scholarly journals The ecology and quantitative genetics of seed and seedling traits in upland and lowland ecotypes of a perennial grass

2021 ◽  
Author(s):  
Samsad Razzaque ◽  
Tom Juenger
Keyword(s):  
Local Adaptation ◽  
Seed Size ◽  
Field Experiments ◽  
Seed Mass ◽  
Strong Support ◽  
Directional Selection ◽  
Seedling Vigor ◽  
Seed Traits ◽  
Ecotypic Differentiation ◽  
Seed Trait

Plants have evolved diverse reproductive allocation strategies and seed traits to aid in dispersal, persistence in the seed bank, and establishment. In particular, seed size, dormancy, and early seedling vigor are thought to be key functional traits with important recruitment and fitness consequences across abiotic stress gradients. Selection for favored seed-trait combinations, or against maladaptive combinations, is likely an important driver shaping recruitment strategies. Here, we test for seed-trait plasticity and local adaptation in contrasting upland and lowland ecotypes of Panicum hallii with field experiments in native versus foreign habitats. Furthermore, we test whether seed traits have been under directional selection in P. hallii using the v-test (Fraser 2020) based on trait variance in a genetic cross. Finally, we evaluate the genetic architecture of ecotypic divergence for these traits with Quantitative Trait Locus (QTL) mapping. Field experiments reveal little plasticity but support a hypothesis of local adaptation among ecotypes based on recruitment. Patterns of segregation within recombinant hybrids provides strong support for directional selection driving ecotypic divergence in seeds traits. Genetic mapping revealed a polygenic architecture with evidence of genetic correlation between seed mass, dormancy, and seedling vigor. Our results suggest that the evolution of these traits may involve constraints that affect the direction of adaptive divergence. For example, seed size and germination percentage shared two colocalized QTL with antagonistic additive effects. This supports the hypothesis of a functional genetic relationship between these traits, resulting in either large seed/strong dormancy or small seed/weak dormancy trait combinations. Overall, our study provides insights into the factors facilitating and potentially constraining ecotypic differentiation in seed traits.

Effect of seed size on seedling vigor and forage production of winter wheat

1996 ◽  
Vol 76 (1) ◽  
pp. 101-105 ◽  
Author(s):  
W. W. Bockus ◽  
J. P. Shroyer
Keyword(s):  
Soil Erosion ◽  
Winter Wheat ◽  
Seed Size ◽  
Field Experiments ◽  
Ground Cover ◽  
Seedling Vigor ◽  
Seed Number ◽  
Forage Production ◽  
Large Seed ◽  
Small Seed

There are numerous reports of increased wheat (Triticum aestivum L.) grain yields with large seed compared with small, but these do not relate to use of wheat for grazing purposes. Field experiments were conducted over 3 yr to measure the effect of seed size on stands, percentage ground cover, and fall and spring forage production. Other variables included sowing plots by seed number or volume per unit area. When sown at the same number of seed per square metre (220), large (> 0.24-cm diameter) seed resulted in 16–74% more plants per area than small (< 0.20-cm) diameter seed. When sown by volume (8.7 mL m−2), stands from small seed were similar to or more dense than those from large seed. When sown by seed number, large seed increased fall ground cover by 58–100% over small seed; however, even when sown by volume, large seed increased ground cover by 13–26%. Similarly, when seeded on an equal-number basis, large seed increased fall and spring forage 23–214% over that produced by small seed. Although sowing on an equal-volume basis resulted in fewer significant differences among seed sizes, large seed produced 35% more fall forage one year and 44% more spring forage another year. Therefore, sowing large seed should help reduce soil erosion by producing plants with greater ground cover. Similarly, large seed should increase the amount of forage for producers who sow winter wheat early as a prelude to grazing livestock. Key words:Triticum aestivum, forage, seed size, soil erosion control, seedling vigor

scholarly journals The reproductive strategy in a Chloris virgata population in response to precipitation regimes

2018 ◽  
Vol 5 (8) ◽  
pp. 180607 ◽  
Author(s):  
Wang Ying ◽  
Wang Chunxia ◽  
Zhang Jukui ◽  
Wang Chunqing
Keyword(s):  
Seed Size ◽  
Reproductive Strategy ◽  
Seed Mass ◽  
Seed Traits ◽  
Seed Number ◽  
Water Addition ◽  
Precipitation Regimes ◽  
High Precipitation ◽  
Chloris Virgata ◽  
Low Precipitation

