Seed Length Research Articles

Sterility in Rice Induced by Chemical Treatment

Several chemicals were evaluated for their efficacy to induce sterility in rice (Oryza sativa L., Yamabiko) in 1990. Two chemicals, kasugamycin and aminooxyacetic acid (AOA), indicated a remarkable effect to induce sterility in rice when treated at meiosis. In 1991, kasugamycin and AOA were applied to rice plants at two different growth stages to find the optimum application period and dosage for the induction of sterility. Kasugamycin affected sterility in rice only at meiosis, but AOA affected it from the panicle formation stage to meiosis at a low concentration of 100 mg/liter. Rice plants treated with kasugamycin were similar to control for the number of seeds, spike length, culm length and weight of ripe seeds, but rice plants treated with AOA were inferior to the control in these respects. Interaction between kasugamycin and the plant hormone for the restoration of fertility was shown in rice when α-naphthylacetic acid (NAA) was applied simultaneously with kasugamycin.

Comparison of Machine Vision With Human Measurement of Seed Dimensions

Abstract Length, width, and thickness of tall fescue (Festuca arundinacea), orchardgrass (Dactylis glomerata), and perennial ryegrass seeds (Lolium perenne) were measured by a machine vision system and by four human operators using a microscope with a reticle. Statistical analysis showed that the consistency of machine vision measure-ments was greater than that of the human measurements and required about one-third of the time. Overall accuracy of machine vision system measurements appears to be sufficient to be the basis for selection of screen opening and indent pocket sizes used in seed conditioning operations.

Seedstalk Production of Mountain Big Sagebrush Enhanced through Short-Term Protection from Heavy Browsing

Mountain big sagebrush (Artemisiu tridentata ssp. vuseyuna Nutt.) is an important browse species on many key mule deer winter ranges in the western United States. Big sagebrush on many of those ranges is declining due to the lack of recruitment. Phnts subjected to heavy 0 8% use) browsing produce 50 to 93% fewer seedstalks than those not subject to such use. The objectives of this study were to determine: (1) whether protection from browsing for 1 winter would increase the number of seedstalks the following fall; (2) if protection increased length of seedstalk; (3) if there is a relationship between seedstalk length and number of seeds per seedstalk; and (4) if increasing seed production increased seedling establishment. Fifty-eight plots containing 344 plants at 4 sites in north-central Utah were established. At each plot, plants were randomly assigned to be either protected or browsed. The protected plants produced significantly (P<O.OS) more seedstalks than those browsed during the previous winter. Length of seedstalks on a given plant and among plants showed considerable variation, and the data indicated no clear differences between average seedstalk length on browsed and protected plants. Seed per unit length of seedstalk was also highly variable. No seedlings were found during 7 years of observations of the original plot or in 4 years for the 57 plots established in 1986, regardless of the numbers of seedstalks on a plant. Seed production does not appear to be a limiting factor in seedling establishment for the study populations.

The influence of seed apparency, nutrient content and chemical defenses on dietary preference in Dipodomys ordii.

Physical, nutritional and defensive qualities of seeds differ in the extent to which they influence granivore preference. In a study aimed to quantifying those differences, Ord's kangaroo rats (Dipodomys ordii) were found to prefer the seeds of just three of twenty-nine species: Cryptantha crassisepala, Oryzopsis hymenoides and Salsola kali. Oryzopsis hymenoides was most preferred during the early plant growth season (April-July); preference for S. kali peaked during late (August-November) and dormant (December-March) seasons; and greatest preference for C. crassisepala occurred during dormant and early seasons. Regression of forage ratios, averaged across seasons, against seed length, mass, abundance, patchiness, percent nitrogen, energy content, and chemical defenses showed seed length to be the most important predictor of seed preference. Seed length combined with nitrogen (protein) content and levels of two defensive compounds, saponins and non-protein amino acids, to account for 68% of the variation in seed preference. The importance of seed length rather than biomass indicated that there are limits to the ability of D. ordii to detect small seeds and that small size facilitated escape of dispersed seeds. Seasonality in preference suggested, however, that seed escape was encountered by predispersal harvesting of newly maturing seeds still on plants. Maximization of protein intake contradicted previously published observations, but presumably reflected low nitrogen availability. In addition to small size, the presence of saponins or non-protein amino acids in seeds was sufficient to negate the positive influence of higher protein content.

