bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pollen Production Classification in Male‐Sterile Alfalfa: Location and Observer Effects1
Authors: Barnes D. K. , Pedersen M. W. , Elgin J. H. , Axtell J. D. , Garboucheva Rada A. , Smith D. M. 
Published: July 2010

A system to evaluate the amount of pollen shedding in male‐sterile alfalfa (Medicago sativa L.) was tested by observers at different locations. Flowers were tripped and visually classified as: 1 = no pollen, 2 = trace of pollen, 3 = moderate amount of pollen, and 4 = much pollen. Populations segregating for degrees of male sterility were classified for amount of dehisced pollen by observers in Utah and Minnesota. The differences in mean scores between locations were small but significant. Differences among observers within locations and the populations × locations interaction were nonsignificant.Dehisced‐pollen scores for 31 clones with varying degrees of male sterility were recorded during the summer at Presser, Wash.; Logan, Utah; St. Paul, Minn.; and Lafayette, Ind. Small but significant location differences were noted. There were no obvious associations between climatic conditions and pollen scores. Therefore, we as. sumed that the location differences primarily were due to variations in interpretations of class limitations by observers. At three locations, no significant differences existed among sampling dates within locations. At three locations, the clones ×; sampling dates interactions were significant.A pictorial classification description is presented to help reduce variability among observers in future studies. We suggest that a 200‐plant sample is sufficient to determine accurately the level of dehisced pollen in an alfala population.
Combining Ability for Eight Characters of a Four‐Parent Diallel Cross in Vernonia anthelmintica (L.) Willd.1
Authors: Lai W. Y. , Lessman K. J. 
Published: July 2010

A diallel set consisting of all combinations of four parents, F1 and F2, and reciprocals of Vernonia anthelmintica (L.) Willd. showing diverse phenotypes were grown at West Lafayette, Indiana. The study was aimed at elucidating the inheritance of eight traits: days to first bloom, plant height, days to harvest, plant weight, primary branch number, heads per plant, clean seed weight, and percent oil.Combining ability analyses showed that effects of general combining ability were highly significant for days to first bloom, plant height and days to harvest in F1 and F2, and significant for plant weight and percent oil in F2, suggesting the major portion of total genetic variation was additive in nature. Specific combining ability was highly significant only for days to first bloom and plant height in F1. General reciprocal effects were highly significant for days to first bloom in both F1 and F2, significant for plant height, days to harvest, and heads per plant in F2, while specific reciprocal effects were significant for primary branch number in F1, significant for days to first bloom, and highly significant for days to harvest in F2.
Stomatal Length, Frequency, and Distribution in Bromus inermis Leyss I1
Authors: Tan Geok‐Yong , Dunn G. M. 
Published: July 2010

AbstractOctoploid (2n = 56) bromegrass (Bromus inermis Leyss.) had significantly larger but fewer stomata than tetraploid (2n = 28) plants at all leaf positions sampled and on both leaf surfaces. Both ploidies showed a similar pattern of stomatal length and frequency at four positions on the culm and three positions on the individual leaf. Stomatal length increased and frequency decreased progressively from the top (LI) to lower (IA) leaves. The tip of the leaf had the largest but fewest number of stomata with the reverse for the base of the leaf.Seven bromegrass cultivars within the octoploid level differed significantly in stomatal length and frequency of adaxial and abaxial surfaces and at five different leaf positions on the culm. ‘Carlton’ and ‘Blair’ had consistently smaller stomata with greater frequency, whereas ‘Saratoga’ and ‘Red Patch’ had larger, but fewer, stomata. Stomatal length increased while frequency decreased from L1 to L3 and leveled off from L3 to L5 (fifth leaf below panicle). Varietal differences in stomatal length and frequency were mainly associated with the center position of a leaf surface.Correlations between the adaxial and abaxial surfaces of L1 showed highly significant positive values for both stomatal length and frequency. Stomatal length and frequency were negatively associated at either surface of LI. The ratio length ✕ frequency was affected more by stomatal frequency than length on the same leaf surface. The interrelationships among stomatal and leaf characters and tiller dry weight suggested that a cultivar with lower stomatal frequency is likely to have larger stomata, longer and wider leaves, and greater dry weight/tiller.
Effect of Root Genotype on Shoot Water Relations in Soybeans1
Authors: Sullivan T. P. , Brun W. A. 
Published: July 2010

