (GA4+7) and 1-naphthaleneacetic acid (NAA) applications. However, the molecular mechanisms that regulate the effects of these factors are not well understood. We studied the effect of local spur defoliation, GA4+7 and NAA applications on ‘Honeycrisp’ flower formation. Furthermore, we investigated the effect of local defoliation and local GA4+7 application on the transcript levels of two major flower formation genes in the meristems of apple spurs. The floral inhibition gene terminal flower1-1 (MdTFL1-1) and floral promoting genes flowering locus T (MdFT1 and MdFT 2) of apple. Local application of GA4+7 and defoliation treatments inhibited flower formation...
New Zealand Journal of Crop and Horticultural Science, Sep 1, 1995
Eighteen‐year‐old, top‐dominant central leader trees of ‘Granny Smith’ apple (Malus domestica Bor... more Eighteen‐year‐old, top‐dominant central leader trees of ‘Granny Smith’ apple (Malus domestica Borkh.) were restructured during the 1987 and 1988 dormant seasons into either palmette central leader (initially) or pyramid central leader forms. In the palmette form, pruning was restricted to the total removal of the uppermost east‐ and west‐facing fruiting scaffolds in 1987, and the shortening of all middle scaffolds
Spurs were collected periodically throughout three growing seasons from the 1-year-old section of... more Spurs were collected periodically throughout three growing seasons from the 1-year-old section of wood of `Royal Gala' trees growing in New Zealand. Three classes of spurs were sampled: purely vegetative spurs, those that flowered but did not carry fruit, and spurs on which a single fruit was borne. The bourse bud, in which flowers may form for the following year's crop, was dissected and bud appendages classified and counted. In addition, axillary buds from current-season shoots were sampled and dissected. Over the period 50–200 days after full bloom, the number of appendages in buds on vegetative spurs increased from ≈14 to 22, whereas the increase in buds on fruiting spurs was 14 to 20. In contrast, axillary bud appendage numbers increased from ≈11 to 14 over this period. By the end of the growing season, flowers were evident in a high proportion of buds of all classes. The critical appendage number at which the change from a vegetative to floral status became visible was...
Fruit growth and development are physiological processes controlled by several internal and exter... more Fruit growth and development are physiological processes controlled by several internal and external factors. This complex regulatory mechanism comprises a series of events occurring in a chronological order over a growing season. Understanding the underlying mechanism of fruit development events, however, requires consideration of the events occurring prior to fruit development such as flowering, pollination, fertilization, and fruit set. Such events are interrelated and occur in a sequential order. Recent advances in high-throughput sequencing technology in conjunction with improved statistical and computational methods have empowered science to identify some of the major molecular components and mechanisms involved in the regulation of fruit growth and have supplied encouraging successes in associating genotypic differentiation with phenotypic observations. As a result, multiple approaches have been developed to dissect such complex regulatory machinery and understand the genetic...
Pollination is an important factor in growing fruits and nuts, since for most of these crops poll... more Pollination is an important factor in growing fruits and nuts, since for most of these crops pollination is a prerequisite for fruit production. Pollination is the transfer of pollen from the stamen, or male part of a flower, to the pistil, or female part of a flower. Pollen is transferred by wind, splashing rain, moths, butterflies, birds, or honey-bees, depending on the plant species. Most fruit trees are pollinated primarily by bees, while most nut trees are pollinated primarily by wind. The agent of pollen transfer (for example, a bee) is called the "pollinator" whereas the "pollinizer" is the source of pollen. After pollination occurs, the pollen grain must germinate and grow into the ovary of the flower where the male pollen cell unites with the female egg cell in a process called fertilization. The success of pollination and fertilization depends upon the favorable environmental conditions as well as the right pollen grain reaching the pistil of the right ...
