Percentage Of Seedling Emergence Research Articles

Effects of seed covering treatments on the emergence and seedling growth of crisp lettuce drilled with an experimental dibber drill

SUMMARYPelleted seed of the crisp lettuce variety Pennlake was sown on five occasions with units from either the experimental dibber drill designed by the National Institute of Agricultural Engineering or a Stanhay S870 drill. There were three dibber-drill treatments: seeds left in open holes or covered with peat–vermiculite or perlite. Seedling emergence and growth from each sowing of the four drill treatments were compared under different moisture regimes.There were large differences between drill treatments in emergence percentage, time to emergence of 50% of the seedlings which emerged (t50) and seedling weight at all sowings but there was a significant effect of drill treatment on the standard deviation of seedling emergence times at only one sowing. Of the dibber-drill treatments, only very occasionally did open holes or perlite cover give significantly better emergence than peat-vermiculite cover, which gave the most consistent results. In general, the dibber drill with peat-vermiculite cover gave significantly faster and higher emergence and heavier seedlings than the Stanhay drill. Differences in percentage seedling emergence tended to be greater under dry conditions.

Seed placement effects on seedling establishment in direct-drilled fields

Two techniques for measuring seed placement distribution, a seedling tracing method and a soil core X-ray technique, were compared. Based on these methods, three determinant parameters were developed to define seed distribution; variation of depth, variation of lateral width and depth variation between rows. In the presence of a desirable in-groove micro-environment, both seed depth variations within and between rows had a negative relationship with seedling emergence percentage. Correlations between emergence and lateral width were low. Variations in seed depth were found to be associated with the mechanisms of seed ejection, and with the depth control method used on the openers. At two trial sites (in a sandy and silt loam soil) a simple winged chisel opener gave higher plant emergence than an experimental chisel S/2000 opener, a slot opener, a modified slot opener and a triple disc opener.

The influence of sowing depth and seed press wheel weighting on seedling emergence of crisp lettuce

SummaryThe effects on emergence and growth of crisp lettuce seedlings as a result of sowing seeds at different depths and pressing them into the furrow bottom with a weighted seed press wheel were examined in three similar experiments in 1982, 1983 and 1984. Sowing depth had a considerable effect on percentage seedling emergence and the spread of emergence times but the pattern of response varied from year to year and appeared to be related to differences in soil moisture content. The most uniform emergence and the highest level of emergence were achieved by sowing shallowly (< 10 mm) with rainfall almost immediately after sowing then keeping the soil moisture content close to field capacity for 2 days. When rainfall or irrigation were delayed, drilling 15–20 mm deep gave more consistent results. Effects on seedling weight and variability of weight were associated with the time and uniformity of seedling emergence. Later emerging seedlings were lighter and a wide spread of emergence times gave seedlings of variable weight. There was virtually no effect on emergence of using additional weights on a seed press wheel.

Gibberellin-like stimulation of celery ( Apium graveolens L.) seed germination by N-substituted phthalimides

Thermodormancy of celery seeds incubated in the dark at 22°C was alleviated by two N-substituted phthalimides to the same extent as that normally achieved with a mixture of the gibberellins A 4 and A 7. As previously demonstrated with GA 4+7, the highly dormant cultivar ‘Lathom Blanching’ responded more to phthalimides in the presence of cytokinin, whereas ‘Florida 683’ required no cytokinin to elicit the maximum response to phthalimide treatment. Seed-soak treatments with either N-substituted phthalimide improved both the rate of germination and the percentage seedling emergence of both cultivars sown in compost under glasshouse conditions.

Viability of onion (Allium cega) seed as influenced by temperature during seed growth

SUMMARYThe yield and performance of seeds from crops of winter‐hardy, bolting‐resistant onion grown at temperatures of 15–16, 18–19 and 22–23°C in 1979, 1980 and 1982 were compared.Yields of seed from crops grown at 22–23°C were lower than those from crops grown at lower temperatures but the seeds ripened between 11 and 32 days earlier. Seeds from crops grown at mean temperatures of above 18°C gave higher percentage germination when imbibed at 30°C than 20°C and they also gave higher percentage seedling emergence than those from crops grown at lower temperatures. Seedlings from seeds produced at mean temperatures above 18°C were heavier than those from seeds of a similar weight but produced at lower temperatures. None of these differences were associated with differences in seed weight, embryo weight or seed dormancy but were positively correlated with differences in seed N‐concentration. The differences were also associated with the rate of imbibition of water as high germination, high N‐content seeds had a slower rate of imbibition than low germination, low N‐content seeds of the same weight.

