Effect Of Seed Size Research Articles

Effect of Seed Size and Density on Near-infrared Transmittance Analysis of Corn and Soybeans

Soybean physical and chemical properties changed by size (from 4.8 to 8.8 mm diameter), but soybean size and seed density did not affect the protein and oil determination accuracy of three near-infrared transmission analyzers. Corn samples were also separated by size and kernel density. Changes in corn kernel density and size introduced small errors in near-infrared transmission protein, oil, and starch measurements. In corn protein, the maximum error was about 0.2% points. A robust calibration set is needed to eliminate the weak seed weight and density effects, as well as to support the corn density calibration for near-infrared analyzers.

Seed Size Effects on Yields of Two Corn Hybrids

While a number of studies have shown that seed size and grade have little effect on grain yield of corn (Zea mays L.), producers remain concerned about the use of very small seeds that may result from genetics, seed position on the ear, or poor growing conditions. Recent evidence that uneven emergence and uneven plant size can decrease yield also raises concern about the use of mixed seed sizes. This study was conducted in three Illinois environments to test the effect of seed size and of mixtures of seed sizes hand-planted in specific arrangements on the grain yield of two corn hybrids. Grain yields among the three environments were quite high, ranging from about 140 to more than 200 bu/acre. Seed size had no effect on the yield of either hybrid, regardless of whether the plantings were of uniform seed size or were mixtures of sizes. Seed size thus appears to be of no importance as a factor in corn production.

Effects of Seed Size and Seedling Emergence Time on the Fitness Components of Ambrosia trifida and A. artemisiaefolia var. elatior in Competition with Grass Perennials

Germination physiology responsible for seedling emergence timing of Ambrosia trifida and A. artemisia-efolia var. elatior as well as the effects of seed size and seedling emergence time on the fitness were studied in order to understand successful invasion by these annuals of a perennial grass community. Seed biomasses of these species differ greatly (A. trifida, 34.6±14.7 mg; A. artemisiaefolia var. elatior, 4.7±1.8 mg). Seed germination /dormancy responses to temperature were rather similar. The primary dormancy of the seeds of both species could be effectively removed by a combination of moist chilling and alternating temperature regimes. The variation of the rate of germination among individual seeds in the laboratory tests well explains the variation of seedling emergence time in the field. Microsite variation of light availability had little effect on the fitness and its components in either species. In A. trifida, both initial seed biomass and emergence time significantly influenced the fitness and its components. No significant correlation between the fitness and seed size was found for A. artemisiaefolia var. elatior.

Seed Size Effects on Emergence, Head Number, and Grain Yield of Winter Wheat

There is little information on the effect of seed size on grain yield of soft red winter wheat (Triticum aestivum L.) in the eastern USA, and research elsewhere has produced inconclusive results. This study was conducted during two growing seasons (1988-1989 and 1989-1900) to examine the effect of three seed sizes―produced by harvesting at intervals after anthesis―and two seed rates―19 and 38 seeds/sq ft―on emergence, head number, and yield of three wheat cultivars. All seed sizes emerged equally well, and compensated equally well for low plant stands under the low seed rate, by producing larger numbers of heads/plant (...)

Effects of seed size and photoperiod response on crop growth and yield of common bean

Seed size and yield are usually negatively associated among common bean ( Phaseolus vulgaris L.) cultivars of bush growth habit. Furthermore, among cultivars varying in photoperiod response for flowering, yields are often lower in photoperiod-sensitive genotypes. While the seed-size effect might extend to overall crop growth, photoperiod response would be expected primarily to influence phenology and, possibly, partitioning. To examine these hypothesized effects, yield, crop dry weight at two stages, harvest index ( hi), and day to maturity were evaluated for 62 genotypes grown at three sites in Colombia and at Davis, California. Regression analyses indicated highly significant negative relationships between seed weight and all variables except days to maturity, even when significant photoperiod effects were accounted for or when analyses were restricted to genotypes from highland environments. Greater sensitivity to photoperiod was associated with lower yields and hi, and delayed maturity, at Davis, and there was a similar, but much weaker, trend of lower yield and hi in the other environments. Because large seed size was associated with reduced growth, relative growth rate ( rgr) of 16 bean genotypes was measured at two of the Colombian sites. At both sites, rgr was negatively correlated with seed weight ( R 2 = 0.59 and R 2 = 0.44, P < 0.01). These results suggest that greater seed size is associated not only with reduced yield, but also with reduced overall growth, and that the effect is largely independent of photoperiod sensitivity, even though the latter influenced phenology and partitioning.

