scholarly journals Self-Fertilization, Inbreeding, and Yield in Alfalfa Seed Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Molly E. Dieterich Mabin ◽  
Johanne Brunet ◽  
Heathcliffe Riday ◽  
Lauren Lehmann
Keyword(s):  
Pacific Northwest ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Seed Yield ◽  
Seed Set ◽  
Central Valley ◽  
Selfing Rate ◽  
Alfalfa Seed ◽  
The Impact ◽  
Number Of Seeds

Selfing (self-pollination) is the ultimate form of inbreeding, or mating among close relatives. Selfing can create yield loss when inbreeding depression, defined as a lower survival and reproduction of inbred relative to outbred progeny, is present. To determine the impact of selfing in alfalfa (Medicago sativa L.), we quantified the selfing rate of 32 alfalfa seed production fields located in three regions, namely, the Pacific Northwest (PNW), the Central Valley of California (CEV), and the Imperial Valley of California (IMP). Selfing rates (the proportion of selfed seeds) varied between 5.3 and 30% with an average of 12.2% over the 32 seed production fields. In both the parents and their progeny, we observed an excess of heterozygotes relative to Hardy–Weinberg expectations. We detected notable levels of inbreeding in parents (0.231 ± 0.007 parental inbreeding coefficient) and progeny (0.229 ± 0.005). There were a 15% decrease in the number of seeds per stem (seed set) and a 13% decline in the number of seeds per pod in selfed relative to outcrossed stems, but negligible inbreeding depression for pods per raceme and seed weight. The number of racemes on selfed stems increased significantly in fields with greater selfing rates, supporting the presence of geitonogamous or among flower selfing. Despite the significant level of inbreeding depression, seed set did not decrease in fields with higher selfing rates, where the greater number of racemes on the selfed stems increased the seed set. The effects of the field selfing rate on the seed yield metrics were mostly indirect with direct effects of the number of racemes per stem. Available data indicate that the majority of selfing in alfalfa is pollinator-mediated, and thus, eliminating selfing in alfalfa seed production would require the selection of self-incompatible varieties, which, by eliminating inbreeding depression, would provide a 15% potential increase in seed yield and an increase in future hay yield.

Residue management increases seed yield of three turfgrass species on the Canadian prairies

2002 ◽  
Vol 82 (4) ◽  
pp. 687-692 ◽  
Author(s):  
B. D. Gossen ◽  
J. J. Soroka ◽  
H. G. Najda
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Poa Pratensis ◽  
Creeping Bentgrass ◽  
Kentucky Bluegrass ◽  
Residue Management ◽  
Row Spacing ◽  
Seeding Rate ◽  
Canadian Prairies ◽  
The Impact

Little information is available on the management of turfgrass species for seed production in the Canadian prairies. The objective of these studies was to assess the impact of residue management and row spacing on seed yield under irrigation. A factorial experiment was seeded at Saskatoon, SK, in 1993 to assess the impact of burning or scalping (very close mowing with residue removal) vs. mowing, and 20- vs. 40-cm row spacing on seed yield of Kentucky bluegrass (KBG) (Poa pratensis), creeping red fescue (CRF) (Festuca rubra subsp. rubra) and creeping bentgrass (CBG) (Agrostis palustris). Also, a residue management trial on KBG was seeded at Brooks, AB, in 1993. At Saskatoon, yield was higher at 20-cm spacing across all three species in 1994, but spacing had no impact on winter survival, stand density, tiller growth or yield in subsequent years. Burning and scalping consistently resulted in earlier spring green-up, a higher proportion of fertile tillers, and higher seed yield than mowing. Even with residue management, yield declined after one harvest in CBG and CRF, and after two harvests in KBG. At Brooks, residue management had a similar impact on yield of KBG. A second trial at Brooks examined the impact of row spacing (20, 40, 60 cm) and seeding rate (0.5 to 6 kg seed ha-1) on KBG. Seed yield was highest at 40-cm spacings in 1994, at 60 cm in 1995, and at 40 to 60 cm in 1996. Seeding rate did not have a consistent effect on yield. We conclude that a combination of residue management and 20- to 40-cm spacings provide the highest, most consistent seed yields for these turfgrass species in this region. Key words: Burning, clipping, turfgrass, seed production, row spacing, Poa, Festuca, Agrostis