Relationship of Sunflower Germination and Vigor Tests to Field Performance1

Currently, only the standard germination test is used to evaluate sunflower (Helianthus annuus L.) seed quality. Accurate evaluation of seed quality and related field performance are difficult to obtain with this test since it determines germinability of seed under optimum conditions. Additional seed quality evaluations such as vigor tests, are often valuable in estimating seed quality. Common tests of seed vigor such as germination at cool temperatures, accelerated aging, cold soil, seedling vigor classification, seedling growth rates, seed leachate electrical conductivity, tetrazolium, and mitochondrial efficiency were evaluated to determine their applicability for evaluating sunflower seed quality. Percent seedling emergence in the field was compared with laboratory vigor test results to determine which laboratory method(s) most accurately evaluated seed‐seedling vigor of sunflower. Seed leachate electrical conductivity tests, seedling vigor classification, germination at 10°C, and accelerated aging tests resulted in significantly higher correlations with percent seedling emergence in the field than did the germination test at 21°C.

Priming and pre-germination of parsnip (Pastinaca sativaL.) seed

SummarySeedling emergence and growth responses to priming seeds in polyethylene glycol solutions, to germinating them before sowing and to a combined priming and pre-germination treatment were examined in the field and growth rooms using several stocks of seed. Priming or priming and pre-germinating seeds of a slowly germinating stock improved the percentage seedling emergence compared with untreated and pre-germinated seeds. In rapidly germinating stocks all three seed treatments showed similar levels of emergence which were higher than those of untreated seeds. Both priming and pre-germinating seeds reduced the mean emergence time and, in general, the effect of the combined treatment was greater than either treatment alone. Priming alone generally had no effect on the spread of emergence time or on seedling or plant weight variability, but pre-germinating seeds increased variability, particularly in a slowly germinating stock. Priming seeds before pre-germinating them reduced this variability.

The establishment of direct-sown germinating celery seeds in peat blocks

SummaryAs part of a study to improve celery seed germination five methods of preparing germinating seeds for sowing were compared: (1) upon filter paper, (2) in aerated water, (3) on the surface of a gel, (4) on the surface of water, and (5) by alternate soaking and draining. The percentage germination of seeds prepared by methods (2) to (5) was not significantly different from seed prepared by the control method (1) but there was a more uniform and more rapid seedling emergence from seeds germinated by methods involving a reservoir of water or a water change (2), (4) and (5). The percentage germination of seeds ready for sowing (with the longest radicles less than 2 mm) was increased from 36.8% to 91.7% by the use of a specific gravity seed separation technique. A cold treatment was developed for improving the uniformity of seed germination. Seeds treated for 24 at 1°C following 32 himbibition at 18°C had 79% of seeds germinated at sowing time compared to 26% for the untreated control. Cold-treated seeds gave higher percentage seedling emergence from peat blocks than growth regulator-soaked and untreated germinating seeds. All treatments with germinating seeds had significantly higher percentages of seedling emergence than that from the dry seed treatment.

A comparison of methods for evaluating seed quality in carrots (Daucus carota)

SUMMARYComparisons of embryo length, ISTA (International Seed Testing Association), cold (10 oC), controlled‐deterioration, and slope tests for estimating seedling size variability and percentage seedling emergence were made using eighteen stocks of carrot seeds.The coefficient of variation (C.V.) of seedling weight was closely correlated with the C.V. of embryo length (r = 0–87 D.F., 16) and also with the C.V. of root length from the slope test (r = 0–63 D.F., 16).Poorer estimates of percentage seedling emergence were obtained from the cold test in all three sowings (correlation coefficients were between 0–65 and 0–70 D.F., 16) compared with the ISTA, controlled deterioration, and slope tests. For these three tests the correlation coefficients varied between 0–80 and 0–87 (D.F., 16) for all sowings.The embryo test is a rapid (1 man hour per seed lot) and accurate method of assessing potential variability between seed lots. The slope test could provide a less labour demanding method of assessing potential variability than the embryo length test though the results would not be available immediately. However, the slope test could also provide as good an estimate of seedling emergence in the field as the ISTA or controlled‐deterioration tests.

