Temperate Fuits Production in the Tropics: A Review on Apples in Kenya

Njuguna, Joseph; Wamocho, L. S.; Morelock, T.E.

doi:10.21273/hortsci.39.4.841a

Cited by 8 publications

(13 citation statements)

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“…Deciduous trees require exposure to low winter temperatures is called a chilling requirement to overcome dormancy and grow in the following spring (Howe et al, 1999 andArora et al, 2003). Also, Njuguna et al (2004) reported that, temperate zone fruit crops undergo bud dormancy which can be described as a mechanism for avoiding the exposure of tender flowers and leaves to low winter temperatures. The induction of dormancy occurs in response to seasonal environmental signals.…”

Section: Introductionmentioning

confidence: 99%

Metabolic Changes in Phenolic Compounds in Buds during and after Dormancy Releasing in early and late (<i>Malus sylvestris, </i>Mill) Apple Varieties as Effected by Chilling Requirements

El-Yazal

2021

ILNS

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In order to study the relation between seasonal changes in phenolic compounds and flower opining date according to chilling requirements. The early and late-opining apple varieties, Barkhar, Local and Strakhan (Malussylvestris) were used. This study investigated variations in chilling requirements, bud burst and development in early and late varieties of apple trees. Results showed less bud burst in late varieties than in early ones. In the former, there were increased in phenolic compounds (conjugated and total phenols) at budburst in all varieties. As dormancy begins, free phenols are increased, coinciding with a reduction in the levels of conjugated phenols. Consequently, as dormancy breaks, these free phenols are conjugate with organic constituents, and a decrease in the concentrations of free phenols occurs, in order to reduce inhibitory effect on growth. We conclude that late varieties (Strakhan) are less economical in manufacturing new growth, as indicated by less bud vigor at budburst than early varieties (Barkhar and local) and show a marked differential phenols compound pattern throughout bud development compared to early varieties.

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Section: Introductionmentioning

confidence: 99%

Metabolic Changes in Phenolic Compounds in Buds during and after Dormancy Releasing in early and late (<i>Malus sylvestris, </i>Mill) Apple Varieties as Effected by Chilling Requirements

El-Yazal

2021

ILNS

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“…Temperate zone fruit crops bear bud dormancy which may be represented as a mechanism for avoiding the exposure of tender flowers and leaves to low winter temperatures (Njuguna et al (2004).…”

Section: Introductionmentioning

confidence: 99%

Seasonal Changes in Soluble and Non-Soluble Carbohydrates during and After Dormancy Release in Early and Late Varieties of Apple (Malus Sylvestris, Mill) Trees

El-Yazal

2019

IJEER

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The flower bud abortion is one of the main problems that limit apple varieties production in the Egypt. Insufficient chilling during the dormancy period is known as the main factor of this problem. One of the hypotheses to explain this problem is that the starch mobilization and carbohydrate fluxes to the buds are impeded when mild temperatures occurred during winter. In order to produce the physiological bases for choosing early- opining apple varieties that may avoid the depleted low winter temperatures, the terribly early and late- opining apple variety Barkhar, Local and Strakhan (Malus domestica) were used to study the relation between the seasonal changes and balance of water, dry weight and carbohydrates metabolism and opining time. This study investigated potential variations in chilling requirements, bud burst and development in early and late varieties of apple trees. The budburst and carbohydrates metabolism of flower and vegetative buds of early and late varieties were additionally investigated. Results showed less bud burst in late varieties than in early ones. In the former, there were increased in water, dry weight and soluble carbohydrates (sugars) at budburst. Although non-soluble carbohydrates levels was considerably reduced by bud development in all varieties. We conclude that late varieties (Strakhan) are less economical in manufacturing new growth, as indicated by less bud vigor at budburst than early varieties (Barkhar and local) and show a marked differential in water content and carbohydrates metabolism throughout bud development compared to early varieties.

