scholarly journals Genetic and Morphological Factors Influence Mummy Berry Blight Resistance in Highbush Blueberry Cultivars

HortScience ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 252-254 ◽  
Author(s):  
M.K. Ehlenfeldt ◽  
A.W. Stretch ◽  
V. Brewster
Keyword(s):  
Multiple Regression ◽  
Primary Infection ◽  
Shoot Growth ◽  
Shoot Elongation ◽  
Blight Resistance ◽  
Highbush Blueberry ◽  
Vaccinium Angustifolium ◽  
Resistant Cultivars ◽  
Fruit Maturity

The resistance of 48 highbush blueberry cultivars and selections to the blight phase of mummy berry disease, incited by the fungus Monilinia vaccinii-corymbosi (Reade) Honey, was examined in relation to percent Vaccinium angustifolium Ait. ancestry, season of fruit maturity, and shoot growth during the primary infection phase. Correlations of percent blighting with percent V. angustifolium ancestry were significant across 3 years, but correlations with fruit maturity were significant in only 2 of 3 years. Correlations of percent blighting with early shoot growth were significant in both years measured, with r values of 0.54 in 1994, 0.83 in 1995, and 0.83 across years. A multiple regression found only shoot growth highly significant for susceptibility and rendered V. angustifolium ancestry and season of fruit maturity nonsignificant. Resistant cultivars exhibiting early shoot elongation suggest that resistance can be either biochemically or escape based.

scholarly journals Shoot Length Affects Susceptibility to Mummy Berry Blight within Highbush Blueberry Cultivars

HortScience ◽  
1997 ◽  
Vol 32 (5) ◽  
pp. 884-887 ◽  
Author(s):  
M.K. Ehlenfeldt ◽  
A.W. Stretch ◽  
J.S. Lehman
Keyword(s):  
General Condition ◽  
Primary Infection ◽  
Shoot Growth ◽  
Vaccinium Corymbosum ◽  
Shoot Length ◽  
Highbush Blueberry ◽  
Susceptible Cultivar ◽  
Disease Avoidance ◽  
Infection Period ◽  
Resistant Cultivars

Shoot growth of six blight-resistant highbush blueberry (Vaccinium corymbosum L.) cultivars and of one susceptible cultivar was manipulated during the primary infection period of mummy berry disease to determine if some portion of the observed resistance was based on disease avoidance. In experiments across 2 years, resistant cultivars either increased continually in susceptibility or exhibited a peak and then decreased in susceptibility as shoots elongated. In a larger experiment that included both susceptible and resistant cultivars, peaks of susceptibility were identified for `Bluejay', `Darrow', and `Jersey'. In contrast, general decreases in susceptibility were identified for `Duke', `Blueray', and `Croatan' as shoots elongated. Shoot lengths associated with peak susceptibility varied among and within cultivars across experiments. The increases in susceptibility observed at longer shoot lengths were generally small. This finding suggests that cultivars identified as resistant have intrinsic levels of resistance, but maturity and general condition of the plant tissue can also affect disease levels.

scholarly journals Inflorescence Bud Initiation, Development, and Bloom in Two Southern Highbush Blueberry Cultivars

2015 ◽  
Vol 140 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Alisson P. Kovaleski ◽  
Jeffrey G. Williamson ◽  
James W. Olmstead ◽  
Rebecca L. Darnell
Keyword(s):  
Interspecific Hybrids ◽  
Shoot Growth ◽  
Late Summer ◽  
Vaccinium Corymbosum ◽  
Highbush Blueberry ◽  
Bud Development ◽  
Late Fall ◽  
Southern Highbush ◽  
Bud Initiation ◽  
The Relationship

