Convergent‐Divergent Selection for Seed Production and Forage Traits in Orchardgrass: II. Seed Yield Response in Oregon

Crop Science ◽  
1997 ◽  
Vol 37 (4) ◽  
pp. 1054-1059 ◽  
Author(s):  
R. E. Barker ◽  
M. D. Casler ◽  
I. T. Carlson ◽  
C. C. Berg ◽  
D. A. Sleper ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Divergent Selection ◽  
Yield Response ◽  
Selection For

Effect of shallow, rotary cultivation with vertical tines and nitrogen fertilization on the seed productivity of creeping red fescue

2002 ◽  
Vol 82 (4) ◽  
pp. 709-719
Author(s):  
N. A. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Yield Response ◽  
Physiological Status ◽  
Rotor Speed ◽  
Red Fescue ◽  
Time Of Application ◽  
River Region ◽  
Harvest Year ◽  
Seed Crops

A field study in the Peace River region of north-western Canada evaluated the effect of shallow rotary cultivation with vertical tines on the seed production of stands of creeping red fescue (Festuca rubra L. var. rubra). At four sites, rotary cultivation treatments (None, Low, Medium and High tine rotor speed) were applied after the harvest of the first and second seed crops, in factorial combination with the time of application of 68 kg ha-1 N fertilizer (Early fall, Late fall, and Split 1:1 early:late fall). In harvest years 2 and 3, the effect of site on seed yield per unit land area was modified by both N and rotary cultivation. In harvest year 2, seed yield at Site 1 was increased greatly by rotary cultivation, regardless of the tine rotor speed, but there was little difference among the four cultivation treatments at the other three sites. In harvest year 3, seed yield was increased with Low, Medium and High rotary cultivation to 6- to 11-fold that without rotary cultivation at Sites 1 and 2 but only to 1.4- to 2-fold at Sites 3 and 4. Seed yield response to rotary cultivation was dependent on site and year, a reflection of the physiological status of the fescue plants at each specific site. Rotary cultivation treatments may have been too detrimental to tiller growth and development for sustaining and enhancing seed yield, particularly at Sites 3 and 4 prior to harvest year 2. There was no consistent pattern of response in seed yield among the four sites to the three N treatments in either harvest year 2 or 3. Although there was a significant (P < 0.001) N × rotary cultivation interaction for seed yield in harvest year 3, the pattern among cultivation treatments was generally similar for each N treatment; compared to no cultivation, the three cultivation treatments more than doubled seed yield to 255–322 kg ha-1 with Early and Split N and increased it 4- to 6-fold to 203–288 kg ha-1 with Late N. There is some potential for rotary cultivation, but the selected treatments were generally too aggressive in suppressing tillers. Key words: Rejuvenation of creeping red fescue, mechanical rejuvenation, rotary cultivation, power-harrowing, grass seed production

Physiology of growth and seed production in Lupinus angustifolius L. III. Effects of defoliation and lateral branch excision on dry matter and seed production at different growth temperatures

1984 ◽  
Vol 35 (4) ◽  
pp. 511 ◽  
Author(s):  
RW Downes ◽  
JS Gladstones
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Dry Matter ◽  
Reproductive Investment ◽  
Stem Growth ◽  
Lupinus Angustifolius ◽  
Yield Response ◽  
Vegetative Development ◽  
Pod Number ◽  
Cool Conditions

Plants of Lupinus angustifolius cv. Unicrop were raised at 27/22 or 21/16�C dayhight temperatures until flowering. They were then either grown on to maturity at these conditions or moved to the other regime. Branches were removed as they started to develop and leaves were removed at the start of flowering so that 0, 3, 6, 9, 12 upper leaves or all 21 leaves were retained. Conditions before flowering determined potential pod number. Defoliation treatments revealed that under favourably cool conditions all leaves contributed to seed yield but in treatments involving 27/22'C there was no seed yield response to more than about six leaves, emphasizing the significance of environmental conditions rather than current assimilate on pod set and other yield components. In another experiment, plants were raised to flowering at 27/22, 21/16 or 15/10�C before flowering, when all were moved to 21/16�C. Half the plants were allowed to develop branches and on the remainder branch buds were removed. Branch and stem growth appeared to provide severe competition for the development of the primary inflorescence. Though branching was much more pronounced in plants at 15/10�C before flowering than in other treatments, vegetative development exceeded reproductive investment and harvest index was low under these conditions. It was suggested that there appears to be a need to develop and evaluate unbranched or less-branched lupin genotypes.