Plantings State/Province Cooperators 2 1995 1999 AL H AR Curt Rom* Donn Johnson Ron McNew Pat Fen... more Plantings State/Province Cooperators 2 1995 1999 AL H AR Curt Rom* Donn Johnson Ron McNew Pat Fenn CT-NH Victoria L. Smith* P P GA Dan Horton* Kathryn Taylor H,P ID Esmaeil Fallahi* Krishna Mohan P IN Peter Hirst* Rick Foster Paul Pecknold H KY Joseph Masabni MA Duane Greene* Wes Autio Jon Clements Dan Cooley H H,P ME Renae Moran* H MI George Sundin* Phil Schwallier R. Beaudry Greg Lang H,P H,P,P MO W. Hal Schaffer* M. Warmund H H NC Dick Unrath* J. Obermiller M. Parker H NH William Lord* H H NJ Win Cowgill* Bob Belding Bill Tietjen Joe Goffreda Dean Polk H
It is believed that gibberellins (GA) produced in apple seeds act as an inhibitory signal to flow... more It is believed that gibberellins (GA) produced in apple seeds act as an inhibitory signal to flower induction in the neighboring buds. The alternate bearing behavior of an apple cultivar is therefore likely to be associated with the activity of endogenous GAs in the seeds of that cultivar. To elucidate the impact of GAs on the flowering of biennial and non-biennial apple cultivars, fruits were sampled from `Fuji' (biennial, on-year) and `Gala' (non-biennial) trees periodically during the early part of the growing season. Seeds were removed from fruits immediately, frozen in liquid Nitrogen and freeze dried. Full scan analysis for GAs using GC-MS identified 16 GAs: GA1, GA3, GA4, GA7, GA20, GA31, GA34, GA35, GA44, GA50, GA54, GA61, GA63, GA68, GA80, and GA88. In addition, we also traced a number of GA-like mass spectra that do not match any published GA mass spectrum reference. The possible structures of these GA-like compounds were also proposed. More types of GAs were found...
Buds were sampled from nonflowering spurs on 1-year-old wood of 10 apple cultivars during the 200... more Buds were sampled from nonflowering spurs on 1-year-old wood of 10 apple cultivars during the 2004 growing season and dissected to determine floral commitment and morphogenesis. Dissected buds were classified into five stages based on floral bud morphogenesis. The 10 cultivars differed in their patterns of floral commitment and morphogenesis. At the end of the growing season, the proportion of floral buds was 30% to 100% depending on cultivar. The probability of observing doming, indicating floral commitment, was from 5% to 50% depending on cultivar, with `NJ90' (50%), `Zestar' (30%), and `CQR10T17' (30%) rated among the highest. The lowest probability (5%) was with `Ambrosia', `Pinova', and `Silken'. The time of a peak of floral commitment was earliest in `Delblush' and `CQR10T17' and latest in `Sundance'™ and `Pinova'. Most cultivars exhibited a single peak of floral commitment, except for `Pink Lady' in which two peaks were present. The...
Journal of the American Society for Horticultural Science
Irregular flowering and biennial bearing are challenging in many apple (Malus ×domestica) cultiva... more Irregular flowering and biennial bearing are challenging in many apple (Malus ×domestica) cultivars such as Honeycrisp. Apple flowering is influenced by many factors including crop load, fruit weight, seed number, and bourse shoot length. However, it is unclear how these factors exert their control. We investigated flowering in ‘Honeycrisp’ and whether flower formation is regulated locally within the spur or if it is under the control of the whole tree system. Treatments consisting of 30 to 240 fruit per tree with one or two fruit per spur were applied, and seed number, fruit weight, bourse shoot length, bourse number, and resulting flower formation measured. In 2013, flowering was affected by fruit number per tree, fruit number per spur and their interaction, and with lower total tree crop loads, spurs bearing two fruit had fewer flowers than those with a single fruit. In 2014, few spurs formed flowers regardless of treatment. In 2013, flowering was unaffected by seed number on sin...
Pollination is an essential prerequisite for the production of many fruit and seed crops, includi... more Pollination is an essential prerequisite for the production of many fruit and seed crops, including apple. In apple, successful fertilization requires pollen transfer to the stigma, pollen germination, and successful pollen tube growth resulting in fruit set. Precise selection of the most effective pollinizers for commercial orchards is not possible however, until these processes are more fully understood. The present study was undertaken to compare pollinizers in terms of pollen tube growth and fruit set. On trees of ‘Honeycrisp’, ‘Fuji’, and ‘Gala’ from which bees were excluded, flowers were hand-pollinated using pollen collected from crabapple (‘Ralph Shay’ or Malus floribunda), ‘Delicious’ and ‘Golden Delicious’. Flowers were harvested at one, two, three, and four days after pollination (DAP). Pollen source had a significant influence on pollen germination on the stigmatic surface, number of pollen tubes penetrating the stigma, distance of pollen tube growth down the style, and ...