Blueberry (Vaccinium spp.) production is increasing worldwide, particularly in subtropical growing regions, but information on timing and extent of inflorescence bud development during summer and fall and effects on bloom the next season are limited. The objectives of this study were to determine time of inflorescence bud initiation, describe internal inflorescence bud development, and determine the relationship between internal inflorescence bud development and bloom period the next spring in two southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrids)] cultivars. ‘Emerald’ and ‘Jewel’ SHB buds were collected beginning in late summer until shoot growth cessation in late fall for dissection and identification of organ development. Inflorescence bud frequency and number, vegetative and inflorescence bud length and width throughout development, and bloom were also assessed. Inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’. Five stages of internal inflorescence bud development were defined throughout fall in both cultivars, ranging from a vegetative meristem to early expansion of the inflorescence bud in late fall. ‘Emerald’ inflorescence buds were larger and bloomed earlier, reflecting the earlier inflorescence bud initiation and development. Although inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’, the pattern of development was not different. Timing of inflorescence bud initiation influenced timing of bloom with earlier initiation resulting in earlier bloom.

scholarly journals Enhanced Bud Production in Highbush Blueberry (Vaccinium corymbosum L.) in Response to Paclobutrazol

HortScience ◽  
1998 ◽  
Vol 33 (1) ◽  
pp. 75-77 ◽  
Author(s):  
Mark K. Ehlenfeldt
Keyword(s):  
Fruit Ripening ◽  
Fruit Size ◽  
Shoot Elongation ◽  
Plant Size ◽  
Vaccinium Corymbosum ◽  
Highbush Blueberry ◽  
Flower Bud ◽  
Bud Formation ◽  
Bud Set ◽  
Determining Factor

Blueberry cultivars were treated with either soil drenches or foliar applications of paclobutrazol. Soil drenches of 25 mg·L-1 inhibited shoot elongation and stimulated earlier and greater flower bud production on `Bluetta', `Bluecrop', and `Jersey'. The treatments increased bud numbers 359% to 797%, and stimulated compound bud formation, while reducing formation of vegetative buds. This resulted in overcropping and reduced fruit size. Foliar applications at concentrations of 5, 10, 50, and 100 mg·L-1 increased bud set. Treatments did not significantly alter time to 50% flowering in `Bluecrop' or `Duke', but hastened flowering up to 5 days in `Blueray' at 200 ppm. Fruit ripening was significantly delayed at 100 and 200 ppm in `Bluecrop' due to overcropping, but no delays were observed in `Blueray' or `Duke'. Plant size and vigor appeared to be a determining factor in plant response. Chemical name used: PP333 or (2RS,3RS)-l(4-chlorophenyl)-4,4-dimethyl-2-(l,2,4-triazol-1-yl)pentan-3-ol (paclobutrazol).

Shoot morphology and shoot growth potential in 1-year-old Scots pine seedlings

1981 ◽  
Vol 11 (4) ◽  
pp. 789-795 ◽  
Author(s):  
S. Thompson
Keyword(s):  
Scots Pine ◽  
Shoot Growth ◽  
Growing Season ◽  
Shoot Elongation ◽  
Growth Potential ◽  
Shoot Morphology ◽  
Growing Seasons ◽  
Pine Seedlings

When seedlings of a single seed source of Scots pine (Pinussylvestris L.) were raised for 26 weeks in a naturally lit, heated greenhouse, two types of shoot morphology were observed. Type 1 was that normally found in 1-year-old seedlings. Type 2 had a shoot morphology similar to that of seedlings raised outdoors for two growing seasons. When compared with type 1 plants, type 2 plants had an earlier start to shoot elongation, set their buds earlier, and stopped shoot elongation sooner. After one growing season, type 2 plants were shorter, had fewer stem units for shoot elongation in the second season, but carried a greater foliage biomass than 1-year-old type plants. After two seasons they remained shorter. Thus, plant rearing practices which result in the production of seedlings with this type of shoot morphology arc undesirable.The relationship between early "budsct," shoot morphology, and plant height suggests that the proportion of seedlings with a 2-year-old shoot morphology after one growing season in a heated greenhouse may be used as an early test for height growth potential in seed origins and possibly in progenies of north temperate pine species.