Seed Size and Planting Depth Effects on Emergence and Yield of Pinto Bean

Seed size and planting depth affect plant performance of many crop species. Growers claim that large pinto bean (Phaseolus vulgaris L.) seeds emerge faster and produce higher seed yields than small seeds. A study was conducted during 1986 and 1987 on Billings silty clay loam soil (fine-silty, mixed [calcareous], mesic Typic Torrifluvents) at the Colorado State University Fruita Research Center to investigate the effects of seed size class (small, medium, and large), representing 30, 40, and 30% of the original bulk sample by weight, respectively, and a check; and planting depth (1-, 2-, and 3-in.) and their interaction on seedling emergence and yield of pinto bean. No seed size × planting depth interactions occurred. Seed size effects varied. Seedling emergence of small seeds in 1987 was greater than large and medium seeds. The plant stand from small seeds in 1986 was lower than large and check seeds. Plants grown from large and medium seeds yielded more than small seeds in 1986. Planting seeds at a 3-in. depth slowed seedling emergence and reduced plant stand both years, and lowered yield in 1987. These data suggest that an uneconomical, high cleanout percentage during seed conditioning would be necessary to obtain large seeds and the improved performance of large seeds would not be predictably advantageous. Currently recommended commercial seed conditioning practices to size pinto bean seed lots are probably adequate.

Effect of Seed Size and Cultivar on Emergence and Stand Establishment of Broccoli in Crusted Soil

Greenhouse and field experiments were conducted in 1988 and 1989 to determine the effect of seed size and cultivar on seedling emergence through crusted soil for several hybrid broccoli cultivars (Brassica oleracea ssp. italica). Seed was separated into four sizes (2.0, 1.8, 1.6, and 1.4 mm in diameter) for the greenhouse investigations, and soil crusting was achieved using a crusting resin. In 1989, field experiments using three seed sizes (small = 1.4 to 1.6 mm, medium = 1.7 to 1.9 mm, and large = 2.0 to 2.2 mm in diameter) were planted at the Long Island Horticultural Research Laboratory in a Riverhead sandy loam that crusted readily following rainfall. Seedling emergence data from the greenhouse and field studies indicate that seed size and cultivar significantly affect emergence and stand establishment. Seedling stand, dry weight, and final yield significantly increased as seed size increased for both cultivars in the field experiments. The emergence of `Mariner' generally was significantly better than that of `Greenlady' for each seed size. Seed of `Greenlady' also weighed significantly less than that of `Mariner' within each seed size tested.

Characterization of the negative association between seed yield and seed size among genotypes of common bean

Contrary to expectations from arguments of exponential growth or limiting factors, seed yield and seed size of different bush-bean (Phaseolus vulgaris L.) genotypes are frequently negatively associated. Four sets of yield data are analyzed to characterize this apparent seed size limit to yield potential. Comparisons of 57 genotypes, classified as small-seeded vs. medium-to-large-seeded and grown in three trials at two locations in Columbia, gave mean yields of 2190 and 1740 kg ha−1 for the respective seed-size classes, corresponding to a 280 kg ha−1 reduction in yield per 100 mg increase in cultivar seed weight. Published data for a trial conducted at five sites with 190 genotypes, for 19 experiments of an international yield trial, and for 42 nurseries conducted in Michigan, confirmed this relation, but also showed that positive relations between seed size and yield occur in certain environments. Including effects of length of growth-cycle did not eliminate overall negative relationships. Possible causes of the seed-size effect include effects of characteristics correlated with seed size that in turn affect efficiency of certain physiological processes, or differences in adaptation resulting from limited gene exchange among gene pools differing in characteristic seed size. To examine the possibility of a physiological cause related to developmental correlations between seed size and tissue cell volumes, seed weight and approximate cell volumes of cotyledons, hypocotyl and root endodermis, guard cells, and palisade mesophyll, and volumes of pollen grains, were determined for 15 genotypes, including two wild accessions. All volume measurement had positive correlations with seed weight except for palisade mesophyll. Principal-components analysis of cell volumes defined a first component accounting for 51% of total variance, and which had a correlation of r = − 0.91 (P < 0.01) with seed weight. Further comparison of seed weightand pollen grain volume in 33 genotypes gave a correlation of r = 0.67 (P < 0.01).