AbstractThe maintenance of adequate water relations in the above ground portions of plants is partially determined by the effectiveness of water absorption by the root system. The object of this study was to determine if reportedly different soybean [Glycine max (L.) Merr.] root types differ in ability to maintain leaf water potential, stomatal opening, the photosynthesis in a genetically common top. ‘Chippewa 64’ tops were grafted to rootstocks of four different genotypes (‘Aoda,’ PI 79648, ‘Chippewa 64,’ and ‘Harosoy 63‘) when in the seedling stage. Grafted plants were subjected to water stress at three stages of development. Symptoms of water stress were more severe in Chippewa 64 scions grafted on Aoda and PI 79648 rootstocks than in those grafted on Harosoy 63 and Chippewa 64 root stocks. These effects become increasingly evident during flowering and pod filling. When stressed during pod filling, Chippewa 64 tops grafted on Aoda and PI 79648 rootstocks snowed significantly higher stomatal resistances and lower leaf water potentials and photosynthetic rates than did Chippewa 64 tops grafted on Harosoy 63 and Chippewa 64 rootstocks.
Regeneration of Ryegrass Plants in Tissue Culture1
Authors: Ahloowalia B. S. 
Published: July 2010

Ryegrass plants (Lolium spp.) were regenerated in callus cultures induced from triploid (2n = 21) embryos. Developing seeds from diploid Χ tetraploid and reciprocal crosses were cultured on i) Bacto‐Orchid agar and ii) modified medium of Niizeki and Oono containing 1.5 mg 2,4‐dichlorophenoxyacefic acid (2,4‐D); 6.5 mg indoleacetic acid (IAA); and 0.25 mg zeatin/liter.Of the 219 seeds cultured, 10% formed triploid callus and 35% produced triploid and near‐triploid (2n = 19, 20, 22) plants. The calli differentiated root and shoot primordia on modified Murashige and Skoog RM medium containing 1.5 mg 2,4‐D; 6.5 mg IAA; and 2.15 mg kinetin/liter. Addition of 1 ml coconut milk, with or without 2 mg IAA and 2 mg zeatin/liter, to the medium stimulated chlorophyll development in the calli. Subsequent culture of these calli on half‐strength Murashige and Skoog RM medium containing 0.75 mg 2,4‐D; 3.25 mg IAA; and 1.075 mg kinetin/liter produced numerous normal and a few albino plants. The calli maintained for 18 months stayed totipotent through eight subcultures. Callus suspensions formed roots in liquid medium conraining 0.05 mg/liter each of IAA and kinetin. Cell suspensions plated on half‐strength RM medium with 2,4‐D; IAA; and kinetin, developed colonies which included elongate and spherical parenchymatous cells, cells with bipolar axis, vacuolated hair‐like cells, etc., of varying size.The established procedures permitted a rapid regeneration of xyegrass plants in large numbers through tissue culture and hold potential for chromosome manipulation and selection at cell level.
Direct and Indirect Mass Selection for Grain Yield in Bulk Oat Populations1
Authors: Geadelmann J. L. , Frey K. J. 
Published: July 2010

One cycle of direct mass selection was conducted separately for heading date, plant height, grain yield, width/seed, weight/seed, and spikelets/panicle of oats (Avena sativa L.). One cycle of indirect mass selection for grain yield was also conducted in each of the remaining five traits and weight/primary panicle. Selection was practiced among 1,500 random, nearly‐homozygous lines grown at two levels of interplant competition, and was bidirectional with selection intensities corresponding to 10 and 30%.Variations of basic hill‐plot technique simulated the two selection environments, noncompetitive (one oat seed sown/hill) and competitive (1 oat seed plus 30 barley seeds sown/hill). Hill plots sown with 30 oat seeds/hill simulated planting arrangements common to commercial practice and provided a standard by which gains from mass selection were determined.Direct mass selection was effective for each trait. Actual gains ranged from 15 to 83% of gains predicted from selection among line means in replicated trials. Selection for heavy primary panicles was the most effective method of indirect mass selection for grain yield. In general, the level of interplant competition had little effect on gains from mass selection. Considerations of technique and monetary costs seem of greater importance than interplant competition in the choice of an environment for mass selection in oats. Environmental effects on genotypic expression of grain yield were not sufficiently large to prevent improvement of this trait by mass selection at either level of interplant competition.
Herbicide Influence on Arrowleaf Clover Seedling Establishment1
Authors: Smith A. E. 
Published: July 2010