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“…Warm winters result in prolonged dormancy leading to poor flowering, very strong apical dominance, unsynchronized growth patterns and, consequently, low yields (Cook and Jacobs, 2000;Jacobs et al, 1981). Apple growing is commonly hampered by inadequate winter chilling in Kenya (Njuguna et al, 2004) and Moroccan valleys (Mahhou et al, 2003). One of the possible solutions to avoid such problems is using low chilling requirement cultivars such as Anna (Erez, 2000;Njuguna et al, 2004;Webster, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Apple growing is commonly hampered by inadequate winter chilling in Kenya (Njuguna et al, 2004) and Moroccan valleys (Mahhou et al, 2003). One of the possible solutions to avoid such problems is using low chilling requirement cultivars such as Anna (Erez, 2000;Njuguna et al, 2004;Webster, 2005). However, these cultivars do not always meet the demands of growers and consumers with respect to production volume and fruit quality.…”

Section: Introductionmentioning

confidence: 99%

“…Many chemicals show rest-breaking properties on buds but only a few have gained commercial acceptance (Erez, 2000;Tromp, 2005). Effects of chemicals such as Dormex (hydrogen cyanamide, CH 2 N 2 ), potassium nitrate and winter oil (Willett and Westigard, 1988) on the bud break of apple trees have been evaluated in Kenya, Morocco and Zimbabwe and positive responses produced (Jackson and Bepete, 1995;Mahhou et al, 2003;Njuguna et. al., 2004).…”

Section: Introductionmentioning

confidence: 99%

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GROWING APPLE (MALUS DOMESTICA) UNDER TROPICAL MOUNTAIN CLIMATE CONDITIONS IN NORTHERN ETHIOPIA

et al. 2009

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SUMMARYLack of effective chilling during the dormant season is one of the major problems when apples are growing under a tropical climate. We evaluated the response of different apple cultivars (Golden Delicious, Gala, Fuji, Granny Smith and Jonagold) grown on M9 rootstock with different dormancy-management practices. The trials were carried out between 2004 and 2006 in a tropical mountain area (Tigray, Ethiopia), where chilling conditions are poor with the aim of improving and synchronizing the bud break and the blossoming period of these apple cultivars. Two-year-old well-feathered trees were planted in two experimental trial sites in a randomized complete block design. Trees were subjected to the following treatments in two sets of experiments: one defoliation per year only; two defoliations per year, one defoliation followed by 1% hydrogen cyanamide (Dormex) treatment; one defoliation followed by 2% Dormex treatment; one defoliation followed by 4% winter oil; one defoliation followed by 0.5% Dormex and 2% winter oil; and a control with no defoliation or dormancy breaking treatments. The results show positive effects of the dormancy breaking agents on the productivity of the trees after defoliation, with comparable results for the effectiveness of both Dormex and winter oil. There were no statistically significant differences between the Dormex doses. The defoliation treatment alone was not sufficient to break dormancy for the cultivars Golden Delicious, Granny Smith or Gala but showed promising results with dormancy breaking on Jonagold. Yields increased as a result of better flowering time synchronization within a tree but even with the dormancy treatments the length of the flowering period was still spread over five weeks, where under a more temperate climate it lasted two to three weeks. The average fruit weight of Jonagold and Granny Smith can be considered as a good fruit quality while the fruit of other diploid cultivars like Golden, Gala and Fuji were rather small, which indicates that fruit thinning by hand will be a necessity for these cultivars. Red colouration of the apples on the cultivars Gala and Jonagold was excellent and meets ‡Corresponding author.

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Temperate Fuits Production in the Tropics: A Review on Apples in Kenya

Cited by 8 publications

References 0 publications

Metabolic Changes in Phenolic Compounds in Buds during and after Dormancy Releasing in early and late (<i>Malus sylvestris, </i>Mill) Apple Varieties as Effected by Chilling Requirements

Metabolic Changes in Phenolic Compounds in Buds during and after Dormancy Releasing in early and late (<i>Malus sylvestris, </i>Mill) Apple Varieties as Effected by Chilling Requirements

Seasonal Changes in Soluble and Non-Soluble Carbohydrates during and After Dormancy Release in Early and Late Varieties of Apple (Malus Sylvestris, Mill) Trees

GROWING APPLE (MALUS DOMESTICA) UNDER TROPICAL MOUNTAIN CLIMATE CONDITIONS IN NORTHERN ETHIOPIA

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