scholarly journals Pollination Characteristics of Pecan Trees and Orchards

2000 ◽  
Vol 10 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Bruce W. Wood
Keyword(s):  
Fruit Set ◽  
Tree Age ◽  
Block Type ◽  
Type I ◽  
Crop Losses ◽  
Fruit Drop ◽  
Scattered Trees ◽  
Spring Temperatures ◽  
Relative Differences ◽  
Selection Of

There is increasing evidence of substantial pollination related crop losses by pecan [Carya illinoensis (Wangenh.) K. Koch] orchards. These most likely occur in block-type orchards consisting of only one or two cultivars, but can also occur at locations with a great number of different genotypes nearby. Main crop cultivars should generally be within about two rows of pollinizers to ensure cross-pollination. Thus, block widths exceeding about four rows between pollinizers are especially likely to exhibit serious pollination problems. Scattered trees of off-type genotypes are potentially of major importance as backup orchard pollinizers. Tree age/size and spring temperatures influence the characteristics of flower maturity windows and are probably primary factors contributing to pollination-related fruit-set losses in many block-type orchards. Flower maturity tends to be earlier in older/larger trees while warmer springs accelerate catkin development relative to that of pistillate flowers. Because of substantial variability in relative differences associated with initiation and duration of flower maturity windows within either protandrous or protogynous flowering types (i.e., Type I or II), selection of complementary pollinizers should be based on the relatively high resolution 30-class flowering classification system rather than the traditional low resolution 2-class system. Other factors sometime causing pollination related crop losses are either abnormally wet weather or strong dry winds during the pollination period or abnormally warm or cool springs. Pollination problems can be visually detected by noting premature non insect related post pollination fruit drop or diminishing fruit set with increasing distance from pollinator trees or off-type genotypes within the orchard.

scholarly journals Source of Pollen, Distance from Pollinizer, and Time of Pollination Affect Yields in Block-type Pecan Orchards

HortScience ◽  
1997 ◽  
Vol 32 (7) ◽  
pp. 1182-1185 ◽  
Author(s):  
Bruce W. Wood
Keyword(s):  
Fruit Set ◽  
Southeastern United States ◽  
Temporal Distribution ◽  
Carya Illinoinensis ◽  
Tree Age ◽  
Block Type ◽  
Spring Temperature ◽  
Crop Losses ◽  
Main Crop ◽  
Spring Temperatures

Inadequate cross-pollination of pecan [Carya illinoinensis (Wangenh.) K. Koch] occurred in block-type orchards generally thought exempt from pollination-related crop losses because of an abundance of nearby potential pollinizers. “Off-genotypes” appeared to be potentially major assets in such orchards due to their role as backup pollinizers; hence, their presence insures against crop losses due to poor pollination. Fruit-set in `Desirable' main crop rows declined sigmoidally as distance from 'Stuart' pollinizer rows increased. For 15.4-m row spacings, rate of decrease was maximum between 49 and 78 m, depending on crop year. Maximum fruit-set was in rows immediately adjacent to the pollinizer. Tree age/size and spring temperature influences on the characteristics of flower maturity windows are probably primary factors contributing to pollination-related fruit-set losses in block-type orchards relying upon pollen from a single complementary pollinizer or from neighborhood trees. For example, flower maturity was earlier in older/larger trees, and higher spring temperatures accelerated catkin development relative to that of pistillate flowers. Maximum fruit-set occurred when pistillate flowers received pollen around 1 day or less after becoming receptive, whereas no fruit-set occurred when they were pollinated around four or more days after initial receptivity. These findings indicate that many block-type orchards in the southeastern United States are exhibiting pollination-related crop reductions and that future establishment of such orchards merits caution regarding the spatial and temporal distribution of pollinizers.

Idiosyncrasies of Pecan Pollination

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 555e-556
Author(s):  
Bruce W. Wood
Keyword(s):  
Fruit Set ◽  
Tree Age ◽  
Block Type ◽  
Type I ◽  
Yield Losses ◽  
Stigma Receptivity ◽  
Complete Development ◽  
Main Crop ◽  
Spring Temperatures ◽  
Crop Variety

Pecan orchard productivity and yields often suffer due to pollination problems despite copious pollen produced within or near orchards. The problem is most acute in large block-type orchards of one or two varieties and can be due to pollen not being present at time of stigma receptivity or due to selfing. Fruit-set problems do not appear to be due to excessive pollen on stigmatic surfaces, as is the case in walnut. Pistillate flowers set best when pollen is received within about 1 day after becoming receptive. While stigma receptivity appears to lasts several days, pistillate flowers usually fail to complete development if pollinated after ≈2 days. Flowering dichogamy of given varieties varies with tree age and spring temperatures, thus often leading to poor pollination and low fruit-set. Orchards are therefore likely to benefit from the presence of two complementary pollinizers for the main crop variety. Trees in block-type orchards and are beyond about three rows or 50 m from pollinizers are likely to exhibit pollination related yield losses. Many orchards exhibit pollination problems because adherence to the standard two-class Type I/II flowering system often caused planting of noncompatible varieties. A recently developed 30-class Type I/II system allows for greater probability of avoiding pollination problems. Removal of “off-genotype” trees from orchards may reduce yields in block-type orchards.

