Variability in chilling requirements for the breaking of flower bud dormancy in jojoba (Simmondsia chinensis[Link] Schneider)

1989 ◽  
Vol 64 (3) ◽  
pp. 379-387 ◽  
Author(s):  
J. Ferriere ◽  
P. L. Milthorpe ◽  
R. L. Dunstone
Keyword(s):  
Bud Dormancy ◽  
Simmondsia Chinensis ◽  
Flower Bud ◽  
Chilling Requirements

scholarly journals Monitoring Dormancy Transition in Almond [Prunus Dulcis (Miller) Webb] during Cold and Warm Mediterranean Seasons through the Analysis of a DAM (Dormancy-Associated MADS-Box) Gene

Horticulturae ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 41 ◽  
Author(s):  
Ángela Prudencio ◽  
Federico Dicenta ◽  
Pedro Martínez-Gómez
Keyword(s):  
Flowering Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Dominant Gene ◽  
Prunus Dulcis ◽  
Bud Dormancy ◽  
Mads Box ◽  
Prunus Species ◽  
Flower Bud ◽  
Japanese Apricot ◽  
Chilling Requirements

For fruit tree (Prunus) species, flower bud dormancy completion determines the quality of bud break and the flowering time. In the present climate change and global warming context, the relationship between dormancy and flowering processes is a fundamental goal in molecular biology of these species. In almond [P. dulcis (Miller) Webb], flowering time is a trait of great interest in the development of new cultivars adapted to different climatic areas. Late flowering is related to a long dormancy period due to high chilling requirements of the cultivar. It is considered a quantitative and highly heritable character but a dominant gene (Late bloom, Lb) was also described. A major QTL (quantitative trait loci) in the linkage group (LG) 4 was associated with Lb, together with other three QTLs in LG1 and LG7. In addition, DAM (Dormancy-Associated MADS-Box) genes located in LG1 have been largely described as a gene family involved in bud dormancy in different Prunus species including peach [P. persica (L.) Batsch] and Japanese apricot (P. mume Sieb. et Zucc.). In this work, a DAM transcript was cloned and its expression was analysed by qPCR (quantitative Polymerase Chain Reaction) in almond flower buds during the dormancy release. For this purpose two almond cultivars (‘Desmayo Largueta’ and ‘Penta’) with different chilling requirements and flowering time were used, and the study was performed along two years. The complete coding sequence, designated PdDAM6 (Prunus dulcis DAM6), was subjected to a phylogenetic analysis with homologous sequences from other Prunus species. Finally, expression dynamics analysed by using qPCR showed a continuous decrease in transcript levels for both cultivars and years during the period analysed. Monitoring almond flower bud dormancy through DAM expression should be used to improve almond production in different climate conditions.

Jojoba flower buds: effects of preconditioning temperature.

1982 ◽  
Vol 33 (4) ◽  
pp. 649 ◽  
Author(s):  
RL Dunstone
Keyword(s):  
Environmental Factors ◽  
Reproductive Cycle ◽  
Female Flower ◽  
Treatment Temperature ◽  
Bud Dormancy ◽  
Simmondsia Chinensis ◽  
Flower Buds ◽  
Flower Bud ◽  
Lower Treatment ◽  
Pretreatment Temperature

The environmental factors which control the reproductive cycle of jojoba (Simmondsia chinensis [Link] Schneider), were studied under controlled conditions. Plants were placed under a warm pretreatment temperature which resulted in the growth of new shoots bearing dormant flower buds. The plants were later moved to lower treatment temperatures which have been shown to break flower bud dormancy. Pretreatment temperature affected the percentage of nodes which produced flower buds. Both the pretreatment and the treatment temperature affected flowering percentage, there being an optimum pretreatment effect at 30/25�C day/night temperatures. Flowering percentage responded to absolute treatment temperature rather than to the drop in temperature from pretreatment to treatment. Flowering percentage increased with decrease in treatment temperature down to 15/10�C (male clone) and 12/7�C (female clone). The lowest pretreatment-treatment temperature combination was associated with the production of female flower parts on the male inflorescences.

scholarly journals Identification of early and late flowering time candidate genes in endodormant and ecodormant almond flower buds

2020 ◽  
Author(s):  
Ángela S Prudencio ◽  
Frank A Hoeberichts ◽  
Federico Dicenta ◽  
Pedro Martínez-Gómez ◽  
Raquel Sánchez-Pérez
Keyword(s):  
Flowering Time ◽  
Candidate Genes ◽  
Weather Conditions ◽  
Tree Breeding ◽  
Prunus Dulcis ◽  
Fruit Tree ◽  
Flower Buds ◽  
Flower Bud ◽  
Late Flowering ◽  
Chilling Requirements