Patterns of variation in Ontario wild rice ( Zizania aquatica L.) 4. Influence of regional and local environmental factors on variation within and among field populations

Analyses of covariance were used to examine morphological and productivity data from 17 indigenous wild rice populations in six empirically defined climatic regions. Statistical compensation for effects of local environmental factors (principal components of sediment nutrient concentrations, water depth and other emergent macrophytes) permitted direct comparisons of populations in different regions. there was a general trend of increasing stem and root weight, leaf width, and pistillate floret number with decreasing climatic severity. Tiller production was greatest in populations from intermediate climatic regimes. These results were consistent with those obtained in greenhouse experiments. Seed length and weight did not appear to be systematically related to climatic regime, and plant height was primarily a function of local environmental factors, especially water depth.

Snap Bean Pod Quality as Affected by Cultivar and Harvest

Sieve size distribution has long been used as the index for snap bean (Phaseolus vulgaris L.) crop maturity and subsequent harvest. The development of new cultivars exhibiting high pod quality has led to a need to use criteria other than sieve size as a measurement of maturity. Pod characteristics of these new cultivars vary from slim, small sieve pods for some cultivars to large sieve pods for other cultivars. Seven snap bean cultivars were evaluated for yield and pod quality characteristics at different harvest maturities at Crossville, TN, in 1986 and 1987. Each characteristic that was evaluated differed significantly among cultivars. Tender-podded processing type cultivars retained quality in the field longer than the more fibrous fresh-market cultivars. Yield increased as harvest was delayed, but declined at the last harvest date. Pod clustering, broken pods, percentage of pod passing no. 5 sieve, length of seed in pods, and pod firmness increased as harvest was delayed. Seed length was negatively correlated with yield and positively correlated with percentage seed in pods, pod firmness, and the Hunter “L” color value. Seed length appeared to be a good single index of maturity.

Decision-Support System Development for Conditioning Seeds with Indent Cylinder

ABSTRACTt Seed conditioning tests were conducted using the indent cylinder. Fifty-four sublots of Stevens wheat seed were separated into two length fractions using 27 combinations of operating parameters with two replications. Three cylinder pocket sizes were selected along with three cylinder revolution speeds and three catch-pan positions. Each test was conducted as a batch until separation was complete. Length measurements of 50 randomly selected seeds from each fraction were made using a machine vision system. The average length of the wheat seed was 6.9 mm. Cylinder pocket size, catch-pan position and cylinder revolution speed all had significant effects on the length of seeds in the lifted fraction, but cylinder revolution speed did not have a significant effect on the length of seeds in the unlifted fraction.

Einfluß des schwermetallhaltigen Bodens auf die Getreidekultur

AbstractInfluence of metalliferous soil on grain cultivationThe effect of metalliferous soil (rich in Zn and Pb) over development and productivity of cultivated Triticum aestivum L. is considered. After statistical elaboration of the morphological parameters of the above mentioned species is concluded that the height of the plant, the length of spike, the number of seeds per spike, the weight of seeds per spike, the width and the length of seeds, are diminished.

Taxonomy of the genus Najas L. (Najadaceae) in the neotropics

The taxanomy, geography and evolutionary affinities are treated for the nine Najas taxa occurring in the sub-tropical and tropical regions of the Americas. Outstanding taxonomic characters are fruit dimensions, seed reticulations, leaf sheaths and teeth along leaf blades. Najas conferta (A. Br.) A. Br., N. marina L. and N. guadalupensis (Sprengel) Magnus are dispersed throughout the Neotropics. Two forms of N. guadalupensis, forma guadalupensis and forma floridana (Haynes and Wentz) Lowden, comb. nov., are recognizable on the basis of visibility of teeth along leaf margins. The original descriptions and types chosen for N. conferta and N. wrightiana A. Br. are presented in order to clarify past confusion between these two very distinct species. Primarily, N. wrightiana is restricted to northern Mesoamerica and Cuba, with a more recent extension into southern Florida and the Bahamas. The presence of N. graminea Del. in the flora of Brazil is substantiated with the collection of N. graminea var. minor Rendle from the State of Maranhão. In South America, N. microcarpa Schumann is treated as a species complex demonstrating close affinities with N. arguta H.B.K. and N. conferta. Najas arguta var. arguta and N. arguta var. podostemon (Magnus) Lowden, comb. nov., are different in length of seeds and areolae. What has recently been misinterpreted as N. ancistrocarpa A. Br. ex Magnus in North America is really N. conferta which reaches its northernmost extension in the areas of Georgia and Florida in the southeastern United States.