Resource availability influences plant growth and reproduction. Here, a controlled experiment was conducted in order to evaluate the adaptation response of Chloris virgata to different precipitation conditions, and to further predict the reproductive strategy in a population of C. virgata under different precipitation regimes. Three regimes (low, typical and high) of water addition were used to simulate current precipitation patterns. In total 20 individuals for each treatment were analysed to compare tiller number, spike traits, seed traits, the relationship between seed size and seed number, and so on. In addition, the effects of different precipitation regimes on offspring vigour of C. virgata were also studied. Results indicated that tiller number, spike number, seed yield and seed number were unchanged under different water addition regimes, while seed size was about 0.5 mg at typical and high precipitation levels and was higher than that in the low precipitation level. The higher seed mass per spike and spike mass both occurred at typical and high precipitation levels. Significant positive correlations between seed mass and non-seed mass in C. virgata in response to precipitation regimes were largely allometric (size dependent), as was a significant negative correlation between seed size and seed number at low precipitation. The highest germination rates and seedling weights both occurred at typical and high precipitation levels. These findings showed that different precipitation regimes affected reproductive strategy of C. virgata. Chloris virgata will not benefit from low precipitation, while typical and high precipitation will improve seed traits and offspring vigour of this species.

scholarly journals Genome-wide association study identified candidate genes for seed size and seed composition improvement in M. truncatula

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhijuan Chen ◽  
Vanessa Lancon-Verdier ◽  
Christine Le Signor ◽  
Yi-Min She ◽  
Yun Kang ◽  
...  
Keyword(s):  
Association Study ◽  
Protein Content ◽  
Seed Size ◽  
Seed Protein ◽  
Genome Wide Association Study ◽  
Genome Wide Association ◽  
Strong Positive Correlation ◽  
Seed Composition ◽  
Seed Traits ◽  
Genome Wide

AbstractGrain legumes are highly valuable plant species, as they produce seeds with high protein content. Increasing seed protein production and improving seed nutritional quality represent an agronomical challenge in order to promote plant protein consumption of a growing population. In this study, we used the genetic diversity, naturally present in Medicago truncatula, a model plant for legumes, to identify genes/loci regulating seed traits. Indeed, using sequencing data of 162 accessions from the Medicago HAPMAP collection, we performed genome-wide association study for 32 seed traits related to seed size and seed composition such as seed protein content/concentration, sulfur content/concentration. Using different GWAS and postGWAS methods, we identified 79 quantitative trait nucleotides (QTNs) as regulating seed size, 41 QTNs for seed composition related to nitrogen (i.e. storage protein) and sulfur (i.e. sulfur-containing amino acid) concentrations/contents. Furthermore, a strong positive correlation between seed size and protein content was revealed within the selected Medicago HAPMAP collection. In addition, several QTNs showed highly significant associations in different seed phenotypes for further functional validation studies, including one near an RNA-Binding Domain protein, which represents a valuable candidate as central regulator determining both seed size and composition. Finally, our findings in M. truncatula represent valuable resources to be exploitable in many legume crop species such as pea, common bean, and soybean due to its high synteny, which enable rapid transfer of these results into breeding programs and eventually help the improvement of legume grain production.

scholarly journals Glyphosate Resistance in Perennial Ryegrass (Lolium perenneL.) is Associated with a Fitness Penalty

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marcos Yanniccari ◽  
Martín Vila-Aiub ◽  
Carolina Istilart ◽  
Horacio Acciaresi ◽  
Ana M. Castro
Keyword(s):  
Perennial Ryegrass ◽  
Water Availability ◽  
Field Experiments ◽  
Seed Mass ◽  
Selection Effect ◽  
Glyphosate Resistance ◽  
Shoot Biomass ◽  
Seed Number ◽  
Fitness Costs ◽  
Weed Species

The net selection effect of herbicides on herbicide-resistance traits in weeds is conditioned by the fitness benefits and costs associated with resistance alleles. Fitness costs play an important evolutionary role preventing the fixation of adaptive alleles and contributing to the maintenance of genetic polymorphisms within populations. Glyphosate is widely used in world agriculture, which has led to the evolution of widespread glyphosate resistance in many weed species. The fitness of glyphosate-resistant and -susceptible perennial ryegrass plants selected from within a single population were studied in two field experiments conducted during 2011 and 2012 under different soil water availability. Glyphosate-resistant plants showed a reduction in height of 12 and 16%, leaf blade area of 16 and 33%, shoot biomass of 45 and 55%, seed number of 33 and 53%, and total seed mass of 16 and 5% compared to glyphosate-susceptible plants in 2011 and 2012, respectively. The reduction in seed number per plant resulted in a 40% fitness cost associated with the glyphosate-resistance trait in perennial ryegrass. Fitness costs of glyphosate-resistant plants were expressed under both conditions of water availability. These results could be useful for designing management strategies and exploiting the reduced glyphosate-resistant perennial ryegrass fitness in the absence of glyphosate selection.

