Percentage Of Normal Seedlings Research Articles

Seed Soaking Damage in Some Grain Legumes

ABSTRACT Seeds of soybeans (Glycine max), peas (Pisum sativum), faba beans (Vicia faba) and dwarf beans (Phaseolus vulgaris) were used. The effects of soak water whether untreated, air-enriched or CO2-en-riched on germination, membrane integrity and the vital staining with tetrazolium chloride of embryo tissues were assessed. Imbibition damage, expressed as low percentage of embryo tissue stained with tetrazo-lium chloride, was observed when seeds soaked in water. In soybeans and faba beans, imbibition damage was enhanced by the CO2-enriched soaking treatment whereas in peas imbibition damage was greater after soaking in air-enriched soak water. Most of the soak-damaged seeds could not sustain normal growth as indicated by the reduced percentage of normal seedlings or low embryonic axis growth recorded. Where soaking reduced germination, seed drying after soaking resulted in increased germination capacity, possibly because membrane integrity and embryo viability were restored upon drying.

Chlorophyll fluorescence of Brassica oleracea seeds as a non-destructive marker for seed maturity and seed performance

AbstractA method is proposed for assessing the maturity and quality of seeds, based on measuring the amount of chlorophyll fluorescence (CF) signals of intact seeds. In general, the amount of chlorophyll is directly related to the degreening process and thus the maturity. Cabbage seeds (Brassica oleracea var. capitata) were separated into three subsamples based on the CF signals of the individual intact seeds. Seeds with the lowest amount of CF had the highest percentage of germination and normal seedlings. In a controlled deterioration test, the subsample with the lowest CF signal had slightly lower germination and normal seedling percentages than the non-treated seeds, whereas the seeds with the highest CF signals had much lower germination and normal seedling percentages. Advantages of the CF method for determining seed maturity and seed quality are its high sensitivity and fully non-destructive nature and the high speed at which the fluorescence is generated and measured.

Germination and vigour loss of non-sprouted and sprouted wheat seeds during storage – testing the viability constants

AbstractThe loss of percentage germination and vigour of non-sprouted and sprouted seeds of winter wheat was determined during storage for 80 days at 11 different combinations of moisture content and temperature. Before storage the initial percentage germination and vigour were reduced according to the level of sprouting. During storage the percentage germination and vigour decreased. The rate of germination loss increased with increasing seed moisture content and/or increasing temperature. The species-specific constants KE, CW, CH and CQ of the viability equation were not different for non-sprouted and sprouted seeds. Likewise, the relation between the percentage of normal and abnormal seedlings was independent of sprouting. The rate of vigour loss was also independent of the storage conditions and of sprouting.

Effect of Pollen Selection for Alachlor Tolerance in Maize

Pollen selection can lead to correlated responses in the subsequent sporophytes because many genes are expressed in both haploid and diploid phases. This study was conducted to evaluate the effects of pollen selection for tolerance to the herbicide alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl) acetamide] in maize (Zea mays L.). Tassels of the single cross hybrid K55 (tolerant) x Ky226 (susceptible) were grown in absence (control) and in presence (selected) of alachlor (1 g L -1 ). Mature pollen from this process was used to make backcrosses to Ky226 (susceptibility being recessive). The selected population outperformed the control population (88 vs. 81%; P ≤ 0.01) for percentage of normal seedlings (i.e., not injured by alachlor) when compared in a field trial treated with the herbicide (5 kg a.i. ha -1 ). Pollen of plants grown without alachlor was analyzed in vitro; in presence of the herbicide in the medium (50 mg L -1 ) the selected population exceeded the control population for pollen tube length (334 vs. 308 μm; P ≤ 0.01). Two cycles of pollen selection were also conducted in the single cross hybrid K55 x H99 (susceptible) following the backcross procedure to the susceptible parent. Seeds of control and selected populations were exposed to alachlor (1 g L -1 ), and seedlings were grown in the greenhouse. For percentage of normal seedlings, we obtained a gain (16%) in the first cycle and an additional gain (10%) in the second cycle. The results indicate that genes controlling alachlor tolerance in maize are expressed in both haploid and diploid phases and that pollen selection can be effectively applied to improve the trait.