Correlations between variability in carrot (Daucus carotaL.) plant weight and variability in embryo length

SummaryThe variation in embryo length of Chantenay type carrot seeds, seedling and root weight were examined for 16 lots of commercial origin in 1983, and for six lots in 1984 at three sites for crops grown at low plant densities. The coefficients of variation (CV) of embryo length of the seed lots varied from c. 19 to 50%. The CVs of seedling weight ranged from c. 45 to 75% and of root weight from c. 50 to 70%. The ranking of lots by the CV of seedling weight in both years was similar at each site and both the CV of seedling weight and, in 1984, the CV of root weight increased with an increase in the CV of embryo length. The Spearman rank correlation coefficients (rs) for the relation between the CV of seedling weight and the CV of embryo length in both years ranged from 0.49 to 0.94 and rs for the CV of root weight and the CV of embryo length in 1984 from 0.83 to 0.94.

Insect Pollination Increases Seed Production in Cruciferous and Umbelliferous Crops

SummaryThe effect of insect visits on seed production was studied in 9 cruciferous and 4 umbelliferous crop species at Hissar, India, by comparing several yield parameters in open-pollinated plants and plants in cages or with stems bagged. Bees (Apis dorsata, A. florea, A. mellifera and 6 solitary species) were the dominant flower visitors, and were the only species which collected pollen and acted as potential pollinators. Weight of seeds per plant and weight of seeds per ha were significantly greater in open plots of both cruciferous and umbelliferous species than in caged plots. Mean pod (silique) length and numbers of seeds set per pod in open plots of cruciferous plants, and numbers of seeds set per plant in open plots of umbelliferous plants, were significantly greater than in caged plots. Seed size (weight/1000 seeds) was greater in caged plots of umbelliferous plants than in open plots. Per cent seed germination did not differ significantly between treatments. The management of bees for seed production in cruciferous and umbelliferous crop species is recommended.

EFFECT OF FNVIRONMENT ON PATH-COEFFICIENT ANALYSIS IN SESAME (SESAMUM INDICUM L)

Genotypic correlation coefficients and path-coefficient analysis were studied in 84 genotypes of sosome (Sesamum indicum L) under three environments. Grain yield per plant had significant positive correlation with number of effective branches per plant, number of capsules per plant, capsule length and number of seeds per 5 capsules over the environments studied. The magnitude of correlation coefficients, direct and indirect effects of various yield contributing traits differed from location to location suggesting considerable amount of genotype x environment interaction in the expression of various charactus. Path analysis revealed that number of capsules per plant was the most important component trait contributing to seed yield due to its positivo direct and indirect effect on seed yield in all the environ- ments under study.

Cytogenetical studies on african rice, Oryza glaberrima Steud. 2. Autotriploid produced by crossing between autotetraploid and diploid.

Cytogenetical study on the artificial autotriploid of Oryza glaberrima was carried out.The reciprocal crosses between the autotetraploid and the diploid were made to produce the autotriploid. Four (0.05%) autotriploids were obtained only by pollinating the autotetraploid with the pollens of the diploid.As compared with the diploid, the autotriploid increased in stomata length, pollen diameter and length of unhulled and hulled seeds; decreased in number of panicles, pollen stainability, seed fertility and width, thickness and weight of hulled seed. The differences between them were conspicuous in stomata length, pollen diameter, seed fertility and seed weight. The autotriploid had awned spikelets, which was a single character different qualitatively from the diploid. The autotriploid was easily recognized by its seed sterility, but did not show semigigas characteristics so much expected in appearance. In pollen mother cells of the autotriploid, 5 to 12III were observed at the stage of diakinesis to metaphase I, and 12III most frequently. The mean chromosome configuration was 9.20III+2.68II+3.05I.