The chlorophenoxy and benzoic acid herbicides are used extensively for the control of pasture weeds. The increasing importance of legumes to the pasture ecosystem has made it necessary to determine the influence of these herbicides on certain forage species. The purpose of this study was to determine the influence of chlorophenoxy and benzoic acid herbicides on ‘Amclo,’ ‘Yuchi,’ and ‘Meechi’ arrowleaf clover (Trifolium vesiculosum Savi.) germination and seedling development. The experiments were conducted in a programmed germinator and the greenhouse.Increasing 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] concentration decreased the percent germination of Yuchi. Whereas, 750 ppb 2,4,5‐T [(2,4,5‐trichlorophenoxy)acetic acid] and MCPA ([(4‐chloro‐v.tolyl)oxy]acetic acid) 500 ppb 2,4‐DB[4.(2,4‐dichlorophenoxy)butyric acid] adversely influenced the seed germination of Yuchi, Amclo, and Meechi, respectively.The lowest concentration (63 ppb) of all herbicides except 2,4,5‐T reduced radicle development on all three cultivars. The 63 ppb treatment of 2,4,5‐T stimulated radicle development on Meechi and Yuchi. The order of increasing influence of these herbicides on seedling establishment was 2,4‐DB < 2,4,5‐T = 2,4‐D < MCPA = dicamba [3,6‐dichloro‐o‐anisic acid].
Inheritance of a Chlorophyll Deficiency in Diploid Alsike Clover1
Authors: McConnell R. L. , Townsend C. E. 
Published: July 2010

Inheritance of a variegated chlorophyll deficiency in diploid alsike clover (Trifolium hybridum L.), was determined under greenhouse conditions. The variegated character was first observed in the S2 progeny of a normal green S1 clone. The S2 progeny segregated 9 green: 7 variegated plants. Reciprocal F1 progenies of this S1 clone and another S1 clone whose S2 progeny was normal green in color, were green also. The F2 data fit phenotypic ratios of 9 green: 7 variegated plants or 3 green: 1 variegated plant depending upon the genotype of the F1 parent. F2 intercross progenies were grown to confirm the F2 segregations and to assign genotypes to several F2 plants.Two recessive genes controlled the chlorophyll deficiency. The homozygous recessive conditions for either pair or both pairs of allcles produced the variegated character and the gene symbols v1 and v2 were suggested for the two loci.
Lattice Designs for Unreplicated Yield Trials of Maize Varieties at Several Plant Densities1
Authors: Cornelius P. L. , Byars J. 
Published: July 2010

The analysis of lattice designs with varieties showing a linear response to levels of some factor confounded with replications is described and illustrated with a hypothetical example. The theory is applied to a 7✕7 quadruple lattice maize (Zea mays L.) variety trial with replications of the lattice planted at different plant densities. A linear regression model is used which assumes that the yield of each variety expressed as log (yield/plant) responds linearly to plant density. In a manner analogous to ordinary lattice designs, corrections for block differences to be applied Jo variety means and regression coefficients are obtained. Two methods of adjusting for variable stands, viz., covariance analysis with deviation from average stand at) a given plant density level as the covariable (Method I) and adjustment of the raw data using preliminary estimates of the variety regression coefficients (Method II), are suggested and compared with a generalized least squares solution (Method III). Method III is the theoretically correct procedure but we consider it impractical for large experiments. Both Methods I and II gave good approximations to the results for Metlfod III.The experiment showed significant differences among variety means and among variety regression coefficients. Information on varietal response to plant density is obtained at the cost of very little loss of precision on variety means. It is suggested that for equivalent varietal replication more comprehensive yield trial data could be obtained by evaluation at more plant density levels with less (or possibly no) replication ot each density.
Cytological Characteristics and Nuclear DNA Bouyant Densities of Corn, Teosinte, Tripsacum, and Corn‐tripsacum Hybrids1
Authors: Levings C. S. , Timothy D. H. , Hu W. W. L. 
Published: July 2010