Convergent‐Divergent Selection for Seed Production and Forage Traits in Orchardgrass: I. Direct Selection Responses

Crop Science ◽  
1997 ◽  
Vol 37 (4) ◽  
pp. 1047-1053 ◽  
Author(s):  
M. D. Casler ◽  
I. T. Carlson ◽  
C. C. Berg ◽  
D. A. Sleper ◽  
R. E. Barker
Keyword(s):  
Seed Production ◽  
Divergent Selection ◽  
Direct Selection ◽  
Selection Responses ◽  
Selection For

scholarly journals Influence of Detasseling Methods on Seed Yield of Some Parent Inbred Lines of Turda Maize Hybrids

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 729
Author(s):  
Alexandru Bogdan Ghețe ◽  
Voichița Haș ◽  
Roxana Vidican ◽  
Ana Copândean ◽  
Ovidiu Ranta ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Weather Conditions ◽  
Inbred Lines ◽  
Plant Performance ◽  
Yield Response ◽  
Genetic Purity ◽  
Short Period ◽  
Number Of Leaves ◽  
Hybrid Maize

During the process of maize seed production, in order to ensure the genetic purity of parental forms of hybrid maize, an important work performed is the removal of male inflorescences from plants on mother rows. Hand detasseling has high precision but is labor-intensive. Mechanical detasseling offers the possibility to cover large acreages in a short period of time, but the number of leaves removed has a varying influence on plant performance and seed yield. The aim of this study was to simulate three types of damages on plants similar to those induced through mechanical detasseling and to assess the effects for five inbred lines during the course of three years. Results show that when tassels alone were removed, the average seed yield decreased an average of 4–21%. When two leaves were removed with the tassel, yield decreased an average of 22–31%, while when plants were cut above the main ear, seed yield decreased an average of 31–66%. Environmental conditions influenced seed yield, especially high temperatures during flowering. Yield response to tassel and leaves removal varied between the inbred lines. Genotype controls maize ear and kernel characters, while environmental factors exercise a strong influence on seed yield, due to the succession of years with contrasting weather conditions in a key phenophase. Within the trend of full mechanization in agriculture, identification of inbred lines that cope better with plant damage can assist in optimizing seed production.

SEED YIELD RESPONSE OF THREE FORAGE GRASSES TO THINNING

1972 ◽  
Vol 52 (4) ◽  
pp. 613-618 ◽  
Author(s):  
R. S. FULKERSON
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Yield Response ◽  
Forage Grasses ◽  
Production Methods ◽  
Orchard Grass ◽  
Row Width ◽  
Weight Data

Orchard grass, timothy, and bromegrass were grown for seed production in 35.5- and 71.0-cm row widths, containing plants in a solid or in a 35.5-cm thinned row arrangement. Seed yield, head numbers, head length, seed per head, and seed weight data were collected for 3–5 crop years. Orchard grass produced its highest yield of seed from the 71.0-cm thinned rows. Yield differences were present for the first 3 years only. Yield components were affected to a larger extent by row width than by thinning. However, with timothy, row widths did not influence yield and components some years. The production methods affected the bromegrass seed crop in the 1st crop year but had no influence by the 3rd year. Although some relations were established between seed yield and the components with the species studied, none appeared to clarify the physiological relations involved.

Forage seed yield response to N and P fertilizers and soil nutrients in northeastern Saskatchewan

1999 ◽  
Vol 79 (2) ◽  
pp. 265-271 ◽  
Author(s):  
H. A. Loeppky ◽  
P. R. Horton ◽  
S. Bittman ◽  
L. Townley-Smith ◽  
T. Wright ◽  
...  
Keyword(s):  
Seed Production ◽  
Soil Nutrients ◽  
Seed Yield ◽  
Yield Response ◽  
Soil N ◽  
Smooth Bromegrass ◽  
Available N ◽  
Intermediate Wheatgrass ◽  
Seed Yields ◽  
P Fertilizers