Propagule size, dispersal ability, and seedling performance in Asclepias syriaca

Using the propagules of common milkweed (Asclepias syriaca L.) we tested the predictions that decreasing size may increase dispersal ability, but also decrease the probability of seedling success, of wind-dispersed seeds. In 1982 and 1983 we released seeds from four milkweed clones at two heights in an open field and measured their dispersal distances. In the laboratory we measured falling times in a dead air space, seed mass and area, and coma mass and length of the same seeds. The seeds were later planted in a greenhouse and germination, mortality, and seedling dry mass were recorded.Seed mass was negatively correlated with dispersal distance in 1982, but not in 1983 under highly variable wind conditions. Coma mass/seed mass ratio was positively correlated with dispersal distance in 1982. During both years seed mass and coma mass/seed mass ratio were highly significantly correlated with falling time in dead air space. However, heavy seeds had superior germination, survivorship, and seedling mass at harvest, and seeds that germinated fell faster in dead air than those that did not. We found substantial variation in seed morphology both among clones and among pods within clones. Propagule falling times in dead air and (in 1982) dispersal distances in the field also differed significantly among clones and pods. The potential therefore exists for differential dispersal and establishment of milkweed genotypes.

Environmental Conditions Required for Germination of Prickly Sida (Sida spinosa)

Various environmental factors were tested under laboratory conditions to determine their effects on germination of seeds of prickly sida (Sida spinosaL. ♯3SIDSP). Neither freezing and thawing nor moist chilling at 5 C promoted seed germination. However, increasing the incubation temperature and subjecting seeds to wet-dry cycles enhanced germination; high temperatures were more effective than alternate wetting and drying. Shifting seeds from a lower to a higher temperature regime increased germination. Seeds shifted from 15/6, 20/10, 25/15, or 30/15 C to higher regimes of 20/10, 25/15, 30/15, 35/20, or 40/25 C germinated to greater percentages than did seeds kept continuously at the lower thermoperiods. With an increase in length of time seeds were at a lower temperature, there was an increase in the percentage that germinated after they were moved to a higher regime.

Yield Components and Pod Quality of Snap Beans Grown under Differential Irrigation

Abstract Field experiments were conducted to evaluate the effects of differential irrigation treatments on the yield and pod quality of ‘Oregon 1604’ and ‘Galamor’ snap beans (Phaseolus vulgaris L.) in 1981 and 1982. Treatments in which various levels of positive canopy minus air temperature differences [stress-degree-days (SDD)] accumulated between irrigations were evaluated along with irrigation at 4 growth stages, a dry treatment which received only one irrigation to establish plants, and a control treatment irrigated at -0.06 MPa soil water potential (SWP). In both seasons, yield was related strongly to the average soil water potential from planting to harvest. Yields in 1982 were at least 5 MT/ha greater at a given average soil water potential than in 1981. Yields of ‘Oregon 1604’ and ‘Galamor’ were similar under adequate irrigation, but under greatest water stress, yield of ‘Oregon 1604’ was higher than for ‘Galamor’. Pod number was reduced only in the dry treatment. Percentage of set pods, pod length, and number of seeds per pod were all reduced by low irrigation, while fiber content of pods and weight per seed were increased by low irrigation.

A numerical-taxonomic study of theJuncus bufonius aggregate (Juncaceae) in Slovakia

Samples of 34 populations of theJuncus bufonius aggregate in Slovakia have been submitted to a numerical-taxonomic treatment. Three species corresponding to three known cytodemes, i.e.J. bufonius L. s. str. (2n = c. 100–110),J. ambiguusGuss. (2n = 34) andJ. minutulus (Alb. etJahan.)Prain et al. emend.Snog. (2n = c. 72), have been confirmed for the study area. A survey of quantitative characters by various ordination and cluster techniques reveals that the length of capsules, seeds, inner tepals and anthers as well as the ratio of anther to filament length are significant for the segregation of the cytodemes.