Interactions between seed priming treatments and nine seed lots of carrot, celery and onion. II. Seedling emergence and plant growth

SUMMARYSamples of three seed lots of each of three cultivars of carrot, celery and onion were primed in polyethylene glycol solution for two weeks at 15 °C. Seedling emergence was recorded in the field for carrot and onion and in the glasshouse for celery. Compared to the untreated control, priming increased the percentage seedling emergence in certain poorly‐emerging seed lots of carrot and celery, but had no effect on onion. Mean emergence times were reduced by priming in all seed lots, by 3–5, 5–8 and 3–9 days in carrot, celery and onion respectively. The largest effects occurred in the slowest‐emerging seed lots. There were significant interactions between priming and seed lots within cultivars in carrot and celery and between priming and cultivars in celery and onion. Priming generally reduced the spread of emergence times, but the effects were not statistically significant in carrot.Drying back the primed seeds had no effect on percentage emergence in onion, but reduced it (compared to primed seed which had not been dried‐back) in certain carrot and celery seed lots. Primed and dried‐back seeds emerged later than primed seeds, by up to 1·5, 2·6 and 2·6 days in carrot, celery and onion respectively. The spread of emergence times was generally larger for primed and dried‐back seeds than for primed seeds, but the differences were not always statistically significant.Plant fresh weights were recorded 9, 7 and 12 wk after sowing for carrot, celery and onion, respectively. In each species, mean plant weight was inversely related to seedling emergence time; thus plants grown from primed seed were always heavier than the controls, by up to 33%, 182% and 47% in carrot, celery and onion respectively.

Stand Establishment and Yield of Corn as Affected by Herbicides and Seed Vigor1

AbstractSeed quality and herbicide injury are factors that might interact to affect corn {Zea mays L.) yields. Field studies were conducted to determine if corn grown from low‐quality seed was more susceptible to herbicide injury than corn grown from high‐quality seed. Seed lots with standard warm germinations above 90% but cold test germinations ranging from 50 to 96% were obtained for three U.S. Corn Belt hybrids. Herbicide treatments of cyanazine {2‐[[4‐chloro‐6‐(ethylamino)‐s‐triazin‐2‐yl] amino]‐2‐methylpropionitrile}, metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamide], and EPTC+ [S‐ethyl dipropylthiocarbamate plus R‐25788 (N,N‐dially1‐2,2‐dichloroacetamide)] were preplant incorporated at rates ranging from one to three times those normally used for soil types common to these experiments. The soils were Drummer silty clay loam (Typic Haplaquoll) and Flanagan silt loam (Aquic Arguidoll). Seed quality, hybrid, and seedbed environment all interacted to affect emergence, herbicide injury, stand density at harvest, and grain yield. Seedlings from seed lower in vigor received greater herbicide injury in two of the five seedbed environments investigated, but this interaction was not significant for percent seedling emergence, plant density at maturity, and grain yield. Some herbicide treatments caused grain yield reductions of 4 to 13% but were limited to above‐normal rates of cyanazine and EPTC+ and were not associated with plant death. Visual symptoms of herbicide injury on seedlings were usually out‐grown with no resultant effect on grain yield. Grain yield reductions of up to 32% occurred from seed low in cold test germination. Yield reductions from low quality seed did not occur with all hybrids or in all seedbeds, but when yield reductions did occur, they were associated with decreases in plant density. We conclude that any interaction of corn seed quality with herbicides applied at recommended rates is minor compared with effects of poor seed quality per se, unwarranted high herbicide rates, hybrid differences, or limited soil moisture.

Field Emergence Comparisons of Opaque‐2 and Surgary‐2 Opaque‐2 Segregates in Two Maize Synthetics1

The improved protein quality associated with opaque‐2 (o2) maize (Zea mays L.) has not been widely used because grain yield, grain quality, and field stands generally are reduced relative to normal maize. This study was conducted to determine if the superior grain quality of sugary‐2 opaque‐2 (su2 02) would be expressed also in seedling emergence percentage, rate of emergence, and seedling weight by comparing 02 and su2 o2 segregates of S1 and S2 ears from two maize synthetics.Very similar emergence responses were obtained [or the two endosperm classes when S1 segregates were examined. The means for emergence percentage, rate of emergence, and seedling weight favored the o2 phenotype over the su2 o2 phenotype; however, significant differences were obtained only [or rate of emergence and seedling weight.Under the cold field conditions encountered when S2 segregates were examined, o2 kernels were significantly superior to su2 o2 in emergence percentage and rate of emergence. Opaque‐2 kernels were larger, heavier, and had lower specific gravity than su2 o2 kernels. Relationships among traits within endosperm classes were different than [or the pooled endosperm classes, however. Percentages of seedling emergence within the o2 and su2 o2 classes were positively correlated with specific gravity of S2 kernels and rate of emergence, but were negatively correlated with weight and size of kernels. The apparent contradiction reflects the negative relationship between seed size and specific gravity within both the 02 and su2 o2 classes. Heritability estimates for the emergence traits were large and suggest that selection for improved emergence should be effective within either of the endosperm classes. Seedling emergence of o2 was not improved by the superior kernel texture of su2 o2 contributed by the su2 gene.