Effect of Pollen Selection for Alachlor Tolerance in Maize

Pollen selection can lead to correlated responses in the subsequent sporophytes because many genes are expressed in both haploid and diploid phases. This study was conducted to evaluate the effects of pollen selection for tolerance to the herbicide alachlor [2‐chloro‐N‐(2,6‐ diethylphenyl)‐N‐(methoxymethyl) acetamide] in maize (Zea mays L.). Tassels of the single cross hybrid K55 (tolerant) ✕ Ky226 (susceptible) were grown in absence (control) and in presence (selected) of alachlor (I g L−1). Mature pollen from this process was used to make backcrosses to Ky226 (susceptibility being recessive). The selected population outperformed the control population (88 vs. 81%; P ≤ 0.01) for percentage of normal seedlings (i.e., not injured by alachlor) when compared in a field trial treated with the herbicide (5 kg a.i. ha−1). Pollen of plants grown without alachlor was analyzed in vitro; in presence of the herbicide in the medium (50 mg L−1) the selected population exceeded the control population for pollen tube length (334 vs. 308 μm; P ≤ 0.01). Two cycles of pollen selection were also conducted in the single cross hybrid KS5 ✕ H99 (susceptible) following the backcross procedure to the susceptible parent. Seeds of control and selected populations were exposed to alachlor (I g L−1), and seedlings were grown in the greenhouse. For percentage of normal seedlings, we obtained a gain (16%) in the first cycle and an additional gain (10%) in the second cycle. The results indicate that genes controlling alachlor tolerance in maize are expressed in both haploid and diploid phases and that pollen selection can be effectively applied to improve the trait.

Threshing Cylinder Speed Affects Germination of Amaranths cruentus L. Seeds

The percentage of normal grain amaranth seedlings decreased and that of abnormal seedlings increased as threshing cylinder speed increased from 8.1 to 30.7 m·s-1. At the highest threshing speed, seed deterioration (loss of germination and increase in the percentage of abnormal seedlings) was exacerbated by increasing seed storage from 7 to 47 months. Threshing cylinder speeds of 8.1 to 12.8 m·s-1 resulted in similar percentages of normal seedlings as those achieved with hand-harvesting and threshing. Although injury to hand-harvested seeds or seeds threshed at 8.1 m·s-1 was not apparent, scanning electron micrographs of seeds threshed at 12.8 or 22.4 m·s-1 revealed damage to the seedcoat and the endosperm. Damage extended to the embryo when threshing cylinder speed was increased to 30.7 m·s-1.

Priming Improves Germination and Emergence of Combine-harvested Amaranths cruentus L. Seeds

Hand-harvested and threshed grain amaranth seeds stored for 6.5 years and combine-harvested and threshed seeds (cylinder speed 26.4 m·s-1) stored for 9.5 years were subjected to several osmotic priming treatment. The selected priming treatment (–1.25 MPa polyethylene glycol at 15C for 10 days) increased percent radicle emergence of hand-harvested seeds and mechanically damaged, combine-harvested seeds and resulted in germination rates that were at least as high as those achieved with other priming treatments. In an incubator test, priming increased percent radicle emergence of hand-harvested seeds only at 15C; however, it increased percent radicle emergence of combine-harvested seeds at 15 and 35C. Priming also increased radicle emergence rate, but this response was more pronounced and exerted over a wider temperature range for the older, lower-vigor, combine-harvested seeds than for the younger, higher-vigor, hand-harvested seeds. In a greenhouse test, hand-harvested seeds had a higher percentage of normal seedlings and a lower percentage of abnormal seedlings than combine-harvested seeds. Priming had no effect on these variables. As a result of priming, normal seedling emergence rate and shoot fresh weight were higher from combine-harvested seeds than from hand-harvested seeds, such that values of these variables for primed, combine-harvested seeds were at least equal to those for nonprimed, hand-harvested seeds. Thus, the invigorating effect of priming was more pronounced for the lower-vigor, mechanically damaged, combine-harvested seeds than for the higher-vigor, hand-harvested seeds.