Effect of Seed Size on Germination and Seedling Growth in Greengram (Vigna radiata L. Wilczek) and Blackgram (Vigna mungo L. Hepper) Cultivars

AbstractThe effect of seed size on germination and seedling growth was assessed using cultivars of greengram and blackgram. Significant positive correlation was noticed between seed size and germination, seedling height, root length, primary leaf size and seedling weight. The possible advantages of choosing cultivars with heavier seeds for attaining better crop stand especially under rainfed situation are discussed.

Kernel Maturity, Seed Size, and Seed Hydration Effects on the Seed Quality of a Sweet Corn Inbred

Abstract To understand early development of seed quality, seed lots of sweet corn (Zea mays L.) inbred PGG-27B were harvested from an increase field at 10 stages of maturity, beginning when kernel moisture was at 59% and continuing to 19% kernel moisture content (42 to 103 days after pollination, respectively). Seed lots were dried, hand-shelled, sized, and tested for standard germination and subjected to the seedling growth cold test (SGCT). Endosperm, embryo, and kernel dry weights, and endosperm : embryo (END:EMB) ratios were monitored as the seed matured. Field tests were planted to determine the influence of kernel maturity, grade, and hydration on stand establishment and early seedling growth. Seeds were partially hydrated by mixing with moist vermiculite and screening from the substrate when seeds had reached 30% moisture content. Results from hydrated seeds were compared to those from seeds at ≈10% seed moisture to determine the effect of presowing seed hydration on seedling establishment. The seed hydration effect depended on the environment, but seed size was shown consistently to influence emergence and early seedling dry weight. Seed harvested at 45% to 54% moisture had better stand establishment than seed harvested at the more typical moisture of near 35%. The stage of maturity, determined by kernel moisture, at which PGG-27B was harvested had little effect on standard germination. Hydrating the seed prior to the SGCT improved seedling growth for all early kernel maturities and all seed grades. Embryo dry weight of composite samples increased steadily up to the fifth harvest period (38% seed moisture), then leveled off. Kernel and endosperm dry weights were more variable at the fifth harvest than at others, but followed the same general pattern. The ratio of END:EMB dry weight decreased from the first to the fifth harvest, where it continued at a value near 4.9 through harvest 10. Seed moisture at harvest, seed size, and presowing seed hydration were shown to influence the seed quality of PGG-27B.

EFFECT OF SEED DIMORPHISM ON THE DENSITY‐DEPENDENT DYNAMICS OF EXPERIMENTAL POPULATIONS OF ATRIPLEX TRIANGULARIS (CHENOPODIACEAE)

The importance of seed size and density in determining individual plant performance and plant population dynamics in experimental populations of the halophyte Atriplex triangularis was studied. Two distinct seed morphs—large, light seeds and small, dark seeds—are produced by individual A. triangularis plants. Experimental populations consisting of seed size monocultures (large or small seeds) and seed size mixtures were established at three different densities, and the time of germination, plant size, plant survivorship, and plant fecundity were monitored. Marked variation in time of germination was observed among treatments and between seed sizes, but germination within any given treatment occurred over a five‐ to ten‐day period. Large seeds produced larger plants than small seeds did, and this dichotomy was maintained over the course of the entire experiment. Germination date and seed size interacted such that larger plants grew from seeds which germinated earlier than those which germinated later, regardless of seed size. Germination date had a more pronounced effect than seed size did on plant mortality in high density populations. At high density, large seed monocultures experienced greater mortality than small seed monocultures did, but in seed size mixtures, the mortality was evenly distributed between plants from the two seed sizes. Regardless of density conditions and parentage, large and small seeds were produced in equal proportion by the plants. Total seed production, however, was dramatically affected by plant density, and to a lesser degree by germination date. Although seed size effects alone did not appear to affect directly final plant biomass and fecundity, effects of seed size early in ontogeny may have contributed to differences in fecundity.