Abstract Flower bud dormancy in temperate fruit tree species, like almond [Prunus dulcis (Mill.) D.A. Webb], is a survival mechanism that ensures flowering will occur under suitable weather conditions for successful flower development, pollination and fruit set. Dormancy is divided into three sequential phases: paradormancy, endodormancy and ecodormancy. During the winter, buds need cultivar-specific chilling requirements to overcome endodormancy and heat requirements to activate the machinery to flower in the ecodormancy phase. One of the main factors that enables the transition from endodormancy to ecodormancy is transcriptome reprogramming. In this work, we therefore monitored three almond cultivars with different chilling requirements and flowering times by RNA sequencing during the endodormancy release of flower buds and validated the data by qRT-PCR in two consecutive seasons. We were thus able to identify early and late flowering time candidate genes in endodormant and ecodormant almond flower buds associated with metabolic switches, transmembrane transport, cell wall remodeling, phytohormone signaling and pollen development. These candidate genes were indeed involved in the overcoming of the endodormancy in almond. This information may be used for the development of dormancy molecular markers, increasing the efficiency of temperate fruit tree breeding programs in a climate-change context.

scholarly journals Analysis of Evolution, Expression and Genetic Transformation of TCP Transcription Factors in Blueberry Reveal That VcTCP18 Negatively Regulates the Release of Flower Bud Dormancy

2021 ◽  
Vol 12 ◽  
Author(s):  
Yongqiang Li ◽  
Shuang An ◽  
Qiangqiang Cheng ◽  
Yu Zong ◽  
Wenrong Chen ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Plant Growth ◽  
Gene Family ◽  
Fruit Development ◽  
Germination Rate ◽  
Expression Patterns ◽  
Bud Dormancy ◽  
Dormancy Release ◽  
Flower Bud ◽  
Bud Dormancy Release

Plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, PROLIFERATING CELL FACTORS (TCP) transcription factors have versatile functions in plant growth, development and response to environmental stress. Despite blueberry’s value as an important fruit crop, the TCP gene family has not been systematically studied in this plant. The current study identified blueberry TCP genes (VcTCPs) using genomic data from the tetraploid blueberry variety ‘Draper’; a total of 62 genes were obtained. Using multiple sequence alignment, conserved motif, and gene structure analyses, family members were divided into two subfamilies, of which class II was further divided into two subclasses, CIN and TB1. Synteny analysis showed that genome-wide or segment-based replication played an important role in the expansion of the blueberry TCP gene family. The expression patterns of VcTCP genes during fruit development, flower bud dormancy release, hormone treatment, and tissue-specific expression were analyzed using RNA-seq and qRT-PCR. The results showed that the TB1 subclass members exhibited a certain level of expression in the shoot, leaf, and bud; these genes were not expressed during fruit development, but transcript levels decreased uniformly during the release of flower bud dormancy by low-temperature accumulation. The further transgenic experiments showed the overexpression of VcTCP18 in Arabidopsis significantly decreased the seed germination rate in contrast to the wild type. The bud dormancy phenomena as late-flowering, fewer rosettes and main branches were also observed in transgenic plants. Overall, this study provides the first insight into the evolution, expression, and function of VcTCP genes, including the discovery that VcTCP18 negatively regulated bud dormancy release in blueberry. The results will deepen our understanding of the function of TCPs in plant growth and development.

scholarly journals A Model Describing rRelease of Flower Bud Dormancy in `Prize' and `Gloria' Azaleas

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 760B-760
Author(s):  
William M. Womack ◽  
James E. Barrett ◽  
Terril A. Nell
Keyword(s):  
Growth Regulators ◽  
Bud Dormancy ◽  
Flower Bud ◽  
Cooling Temperature ◽  
Growth Chambers ◽  
Cool Treatment

`Prize' and `Gloria' azaleas were budded at 29C day/24C night without growth regulators. Dormant-budded plants were held at 2, 7, 13, or 18C for 0, 0.5, 1, 2, 4, 6, 8, or 10 weeks and then forced in walk-in growth chambers (29C day/24C night). A model was developed to describe the effect of cooling temperature and duration on days to marketability (eight open flowers) and percent of buds showing color. Holding at temperatures below 7C, increases days to marketability up to 7 days. Extended cooling (beyond 6 weeks) at temperatures <7C increases percent of buds showing color. Extended holding at temperatures >7C decreases buds in color due to development of bypass shoots during cooling and increased bud abortion. Plants not receiving a cool-treatment or cooled for <2 weeks do not flower uniformly. Furthermore, the percentage of plants reaching marketability dramatically decreases for plants held longer than 6 weeks at temperatures >7C. Both cultivars show similar trends, but `Gloria' has greater variability.