Calcium and Relative Humidity Effects on Soybean Seed Nutrition and Seed Quality

Reduced seed calcium concentrations have been observed in soybean [Glycine max (L.) Merr.] seed lots with reduced seed germination. Soybean plants were grown hydroponically at Ames, IA, 1991, to determine if the Ca concentration of the root medium and relative humidity (RII) could influence seed Ca concentration and, subsequently, seed quality. Plants were grown in solution culture in a controlled environment growth chamber, with Ca concentrations of 0, 0.6, 1.2, and 2.5 mM in the root medium from beginning seed (R5) to beginning maturity (R7). In addition, concentrations of 0.6 and 2.5 mM Ca and RH of 55 and 95% were applied from R5 to R7 to plants grown in sand culture in the greenhouse. Treatments were arranged in a randomized compete‐block design in both studies, with the blocks replicated in time in the growth‐chamber study. Seed Ca concentrations increased with increased Ca supply to the plant. Relative humidity had not effect on either seed Ca concentration or germination. A decrease in the percentage of normal seedlings from 96.7 to 41.8% coincided with a decrease in seed Ca from 2.37 to 0.87 mg g−1. Reduced germination of low‐Ca seeds was primarily due to an increase in the percentage of abnormal seedlings. The percentage of normal seedlings was significantly and positively correlated with Ca (r = 0.83) and negatively correlated with the B/Ca ratio and B (r = ‐0.97 and −0.83, respectively) in seeds. Results indicate that reduced Ca supply to the plant may reduce seed Ca concentration in addition to altering other seed nutrients. Reduced seed Ca was associated with poorer seed germination, but additional studies are needed to clarify the role of Ca and other nutrients in the germination of seeds and seedling establishment.

QUEBRA DE DORMÊNCIA EM SEMENTES DE CROTALARIA

A germinação de sementes de quatro espécies de Crotalaria foram avaliadas após tratamentos químicos, físicos e mecânicos de superação de impermeabilidade do tegumento. Os métodos mais eficientes para a quebra de dormência foram: para a C. retusa, a escarificação em engenho e embebição em água fervente por cinco minutos; para a C. espectabilis a escarificação química em H2SO4 e embebição prévia em água destilada à temperatura ambiente; para a C. mucronata a escarificação em engenho, os quais possibilitaram a maior percentagem de plântulas normais. Já para a C. grantiana, nenhum tratamento testado foi estatisticamente superior à testemunha.

Infusion of shrunken-2 Sweet Corn Seed with Organic Solvents: Effects on Germination and Vigor

Sweet corn (Zea mays L. var. rugosa Bonaf.) seed carrying the mutant endosperm gene shrunken-2 (sh2) are very susceptible to seed rot and pre- and post-emergence damping off. Experiments were conducted to determine if selected organic solvents were suitable carriers for fungicide infusion of sh2 sweet corn seed for improved germination and stand establishment. Seed of `Florida Staysweet' and `Crisp-n-Sweet 710' were immersed in acetone, cyclohexane, decahydronaphthalene (Decalin), dimethylsulfoxide (DMSO), ethanol, or xylene for 5 seconds, 0.25, 0.50, 1.0, 2.0, 4.0, or 8.0 hours, air-dried, and subjected to a cold-stress test. Total germination and percentage of normal seedlings in both cultivars were significantly decreased after 8 hours of immersion in acetone. Average seedling dry weight, however, did not decrease. DMSO was highly toxic to both cultivars. Ethanol increased seed mortality with increasing immersion times. Cyclohexane, Decalin, and xylene caused erratic responses in all measured variables as immersion time increased. In a second experiment, the effects of immersion time up to 4 hours in acetone on germination and vigor of 11 sh2 cultivars were compared. There was no correlation between cultivar germination or vigor and immersion in acetone. Results indicate acetone could be used to infuse fungicides into the seed of some sh2 cultivars without compromising seed germination or vigor. However, each sh2 cultivar must be screened individually to determine if it is a suitable candidate for organic solvent infusion of fungicides.