scholarly journals Cross-pollination within Pecan Orchards

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 583d-583 ◽  
Author(s):  
Bruce W. Wood
Keyword(s):  
Dna Analysis ◽  
Fruit Set ◽  
Low Frequency ◽  
Large Block ◽  
Block Type ◽  
Type I ◽  
Type Ii ◽  
Yield Losses ◽  
Late Data ◽  
Very Low Frequency

Pecan is wind pollinated, exhibits heterodichogamy and are either protandrous (I) or protogynous (II). Orchards are typically established using two complimentary flowering types but with no further scrutiny as to the degree of compatibility of these two types. Additionally, orchards are sometime established with a very low frequency of pollinator. An evaluation of several orchards revealed that yield losses are due to poor pollination is likely common. Data indicate that trees beyond about 46 m (150 feet) from a complementary pollinator exhibit substantial reductions in fruit-set; therefore, large block-type plantings are disadvantaged. Flowering data over several years show that Type I and Type II cultivars are often functionally noncomplementary, suggesting that pecan cultivars should also be identified with a seasonal identification (i.e., early, mid, and late). Data also indicate that dichogamy patterns substantially change as trees age or with abnormally warm or cool springs; hence, pollination patterns will vary depending upon orchard age. Data indicate that orchards should be comprised of 3+ cultivars. RAPD-DNA analysis of “hooked-nuts” indicates that this trait is not reliable as an indicator of selfing.

Gene for Progressive Familial Heart Block Type I Maps to Chromosome 19q13

Circulation ◽  
1995 ◽  
Vol 91 (6) ◽  
pp. 1633-1640 ◽  
Author(s):  
Paul A. Brink ◽  
Alet Ferreira ◽  
Johanna C. Moolman ◽  
Hettie W. Weymar ◽  
Pieter-Luttig van der Merwe ◽  
...  
Keyword(s):  
Heart Block ◽  
Block Type ◽  
Type I ◽  
Chromosome 19Q13

Exposure–Response Analysis for Selection of Optimal Dosage Regimen of Anifrolumab in Patients With Systemic Lupus Erythematosus

Rheumatology ◽  
2021 ◽  
Author(s):  
Yen Lin Chia ◽  
Linda Santiago ◽  
Bing Wang ◽  
Denison Kuruvilla ◽  
Shiliang Wang ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Drug Clearance ◽  
Optimal Dosage ◽  
Type I ◽  
Efficacy And Safety ◽  
Response Relationship ◽  
Phase 3 ◽  
Optimal Dosage Regimen ◽  
Exposure Response ◽  
Selection Of

Abstract Objectives The randomized, double-blind, phase 2 b MUSE study evaluated the efficacy and safety of the type I interferon receptor antibody anifrolumab (300 mg or 1000 mg every 4 weeks) compared with placebo for 52 weeks in patients with chronic, moderate to severe SLE. Characterizing the exposure–response relationship of anifrolumab in MUSE will enable selection of its optimal dosage regimen in two phase 3 studies in patients with SLE. Methods The exposure–response relationship, pharmacokinetics (PK), and SLE Responder Index (SRI[4]) efficacy data were analysed using a population approach. A dropout hazard function was also incorporated into the SRI(4) model to describe the voluntary patient withdrawals during the 1-year treatment period. Results The population PK model found that type I IFN test–high patients, and patients with a higher body weight, had significantly greater clearance of anifrolumab. Stochastic clinical simulations demonstrated that doses <300 mg would lead to a greater-than-proportional reduction in drug exposure owing to type I interferon alpha receptor–mediated drug clearance (antigen-sink effect, more rapid drug clearance at lower concentrations) and suboptimal SRI(4) responses with wider confidence intervals. Conclusions Based on PK, efficacy, and safety considerations, anifrolumab 300 mg every 4 weeks was recommended as the optimal dosage for pivotal phase 3 studies in patients with SLE.

The Comparison Between Therapeutic Effects of Different Classes of Antidepressant Drugs in Treatment of Genetical and Reactional Depression

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
P. Molavi ◽  
M. Karimollahi ◽  
M. Faridi
Keyword(s):  
Antidepressant Drugs ◽  
Response Speed ◽  
Point Of View ◽  
Block Type ◽  
Therapeutic Effects ◽  
Response Type ◽  
Analysis Method ◽  
Dsm Iv ◽  
Selection Of ◽  
Analyze Data

Background:Depression as a common psychiatric disorder can occur in two types: Endogenous or genetic and exogenous or Reactional. These two types of depression, from the point of view of response speed to treatment and type of appropriate drug for treatment are different. This study has been executed to compare therapeutic effects of different classes of anti-depressant drugs in treatment of genetic and Reactional depression.Materials and methods:Present survey is a clinical-trial study, a completely randomly block type, that has performed on 30 patients (male and female). Selection of study sample accomplished randomly among unipolar depressed patients that has referred to Ardabil’s psychiatry clinic diagnosed based on DSM-IV criteria. Researcher - Made questionnaire, Beck, and Catelle depression test were used to collect data. To analyze data, for completely randomly blocked designs, two-factor variance analysis method and F test were used.Results:This study showed that Genetical depression does not response treatment Rapidly and its response type is not good and persistent. From the point of view of time, Reactional depression has a delaying response but its response type is good and persistent. In addition, no difference was observed in efficacy of different classes of drugs for treatment of these two types of depression. The results of this research showed that there is no difference between treatment response of two types of depression (Genetical and Reactional).Conclusions:There is no preference in efficacy of different classes of drugs in treatment of these two types of depression.