This study assesses the variability in buoyant density of nuclear DNA (nDNA) of corn and its relatives and the effect of several cytological phenomena on the demity of nDNA. The nDNAs of four Tripsacum L. spp., corn (Zea mays L.), annual teosinte (Z. mexieana [Schrad.] Kuntze), perennial teosinte (Z. perennis [Hitchc.] Reeves and Manglesdorf), and corn‐tripsacum hybrids were characterized for buoyant densities. Corn and perennial teosinte nDNA densities were similar but were significantly greater than those of tripsacum and annual teosinte. The latter two did not differ in densities. The corntripsacum hybrid densities resembled those of the higher parent. However small significant differences in parental base composition did not preclude hybridization. In all cases, and typical of grasses, nDNAs were resolved as single bands without satellites and with relatively high guanine and cytosine contents.Chromosome numbers of T. andersonii Gray, in ed., Guatemala grass, are reported for the first time (2n = 64). Chromosomal knob numbers of 12 Tripsocum accessions ranged from 0 to 40. One Tripsacum accession had 3 to 4 B chromosomes. The presence of chromosomal knobs and B chromosomes in tripsacums had no effect on the banding pattern and buoyant density of the nDNAs as determined by neutral CsCI analytical eentrifugation.Although similarities and significant differences in buoyant densities of nDNA were found among corn and its relatives, the value of these results for establishing genetic relationships is not clear.
Light and Temperature Controls of Dormancy and Germination in Bentgrass Seeds1
Authors: Toole Vivian K. , Koch E. James 
Published: July 2010

Germination on a two‐way thermogradient plate indicated a temperature range for intensive study of alternating temperatures in germination chambers for ‘Emerald’, ‘Penncrow’, and ‘Seaside’ cultivars of A. palustris and for ‘Astoria’ and ‘Bardot’, but not ‘Highland’ cultivars of A. tenuis. Studies of the seeds subjected to reciprocal periods on the low and high parts of daily temperature cycles showed that optimum temperature alternations depended on the length of exposure to the higher temperature of the cycle. Germination for all cultivars, except Highland, were not significantly different from maximum germination in an incubation regimen of 15 C for 16 hours alternated with 25 C for 8 hours daily. Emerald, Penncross, and Seaside required red light during the 25 C part of the cycles for optimum germination. For optimum germination, Highland required 1 to 2 hours at 30, 35, or 40 C alternated with 23 and 22 hours at 15 C and light.Germination of all cultivars was under phytochrome control. Astoria and Bardot required a red light treatment at marginal temperatures, but not at the optimum temperatures. All other cultlvars required red light to germinate at the optimum temperatures. Response to light showed the typical reversible phytochrome reaction
Anther Lewngth in Wheat: Optimum Sample Size1
Authors: Atashi‐Rang G. , Lucken K. A. 
Published: July 2010

Sampling procedures for determining anther length in wheat (Triticum aestivum L. em Thell.) were evaluated using variance components to calculate the relative efficiency of different anther sampling combinations of anthers/ floret, florets/spikelet, spikelets/spike, spikes/replication, and number of replications for two cultivars.Anther length is a useful indicator of anther size and is correlated with pollen grains per anther, a possible index of pollen available for cross‐pollination in hybrid wheat seed production.Variation for anther length among anthers within florets, florets within spikelets, and spikelets within spikes was small relative to variation among spikes and replications. Relative efficiency calculations indicated that a cultivar's anther length could be determined satisfactorily by measuring as few as one to three anthers/spike —with sufficient replication and sampling of spikes/plot. The relationship between relative efficiency and number of spikes sampled/plot was curvilinear; relative efficiency was improved only slightly by sampling more than 10 spikes/plot. Relative efficiency increased linearily with each additional replication for all sampling combinations.
Genetic Variability for Yield and Plant Height in Crownvetch1
Authors: Baluch S. J. , Risius M. L. , Hill R. R. , Cleveland R. W. 
Published: July 2010

Fifty randomly selected crownvetch plants (Coronilla varia L. ‘Chemung’) were mated in a nested sib‐mating design, and the parents and their progenies were analyzed to obtain information on the nature of genetic variability of forage yield and plant height. Forage yield at each of two harvests per season, total forage yield, and plant height at each harvest time were evaluated in each of two growing seasons.Significant variability among the parents and crosses indicated that genetic variance was present for each character. Most of the genetic variance was additive for each character studied. Heritability estimates (in decimal fraction) for yield ranged from 0.05 to 0.28 while those for plant height ranged from 0.10 to 0.22. Mass or individual plant selection should be effective in changing plant height, but family or progeny test selection should be practiced for yield in crownvetch.
A Diversity Analysis of a World Collection of Barley1
Authors: Tolbert D. M. , Qualset C. O. , Jain S. K. , Craddock J. C. 
Published: July 2010