A comparison of the performance and growth of a range of turfgrass species under shade

2004 ◽  
Vol 44 (3) ◽  
pp. 353 ◽  
Author(s):  
R. S. Tegg ◽  
P. A. Lane
Keyword(s):  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Shade Tolerance ◽  
Shoot Growth ◽  
Field Experiments ◽  
Poa Pratensis ◽  
Shoot Elongation ◽  
Kentucky Bluegrass ◽  
Ambient Conditions ◽  
Rate Of Increase

The increased use of semi and fully enclosed sports stadiums necessitates the ongoing selection, development and assessment of shade-tolerance in turfgrass species. Vertical shoot growth rate is a simple biological measure that may supplement visual turfgrass assessment and provide a useful measure of shade adaptation. Cool-season temperate turfgrasses; Kentucky bluegrass–perennial ryegrass (Poa pratensis L.–Lolium perenne L.), creeping bentgrass (Agrostis palustris Huds.), supina bluegrass (Poa supina Schrad.) and tall fescue (Festuca arundinacea Schreb.), and a warm season species, Bermudagrass (Cynodon dactylon L.), were established in pot and field experiments and subjected to 4 shade treatments (0, 26, 56 or 65% shade) under ambient conditions. Average light readings taken near the winter and summer solstice in full sunlight at midday, were 790 and 1980�μmol/m2.s, respectively. Field and pot trials confirmed supina bluegrass and tall fescue to have the greatest shade tolerance, producing high turf quality under 56 and 65% shade. However, all turfgrass species declined in quality under high shade levels as indicated by an increase in thin, succulent vertical growth, and a less-dense turf sward. Vertical shoot growth rates of all species increased linearly with increasing shade levels. Kentucky bluegrass–perennial ryegrass had the highest rate of increase in vertical shoot elongation under shade, approximately 3.5 times greater than supina bluegrass, which had the lowest. Low rates of increase in vertical shoot elongation under shade indicated shade tolerance whereas high rates inferred shade intolerance.

Promotion of flowering in potted Piceaengelmannii (Perry) grafts: effects of heat, drought, gibberellin A4/7, and their timing

1985 ◽  
Vol 15 (4) ◽  
pp. 618-624 ◽  
Author(s):  
Stephen D. Ross
Keyword(s):  
High Temperature ◽  
Shoot Growth ◽  
Critical Time ◽  
Shoot Elongation ◽  
The Other ◽  
Severe Drought ◽  
Lateral Shoot ◽  
Gibberellin Metabolism ◽  
Genetically Improved ◽  
Needle Water Potential

Young, potted grafts ofPiceaengelmannii were moved into a 30:20 °C (day:night) heated polyethylene house at different stages of lateral shoot elongation; and there they were subjected to low, moderate, or severe drought stress with and without branch applications of gibberellin A4/7 (GA4/7). The critical time for promoting flowering by high temperature was the late stage of slow shoot elongation, whereas for drought it was during early and rapid shoot growth. Each treatment inhibited flowering at the time the other was maximally effective and the effective treatment period for GA4/7 appeared to include that both for high temperature and drought. In contrast to drought, optimally timed heat treatment did not retard shoot elongation, nor did it result in a decreased needle water potential relative to well-watered grafts outdoors. It appears that heat and drought promote flowering through different mechanisms, albeit mechanisms which may be mediated, at least in part, through their influence on gibberellin metabolism. Advantages of indoor-potted orchards over conventional soil-based orchards for accelerating the breeding and production of genetically improved P. engelmannii seeds are discussed.