scholarly journals Almond Fruit Drop Patterns under Mediterranean Conditions

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 544
Author(s):  
Jaume Lordan ◽  
Lourdes Zazurca ◽  
Mercè Rovira ◽  
Laura Torguet ◽  
Ignasi Batlle ◽  
...  
Keyword(s):  
Fruit Set ◽  
Growing Season ◽  
Fruit Weight ◽  
Key Factors ◽  
Full Bloom ◽  
Tree Management ◽  
Fruit Drop ◽  
Mediterranean Conditions ◽  
New Cultivars ◽  
Scion Cultivar

Almond is an important tree nut crop worldwide, and planted areas have been increasing year after year. While self-fertility is one of the key factors when it comes to improved almond productivity of new cultivars, yield is also affected by the number of flowers produced, pollination, fruit set, fruit drop, and fruit weight. Almond fruit drop patterns of 20 Mediterranean almond cultivars were studied over three years. In addition, fruit drop patterns of two scion cultivars ‘Marinada’ and ‘Vairo’ budded onto eight to 10 different rootstocks managed with three different pruning strategies were studied for two years. Cumulative flower and fruit drop ranged from 50% to 90% among cultivars and treatments, and there were up to four fruit drop events during the growing season, the main one occurring from 20–60 days from full bloom (DFFB). Subsequent drops were at 100 DFFB, 120–140 DFFB, and the last one at 160–180 DFFB. The later drops were less apparent. In general, about half of the cumulative drop was comprised of buds and flowers, and the remaining percentage was fruit that dropped 20 or more days after full bloom. Furthermore, different fruit drop patterns were observed depending on the cultivar. For late- and extra-late flowering cultivars, cumulative fruit drop began to decrease earlier, with most of the drops occurred already at full bloom, whereas the opposite was observed for the early flowering cultivars. Rootstocks also had an important effect on the fruit drop pattern, with different effects depending on the scion cultivar. Tree management, such as type of pruning, also had an important effect on the rate of fruit drop and cumulative drop. Therefore, each combination of cultivar × rootstock × pruning type will require different strategies in order to reduce the fruit drop and optimize crop loads.

Control of premature fruit drop in Macadamia integrifolia: effects of naphthalene acetic acid application, cincturing, and shoot-tip removal

1980 ◽  
Vol 20 (107) ◽  
pp. 740 ◽  
Author(s):  
RR Williams
Keyword(s):  
Acetic Acid ◽  
Fruit Set ◽  
Shoot Tip ◽  
Naphthalene Acetic Acid ◽  
Fruit Drop ◽  
Macadamia Integrifolia

The effects of NAA application, cincturing and shoot-tip removal on the incidence of premature fruit drop were investigated in orchard-grown trees of Macadamia integrifolia cv. Kakea. A single, post-anthesis application of NAA (1 ppm) increased (P < 0.05) the final set of macadamia fruit by 35%. Limb cincturing combined with shoot-tip removal increased (P < 0.05) initial fruit set and possibly final set. Cincturing alone was less effective and shoot-tip removal had no effect alone.

scholarly journals Development of stem cracks in young hybrid aspen plantations

2016 ◽  
Vol 65 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Silva Šēnhofa ◽  
Mārtiņš Zeps ◽  
Arnis Gailis ◽  
Rolands Kāpostiņš ◽  
Āris Jansons
Keyword(s):  
Crack Width ◽  
Crack Formation ◽  
Fungal Infections ◽  
Wood Quality ◽  
Tree Age ◽  
Hybrid Aspen ◽  
Breast Height ◽  
Grade Scale ◽  
Clear Relation ◽  
Selection Of

Abstract Cracks expose wood to fungal infections that significantly affects wood quality, while rapid wound occlusion decreases probability of infections. Assessment of scars was done at four grade scale in three adjacent hybrid aspen trials at the age of 8-10 years in central part of Latvia three years after bark crack occurrence. Occluded wounds were found for 95% of damaged trees, regardless of tree age. Among trees that had cracks wider than 1 cm, 42% had uniformly healed bark, but 7% still had open wounds. Wound development was significantly affected by crack width and length (both p < 0.001), but had no clear relation with tree DBH (diameter at breast height) and relative DBH increment (both p > 0.05). At clonal mean level, scar grade was significantly affected by grade of crack three years earlier and clone (both p < 0.001), but mean DBH of clone had no relation (p > 0.05) to proportion of trees evaluated by any of the scar grades. The results suggest that three years after the bark crack formation most of them had successfully occluded and selection of clones with better diameter growth has no influence on development of cracks.

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