There is no information on the effect, in northeastern Saskatchewan, of N and P fertilizers on forage seed production as influenced by these nutrients in the soil. Therefore, experiments were conducted at eight sites from 1988 to 1991 to determine the effect of N and P fertilizers and soil nutrients on seed yields of alfalfa (Medicago media Pers.), smooth bromegrass (Bromus inermis Leyss.), crested wheatgrass (Agropyron cristatum L.), intermediate wheatgrass (Agropyron intermedium [Host.] Beauv.) and timothy (Phleum pratense L.). Nitrogen fertilizer (urea) was applied on grasses annually at 0, 50, 100 and 150 kg N ha−1 in factorial combination with 0, 9 and 18 kg P ha−1 (monoammonium phosphate and triple superphosphate) and on alfalfa at 0 and 50 kg N ha−1 in combination with 0, 9, 18, 26 and 53 kg P ha−1. Nitrogen significantly increased forage seed yields of all species except alfalfa. Phosphorus increased yields of forage seed for all crops except intermediate wheatgrass. The site, N, P and year and their interactions influenced seed yields. Seed yields ranged from a low of 0.29 t ha−1 for smooth bromegrass in 1990, a dry year, to a high of 1.24 t ha−1 in 1989 a cool, moist year. The yield response to N and P fertilizers was affected by available soil N and P. Relative to control, the percentage increase in grass seed yield from applied N and P fertilizers was highly related to the available soil N and P (R2 = 0.93). The estimated smooth bromegrass seed yield response to 50N–9P kg ha−1 was 0.54 t ha−1 when the soil had intermediate amounts of available N and P (2 mg N ha−1 and 8 mg P ha−1, 0- to 60-cm and 0- to 15-cm depths, respectively). On a soil that tested high in available N and P, there was no response to fertilizer. Regression equations were developed that can be used to estimate forage seed yield response of different species in relation to available soil nutrients. These results are useful for estimating the most economical return on fertilizer investment for forage seed production in Saskatchewan. Key words: Forage, seed, N, P, fertilizer, soil tests, correlation

scholarly journals Response to selection for seed yield in six white clover cultivars

2004 ◽  
pp. 103-110 ◽  
Author(s):  
K.H. Widdup ◽  
D.R. Woodfield ◽  
I.J. Baird ◽  
P.T.P. Clifford
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
White Clover ◽  
Trifolium Repens ◽  
Leaf Size ◽  
Fourth Generation ◽  
Selection Strategy ◽  
Flowering Pattern ◽  
Selection For ◽  
The Impact

The successful commercialisation of agronomically superior white clover (Trifolium repens) cultivars is dependent on their seed production potential. Field trials were established in 2000 and repeated in 2003 to determine the impact of selection for increased seed yield. The seed yield of the pre-release cultivar (the base population prior to selection for seed yield and cultivar release, representing generation 0) was compared with the field Nucleus generation of the released cultivar (second generation after selection for seed yield, representing generation 2) and the Basic seed generation (the fourth generation after selection for seed yield, representing generation 4), in six recent cultivars (Grasslands Kopu II, Grasslands Challenge, NuSiral, Grasslands Sustain, Grasslands Demand and Grasslands Prestige). The Nucleus and Basic generations had consistently higher seed yield than the pre-release generation for all cultivars. These increases in seed yield were associated with increases in inflorescence density (inflorescences/m2) and to a lesser extent with increased seed yield/inflorescence. Changes were also evident in flowering pattern with four of the six cultivars having a sharper flowering peak following selection. This improved uniformity was also evident through reduced variability in leaf size of the Nucleus generation compared to the pre-release generation. Grasslands Kopu II had the highest seed yields which were associated with moderately high inflorescence density in combination with high seed yield/ inflorescence. The selection strategy used in the final phase of the development of these cultivars has proven successful in increasing seed yield through refining flowering pattern and production while maintaining the morphology and uniformity of the new cultivar. Keywords: cultivars, genetic improvement, seed production, Trifolium repens, white clover

scholarly journals SELECTION FOR HIGHER SEED YIELD IN ALFALFA

1965 ◽  
Vol 45 (2) ◽  
pp. 177-183 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Forage Yield ◽  
The Other ◽  
Yielding Ability ◽  
Parent Variety ◽  
Progeny Tests ◽  
Selection For ◽  
Clonal Lines ◽  
Seed Yields

A breeding program was undertaken in 1957 at Swift Current, Sask., to improve the seed-yielding ability of the variety Rambler. Plants heavily set with seed were selected and evaluated by polycross progeny tests. More than two-thirds of the polycross progeny lines yielded more seed than the parent Rambler variety at each of two locations. There was no significant association of line performance between the two locations. At one location the polycross progeny lines tended to yield in the same order in three successive years, the r values between them being +.571, +.606, and +.493. There was no association between the seed yield of parental clonal lines and their polycross progenies measured in different years. In spite of great inconsistencies in seed yields between locations, it was possible to form a tentative synthetic from eight clones, which, by prediction, should yield about 30% more seed than Rambler at one location and 13% more at the other, with forage yield and winterhardiness remaining the same as that of the parent variety. It is suggested that a precise record be kept of the species of bees doing the pollinating at various locations in order to evaluate the reasons for differential seed production of lines at each location.

Responses of soybean genotypes to intercropping with maize in the Southern Guinea Savanna, Nigeria

2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa
Keyword(s):  
Seed Yield ◽  
Block Design ◽  
Field Trials ◽  
Yield Response ◽  
Ecological Zone ◽  
Land Equivalent Ratio ◽  
Guinea Savanna ◽  
Days To Maturity ◽  
Soybean Genotypes ◽  
Location Interaction

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.

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