One way in which rootstocks may influence production efficiency is by altering the number of spur... more One way in which rootstocks may influence production efficiency is by altering the number of spurs, and in particular reproductive spurs. However, rootstock influences on the morpholgy of shoots have not been quantified. Measurements were made on `Starkspur Supreme Delicious' trees growing on 17 rootstocks and planted in 1984 as part of the NC-140 regional rootstock trial. In each of the 6 years from 1988-1993, the length of the 2-year old section of wood of selected branches was measured and the number of spurs, flowers and shoots counted. For all rootstocks, trunk cross-sectional area was closely related to shoot length. Trees on P.22 (the most dwarfing rootstock in the planting) had shoot lengths 40-50% of those of trees on seedling rootstocks. For each rootstock, there was a strong negative relationship between shoot length and spur density, but there was not a common relationship among rootstocks. Similarly, flower number per shoot was also related to shoot length with diff...
Journal of the American Society for Horticultural Science, 1995
In each of 3 years, vegetative spurs were sampled from l-year-old wood of `Starkspur Supreme Deli... more In each of 3 years, vegetative spurs were sampled from l-year-old wood of `Starkspur Supreme Delicious' apple trees (Malus domestica Borkh.) growing on B.9, M.26 EMLA, M.7 EMLA, P.18, and seedling rootstocks. Mineral concentrations of spur leaves and bud apical meristems were determined, and related to spur bud development. The spur leaf P concentration decreased during the growing season each year, hut was unaffected by rootstock. Spur leaves of trees on B.9 rootstock had 30% higher Ca concentrations than trees on M.26 EMLA or seedling rootstocks. In each year, trees growing on M.26 EMLA rootstocks had the highest leaf Mg concentrations. Mineral concentrations were generally unrelated to spur leaf number, leaf area, leaf dry weight, or specific leaf weight. Phosphorus concentrations in spur bud apical meristems declined during two of the three growing seasons of the study and were unaffected by rootstock. Bud P concentration was weakly negatively related to bud diameter and bud...
Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the pop... more Variability in seed and seedling traits of Xanthoceras sorbifolium Bunge was evaluated at the population level. Seed samples were collected from four provenances in China and examined for variations in morphometric traits, chemical components, and seedling growth in the nursery stage. There were significant differences in the seed length, width, dry weight, 1000-seed weight, oil concentration, Mg and Cu concentrations, root biomass, and root–stem biomass ratio. The largest seed in terms of size and weight was from Ongniud Banner, Inner Mongolia (OB), but these seeds also had the lowest seed oil concentration. At the end of the first growing season in the nursery, seedlings stopped growing one month earlier in height than in diameter. The provenance difference in height was significant at the first 2 months after sowing but disappeared later. Genotypic variance (Vg) was found to be higher than corresponding environmental (Ve) variance for seed length, seed width, seed dry weight, 100...
Journal of the American Society for Horticultural Science
Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major ch... more Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major challenge for apple industries around the world. ‘Honeycrisp’ is a high value apple cultivar, but consistent flowering is difficult to achieve. Apple flower formation is affected by factors including defoliation, girdling, and gibberellin (GA4+7) and 1-naphthaleneacetic acid (NAA) applications. However, the molecular mechanisms that regulate the effects of these factors are not well understood. We studied the effect of local spur defoliation, GA4+7 and NAA applications on ‘Honeycrisp’ flower formation. Furthermore, we investigated the effect of local defoliation and local GA4+7 application on the transcript levels of two major flower formation genes in the meristems of apple spurs. The floral inhibition gene terminal flower1-1 (MdTFL1-1) and floral promoting genes flowering locus T (MdFT1 and MdFT 2) of apple. Local application of GA4+7 and defoliation treatments inhibited flower formation...
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