The Effects of Plant Density, Spatial Arrangement and Time of Harvest on Yield and Root Size in Carrots

SUMMARYFour experiments were carried out over a 2-year period to investigate the effect of plant density and spatial arrangement and the time of lifting on yield and root size of carrots. Plant arrangement was varied by growing the plants in 1-, 2-, 3-, 4-, 5- and 10-row systems in beds with rows 12–5 and 37–5 cm apart. With each row arrangement crops were grown at target densities of 108, 323 and 537 plants/ma. There were three times of harvest. Total root yield was not significantly affected by plant arrangement or, in three out of the four experiments, by plant density but yields progressively increased with later harvests at all density levels. Yields of canning-size roots (20–30 mm diameter) were influenced by plant density and time of harvest and there were highly significant interactions between these variables on canning root yields. Highest absolute yields were obtained from the latest harvests from the medium and high plant density treatments; with the lowest density treatments the highest yields of canners were obtained from the earliest harvests. Mean root weight was significantly affected by plant density and harvest time. Row system effects on mean root weight were shown to be largely accounted for by differences in percentage seedling emergence and hence the plant density obtained under the different row system treatments and a possible reason for this effect is discussed. The relationship between mean root weight and plant density was not affected by the pattern of plant arrangement in these experiments. Total root yields were shown to be related to cumulative potential evapotranspiration from sowing rather than to chronological time. It is concluded that with the range of row systems used in these experiments, row spacing had little effect on root yield but confirmed previous work that plant density and time of harvest were the most important variables controlling mean root size and hence the yield of roots of any particular size grade.

The effects of fluid sowing pre-germinated seeds and transplanting on emergence, growth and yield of outdoor bush tomatoes

SUMMARYExperiments on outdoor bush tomatoes cv. Sleaford Abundance were conducted during 3 years to compare seedling establishment from fluid-sown pre-germinated seeds with that from conventionally sown dry seeds and to compare the effects on ripening and yields of these establishment methods with transplanting. Fluid-sown pre-germinated seeds emerged about 15 days earlier than conventionally sown dry seeds from sowings made in late April (mean soil temperature at seed depth from sowing to emergence ranged from 9 to 11.5 °C) and about 6 days earlier from sowings made in mid-May (mean soil temperature ranged from 12 to 15 °C). The percentage seedling emergence from pregerminated fluid-sown seeds was, on average, 57% from the earlier sowings and 65% from the later sowings, 34 and 24% higher, respectively, than from dry seeds sown conventionally. Plants from fluid-sown pre-germinated seeds were about 50% heavier than those from dry seeds at all stages of growth up to flowering. Crops established by fluidsowing started to ripen 7 days earlier than those established from dry seeds, when averaged over sowing dates and years. Yields of ripe marketable fruit > 35 mm in. size from crops established from pre-germinated seeds were 35·2 t/ha, averaged over sowing and planting dates, 37% higher than from dry seeds though 51% lower than from transplants. In the two years with good growing seasons crops fluid sown in late April gave as good yields as those transplanted in late May and early June, after the last frosts, though in the cool wet year yields from fluid-sown crops were considerably lower than those from transplanted crops. Yields of ripe, marketable fruit from ‘bare-root’ plants raised from pre-germinated seeds in unheated Dutch-light structures were, on average, 48·5 t/ha, 25% higher than from plants raised in soil blocks in a heated glasshouse.

Emergence Comparisons Between Opaque and Normal Segregates in Two Maize Synthetics1

Maize (Zea mays L.) inbred lines and populations with the opaque‐2 gene has several serious agronomic liabilities compared with normal maize counterparts among which are reduced yield, increased ear rot, reduced and slower seedling emergence, and reduced seedling vigor. The objectives of our study were to (1) compare emergence percentages in opaque‐2 and normal segregates from two synthetic populations; (2) determine whether emergence traits were correlated with protein traits; (3) estimate the genetic variances and heritabilities of emergence traits in the two synthetics. In Experiment I, kernels from 118 S1 segregating ears of BSAA+/o2 were germinated in sandbenches in a greenhouse; 93.5% of the normal kernels emerged compared with 82.0% of the opaque kernels. Mean squares for families, endosperm types, and the interaction of families X endosperm type were highly significant for percentage seedling emergence. Emergence percentage was negatively correlated (significant at the 0.01 level of probability) with lysine and protein concentration, and lysine (g/100 g protein). Genetic variances and heritability estimates for seedling emergence were higher in the opaque‐2 class than in the normal. In Experiment II, opaque and normal kernels from 80 segregating 1 ears of BSBB+/o2 were germinated and grown in flats in a growth chamber maintained at 12°C for 13 days and were then transferred to a greenhouse; 88% of the normal and 60.7% of the opaque kernels emerged. The average rate of emergence for normal kernels was slightly faster than for opaque kernels. Mean dry weight of seedlings was higher for normal kernels than for opaque. Genetic variances and heritabilities for these traits usually were larger in the opaque class. The correlations between seedling emergence and protein quality traits were frequently negative or close to zero. We concluded that it should be possible to select for improved seedling emergence in normal and opaque‐2 maize.

