Dwarf sunflower response to row spacing, stand reduction, and defoliation at different growth stages

2003 ◽  
Vol 83 (2) ◽  
pp. 319-326 ◽  
Author(s):  
B. L. Johnson
Keyword(s):  
Helianthus Annuus ◽  
Oil Content ◽  
Growth Stage ◽  
Total Yield ◽  
Reciprocal Relationship ◽  
Yield Response ◽  
Yield Reduction ◽  
Row Spacing ◽  
Growth Stages ◽  
Helianthus Annuus L

Growth compensation of dwarf sunflower (Helianthus annuus L.) hybrids to low initial stands, later stand losses, or plant defoliation has not been reported regarding replanting decisions and crop insurance yield loss assessment. Three experiments were conducted to study the affect of stand reduction, defoliation, and row spacing on dwarf sunflower yield and quality when grown in eastern North Dakota. Experiment 1 evaluated stand reduction (0, 25, 50 and 75%) applied at growth stages (V4, R1 and R6) in 15, 45 and 76 cm spaced rows. Row spacing interactions with stand reduction and growth stage were not significant for yield indicating growth stage and stand reduction effects on yield response were independent of row spacing. In exp. 2, significant growth stage (V4, V8, R1, R2, R3, R5 and R6) by stand reduction (0, 12, 25, 37, 50, 62 and 75%) interaction showed stand reduction at vegetative growth stages not influencing yield, but as maturity progressed yield reductions became greater with increased stand reduction. Achene weight increased with increasing stand reduction at vegetative and early reproductive stages. A reciprocal relationship was noted between achene weight and achene oil content where oil content decreased as achene weight increased. Interaction of growth stage (R1 and R6) and defoliation (0, 25, 50, 75 and 100%) in exp. 3 indicated greater reduction in yield, test weight, 1000-achene weight, and achene oil conte nt as defoliatin increased at growth stage R6. Yield compensating ability of dwarf sunflower is dependent on type and level of damage and growth stage of occurrence, with total yield reduction considering all effects. Key words: Sunflower, Helianthus annuus L., row spacing, stand reduction, defoliation

Greenhouse Data suggest that Growth Stage Impacts Phomopsis Stem Canker Severity Associated with Diaporthe gulyae on Sunflower (Helianthus annuus L.)

2021 ◽  
Author(s):  
Renan Guidini ◽  
Nathan Braun ◽  
Mammen Korah ◽  
Laura Marek ◽  
Febina Mathew
Keyword(s):  
Helianthus Annuus ◽  
Disease Severity ◽  
Growth Stage ◽  
Rating Scale ◽  
Stem Canker ◽  
Growth Stages ◽  
Post Inoculation ◽  
Resistance Response ◽  
Helianthus Annuus L ◽  
The Impact

Diaporthe gulyae Shivas et al. was initially described as causing Phomopsis stem canker of sunflower (Helianthus annuus L.) in the U.S. in 2010. In this study, the impact of growth stage on disease severity associated with D. gulyae in cultivated accessions was investigated. One hundred thirty-nine accessions were inoculated with a single isolate of D. gulyae using the mycelium contact inoculation method at V4-V6 (four to six true leaves) and R4-R6 (inflorescence to ray flower wilting) growth stages in the greenhouse. The experiment was conducted in a completely randomized design with six replications and repeated once. Disease severity was assessed at 14 days post-inoculation using a 0-to-5 rating scale. A significant interaction between growth stage and accessions (p<0.0001) was observed for disease severity [relative treatment effect (RTE)] caused by D. gulyae. Among the 139 accessions, 24, three, and two accessions had significantly lower RTE at V4-V6, R4-R6, and both growth stages respectively, based on 95% confidence intervals, when compared to the inbred susceptible check ‘HA 288’. This study suggests that accessions differ in their susceptibility to D. gulyae possibly because of changes in resistance response during host development. Future studies on sunflower-D. gulyae interaction are warranted for developing commercial hybrids with resistance to the causal fungus.

HETEROSIS, COMBINING ABILITY, AND PREDICTED SYNTHETICS FROM A DIALLEL CROSS IN SUNFLOWERS (HELIANTHUS ANNUUS L.)

1966 ◽  
Vol 46 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Eric D. Putt
Keyword(s):  
Helianthus Annuus ◽  
Combining Ability ◽  
Oil Content ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Helianthus Annuus L ◽  
The Mean ◽  
Seed Characters ◽  
Mature Weight

Heterosis occurred for the eight plant and seed characters studied. It was most frequent for yield of seed and height of plant. Mean squares for general combining ability (gca) and specific combining ability (sca) were significant (P =.01) for all characters. The estimated components for gca were greater than for sca for days to mature, weight per bushel, and percent oil in the seed; less for height and yield of seed; and essentially the same for days to bloom, diameter of head, and weight per 1000 seeds.The yield of seed and percent oil in the seed, for the highest ranking 100 synthetics that could be composed from the 10 lines, was predicted in F6 assuming 50 and 60% outcrossing between F2 and F6. Virtually all values exceeded the mean performance of four check samples of commercial hybrids. Many exceeded the highest rank check for oil content in the seed. Fourteen of the highest ranking 100 synthetics for yield and 30 for oil content consisted of two or three lines. It was concluded that synthetics can be superior to the present hybrids in heterosis and that desirable synthetics can be made from only a few lines.