Preharvest glyphosate in alfalfa for seed production: Effect on alfalfa seed yield and quality

2003 ◽  
Vol 83 (1) ◽  
pp. 189-197 ◽  
Author(s):  
W. E. May ◽  
H. A. Loeppky ◽  
D. C. Murrell ◽  
C. D. Myhre ◽  
J. J. Soroka
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Quality ◽  
Seedling Emergence ◽  
Canada Thistle ◽  
Seedling Vigour ◽  
Yield And Quality ◽  
Alfalfa Seed ◽  
Medicago Sativa L ◽  
Seed Yields

Preharvest applications of glyphosate have been shown to be effective in controlling Canada thistle in annual crops, but may reduce alfalfa seed yield depending on time and rate of application. The objective of this study was to determine the effect of preharvest applications of glyphosate on subsequent alfalfa seed yield and quality. The effects of timing, 1, 26, 51 and 76% alfalfa seed pod maturity, and rate, 0, 440, 880, 1320, and 1760 g a.i. ha-1, of a preharvest application of glyphosate on alfalfa seed yield and quality in the year of application, and regrowth and seed yield in the following year were determined. The rate of glyphosate applied did not affect seed yield in the application year; however, in the following year, growth and seed yield were reduced as rates increased. Delaying the application of glyphosate increased seed yields in the application year, but decreased alfalfa regrowth and flowering the following year. Germination and seedling emergence were not affected by the rate or timing of the glyphosate. A preharvest application of glyphosate at 1760 g a.i. ha-1 at 76% pod maturity is a viable option in the last year of seed production. Key words: Alfalfa (Medicago sativa L.), glyphosate, abnormal seeds, seed quality, and seedling vigour

Effect of companion perennial grasses and lucerne on seed yield and regeneration of subterranean clover in two wheatbelt environments

2001 ◽  
Vol 52 (10) ◽  
pp. 973 ◽  
Author(s):  
B. S. Dear ◽  
J. M. Virgona ◽  
G. A. Sandral ◽  
A. D. Swan ◽  
B. A. Orchard
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Bank ◽  
Seed Set ◽  
Subterranean Clover ◽  
Seedling Regeneration ◽  
Early Autumn ◽  
Background Population ◽  
Seed Reserves ◽  
Clover Seed