Seed Germination in a Seasonal Tropical Forest in Panama: A Community Study

Seed germination in the seasonal tropical forest on Barro Colorado Island, Panama, was studied at the community level to (1) determine the seasonal timing of germination of the community, (2) identify primary selective factors controlling timing of germination, (3) determine the relative importance of dormancy vs. timing of seed dispersal as mechanisms controlling timing of germination, (4) examine inter— and intraspecific components of variance in length of dormancy, and (5) identify major seed germination syndromes. Three community—level measures of seedling emergence indicated that there was a unimodal community peak in germination within the first 2 mo of the 8—mo—long rainy season. Of the °185 dicot, mostly woody, species germinating each year, the median time of emergence of 75% of the species occurred within the 1st 3 mo. There was a unimodal peak in germination in pioneer tree species, lianas, canopy trees, wind— and animal—dispersed species, and seedlings with and without persistent seed reserves. In contrast, there was no distinct peak period of emergence in understory species and shade—tolerant tree species. Initial seedling height of species emerging sequentially throughout the rainy season did not increase. The early emergence of most species, including three—fourths of the 35 species fruiting in the late rainy season, indicated that the early rainy season was the optimal time to emerge. Maximizing the length of the first growing season was not an important factor selecting for early emergence, because later—emerging species did not compensate for the shorter growing season by being larger at germination or by having seed reserves for rapid growth. Seedling—seedling competition is a primary biotic factor selecting for early emergence in pioneer species growing in the intensely competitive light—gap habitat. In shaded understory habitats, where competition among seedlings is much less intense, understory and shade—tolerant tree species emerged throughout the rainy season. Mean length of dormancy (MLD),the time between sowing and germination, of 157 woody dicot species on Barro Colorado Island ranged from 2 to 370 d. In over half the species, MLD exceeded 4 wk; hence, delays in germination are common. The season in which seeds were dispersed and the dispersal mechanism explained small but significant portions of the variance in MLD among species; life form explained none; but differences among three germination syndromes explained two—thirds of this variance. In the delayed—rainy syndrome (18% of all species) seeds were dispersed in the rainy season but were dormant until the beginning of the next rainy season, 4—8 mo later. Dormancy is the primary mechanism controlling time of germination. In the delayed—rainy syndrome and the intermediate—dry syndrome which follows, the length of the dormant period decreased as the interval between seed dispersal and the beginning of the rainy season decreased. In the intermediate—dry syndrome (42% of all species) seeds were dispersed during the during the dry season and remained dormant until the beginning of the rainy season. Seeds are primarily dispersed 1—2 mo before the beginning of the rainy season, which reduces the number of false germination cues encountered and decreases the length of time seeds are exposed to postdispersal predation while dormancy prevents germination during dry season rains. In the rapid—rainy syndrome (40% of all species) seeds were dispersed in the rainy season and germinated during, but not early in, that season. Dormancy has been replaced entirely by timing of dispersal as a mechanism controlling time of germination. Half of these species germinated in &lt;2 wk, the rest in 2—16 wk.

Shell and Seed Size Relationships in Peanuts1

Abstract Three crosses and their reciprocals between peanut (Arachis hypogaea L.) genotypes differing in pod and seed sizes were made to investigate relationships between the pericarp (shell) and seed. Length, width, and weight of the fruit and seed from the F1 generation and selfed parentals were compared. The F2 generation along with plants from the parental lines were grown in the field. The weight, width, and volume of dried fruits and seeds, as well as shell thickness, were obtained from samples of 30 visually mature pods from each plant. Density of fruits and seeds, internal pericarp color, and shelling percentage were also recorded. Length, width, and weight of the F1 seeds tended to be similar to the selfed seeds from the same plants, showing possible maternal influence. The wide distribution in fruit volume obtained among F2 plants is indicative of quantitative inheritance. The larger the difference in fruit and seed size between the parents, the more pronounced was the skewness of the size distributions of the progeny toward the smaller parent. Estimates of pheno-typic correlations for fruit and seed volume were high and positive in most cases. However, fruit density vs fruit volume correlations were essentially negative suggesting that seeds grown inside pods with genetically smaller cavities may be compacted by the shell.

Quantitative determination of endosperm modification and its relationship to the content of 1,3∶1,4-β-glucans during malting of barley

The modification of barley endosperm during malting was quantitatively determined using the fluorochrome Calcofluor. The technique involved image analyser measurement of the area of residual cell wall material in longitudinally cut half seeds. The average modification was found to be highly correlated to both 1,3–1,4-β-glucan content and endo-β-glucanase activity, while a low correlation coefficient was obtained between modification and acrospire length of individual seeds.