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

scholarly journals Can we predict dispersal guilds based on the leaf-height-seed scheme in a disjunct cerrado woodland?

2008 ◽  
Vol 68 (3) ◽  
pp. 553-559 ◽  
Author(s):  
AVF. Jardim ◽  
MA. Batalha
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Field Experiments ◽  
Plant Traits ◽  
Seed Mass ◽  
Soil Nutrient ◽  
Canopy Height ◽  
Southeastern Brazil ◽  
Plant Canopy ◽  
Frugivorous Birds

Although there have been advances in methods for extracting information about dispersal processes, it is still very difficult to measure them. Predicting dispersal groups using single readily-measured traits would facilitate the emergence of instructive comparisons among ecological strategies of plants and offer a path towards improved synthesis across field experiments. The leaf-height-seed scheme consists of three functional traits: specific leaf area, plant canopy height, and seed mass. We tested, applying logistic regression analysis, whether these traits are potential predictors of dispersal guilds in a disjoint cerrado woodland site in southeastern Brazil. According to our results, none of the plant traits studied could predict dispersal guild; this means that abiotically and biotically dispersed species showed similar values of specific leaf area, height, and seed mass. The species of both guilds exhibited sclerophylly, probably a result of the typical soil nutrient deficiency of cerrado, which also may have placed constraints upon plant canopy height regardless of the dispersal mode. In the cerrado, some abiotically dispersed trees might present higher than expected seed mass as support to the investment in high root-to-shoot ratio at the seedling stage. Seeds of bird-dispersed species are limited in size and mass because of the small size of most frugivorous birds. Since soil nutrient quality might contribute to the similarity between the dispersal guilds regarding the three traits of the scheme, other plant traits (e.g., root depth distribution and nutrient uptake strategy) that detail the former should be considered in future predictive studies.

scholarly journals Size Variability in Seed Lot Impact Seed Nutritional Balance, Seedling Vigor, Microbial Composition and Plant Performance of Common Corn Hybrids

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Saveetha Kandasamy ◽  
Nimalka Weerasuriya ◽  
Daniella Gritsiouk ◽  
Greg Patterson ◽  
Soledad Saldias ◽  
...  
Keyword(s):  
Seed Size ◽  
Seed Quality ◽  
Nutritional Composition ◽  
Plant Performance ◽  
Growth Stages ◽  
Seedling Vigor ◽  
Microbial Composition ◽  
Corn Hybrids ◽  
Plant Vigor ◽  
Microbial Profile

Soils with highly uniform textural, physical, and chemical characteristics still give rise to crop stand variability. Seed quality is one of the factors adding to yield variability and has become a concern for corn growers. Hybrid seed producers claim that their seeds provide a uniformity in crop emergence and productivity, but they do not always provide detailed studies to support this claim. Based on growers’ concerns, we examined fields planted with three different hybrid varieties and found that 25% to 50% of the stand had relatively weak vigor, where seed variety A showed 15% of seedlings with lower vigor, and varieties B and C had 30% of seedlings with low vigor. These apparent differences in plant vigor prompted us to initiate a cursory investigation to identify how seed size influenced seedling vigor and if the seedling’s microbial profile played a role in the early growth stages of three commonly grown corn hybrids in Ontario. Seeds were separated based on size, prior to conducting a growth room study. Different sizes of seeds from the same seed lot showed significant differences in vigor capacity and related biometric components. Significant differences were also found in their nutritional composition and microbial profiles within the different seed sizes and the roots and shoots of seedlings derived from such seeds. The results clearly indicate that seed size greatly impacts the plant growth and its microbiome, resulting in seedlings with different plant vigor, microbiomes, and performance.

scholarly journals Impact of Row Spacing, Sowing Density and Nitrogen Fertilization on Yield and Quality Traits of chia (Salvia Hispanica L.) Cultivated in southwestern Germany

Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 136 ◽  
Author(s):  
Samantha Grimes ◽  
Timothy Phillips ◽  
Filippo Capezzone ◽  
Simone Graeff-Hönninger
Keyword(s):  
Field Experiments ◽  
Seed Mass ◽  
N Fertilization ◽  
Row Spacing ◽  
Quality Traits ◽  
Yield And Quality ◽  
Chia Seed ◽  
Salvia Hispanica L ◽  
Growing Conditions ◽  
Seed Yields

To obtain high chia seed yields and seed qualities, a suitable crop management system needs to be developed for the given growing conditions in southwestern Germany. Field experiments were conducted at the experimental station Ihinger Hof in two consecutive years (2016, 2017). The study aimed to evaluate yield and quality traits of chia depending on different (i) row spacing (35, 50 and 75 cm), (ii) sowing densities (1, 1.5 and 2 kg ha−1) and, (iii) N-fertilization rates (0, 20 and 40 kg N ha−1). It consisted of three independent, completely randomized field experiments with three replications. Results showed that chia seed yields ranged from 618.39 to 1171.33 kg ha−1 and that a thousand seed mass of 1.14 to 1.24 g could be obtained. Crude protein-, crude oil- and mucilage contents varied from 18.11–23.91%, 32.16–33.78% and 10.00–13.74%, respectively. Results indicated that the year of cultivation and the accompanied environmental conditions, like precipitation or temperature, influenced the determined traits more than the applied agronomic practices. As average seed yields exceeded those obtained in the countries of origin (Mexico, Guatemala) while having comparable quality characteristics, chia holds great potential as an alternative crop for farmers in southwestern Germany.