Seed production of subterranean clover (Trifolium subterraneum L.) in mixtures with lovegrass (Eragrostis curvula (Schrader) Nees cv. Consol), cocksfoot (Dactylis glomerata L. cv. Currie), phalaris (Phalaris aquatica L. cv. Sirolan), danthonia (Austrodanthonia richardsonii (Cashm.) H.P. Linder, cv. Taranna), and lucerne (Medicago sativa L. cv. Aquarius) was compared with pure and degraded (invaded by annual volunteers) annual subterranean clover pasture at 2 sites (Junee and Kamarah) in the southern wheatbelt of New South Wales. Seed yields, clover seedlings in winter, and the change in the proportion of 3 subterranean clover cultivars (Dalkeith, Seaton Park, Goulburn) when grown with and without perennials were assessed. The effect of thinning the perennials to 10 plants/m2 on clover seed set was examined at the drier site. Seed production of subterranean clover in the mixtures was depressed by up to 50% compared with the pure and degraded annual swards. Initial clover seed poduction in the mixtures was at least 60 kg/ha even in the drought year at the wetter site (Junee), and >85 kg/ha at Kamarah, the drier site (seedling establishment at Kamarah failed in the drought year). Clover seed reserves in the following 2 years progressively increased to >300 kg/ha in the perennial swards at Junee but were <100 kg/ha by the end of the third year at Kamarah. In comparison, seed reserves in the pure clover and degraded annual swards were >650 kg/ha at Junee and >350 kg/ha at Kamarah. Reducing perennial density to 10 plants/m2 at the drier site increased clover seed yield about 3-fold in the first year compared with unthinned perennial swards. The increased seed yield was due to increased numbers of burrs set and increased seeds per burr and, in all perennial pasture treatments except lucerne, increased seed size. Clover seedling regeneration in 3rd and 4th year after sowing was substantially lower in the perennial-based mixtures than annual plots, with a significant (P < 0.05) positive correlation at both sites between clover seedling regeneration and seed bank size (1996, r2 = 0.46–0.64; 1997, r2 = 0.64–0.85). Following false breaks in early autumn, clover seedling populations were substantially higher in the pure and degraded clover treatments than in most perennial treatments. The proportion of the 3 cultivars present in the seed bank at the end of the pasture phase differed between sites but the sward type only influenced the proportion at the drier site. At the medium rainfall site, the later maturing cultivar Goulburn constituted 27–54% of the seed bank and the early flowering Dalkeith 25–46%, with unsown cultivars being insignificant ( <1%). At the low rainfall site, Dalkeith was the major component (33–52%) of the seed bank but the background population of unsown cultivars constituted 11–48%, the lowest proportion being in swards without a perennial component. The proportion of Goulburn was highest (23%) in the pure sward and lowest (10%) in lucerne and phalaris. It was concluded that subterranean clover could form relatively stable mixtures with perennials in medium rainfall environments, with clover populations increasing with time. In lower rainfall environments, clover seedling populations in perennial swards may be low due to reduced seed set and decreased seedling survival following early autumn rains. In these environments earlier maturing, hard-seeded cultivars are more likely to persist in mixtures and there is more potential for unsown cultivars to constitute a greater proportion of the sward. Decreasing perennial density offers scope for improving clover seed set and survival in these environments.

The effect of defoliation on seed production by capeweed (Arctotheca calendula)

1973 ◽  
Vol 13 (65) ◽  
pp. 676 ◽  
Author(s):  
JG McIvor ◽  
DF Smith
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Leaf Removal ◽  
Late Flowering ◽  
Individual Seed ◽  
Number Of Seeds

Two experiments were done in pots to assess the effect of defoliation at different times on the seed yield of capeweed (Arctotheca calendula). Yield components measured were: number of seedheads per plant, number of seeds per seedhead, number of seeds per plant, and weight of individual seeds. Of the components of yield, number of florets per seedhead and individual seed weight were maintained under all treatments; number of seedheads and number of seeds per seedhead were more affected by defoliation. Whether grown as spaced plants or in swards, leaf removal did not significantly reduce the number of seeds produced unless combined with bud and flower removal at late flowering only. The results are discussed in relation to the growth and persistence of capeweed in pastures.

Desiccation of alfalfa for seed production with diquat and glufosinate

1996 ◽  
Vol 76 (3) ◽  
pp. 435-439 ◽  
Author(s):  
J. R. Moyer ◽  
S. N. Acharya ◽  
J. Fraser ◽  
K. W. Richards ◽  
N. Foroud
Keyword(s):  
Key Words ◽  
Seed Production ◽  
Seed Yield ◽  
Seed Weight ◽  
Viable Seed ◽  
Hard Seed ◽  
Alfalfa Seed ◽  
Percent Germination ◽  
Medicago Sativa L ◽  
Seed Yields

Recommendations for desiccation of alfalfa do not clearly define the stage at which desiccants should be applied. To obtain this information, diquat and glufosinate were applied to alfalfa (Medicago sativa L) from 1991 to 1994 at various stages of maturity to determine the effect of desiccant and stage of maturity at desiccation on seed yield 1000-seed weight and seed germinability. Alfalfa seed yields, 1000-seed weights, percent germination and percent viable seed were similar after desiccation with diquat and glufosinate. Desiccation when 60–75% of the alfalfa seed pods were brown permitted maximum seed yields. Percent germination increased slightly in seeds that were exposed to weathering under normal conditions until all pods turned brown. Both desiccants adequately desiccated alfalfa for harvesting but desiccation with glufosinate took 2 or 3 d longer than diquat. Desiccants did not reduce alfalfa growth in the spring after application. Key words: Germination, yield, hard seed, seed weight, stage