scholarly journals GENETIC DIVERSITY IN NON-OILSEED SUNFLOWER (Helianthus annuus L.) GENOTYPES / DIVERSIDAD GENETICA DE GENOTIPOS NO OLEAGINOSOS DEL GIRASOL (Helianthus annuus L.) / DIVERSITÉ GÉNÉTIQUE DANS LES GÉNOTYPES DE TOURNESOL NON-OLÉAGINEUX (Helianthus annuus L.)

Helia ◽  
2001 ◽  
Vol 24 (34) ◽  
pp. 17-24
Author(s):  
K. Manjula ◽  
H.L. Nadaf ◽  
K. Giriraj
Keyword(s):  
Genetic Diversity ◽  
Protein Content ◽  
Helianthus Annuus ◽  
Plant Height ◽  
Genetic Divergence ◽  
Oil Content ◽  
Diversité Génétique ◽  
Helianthus Annuus L ◽  
Volume Weight ◽  
Seed Characteristics

SUMMARYGenetic diversity was assessed in 46 non-oilseed sunflower genotypes for 14 characters by adopting D2 analysis. Oil content and plant height exhibited maximum contributions towards genetic divergence. The genotypes were grouped into 11 clusters. The inter-cluster D2 values ranged from 288.17 to 3972.34. The contribution of oil content towards genetic divergence in the 46 genotypes was confirmed when D2 analysis was performed for seed characteristics such as test weight, volume weight, hull content, kernel recovery, oil and protein content.

Gene Action in the Expression of Achene Yield and Oil Content in Sunflower (Helianthus annuus L.)

2005 ◽  
Vol 8 (11) ◽  
pp. 1517-1520
Author(s):  
Masood Jan . ◽  
Farhatullah . ◽  
Muhammad Tariq Jan . ◽  
Ghulam Hassan . ◽  
Raziudin .
Keyword(s):  
Helianthus Annuus ◽  
Oil Content ◽  
Gene Action ◽  
Helianthus Annuus L

SIMULATION OF LEAF DAMAGE BY ARTIFICIAL DEFOLIATION AND ITS EFFECT ON SUNFLOWER (Helianthus annuus L.) PERFORMANCE / SIMULACION DEL DAÑO DE HOJA POR LA ELIMINACION ARTIFICIAL DE HOJAS Y SU EFECTO SOBRE LAS PERFORMANCES DEL GIRASOL / SIMULATION DE DÉTÉRIORIATION DES FEUILLES CAUSÉE PAR DEFOLIATION ARTIFICIELLE ET SON EFFET SUR LE TOURNESOL (Helianthus annuus L.)

Helia ◽  
2001 ◽  
Vol 24 (34) ◽  
pp. 145-154
Author(s):  
M.A. Khan Shafiullah ◽  
M.A. Poswal ◽  
M.A. Rana ◽  
M.A. Baitullah
Keyword(s):  
Helianthus Annuus ◽  
Seed Yield ◽  
Agricultural Research ◽  
Leaf Damage ◽  
Yield Reduction ◽  
Atmospheric Conditions ◽  
Foliar Diseases ◽  
Yield Decline ◽  
Helianthus Annuus L ◽  
The Impact

SUMMARY Sunflower (Helianthus annuus L.) hybrid NK-212 was planted at National Agricultural Research Center, Islamabad, during 1992 and 1993 to assess the impact of various levels of simulated leaf damage, commonly caused by insects, hail or foliar diseases, on source and sink relationship. Insect attack, hail and foliar diseases often partially defoliate sunflowers and may become important factors limiting the production. Reduction in leaf area may also occur in the field as a consequence of pathogens or atmospheric conditions. Artificial defoliation was chosen as an experimental means to assess its effect on seed yield and plant behavior. It had also made possible to evaluate the effect of such a reduction at different phenological stages and to identify the leaves that contribute greatly to the seed yield. The leaves were clipped in various proportions from different parts of the plant, i.e., lower, middle and upper. The removal of upper 2/3 and 1/2 leaves caused a yield reduction of 29 and 55.8%, in 1992 and 37 and 44.8%, in 1993, respectively. In 1992, about 1% yield decline was recorded when the lower 1/3 leaves were removed and 6% yield decline with the removal of the lower 1/2 leaves. In 1993, the yield reduction was 26.7 and 39.2% due to removal of lower 1/3 and 1/2 leaves, respectively. This indicated that the upper leaves (source) contribute more towards seed yield (sink) than the lower ones. Correspondingly, the results indicated that insects and pests feeding on the upper portion of the sunflower plant can cause larger reduction in seed yield than those feeding on the lower leaves.