Effects ofEriochloa villosadensity and time of emergence on growth and seed production inZea mays

Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 687-692 ◽  
Author(s):  
James A. Mickelson ◽  
R. Gordon Harvey
Keyword(s):  
Seed Production ◽  
Field Experiments ◽  
Seed Mass ◽  
Model Parameters ◽  
Growth Stages ◽  
Vegetative Biomass ◽  
Eriochloa Villosa ◽  
Term Management ◽  
Weed Emergence

Field experiments were conducted in 1997 and in 1998 to determine the effects of density and time of emergence onEriochloa villosagrowth and seed production inZea mays. E. villosawas transplanted at four densities (3, 9, 27, and 81 plants m−2) to simulate emergence at four Z.maysgrowth stages (VE, V2, V5, and V10). Compared toE. villosaplants that emerged withZ. maysplants, total above-groundE. villosabiomass at maturity of plants grown at 3 plants m−2was reduced by 54, 97, and 99% when emergence was delayed until the V2, V5, and V10 stages ofZ. mays, respectively, in 1997. In 1998, total abovegroundE. villosabiomass at maturity was reduced by 70, 87, and 99% when emergence was delayed until the V2, V5, and V10 stages ofZ. mays, respectively.E. villosaaboveground vegetative biomass per plant at maturity was linearly related to seed production per plant in each year.E. villosaseed production m−2decreased nonlinearly as density decreased and time of emergence was delayed. Based on estimated model parameters, maximum seed production was 57,100 and 12,700 seeds m−2in 1997 and 1998, respectively. Within time of emergence,E. villosadensity did not affect seed mass per seed, however, seed mass of late-emerging cohorts was less than that of early-emerging cohorts. Time of weed emergence relative to the crop was a very important factor in determining biomass and seed production. Results suggest that late-emerging plants may not be very important to long-term management ofE. villosa.

Seed Size and Burial Effects on Giant Ragweed (Ambrosia trifida) Emergence and Seed Demise

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 16-22 ◽  
Author(s):  
S. K. Harrison ◽  
E. E. Regnier ◽  
J. T. Schmoll ◽  
J. M. Harrison
Keyword(s):  
Seed Size ◽  
Mixed Model ◽  
Field Experiments ◽  
Linear Mixed Model ◽  
Control Measures ◽  
Habitat Modification ◽  
Agricultural Fields ◽  
Burial Depth ◽  
Growing Seasons ◽  
Giant Ragweed

Giant ragweed is a competitive, allergenic weed that persists in agricultural fields and early successional sites. Field experiments were conducted to determine the effects of seed size and seed burial depth on giant ragweed emergence and seed demise. In a seedling emergence experiment, small (< 4.8 mm in diameter) and large (> 6.6 mm in diameter) seeds were buried 0, 5, 10, and 20 cm in fall 1997, and weed emergence was monitored over the next seven growing seasons. A generalized linear mixed model fit to the cumulative emergence data showed that maximum emergence for both seed sizes occurred at the 5-cm burial depth, where probability of emergence was 19% for small seeds and 49% for large seeds. Emergence probability at the 10-cm burial depth was 9% for small seeds and 30% for large seeds, and no seedlings emerged from the 20-cm burial depth. The model predicted that ≥ 98% of total cumulative emergence was completed after four growing seasons for large seeds buried 5 cm, five growing seasons for small seeds buried 5 cm and large seeds buried 10 cm, and seven growing seasons for small seeds buried 10 cm. Seed size and burial treatment effects on seed demise were tested in a second experiment using seed packets. Rates of seed demise were inversely proportional to burial depth, and the percentage of viable seeds remaining after 4 yr ranged from 0% on the soil surface to 19% at the 20-cm burial depth. Some seeds recovered from the 20-cm burial depth were viable after 9 yr of burial. These results, coupled with previous research, suggest that seed size polymorphism facilitates giant ragweed adaptation across habitats and that a combination of no-tillage cropping practices, habitat modification, and timely weed control measures can reduce its active seed bank in agricultural fields by 90% or more after 4 yr.

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