Data on more than 17,000 accessions of the barley (Hordeum vulgare L.) world collection maintained by the USDA, SEA, were analyzed for variation of five morphological characters (growth habit, caryopsis type, awn type, kernel row number, and kernel color). Phenotypic frequencies within the accessions from each of 48 countries, grouped in 14 regions, were tabulated. Polymorphism was widespread in most countries for different sets of characters. Very weak east‐west clinal patterns were observed and this analysis only partially supported the earlier reported patterns of variation in the postulated centers of diversity. This result may be due to an inadequate sample of characters available for analysis and/or an inadequate number of geographic regions in the world collection.The H' diversity index was computed for each country and region, for individual characters, and after pooling all five characters. Analyses indicated the between‐regions component of diversity to be relatively smaller than the variation in H' among characters and among countries within regions. This analysis shows no distinct geographical patterns in these data, but its use with additional data is warranted.
Physiological Comparisons of Isogenic Diploid‐Tetraploid, Tetraploid‐Octoploid Alfalfa Populations1
Authors: Pfeiffer Todd , Schrader L. E. , Bingham E. T. 
Published: July 2010

Two isogenic paired sets of alfalfa (Medicago sativa L.), a diploid (2n = 2x = 16) and tetraploid (2n = 32) set plus a tetraploid and octoploid (2n = 8x = 64) set, were compared in two growth chamber experiments for photosynthesis, N fixation, and dry matter accumulation on a whole‐plant basis. In Experiment A, each plant was harvested when it had open flowers on two racemes. Plants were harvested on a weekly basis in Experiment B.Within each set, the higher ploidy level reached the harvest stage approximately 9 days earlier. This maturity differential affected the comparisons of dry matter accumulation in Experiment A. Fresh and dry weights of leaves, stems, and roots did not differ in Experiment A. In Experiment B, the 4x had significantly greater herbage fresh weight than the 2x, while the 4x and 8x pair did not differ significantly. Net CO2 exchange (NCE) on a whole‐plant basis was equivalent across ploidy levels in both experiments. Acetylene reduction on both a whole‐plant and nodule‐weight basis and nodule number and nodule weight did not differ significantly at the different ploidy levels in either experiment. For measurements taken only during Experiment A, NCE was greater in the 4x compared to the 8x on a chlorophyll basis; transpiration was significantly greater in the 8x than in the 4x, and the chlorophyll a:b ratio was lower in the 8x than the 4x. Root respiration did not differ. When nonhomogeneous variances between ploidy levels were compared, in 17 out of 18 comparisons the lower ploidy level had the greater variance.The ploidy level had little effect on physiological processes in the isogenic populations of this study. Because greater variance exists with lower ploidy levels, selection should be more easily performed at lower ploidy levels.
Individual Crown Selection for Resistance to Freezing Stress in Winter Oats1
Authors: Marshall H. G. , Kolb F. L. 
Published: July 2010

In recent years, crown freezing tests have been used to classify germplasm of small grain crops for resistance to freezing stress, a major component of winter hardiness. Selection has been based, however, on large numbers of crowns, and techniques for individual plant selection have not been developed. Our objective was to develop a system for growing and hardening winter oats (Avena byzantina K. Koch and A. saliva L.) that will provide uniform expression of the freezing resistance trait and facilitate accurate individual crown selection.A technique of growing plants in individual tubes under controlled conditions of light, temperature, and moisture was developed. Individual crowns were frozen in capped vials on rotating shelves in a freezing chamber. Crowns that survived severe freezing stress and regenerated new roots were saved as selections.Effectiveness of the technique was tested by applying two cycles of crown selection to a four cultivar blend. After cycles 1 and 2, the mean injury scores of the population were 95.6 and 100%, respectively, of the most hardy component cultivar. In a second experiment, crowns of an F6 bulk population were frozen and only 16 out of 640 survived. In subsequent tests of these lines, nine were equal to the hardy parent and 13 were equal or superior to the population mean. Thus, our crown selection technique provided a degree of precision that should be useful in breeding for increased resistance to freezing stress and improved winter hardiness.