EFFECT OF SEED MOISTURE CONTENT AT SWATHING ON EMERGENCE OF FALL RYE

The after-ripening requirement of three fall rye (Secale cereale L.) cultivars, harvested at three seed moisture contents (50, 42, and 32%), was assessed by monitoring the changes in seedling emergence from sowings made over a period of 60 days. All cultivars exhibited a short after-ripening requirement of 1–7 days. The absolute duration of the after-ripening requirement was not affected by the range of seed moisture contents studied. Seed treatment with captan [N[(trichloromethyl) thiol]-4-cyclohexene-1,2-dicarboximide] significantly increased percent seedling emergence. The captan treatment had the greatest effect on seeds harvested at the lowest moisture content.

Effect of Soil Compaction and Depth of Seed Placement on the Emergence of Different Crops

Compacting the soil above 1.2 g/cc delayed the crop emergence and reduced the emergence percentage of seedlings. At shallow sowing wheat tolerated a bulk density of 1.2 g/cc and rice upto 1.8 g/cc. Increasing seeding depth had harmful effect on crop emergence.

Seed Germinability Tests for Predicting Field Emergence of Rice Seeds Infected with Helminthosporium oryzae and Trichoconis padwickii

Seed Germinability Tests for Predicting Field Emergence of Rice Seeds Infected with Helminthosporium oryzae and Trichoconis padwickii

Effects of pre-sowing seed treatments and temperatures on tomato seed germination and seedling emergence

Sowing pre-germinated seeds with radicles 2–3 mm long reduced the time from sowing to seedling emergence to 17 days compared with 41 days in untreated seeds at soil temperatures of 10°C, and to 5 days compared with 11 days at 18°C. Sowing pre-germinated seeds also improved percentage seedling emergence and reduced the variability of times of emergence of individual seedlings. Seeds imbibed for 56 h before sowing (radicles just emerging) emerged about 3 days earlier at both 10°C and 18°C than untreated seeds. Seeds soaked in a solution containing 1.5% each of KNO 3 and K 3PO 4 for 5 days at 24°C, or in “Carbowax 20 M” for 20 days at 15°C, and then dried before sowing, gave results similar to imbibed seeds. Soaking seeds in 70% of their weight of water followed by drying for different lengths of time and for different numbers of cycles of wetting and drying did not improve germination or seedling emergence.

Cottonseed Density: Associated Germination and Seedling Emergence Properties1

AbstractRecent studies have indicated that separation of cottonseed (Gossypium hirsutum L.) for improvement in seed quality should be based on seed density rather than seed size or weight. Seed density is closely related to embryo maturity and is more independent of genotype than are other seed properties.The primary objective of this study was to determine the effect of seed density on some of the processes associated with cottonseed germination and seedling establishment of several cultivars. Acid delinted seed were separated into four density groups using a pneumatic separator. Rate of imbibition, quantity and quality of material leached from the seed, rate of radicle elongation, germination and seedling emergence percentages were measured as indicators of seed quality and seedling vigor potential.Germination percentages were directly related to both seed density and seed weight, with the better correlation existing with seed density. The rates of imbibition and radicle elongation were related to seed density within a cultivar with differences existing between cultivars. A slower rate of radicle elongation was observed for the highest density class during the first 2 to 3 days of germination, which was related to a decreased rate of imbibition during the first 8 hours of contact with water. The quantity of soluble sugars, Ca, and K leached from the seed during imbibition was inversely related to seed density, suggesting interferences existed during seed development or deterioration had occurred in the low density seed. Seed density was highly related to rate of emergence, total emergence, and seedling survival under both growth chamber and field conditions.The results obtained suggest that seed density is the best predictor of cottonseed germination, emergence and potential seedling vigor. Seed separation for improvement in seed quality should be based on density rather than other seed properties.