Germination and Growth of Bird-Dispersed Plants: Effects of Seed Size and Light on Seedling Vigor and Biomass Allocation

Germination and Growth of Bird-Dispersed Plants: Effects of Seed Size and Light on Seedling Vigor and Biomass Allocation

Effects of Temperature, Moisture Stress, and Seed Size on Germination of Nine Spring Wheat Cultivars1

To determine if spring wheat (Triticum aestivum L.) cultivars show differential germination responses to varying levels of temperature and moisture stress, various seed‐size lots of nine cultivars were germinated in water at 5, 8, 12, 20, and 30°C, and in polyethylene glycol (PEG 8000) solutions with osmotic potentials of 0.0, ‐0.4, and ‐0.8 MPa at 10 and 20°C. Numbers of germinated seeds were recorded at intervals of 4 to 12 h depending upon temperature and stage of germination. Germination was expressed as a cumulative percentage of the number of seeds germinated by the final recording and, because of the unequal intervals between successive recordings, germination‐time curves were described as logistic functions of time. Each curve was characterized by final germination percentage, median germination time, and maximum rate of germination. Final germination exceeded 90% in all instances. At 20°C, cultivars differed by as much as 7 h in median germination time. Cultivar differences were consistent, though decreasing in magnitude, as temperature increased from 5 to 30°C. Differences in median germination time could not be attributed to differences in rate of water uptake. The reciprocal of median germination time, a measure of rate of germination, was linearly related to temperature. Small seeds germinated faster than large seeds in all cases. Increasing osmotic moisture stress from 0.0 to −0.8 MPa caused median germination time to increase from 90 to 156 h at 10°C and from 36 to 64 h at 20°C. Relative germination times of the cultivars were consistent over the different levels of osmotic moisture stress.

Effect of Seed Size on Seedling Success in Three Species of Sesbania (Fabaceae)

Effect of Seed Size on Seedling Success in Three Species of Sesbania (Fabaceae)

Effects of Genotype and Seed Size on Speed of Emergence and Seedling Vigor in Nine Spring Wheat Cultivars1

Rapid seedling establishment is an important attribute for successful crop production in short‐season areas. A study was done to determine the role of seed size, speed of emergence and rate of plant development in seedling vigor of nine spring wheat, Triticum aestivum L., cultivars. Six field studies, comprised of three seeding dates in each of 2 years, were conducted. Each study included nine spring wheat cultivars divided into two seed sizes arranged in a randomized complete block design with four replications. Logistic curves were fitted to emergence data expressed as percentage of final number of seeds emerged in a 46 cm row length. Each curve was characterized by median emergence time, the most useful measurement for speed of emergence, and maximum rate of emergence. Cultivar differences were observed in both years for speed of emergence, Haun stage, and seedling shoot dry weight. The average number of growing degree‐days (GDD) required for emergence in 1982 and 1983 were 109 and 103, respectively. With respect to Haun stage, approximately 68 GDD were required per phyllochron (interval between the appearance of successive leaves). ‘Potam’, ‘Siete Cerros’, and ‘Glenlea’ were found to require significantly fewer GDD per phyllochron interval on the third seeding date of 1983. The relative performance of cultivars was similar for speed of emergence, Haun stage and seedling shoot dry weight. Plants grown from small seeds emerged faster but accumulated less shoot dry weight than plants grown from large seeds. There was no cultivar by seed size interaction observed for speed of emergence and seedling shoot dry weight. Seed size, speed of emergence, and Haun stage all contributed to differences between cultivars in seedling vigor. Seed size accounted for approximately 50% of the variation in seedling shoot dry weight. It was concluded that selecting for seedling vigor could be done by selecting for seed size, speed of emergence and/or rate of plant development.

Effects of Seed Size and Microsite on Seedling Emergence of Prunella Vulgaris in Four Habitats

(1) The effects of seed size and microsite characteristics on seedling emergence were examined in two woodland and two old-field habitats of Prunella vulgaris. Seeds of known size were sown in the field and subsequent seedling emergence was monitored. Characteristics of the microsites in which seedlings emerged were also noted. (2) Both seed size and microsite characteristics affected seedling emergence. In general, large seeds had a higher percentage emergence. Litter and herbaceous cover inhibited seedling emergence in woodland habitats and herbaceous cover inhibited emergence in old-field habitats. In all habitats, larger seeds had less stringent requirements. (3) Within a habitat, the magnitude of the effect of seed size on seedling emergence may be influenced by the mean size of seeds produced and the abundance of microsites favourable for germination. (4) Seed size is a phenotypically plastic characteristic in P. vulgaris. A reciprocaltransplant experiment demonstrated that, in a habitat with a high herbaceous cover, plants produced small seeds regardless of their origin. Larger seeds were produced by both transplanted and native individuals in a habitat with a low herbaceous cover.