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

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 841A-841 ◽  
Author(s):  
Joseph K. Njuguna* ◽  
Leonard S. Wamocho ◽  
Teddy E. Morelock
Keyword(s):  
Mineral Oil ◽  
Bud Dormancy ◽  
Bud Break ◽  
Fruit Crops ◽  
Chilling Requirements ◽  
Tropical Conditions ◽  
Winter Temperatures ◽  
The Tropics ◽  
Prolonged Dormancy ◽  
Made In

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. In Kenya, apple growing is mostly hampered by inadequate chilling that causes the plants to have prolonged dormancy leading to poor flowering and consequently low yield. Although the chilling requirements are obligatory, under subtropical and especially tropical conditions avoidance is possible. To achieve this, it is necessary to select cultivars with low chilling requirements. This has proven effective in Zimbabwe with cultivar Matsu which is grown without a need for artificial breaking of dormancy. In Kenya like Zimbabwe, low chilling requiring cultivars such as Anna have been grown successfully. However, for cultivars with high chilling requirements, there is need to apply artificial techniques/methods to enhance bud break. Some of the cultural techniques used are: defoliation after harvesting and bending of the shoots holizontally. Defoliation after harvesting has particularly been used successfully in the island of Java in Indonesia and it enables two crops to be grown per year. Root chilling of rootstock has also been found to enhance bud break of the shoot. In addition, chemicals like KNO3, mineral oil and thiourea (TU) have been found to be effective in breaking bud dormancy in Kenya. This paper is reviewing the challenges encountered in growing apples in the tropics and Kenya in particular and the progress that has made in addressing them.

scholarly journals Natural and Artificial Chilling of Southern Highbush Blueberry

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 825B-825
Author(s):  
Donna A. Marshall* ◽  
Stephen J. Stringer ◽  
James M. Spiers
Keyword(s):  
Bud Break ◽  
Delivery Method ◽  
Flower Bud ◽  
Bud Development ◽  
Chilling Requirements ◽  
Highbush Blueberries ◽  
Southern Highbush ◽  
Chilling Hours ◽  
Floral Bud ◽  
Vegetative Bud

A study was initiated in November, 2002 to determine the effects of exposing two Southern Highbush blueberries (Vaccinium corybosum L) to artificial chilling hours on initiation of bud break and advancement of floral and vegetative bud maturity. Plants of `Jubilee' and `Misty' were divided into 2 groups in which one was left outdoors, allowing chilling to occur and accumulate naturally, while the other group was placed in a growth chamber set at a constant artificial temperature of 4 °C. Five plants of each cultivar were then placed into a heated greenhouse after 0, 200, 400, 600, or 800 hours of chilling (total hours of exposure to <5 °C) had accumulated for forcing of flower bud development. The progression of floral bud development of the terminal three buds on five tagged stems was observed at 7-10 day intervals for 30 days. At the end of the forcing period observations were also made on total percent vegetative and floral bud break. Prior to accumulating sufficient chilling requirements, chilling delivery method did not appear to influence the rate of floral bud development since none advanced past stage 3 regardless of chilling regime used. However after chilling requirements were met, flower buds of plants that were allowed to chill naturally developed more quickly than did those chilled by artificial means.

scholarly journals Irrigation Cut-off Date Affects Growth, Frost Damage, and Yield of Jojoba

1993 ◽  
Vol 118 (6) ◽  
pp. 731-735 ◽  
Author(s):  
John M. Nelson ◽  
David A. Palzkill ◽  
Paul G. Bartels
Keyword(s):  
Water Potential ◽  
Seed Yield ◽  
Seed Weight ◽  
Frost Damage ◽  
First Year ◽  
Simmondsia Chinensis ◽  
Flower Bud ◽  
The Third ◽  
Second Year ◽  
Seed Yields

Flower bud injury resulting from freezing temperatures has been a major problem in jojoba [Simmondsia chinensis (Link) C. Schneid.] production. A 3-year field study, which began with 4-year-old plants, evaluated the effect of three irrigation treatments on growth, flower bud survival, seed yield, seed weight, and seed wax concentration of six clones. After 3 years, irrigation cut-off dates of late May (dry treatment) and early September (medium treatment) resulted in reduced plant height and width compared to irrigating through November (wet treatment). Flower bud survival and seed yields were very low in the first year for all treatments. In the second and third years, bud survival for most clones, even at -8C, was greatly improved by withholding water in the fall. In December of the second and third years, plants in the medium and dry plots had lower leaf water potential than those in the wet plot. In the second year, plants in the medium and dry plots had seed yields that were 3.5 times higher and wax yields that were were 2.3 times higher than plants in the wet plot. In the third year, the medium treatment had the highest seed and wax yields. Average seed weight and seed wax concentration were generally highest for plants in the wet plot where seed yields were low. Withholding irrigation from jojoba in the fall appears to improve flower bud survival and seed and wax yields following cold winters.

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