Sunflower seed deterioration from exposure to u.v.-C radiation

Sunflower ( Helianthus annuus L. cv. Toledo-2) seeds were exposed to u.v.-C radiation for 0, 5, 10, 15, 30 and 60 min. Experiments were carried out using dry and hydrated seeds. In each group, two treatments were considered: (1) dry (treatment D0) and hydrated (treatment W0) seeds were germinated immediately after u.v.-C irradiation, and (2) dry (treatment D7) and hydrated (treatment W7) seeds were exposed to irradiation and then stored in darkness 7 days before the initiation of germination. The percentage of normal seedlings was reduced when u.v.-C irradiation exposure durations increased from 5 to 60 min. The percentage of abnormal seedlings increased and showed a maximum for the 60 min exposure time. As compared to treatments D0 and W0, seeds stored 7 days after irradiation (treatments D7 and W7) showed less inhibition. The results suggest that inhibition caused by u.v.-C radiation may be partially reversed during dark storage of seeds; the extent of this recovery varies with seed treatment. When the results from the seed treatments were combined (D0 + D7 and W0 + W7), the ability of seeds to germinate was described by a linear probit regression between germination performance and u.v.-C exposure time. A probit analysis of the percentage of normal seeds indicated that hydrated seeds (W0 + W7) had a sensitivity to u.v.-C irradiation 2.74 greater than that of dry seeds (D0 + D7).

Effect of gamma-irradiation on germination and leakage of electrolytes from peanut ( Arachis hipogaea L.) seeds

Apical and basal seeds of Spanish peanut (cv. “Valenciana”) were irradiated with 0, 10, 20 and 40 kR gamma-rays, and germinated at 25 ± 1°C. The effect of irradiation on conduction of electrical current (EC in μA) of electrolytes leaked from individualized seed was monitored by an Automatic Seed Analyzer Computer (ASAC-1000), and the percentages of normal, abnormal and dead seeds during the 12-day germination period were recorded. Differences in weight, length, volume, and surface were observed among the two types of seeds. A probit analysis of the percentage of normal seedlings by germination according to ISTA guidelines indicated that the basal seeds, smaller in weight and volume, had a radio-resistance 2.38 times greater than that of the apical seeds.

<i>Petunia hybrida</i> のはい珠培養におけるFe-EDTAの効果

The present investigation dealt with in vitro the growth of the excised ovules just after fertilization in Petunia hybrida.Most of these ovules were cultured on a medium composed of inorganic salts, vitamins, glycine, sucrose and agar without any growth regulators or plant extracts. They were able to develop into viable seeds only when cultured on the medium containing Fe-EDTA as an iron source. Some of the seeds germinated in situ immediately and developed until flowering. However, ovules cultured on a medium containing ferric citrate failed to develop into viable seeds.The addition of some growth regulators to the medium containing Fe-EDTA rather inhibited the normal development of ovules. A supply of casamino acids did not also increase the percentage of normal seedlings; however, the number of normal seedlings increased progressively with decreasing the concentration of sucrose.

Randomness of Mating in a Polycross of Orchardgrass, Dactylis glomerata L.1

Randomness of mating was studied by using a genetic marker. The polycross contained 10 plants from each of five selections including four recessive alboviridis clones and one normal green clone homozygous dominant at the marker locus. Three‐year average percentages of crossing with the normal clone ranged from 30 to 39 among the four alboviridis clones. There was considerable yearly variation in the average percentage for each clone. Data on panicle number and seed yield indicated that the normal clone porduced the most pollen, which may account for average percentages greater than the 25% expected on the basis of random mating and no selling. Amount of crossing with the normal clone was not affected consistently by degree of self‐fertility of the maternal parent except in a year of sparse heading when average percentages of normal seedlings in progenies of two relatively self‐fertile clones were lower than those for two relatively self‐sterile clones. Percentages of normal seedlings in progenies of individual albovirldis plants ranged from 2 to 72, and in 2 of 3 years the percentages were associated with wind conditions and distance downwind from a normal plant.

Effect of Temperature on Germination and Seedling Development of Ladino Clover (Trifolium repens L.) and Salina Strawberry Clover (Trifolium fragiferum L.)1

Germination and seedling development of Ladino and 'Salina' strawberry clovers at 10, 15, and 20 C were studied. Little growth occurred in either species at 10 C. Ladino clover had a lower percentage of normal seedlings when germinated at 15 C as compared to 20 C. The cumulative average leaf index number differed little between species at 15 and 20 C. Petiole elongation was retarded more than blade development at 15 C in both species.

