bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diallel Analysis of Maize for Leaf Angle, Leaf Area, Yield, and Yield Components1
Authors: Mason Lee , Zuber Marcus S. 
Published: July 2010

The 15 possible single‐crosses among six maize inbred lines (Zea mays L.) were grown at three population densities and two leaf conditions (all leaves removed below the ear vs. no defoliation). Three of the six parental lines had relatively small leaf angles while the other three had relatively large leaf angles.The interreationships among leaf angle, grain yield, leaf area, ear size, and prolificacy were examined, and a diallel analysis of combining ability was calculated based on the fixed model. Therefore, the findings reported apply only to the six parental inbred lines included in this study.Defoliation resulted in yield reductions, ranging from 22 to 73%, and leaf area index (LAI) values were reduced by 53 to 68% among hybrids. Upright‐leaf by upright‐leaf (small leaf‐angle) hybrids averaged 42% reduction in yield associated with leaf removal, while upright‐leaf by horizontal‐leaf (large leaf angle) hybrids experienced an average reduction in yield of 39%.For hybrids in this experiment, leaf angle, from vertical orientation, was negatively correlated with yield and with the yield components: grain weight/ear and number of ears/100 plants. LAI was positively correlated with yield, the two yield components, and population density. Plant density was negatively correlated with the two yield components.General combining ability (GCA) and specific combining ability (SCA) effects appeared to be equally important in the expression of leaf angle. One parental line with the upright‐leaf habit exhibited a high GCA value for small leaf angle. There were significant differences in SCA estimates for small leaf angle among the three upright‐leaf inbreds. GCA effects were relatively more important than SCA effects for grain yield, leaf area, ear size, and prolificacy. Population density affected the magnitude of combining ability estimates for certain variables among some crosses.
Water Relations of Field Grown Cotton and Sorghum: Temporal and Diurnal Changes in Leaf Water, Osmotic, and Turgor Potentials1
Authors: Ackerson R. C. , Krieg D. R. , Miller T. D. , Zartman R. E. 
Published: July 2010

Trends in leaf water, osmotic, and turgor potentials of cotton (Gossypium hirsutum L., cv. ‘Dunn 56C’) and sorghum (Sorghum bicolor L. Moench, cv. ‘RS671’) were monitored on both a seasonal and diurnal basis. The effects of differential soil water availability on leaf water potential components were examined in order to ascertain the differences in the water relations of these two species.Decreasing availability of soil water was responsible for decreased morning and afternoon leaf water potentials in sorghum and cotton. The magnitude of degression in leaf water potential was greater in cotton than in sorghum at equivalent soil water potentials. Decreasesin osmotic potentials maintained positive turgor in both species when sufficient soil water was available. However, as water stress increased, turgor potentials became zero due to the failure of osmotic potentials to decrease more than water potentials.Diurnal changes in water potential components were distinctly different for each species. Leaf water potentials of sorghum came into approximate equilibrium with soil water potential in the early morning, whereas leaf water potentials of cotton did not. Concomitant changes in leaf osmotic potentials on a diurnal basis resulted in specific trends of increasing turgor in sorghum, while anomalous fluctuations were evident in cotton leaf turgor potentials.The relationship between leaf water potential and relative water content was determined for each species. The change in relative water content per unit change in leaf water potential was greater in cotton than in sorghum.Drought tolerance of these two species appears to be dependent on species speciIic relationships in leat water potential components.
Nitrogen Nutrition and Grain Protein in Two Spring Wheat Genotypes Differing in Nitrate Reductase Activity1
Authors: Rao K. P. , Rains D. W. , Qualset C. O. , Huffaker R. C. 
Published: July 2010

Two spring wheat (Triticum aestivum L.) genotypes were studied to identify and isolate factors involved in grain protein production, with the aim of establishing physiological criteria for use in breeding and selecting wheat lines efficient in N utilization. ‘Anza’ and ‘UC44‐111’, which differed greatly from each other in tissue nitrate concentration in a field experiment, were tested in a growth chamber experiment to determine any differences in nitrate absorption and nitrate reduction capacities and their effects on straw and grain protein content. Anza, with higher tissue nitrate concentration than UC44‐111, had lower nitrate absorption capacity in short‐term experiments (up to 6 hours). UC44‐111 had a 70% higher in vitro nitrate reductase activity than Anza but differed little in in vivo nitrate reduction. This indicates that UC44‐111 has other factors limiting its potential for nitrate reduction.This study reveals no single identifiable factor that can be used as a physiological criterion in selecting wheat genotypes for efficient N utilization. Selection must consider two or more factors simultaneously, including long‐term capacity for absorption and in vivo reduction of nitrate and efficiency of translocation of vegetative N to the developing grain.
Callus and Suspension Cultures of Melilotus alba Tissues and Cells1
Authors: Taira Tomoaki , Haskins F. A. , Gorz H. J. 
Published: July 2010

These studies were designed to define conditions for the satisfactory establishment and maintenance of sweetclover (Melilotus alba Desr.) callus and cell suspension cultures.Callus was derived from cotyledons and hypocotyls of germinated sweetclover seeds of various genotypes. Under the conditions used, 2,4‐dichlorophenoxyacetic acid (2,4‐D) was effective (optimal concentration ca 1 mg/liter) for callus induction; other auxins and cytokinins were ineffective. Best callus growth occurred at a 2,4‐D concentration of about 2 mg/liter and a sucrose concentration of 2%. Callus growth was improved by casein hydrolysate (0.9 g/liter). Glutamic acid appeared to be the most important single amino acid in the hydrolysate.Suspension cultures failed to survive in the absence of 2,4‐D. Highest cell numbers and final/initial cell‐count ratios were observed at a 2,4‐D concentration of 0.2 mg/liter. The callus type that yielded highest cell counts in suspension culture was friable, but friable growth type on agar was not always associated with highest cell numbers in suspension cultures. Inoculum size was important in determining the performance of suspension cultures, possibly because of the influence of “conditioned” medium.Attempts to regenerate intact plants from the cultured callus tissues were not successful.
A Quantitative Approach to Source Potentials and Sink Capacities Among Reciprocal Grafts of Sweet Potato Varieties1
Authors: Hahn S. K. 
Published: July 2010