The effect of high temperature regimes or short periods of water stress on development of small fruiting saltana vines

1965 ◽  
Vol 16 (5) ◽  
pp. 817 ◽  
Author(s):  
D McEAlexander
Keyword(s):  
High Temperature ◽  
Water Stress ◽  
Shoot Growth ◽  
Fruit Set ◽  
Shoot Elongation ◽  
Night Temperature ◽  
Applied Water ◽  
Temperature Regimes ◽  
Controlled Environments ◽  
Maximum Temperatures

Poor fruit set of sultanas in the Murray Valley is sometimes attributed to excessively high temperatures around flowering time. Experiments with small fruiting sultana vines in pots suggest that water stress is the more important factor. Fruit set was significantly less when a 3-day period of water stress was imposed at flowering or 1, 2, or 4 weeks after flowering, but not when it was imposed 6 weeks after flowering. Three days with maximum temperatures above 45°C at or 1 week after flowering did not reduce fruit set when ample water was supplied. When controlled environments combining day temperatures between 21 and 30°C with night temperatures between 19 and 25° were used, no significant differences in fruit set were found, although shoot growth increased with increasing night temperature. Shoot elongation slowed down during periods of applied water stress but recovered, when the stress was ended, to a rate greater than that of plants which had not been stressed.

A METHOD OF PHENOLOGICAL SURVEY FOR USE IN FOREST INSECT STUDIES

1956 ◽  
Vol 34 (6) ◽  
pp. 533-540 ◽  
Author(s):  
R. F. Morris ◽  
F. E. Webb ◽  
C. W. Bennett
Keyword(s):  
Shoot Growth ◽  
Growth Curves ◽  
Great Majority ◽  
Shoot Elongation ◽  
Balsam Fir ◽  
Objective Method ◽  
Forest Insect ◽  
Correct Sequence ◽  
Insect Sampling ◽  
Selection Of

To ensure correct sequence in the timing of insect sampling or control operations over a large forest area it is desirable to know what phenological differences may be expected. Measurements of shoot elongation provide a simple and objective method for comparing a large number of phenological stations in one season. By this method one or more reference stations have to be visited weekly to permit the plotting of growth curves, but the great majority of the stations have to be visited only twice a year. At any one station the major source of variance in cumulative shoot growth on a given date is between trees and the optimum allocation of sampling resources will usually be based on the selection of one shoot per tree and 10 or more trees of balsam fir per station. The variance is greater for cherry and larger samples are necessary.

scholarly journals Changes in Carbohydrate and Nitrogen Relationships during Episodic Growth of Ligustrum japonicum Thunb.

1997 ◽  
Vol 122 (5) ◽  
pp. 634-641 ◽  
Author(s):  
Jeff S. Kuehny ◽  
William B. Miller ◽  
Dennis R. Decoteau
Keyword(s):  
Root Growth ◽  
Plant Tissue ◽  
Shoot Growth ◽  
Soluble Sugars ◽  
Shoot Elongation ◽  
Total Soluble Sugars ◽  
Mature Leaves ◽  
Episodic Growth ◽  
Ligustrum Japonicum ◽  
Leaf Flush

Rooted cuttings of Ligustrum japonicum Thunb., an episodically growing species, were grown hydroponically in a controlled-environment growth chamber to determine allocation of glucose, mannitol, total soluble sugars, and total protein in mature leaves, flush leaves, stems, and roots. During the 65 days of episodic growth, 43% of the total soluble sugars was glucose and 33% mannitol. Glucose concentrations of mature leaves decreased during the first root growth episode, increased in almost all plant tissue during a shoot growth episode and decreased in all plant tissue at initiation of a second root growth episode. Mannitol concentrations in the roots and stems decreased during episodes of root growth and increased during a shoot growth episode when leaf flush mannitol concentrations increased. Radiolabeled C applied to leaves before the initiation of the first period of shoot elongation was translocated to the roots. After shoot elongation, just before a root growth episode, most labeled C was translocated to new shoots and roots. Autoradiographs indicated that subsequent episodes of shoot growth were supported by photosynthate from the previous shoot flush. Protein concentrations decreased in all plant tissues during shoot growth but increased in roots and mature leaves during root growth. Concentrations of 15N in leaf and stem tissue indicated retranslocated N supported each episode of shoot growth. Changes in endogenous C and N concentrations and allocation patterns in ligustrum were linked to the control of episodic shoot and root growth.

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