Irrigation of field peas (Pisum sativum): response to timing at different crop growth stages

1999 ◽  
Vol 132 (4) ◽  
pp. 417-424 ◽  
Author(s):  
C. M. KNOTT
Keyword(s):  
Pisum Sativum ◽  
Vegetative Growth ◽  
Growth Stage ◽  
Crop Growth ◽  
Yield Response ◽  
Growth Stages ◽  
Field Peas ◽  
Crop Growth Stages ◽  
Different Growth Stages

The response of two cultivars of dry harvest field peas (Pisum sativum), Solara and Bohatyr, to irrigation at different growth stages was studied on light soils overlying sand in Nottinghamshire, England in 1990, when the spring was particularly dry, in 1991 which had a dry spring and summer and in contrast, 1992, when rainfall was greater compared with the long-term (40 year) mean.Solara, short haulmed and semi-leafless was more sensitive to drought than the tall conventional-leaved cultivar Bohatyr and gave a greater yield response to irrigation, particularly at the vegetative growth stage in the first two dry years 1990 and 1991, of 108% and 55% respectively, compared with unirrigated plots. Bohatyr was less sensitive to the timing of single applications.In all years, peas irrigated throughout on several occasions produced the highest yields, but this was the least efficient use of water.

EFFECT OF PLANT DENSITY ON THE AGRONOMIC PERFORMANCE OF SUNFLOWER ON DRYLAND

1984 ◽  
Vol 64 (3) ◽  
pp. 599-605 ◽  
Author(s):  
N. W. HOLT ◽  
S. J. CAMPBELL
Keyword(s):  
Helianthus Annuus ◽  
Seed Weight ◽  
Oil Content ◽  
Seed Oil ◽  
Plant Density ◽  
Agronomic Traits ◽  
Agronomic Performance ◽  
Head Diameter ◽  
Helianthus Annuus L ◽  
Days To Maturity

This study investigated the influence of plant density on several agronomic traits of four sunflower (Helianthus annuus L.) cultivars grown at Indian Head and Saskatoon, Saskatchewan in the semiarid prairies. At populations of 40 000–85 000 plants∙ha−1, plant density had no significant effect on seed yield. The increase in percentage oil content with increase in plant density (44.3–45.6%) was small but significant. As plant density was increased, days to flower, height and test weight increased while days to maturity, head diameter and average seed weight decreased. Cultivars × density interactions were generally not significant. Environment (five location-years) had a significant effect on all variables, and environments × cultivar interactions were significant for most of these. Results of this experiment indicated that testing of sunflower lines at several locations in the growing area would be necessary for best assessment but one plant density, suitable to that area, could be used.Key words: Sunflower, plant density, seed, oil, seed size, Helianthus annuus L.

scholarly journals Response of irrigated sunflower (Helianthus annuus L.) hybrids to nitrogen fertilization: growth, yield and yield components

2011 ◽  
Vol 50 (No. 5) ◽  
pp. 205-211 ◽  
Author(s):  
H. Özer ◽  
T. Polat ◽  
E. Öztürk
Keyword(s):  
Helianthus Annuus ◽  
Nitrogen Fertilization ◽  
Yield Components ◽  
Growth Yield ◽  
N Fertilization ◽  
Yield Response ◽  
Sufficient Information ◽  
Helianthus Annuus L ◽  
Application Rates ◽  
Yield And Yield Components

N fertilization has a substantial influence on sunflower (Helianthus annuus L.) seed yield and quality. It was also well established that high-yielding sunflower hybrids had more N requirement than old cultivars such as open-pollinated ones. However, in Turkey, no sufficient information regarding the response of new developed oilseed sunflower hybrids to nitrogen fertilization under irrigated conditions. Therefore, a 2-year study was conducted to determine the effects of nitrogen application rates on the growth, yield, and yield components of two oilseed sunflower hybrids (AS-508 and Super 25) under irrigated conditions. In this study, all plant parameters were significantly influenced by applied nitrogen fertilizer rates. Yield response to nitrogen rates was positive and linear. Our research data indicated that under irrigated conditions N rate of 120 kg/ha was adequate for sunflower production in this region.

Influence of Herbicide Injury on the Yield Potential of Soybeans (Glycine max)

Weed Science ◽  
1980 ◽  
Vol 28 (1) ◽  
pp. 40-45 ◽  
Author(s):  
E. S. Hagood ◽  
J. L. Williams ◽  
T. T. Bauman
Keyword(s):  
Glycine Max ◽  
Early Growth ◽  
Yield Potential ◽  
Yield Response ◽  
Yield Reduction ◽  
Growth Stages ◽  
The Relationship

The relationship between herbicide injury and soybean [Glycine max(L.) Merr. ‘Amsoy 71’] yield response was studied under weed free conditions at three locations. Reduced crop vigor at early growth stages was not an adequate indicator of yield response. Yield reduction was greater when soybean stand was reduced by herbicides than when stand was reduced to the same level by hand thinning. Yield response was a function of the degree and persistence of crop vigor reduction in a reduced stand of soybeans.

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