The growth of young peach trees following infection by the viruses of peach rosette and decline disease

1977 ◽  
Vol 28 (3) ◽  
pp. 441 ◽  
Author(s):  
PR Smith ◽  
TF Neales

The vegetative growth of young peach trees was reduced greatly in the growing season following a dual infection with Prunus necrotic ringspot and prune dwarf viruses which caused the disease known as 'peach rosette and decline'. Ninety-two days after bud burst, the dry weight and leaf area of cv. Elberta scions were reduced by c. 60% as a result of infection, while the reduction in cv. Golden Queen was about 93%. The latter cultivar thus appears to be the less tolerant of infection by this virus disease.

1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.


2016 ◽  
Vol 47 (4) ◽  
Author(s):  
Sadik & et al.

This study was conducted in experimental fields, Department of Horticulture, University of Bagdad, in Abu-Graib  during season 2011-2012 for jerusalum artichoke. This study was included the effect of dipping tubers in three concentrations of GA3(2.5,5,10g/l) (G1,G2,G3),as well as to control treatment (G0), and spraying nutrient solution Agro leaf A1 (8g/l), as well as to control treatment (A0). This study was made by using Factorial experiment (4*2) within the design RCBD with three replicates. Results could be summarized as follows: G3A0 increased field emergence (12.00 day), G2A0 increased percentage of germination (99.33%) and G2A1 increased number of branches (4.60 stem.plant-1) but the treatment G1A1gave highest rate for number of leaves, leaf area, guide of leaf area, dry weight of the vegetative parts and dry weight of 100gm tubers as(4495.10 leaf.plant-1, 2246.20 dsm2, 99.84, 922.40g, 24.00g.) respectively. The treatments gave significant differences quantity yield, so treatment G3A0 gave highest weight of the tubers as(45.55g.) but the treatment G3A1 gave highest number of the tubers as(68.00 tuber.plant-1 ) and highest yield of plant as (2890g/plant).


1998 ◽  
Vol 130 (4) ◽  
pp. 451-462 ◽  
Author(s):  
D. ROUSSOPOULOS ◽  
A. LIAKATAS ◽  
W. J. WHITTINGTON

The growth and development of cotton was studied on cotton plants grown in pots in growth rooms under constant day/night temperature (C) and varying temperature regimes throughout the day and/or night (V) The V-treatments had a common mean temperature of 22°C. The objectives were to determine the thermal requirements of three cultivars and to observe the extent of genotype×thermal environment interactions throughout the entire growth period.Vegetative growth was found to be almost exclusively time and temperature dependent, varietal differences being largely insignificant. Plant material was found to accumulate four times faster under the warmest C-regime, which was 7°C warmer than the coolest. The C-treatments caused variation in the number and size of lateral shoots and leaves, causing leaf area to be larger at the squaring stage in cool environments but at maturity in warm regimes. Relatively cool nights lowered the position of the first floral or fruiting branch, whereas warm days shortened flowering intervals and thus promoted earliness. However, the effect of temperature in altering the position of the first floral branch seems to be less important than its effect on the shedding of early squares.The effects of fluctuating temperature (V) on vegetative growth and earliness were similar to those from constant temperature environments. Growth and development rates were low in the low minimum V-regimes, especially when the maximum temperature was also low. Temperature variation affected vegetative growth to a greater extent in the early than in the later stages of development. At squaring, leaf area and dry weight were lowest under the regime with the highest minimum and maximum temperatures. Later on, only leaf area at flowering and total dry weight at maturity significantly differed between treatments. High maximum or minimum temperatures produced effects similar to a higher or lower mean temperature, respectively. The low minimum raised the node number of the first floral or fruiting branch, whereas in the case of boll dry weight it acted in the same way as a further drop in temperature, decreasing the weight, regardless of the maximum temperature. Boll period was affected mainly by the temperature variation itself rather by than the type of variation.The inverse of time to a certain stage and the corresponding mean temperature were linearly related and allowed threshold temperatures (T0) and thermal time requirements to be estimated. T0=12°C, except for the initial stage, when it was lower. A cotton growing season cooler on average by only 1°C will considerably delay maturity.