What determines the number of seed produced in a flowering event? A case study of Calyptrogyne ghiesbreghtiana (Arecaceae)

2000 ◽  
Vol 48 (5) ◽  
pp. 659 ◽  
Author(s):  
Saul A. Cunningham
Keyword(s):  
Resource Allocation ◽  
Seed Production ◽  
Natural Variation ◽  
Seed Set ◽  
Plant Seed ◽  
Flower Production ◽  
Number Of Seeds ◽  
Female Flowers

Calyptrogyne ghiesbreghtiana Linden ex. H. Wendl. is an understorey palm that occurs at La Selva Biological Station, Costa Rica. In this paper I combine analysis of natural variation and results of experimental manipulations to ask (1) what limits seed production? and (2) what processes cause variation in seed production by C. ghiesbreghtiana? The number of seed produced per inflorescence ofC. ghiesbreghtiana was limited substantially by the loss of female flowers to floral herbivores. Much variation in the number of seed produced perinflorescence of C. ghiesbreghtiana was due to losses of developing fruits to predators. Together these phenomena illustrate the influential role of natural enemies in the reproductive success of this plant. Seed-set efficiency (number of seeds/number of female flowers) was highly variable in this species, and such high levels of variation appear to be common in other species. For species with highly variable seed-set efficiency, the role of resource allocation to flower production in determining differences in seed production among individual plants is likely to be relatively small.

EFFECTS OF ESTABLISHMENT METHOD AND A RAPESEED COMPANION CROP ON ALFALFA SEED YIELD

1987 ◽  
Vol 67 (1) ◽  
pp. 263-266 ◽  
Author(s):  
J. WADDINGTON ◽  
N. MALIK
Keyword(s):  
Medicago Sativa ◽  
Seed Production ◽  
Seed Yield ◽  
Brassica Campestris ◽  
Establishment Method ◽  
Alfalfa Seed ◽  
Medicago Sativa L ◽  
Companion Crop

In two experiments at Melfort using alfalfa (Medicago sativa L. ’Beaver’) seeded at a rate of 2 kg ha−1 with and without a Polish rapeseed (Brassica campestris L. ’Candle’) companion crop seeded at 5.5 kg ha−1, rapeseed yields in the establishment year were maximum when alfalfa and rapeseed were mixed and planted in 15-cm rows. Alfalfa showed no consistent seed yield differences between broadcast seeding, seeding in 15- or 61-cm rows, or seeding with or without the companion crop.Key words: Alfalfa, rapeseed, Brassica campestris, seed production

Within and among flower sex-phase distribution in Alstroemeria aurea (Alstroemeriaceae)

1995 ◽  
Vol 73 (12) ◽  
pp. 1986-1994 ◽  
Author(s):  
Marcelo A. Aizen ◽  
Alicia Basilio
Keyword(s):  
Inbreeding Depression ◽  
Seed Set ◽  
Phase Distribution ◽  
Selfing Rate ◽  
Pollen Transfer ◽  
Alstroemeria Aurea ◽  
Female Phase ◽  
Male Phase ◽  
Male To Female ◽  
Simultaneous Change

Although dichogamy is a prevailing feature of the angiosperms, the simultaneous change from male to female phases among hermaphrodite flowers within a plant (i.e., synchronous protandry) has been reported for only a few families (e.g., Araliaceae, Umbelliferae). Here we present an example of synchronous protandry at the ramet level in the Alstroemeriaceae. Dichogamy was analyzed in clonal Alstroemeria aurea at the flower, ramet, and at the whole flowering patch level. Alstroemeria aurea is self-compatible but totally dependent on biotic agents for pollen transfer. There was evidence of strong inbreeding depression expressed during seed development. Comparisons of seed set in open-pollinated flowers with those obtained after hand selfing and outcrossing resulted in a selfing rate of 0.3. At the flower level protandry was complete. The male phase lasted about 4 days and the female phase lasted about 3 days. Between the female and male phase, there was an approximately 1-day long "neuter" phase. Flowering ramets produce a terminal inflorescence bearing one or more whorls of flowers. Within a ramet, flowers of the same order opened within a period of 1–2 days, and male and female phases of different flowers did not overlap. When inflorescences held two whorls of flowers, the ramet went through two alternating non-overlapping male–female cycles. Using spatial autocorrelation techniques, we found little evidence for pairs of neighboring ramets expressing the same sexual phase beyond random expectations at any scale ranging between 0.25 to 15 m. By ensuring pollen interchange between flowering ramets, synchronized protandry at the ramet level could be an important feature in reducing selfing in A. aurea. Key words: Alstroemeria aurea, dichogamy, synchronous protandry, inbreeding depression.