Inheritance of Soybean Seed Quality I. Heritability of Laboratory Germination and Field Emergence1

Individual plants of parental, F1 and F2 populations, and F3 progenies of soybeans were evaluated for seed quality as measured by seedling emergence percentage in the field and by six determinations made in a standard laboratory test. The laboratory determinations were percent normal seedlings plus hard seed, normal seedlings at 5 days, total normal seedlings, abnormal seedlings, decayed or dead seed, and hard seed. Five parental populations consisted of two commercial varieties, Chippewa and Harosoy 63, and three Japanese strains, Wasedaizu No. 1 (PI261469), Matsuura (PI200499), and Kimusume (PI229336). Six F1 and six segregating (F2 and F3) populations were produced from crosses of each Japanese strain as female parent with each of the commercial varieties.Estimates of broad sense heritability for the field emergence and laboratory germination characters were generally low positive or negative values because of high environmental variances in parents and F1's. Narrow sense heritabilities ranged from 3 to 29% for field emergence, from 2 to 60% for the three determinations of normal seedlings in laboratory germination tests, and from 31 to 71% for hard seed. Fa population means for the seed quality characters were usually equal to or higher than the mid‐parent values. In each cross 10 to 20% of the F3 families exceeded the high parent for field emergence. Thus, improvement in this character from selection would seem easy, in spite of the low calculated heritabilities, if selection pressure is applied on F3 to Fn families rather than on single plants and if some replication is used in producing family seed for testing.Percentages of normal seedlings plus hard seed, normal seedlings at 5 days, and total normal seedlings were about equally well correlated with percentages of normal seedlings in field emergence tests. Abnormal seedling and hard seed percentage in laboratory tests were not as closely associated with field emergence.

Inheritance of Soybean Seed Quality II. Heritability of Visual Ratings of Soybean Seed Quality1

Seed from the parental, F1, and segregating (F2 and F3) soybean populations were evaluated for quality by visual ratings for wrinkled seedcoats, shriveled cotyledons, green cotyledon color, an arithmetic average of the three previous ratings, and an overall visual rating. These ratings were on a 1 to 5 scale, with 5 being the most extreme expression of the character.The variance among single plants in the commercial varieties for the visual ratings was generally high in relation to the variance in the Japanese strains and in the F1 populations. However, the variance in the F2 populations was generally large in comparison to the arithmetic mean of the variances within the respective parental and F1 populations resulting in broad sense heritability estimates ranging from 41 to 63% for wrinkled seedcoats, 14 to 57% for shriveled cotyledons, 52 to 82% for green cotyledons, 41 to 71% for the average visual rating, and 22 to 64% for the overall visual rating. Narrow sense heritability estimates for the visual ratings ranged from 6 to 30% for wrinkled seedcoats, 10 to 38% for shriveled cotyledons, O to 29% for green cotyledons, 1 to 28% for the average visual rating, and 7 to 28% for the overall visual rating.Low visual ratings for wrinkled seedcoats, shriveled cotyledons, green cotyledons, low average visual ratings, and low overall visual ratings were generally associated with high percentages of normal seedlings in field emergence tests. This was especially true in the F3 and ‘Chippewa’ parental populations in which more variation existed in each of the characters being tested.The average visual rating was somewhat more consistent in predicting relative field emergence than any of the ratings of separate seed characters. However, the overall visual rating appeared to be about equal in this respect. Considering both precision of measurement and time utilization, an overall visual rating followed by field emergence testing may be the most efficient means of evaluating segregating populations of soybeans for seed quality.

Effect of Seed Moisture Content, Field Weathering, and Combine Cylinder Speed on Soybean Seed Quality1

Two varieties of soybeans were harvested at varying dates and at varying seed moisture contents in 1959, 1960, and 1961. Two harvest methods, hand shelling and machine harvesting, were used at each date of harvest. With the machine harvest method combine cylinder speeds of 500, 700, and 900 rpm were used.In all 3 years there was a general trend for the whole seed from later dates of harvest to have a lower percentage of normal seedlings in laboratory germination and field emergence tests, a higher percentage of splits and cracked seedcoats, and smaller average seed size as measured in grams per 100 seed and by a screening method. Exceptions to this general rule occurred in 1961 when the initial quality of the seed was very high.With only a few exceptions, hand harvested seed‐lots had higher viability and a lower incidence of splits and cracked seedcoats than machine harvested seed‐lots. Within the machine harvested seed‐lots, harvesting at lower cylinder speeds produced seed with a higher percentage of normal seedlings in laboratory germination and field emergence tests, a lower percentage of abnormal seedlings in laboratory tests, a lower percentage of splits and cracked seedcoats, and larger average seed size. There was some indication that the threshing effect split a larger percentage of the larger soybean seed within each seed‐lot.