1994 ◽  
Vol 8 (1) ◽  
pp. 154-158 ◽  
Author(s):  
William E. Haigler ◽  
Billy J. Gossett ◽  
James R. Harris ◽  
Joe E. Toler

The growth, development, and reproductive potential of several populations of organic arsenical-susceptible (S) and -resistant (R) common cocklebur biotypes were compared under noncompetitive field conditions. Plant height, leaf area, aboveground dry weights, and relative growth rate (RGR) were measured periodically during the growing season. Days to flowering, bur dry weight, and number of burs per plant were also recorded. Arsenical S- and R-biotypes were similar in all measured parameters of growth, development, and reproductive potential. Populations within each biotype varied occasionally in plant height, leaf area, aboveground dry weights, and reproductive potential.


Weed Science ◽  
1986 ◽  
Vol 34 (6) ◽  
pp. 876-882 ◽  
Author(s):  
David T. Patterson ◽  
Ann E. Russell ◽  
David A. Mortensen ◽  
Robert D. Coffin ◽  
Elizabeth P. Flint

Texas panicum (Panicum texanumBuckl. # PANTE) is a native of the Southwest, now increasing as a weed throughout the southern United States, whereas wild proso millet (Panicum miliaceumL. # PANMI) is an introduced weed currently increasing in importance in the northern Midwest. In controlled-environment chambers, both species produced more tillers, greater leaf area, and more total dry weight at 30/24 C day/night (simulated growing season temperature in Georgia) than at 24/18 C (simulated growing season temperature in Minnesota). Texas panicum accumulated more dry matter at 30/24 C than did wild proso millet, while wild proso millet accumulated more dry matter at 24/18 C than did Texas panicum. When the two species were grown together, Texas panicum was the superior competitor at 30/24 C while wild proso millet was superior at 24/18 C. Exposure to short photoperiods at an intermediate temperature of 27/21 C accelerated flowering and limited vegetative growth in both species. In the range of photoperiods (10 to 16 h) examined, wild proso millet always flowered earlier and, consequently, produced less vegetative growth than Texas panicum. Its responses to temperature and photoperiod indicate that wild proso millet probably would be competitively inferior to Texas panicum and other adapted grass weeds in the southern United States.


2008 ◽  
Vol 43 (No. 3) ◽  
pp. 109-117 ◽  
Author(s):  
H.K. Shannag ◽  
J.M. Al-Qudah ◽  
I.M. Makhadmeh ◽  
N.M. Freihat

The reactions of five commercial varieties of okra, <i>Abelmoschus esculentus</i>, to <i>A. gossypii</i> were evaluated under semiarid field conditions. Each experimental plant of varieties Clemson spineless, Clemson spineless 80, Lee, Perkins dwarf, and Local was infested 60 days after emergence by three late-nymphal instars of the aphid. The results showed that aphid populations increased constantly on the varieties, except for days 42 and 49 after infestation, attaining a peak at about the end of the growing season. Differences in aphid densities were recorded between varieties. The aphids were most numerous on var. Local, while lowest in number on var. Lee. Infestation by aphids on okra varieties reduced yield by 57% on var. Perkins dwarf, 56% on var. Lee, 24% on var. Clemson spineless, 21% on var. Clemson spineless 80, and 5% on var. Local. Reduction in the number of pods produced per plant followed the same pattern as observed for total yield. Aphids had not altered significantly the vegetative plant growth at day 37 following infestation. At day 66, a substantial decrease in shoot fresh and dry weights and also leaf area was evident on var. Perkins dwarf while on var. Clemson spineless only the leaf area was significantly reduced. Moreover, aphid-free controls varied widely in their growth and productivity at the end of growing season. Varieties Clemson spineless and Clemson spineless 80 produced the highest total yield and pod numbers, var. Local the lowest. The varieties Perkins dwarf and Clemson spineless produced significantly higher shoot fresh and dry weight, as well as leaf area, than vars. Lee and Local.