Influence of alfalfa seed belts on yield component and seed yield in mainland China - A review

2019 ◽  
Author(s):  
Wenxu Zhang ◽  
Li Liang ◽  
Xiping Zhang ◽  
Jing Chen ◽  
Hui Wang ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Mainland China ◽  
Hexi Corridor ◽  
Climatic Conditions ◽  
Yield Component ◽  
Tianshan Mountains ◽  
Alfalfa Seed ◽  
Production Area ◽  
Suitable Area

Alfalfa is widely cultivated, and the seed yield differs in different regions due to the climate environment and so on in China. In order to obtain higher yield, alfalfa seed production must choose the most suitable area. Therefore, according to the geographical and climatic conditions, the alfalfa seed production area can be divided into four belts: Hexi Corridor belt, Hetao Plainbelt, the northern slope of the Tianshan Mountains belt and the Hotanbelt in mainland China. Under different cultivation measures, the seed yield of four alfalfa seed production zones, varied in the range of 360-1833 kg/hm2, 234.96-1560.1kg/hm2, 179.10-1197.33 kg/hm2, 225-300 kg/hm2, respectively. These different cultivation measures can provide theoretical guidance for alfalfa seed production in different production zones.

scholarly journals The impact of foliar feeding on the yield components of three winter rape morphotypes (Brassica napus L.)

2020 ◽  
Vol 5 (1) ◽  
pp. 107-116
Author(s):  
Anna Sikorska ◽  
Marek Gugała ◽  
Krystyna Zarzecka
Keyword(s):  
Amino Acids ◽  
Brassica Napus ◽  
Seed Yield ◽  
Growth Type ◽  
Winter Rape ◽  
Foliar Nutrition ◽  
Foliar Fertilization ◽  
Foliar Fertilizer ◽  
The Impact ◽  
Number Of Seeds

AbstractThe aim of the study was to determine the impact of foliar fertilizers containing amino acids, sulphur, boron on the number of productive branches, the number of pods per plant, the number of seeds in pods and the length of pods of three winter rape (Brassica napus) varieties (Monolit, PX115, PT248). The research was carried out in 2016-2017, 2017-2018, 2018-2019 at the Zawady Agricultural Experimental Station (52o03’N and 22o33’E) belonging to the University of Natural Sciences and Humanities in Siedlce, Poland. The field experiment was set up in a split-plot layout in triplicate. The area of one plot for harvest was 21 m2. The examined factors were I - morphotipe of winter rape: population variety (Monolit), hybrid restored with a semi-dwarf growth type (PX115), hybrid restored with a traditional growth type (PT248). II - types of foliar feeding: 1. treatment without biostimulator and foliar feeding, 2. Bioregulator Aminoplant, 3. Foliar fertilizer Siarkomag with foliar fertilizer Bormax, 4. Foliar fertilizer Siarkomag with foliar fertilizer Bormax and Aminoplant. Variable climatic conditions in the years of the experiment affected the studied components of seed yield of three L. morphotypes. In the year 2016-2017 of research, the plants produced the most productive branches, had the longest pods filled with the largest number of seeds. Foliar nutrition with a biostimulator containing amino acids did not significantly affect the increase of the number of productive branches, pods per plant and pod length compared to the variant on which no foliar fertilization was applied. Foliar fertilization with S and B in combination with bio-stimulators was the most effective in increasing the components of seed yield, while the number of productive branches and length of pods under the influence of foliar fertilizers was the same regardless of the application of the biostimulator. The long-stem variety had longer pods that were filled with more seeds than the others.

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