Effect of Seed Size on Heteroblastic Development in Seedlings of Desmodium paniculatum

Effect of Seed Size on Heteroblastic Development in Seedlings of Desmodium paniculatum

Seed Variation in Wild Radish: Effect of Seed Size on Components of Seedling and Adult Fitness

Seed mass in wild radius (Raphanus raphanistrum) varies up to sixfold within single fruits. The impact of such variation on subsequent growth and fecundity was studied. Seeds from single fruits were used to minimize genetic differences among individuals. Weighed seeds were planted close together in a disturbed area typical of Raphanus habitats. Large seeds (&gt;6 mg) were more likely to emerge as seedlings than were small seeds (&lt;4 mg). Seed size had no effect on emergence time. Seedlings from large seeds grew more rapidly and produced more flowers than did those from related smaller seeds. Results from the field experiment contrasted with those obtained in greenhouse growth studies, where seed size had no significant effect on final plant size. This study points out two factors that have led to inconsistent results in previous studies of seed size and seedling success: (1) differences in the timing of growth measurements, and (2) the presence or absence of competitive inequities among neighbors within the experimental design.

Effects of Seed Size and Growth Form on Seedling Establishment of Six Monocarpic Perennial Plants

(1) Effects of seed size and seedling morphology on the establishment of six monocarpic perennials were examined in glasshouse experiments. Both withinand between-species comparisons of seed-size effects were made as seed weight varied by more than two orders of magnitude among species and by 3 to 20-fold within a species. Experiments were conducted in four ground-cover types: bare soil, litter cover, vegetated, and vegetated plus litter. (2) In vegetated cover, emergence of the two small-seeded species, Verbascum thapsus and Oenothera biennis, was significantly lower than in litter and bare soil. In contrast, emergence of the medium (Dacus carota and Dipsacus sylvestris) and large-seeded species (Tragopogon dubius and Arctium minus), was not significantly reduced in the presence of vegetation. Although the rate of emergence of all six species was significantly reduced in vegetated cover, there were no between species differences in seedling emergence rates in any cover type. (3) Relative growth rates of all six species were significantly lower in vegetated cover compared with litter and bare soil and the effect was greatest on the small-seeded species. At the end of the experiment, seedling weight in vegetated cover was positively correlated with seed weight. In non-competitive cover types (litter and bare soil), seedling weight was independent of initial seed weight. (4) Relative growth rates of seedlings in non-competitive cover types were inversely related to seed size. In bare soil and litter, the small-seeded species had relative growth rates twice those of the large-seeded species. In vegetated cover this pattern was reversed; the species with large seeds had the highest relative growth rates. (5) The growth form of a seedling did not have any effect on its probability of establishment in any cover type. Species with different growth forms and similar seed sizes had equal emergence, survival, and relative growth rates in all four cover types. (6) Within species differences in seed size had a significant effect on seedling growth in non-competitive cover, but had no effect on seedling growth in competitive cover. Thus, both withinand between-species differences in seed size had similar effects on seedling establishment success in different types of ground cover.

Effects of Seed Size and Weight on Witchweed (Striga asiatica) Seed Germination, Emergence, and Host-Parasitization

Seed size and weight significantly affected witchweed [Striga asiatica(L.) Kuntze =S. luteaLour. ♯4STRLU] seed germination, witchweed emergence, and host-parasitization. Witchweed seed were divided into four groups for testing; large (&gt; 149 microns in diameter) and heavy (specific gravity greater than one) (LH), large and light (specific gravity less than one) (LL), small (&lt; 125 microns in diameter) and heavy (SH), and small and light (SL). Germination percentages were 87, 84, 58, and 26 for LH, LL, SH, and SL, respectively. Corn (Zea maysL.) was planted in pots containing soil infested with these four seed categories. The total number of witchweed plants (submerged plus emerged) per pot containing LH, LL, SH, and SL witchweed seed was 65, 12, 0, and 0, respectively, and the number of witchweed plants that emerged was 19, 4, 0, and 0 per pot. There were no significant differences in shoot weights of corn grown in the pots either between kinds of witchweed seed infesting the soil or between plants grown in infested soil and plants grown in soil that did not contain witchweed seed. Roots of corn plants grown in soil infested with LH seed were significantly heavier than those grown in soil infested with any other seed class and heavier than those from soil that did not contain witchweed seed. No other seed class significantly affected root weight.