1970 ◽  
Vol 74 (2) ◽  
pp. 363-374 ◽  
Author(s):  
O. Ojeaga Ojehomon

SUMMARYThe vegetative growth, flowering and seed yield of three cowpea varieties—Adzuki, Mala and New Era—with contrasting yields, were compared in one field and two greenhouse experiments. In the field the plants were spaced so far apart that they did not form a closed stand, but were effectively individuals, like the potted plants used in the greenhouse experiments. In all experiments New Era yielded most followed by Mala, although the differences between these two varieties were not significant, and Adzuki least.Seed yield and vegetative growth were not simply related. New Era with the highest seed yield had the largest vegetative dry weight, leaf area and leaf area duration (D), followed by Mala, with Adzuki always least in each parameter. However, the superiority of New Era in total dry weight and leaf area was much greater than in seed yield. Mala and Adzuki were more efficient than New Era in converting dry matter into seed. Large fractions of current assimilates moved from the leaves to the seed of Adzuki and Mala than of New Era.Varietal differences in relative growth rate, net assimilation rate, or leaf area ratio were too small to account for varietal differences in seed yield.New Era and Mala produced more flower buds than Adzuki. However, Adzuki developed the largest proportion of ripe fruits, but had more aborted seeds/fruit than New Era and Mala. Thus, increased flower production and fruit formation did not increase the production of mature seeds. Therefore, little would be gained by breeding or selecting for increased flower production. The heavier seeds of Mala and New Era compared with those of Adzuki contributed greatly to their larger yields. At the spacing of 3 ft x 1 ft used in the field, the leaf area index (L) and leaf area duration (D) were suboptimal, and closer spacing should increase yield.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 614b-614
Author(s):  
A.M. Akl ◽  
A.M. Wassel ◽  
F.F. Ahmed ◽  
M.A. Abdel Hady

This study was performed during the 1991, 1992, and 1993 seasons to study the effect of different concentrations and number of sprays urea and/or boric acid on behavior of buds, vegetative growth, and vine nutritional status of Red Roomy grape vines. Two, three, four, or five sprays for both urea at 0.5%, 1.0%, or 1.5% and/or boric acid at 0.1%, 0.2%, 0.3% in addition to the control treatments were applied. A gradual increase was observed in the percentages of burst and fruiting buds, main branch length, leaf area, cane thickness, total chlorophyll, and total carbohydrates in the leaves and considerable depression was observed in the percentages of dormant and vegetative buds. The most pronounced effect on growth and nutritional status was detected on vines sprayed four times with urea at 1.0% plus boric acid at 0 2% during the growing season.


2011 ◽  
Vol 68 (2) ◽  
pp. 191-199 ◽  
Author(s):  
María Teresa Castellanos ◽  
María Jesús Cabello ◽  
María del Carmen Cartagena ◽  
Ana María Tarquis ◽  
Augusto Arce ◽  
...  

Nitrogen (N) is an important nutrient for melon (Cucumis melo L.) production. However there is scanty information about the amount necessary to maintain an appropriate balance between growth and yield. Melon vegetative organs must develop sufficiently to intercept light and accumulate water and nutrients but it is also important to obtain a large reproductive-vegetative dry weight ratio to maximize the fruit yield. We evaluated the influence of different N amounts on the growth, production of dry matter and fruit yield of a melon 'Piel de sapo' type. A three-year field experiment was carried out from May to September. Melons were subjected to an irrigation depth of 100% crop evapotranspiration and to 11 N fertilization rates, ranging 11 to 393 kg ha-1 in the three years. The dry matter production of leaves and stems increased as the N amount increased. The dry matter of the whole plant was affected similarly, while the fruit dry matter decreased as the N amount was increased above 112, 93 and 95 kg ha-1, in 2005, 2006 and 2007, respectively. The maximum Leaf Area Index (LAI), 3.1, was obtained at 393 kg ha-1 of N. The lowest N supply reduced the fruit yield by 21%, while the highest increased the vegetative growth, LAI and Leaf Area Duration (LAD), but reduced yield by 24% relative to the N93 treatment. Excessive applications of N increase vegetative growth at the expense of reproductive growth. For this melon type, rates about 90-100 kg ha-1 of N are sufficient for adequate plant growth, development and maximum production. To obtain fruit yield close to the maximum, the leaf N concentration at the end of the crop cycle should be higher than 19.5 g kg-1.


1991 ◽  
Vol 116 (3) ◽  
pp. 454-459 ◽  
Author(s):  
Richard P. Marini ◽  
Donald Sowers

Twenty-eight-year-old `Starkrimson Delicious' and 10-year-old `Fullred Delicious' apple (Malus domestics Borkh.) trees were spur-pruned in 1986 and 1987 and/or treated with 500 mg BA + GA4+7/liter in 1986 in an attempt to improve spur growth and increase fruit weight. All treatment combinations generally failed to improve yield or fruit size. BA + GA4+7 reduced yield and fruit weight and increased the number of pygmy fruit in 1986, but had little effect on fruiting or vegetative growth for 3 years after treatment. Spur-pruning reduced spur density in 1986 and 1987 and increased yield, but not fruit weight, in 1987. Although spur-pruning improved spur length, spur bud diameter, leaf area per spur, and leaf dry weight per spur, fruit weight was not improved. Chemical names used: N-(phenylmethyl)-1H -purine-6-amine [benzyladenine (BA)]; gibberellin (GA4+7).


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