Economic yield of sweet potato, Ipomoea batatas L., may be limited by either photosynthetic source potential or tuberous root sink capacity. The relationships between source and sink were investigated quantitatively with special reference to the yield of dry tuberous root yield through the use of reciprocal grafts of a set of varieties in all possible combinations.Responses of the sink to the source and of the source to the sink were examined. The varieties with large sink capacities showed greater responses of sinks to source than the varieties with poor sink capacities. The varieties with the greater source potential showed the greatest response of source to sink.Source‐sink relationships as determinants of yield in the sweet potato are discussed.
Field Evaluation of Resistance in Sorghums to Banks Grass Mite1
Authors: Foster D. G. , Teetes G. L. , Johnson J. W. , Rosenow D. T. , Ward C. R. 
Published: July 2010

The Banks grass mite, Oligonychus pratensis (Banks), is a serious pest of sorghum, Sorghum, bicolor (L.) Moench. Because of the unreliability of chemical control, mite resistant sorghums would be extremely valuable in controlling this pest. To determine levels of resistance in 19 sorghum lines and hybrids, field tests with natural mite infestations were conducted near Pecos, Tex. Evaluations were based on mite numbers, population density ratings, and damage ratings.Field evaluation of selected sorghum lines and F, hybrids indicated the presence of resistance to Banks grass mite. Grain type sorghums of similar maturity did not differ significantly in mite infestations, but some were damaged less than others; those with less damage were relatively high in sugar and were “non‐senescing” types. The two sorghums least infested were late maturing (SC 56‐14) or both late maturing and high in tillering (‘Sweet Sudan’). B Tx 618 was more resistant to damage than B Tx 378, and this resistance was reflected in hybrids between these lines and SC 599. Sorghums identified in this study should be useful in the development of mite resistant sorghum hybrids.
Agronomic Performance and Nature of Gene Effects in Progenitor Species‐Derived Genotypes of Tobacco1
Authors: Oupadissakoon S. , Wernsman E. A. 
Published: July 2010

An investigation was conducted to determine the nature of genetic effects in segregating populations produced by crossing selected progenitor species‐derived tobacco (Nicotiana tabacum L.) lines to the tobacco cultivar used in the original interspecific hybridization.Two genetically stable tobacco lines developed from interspecific crosses of N. tabacum ✕ N. sylvestris Speg. and Comes and N. tabacum ✕ N. otophora Griesbach, respectively, were crossed with the flue‐cured tobacco cultivar, ‘SC 58’, and F2 and backcross generations were produced. Data on agronomic characters and chemical constituents of cured leaf were collected and subjected to generation means analyses.The tobacco parent exhibited poorer performance than other generations for all agronomic characters, except grade index and chemical attributes of cured leaves. Conversely, species‐derived lines were frequently higher performing for yielding ability, days to flower, plant height, and number of leaves per plant, but cured leaf quality was inferior to other genetic entries. Significant positive heterosis for yield was found in three of the four families, and inbreeding depression was usually low.Additive genetic effects were significant for all characters in all families. Yield had significant dominance effects for every family while other chacacters varied from family to family. Frgm an evolutionary aspect of gene action, species germplasm tended to exhibit dominance in a positive direction for yield, days to flower, plant height, and number of leaves per plant, and in a negative direction for leaf quality. Deviations from the additive and dominance model were not observed.
Germination of Polycross Seed of Cicer Milkvetch as Affected by Year of Production1
Authors: Townsend C. E. 
Published: July 2010

In many species, environmental conditions during maturation of seed influence subsequent germination. Comparable information is lacking for cicer milkvetch, Astragalus cicer L. Therefore, the objective of this study was to determine whether environmental conditions, as measured by year of production, influence germination of polycross seed from selected clones of cicer milkvetch. Seeds produced in different years were germinated at 5 to 15, 5 to 20, and 15 to 25 C.Year of seed production significantly influenced subsequent seed germination at all temperature treatments. Germination was most rapid at 15 to 25 C and slowest at 5 to 15 C. Germination by the 14th day (total germination) was generally highest at 15 to 25 C, hut was also high in some years at 5 to 20 C. Variability between years for germination was greatest at 5 to 15 C.Within each year of production there were significant differences among polycross progenies for both rate of germination and total germination at all temperature treatments. Progenies that germinated rapidly at 5 to 20 C also tended to germinate rapidly at 15 to 25 C. However, some progenies that germinated rapidly at 15 to 25 C germinated slowly at 5 to 20 C. Rate of germination and total germination were substantially lower at 5 to 15 C than at the other temperature treatments for all progenies, but several progenies germinated comparatively rapidly at all treatments.
Response of Indeterminate and Determinate Soybean Cultivars to Defoliation and Half‐plant Cut‐off1
Authors: Fehr W. R. , Caviness C. E. , Vorst J. J. 
Published: July 2010

The estimation of yield loss from defoliation and stem cut‐off is based on the assumptions that soybean (Glycine max (L.) Merr.) cultivars do not differ appreciably in their ability to recover from plant injury, recovery is similar across locations, and percentage yield loss at all reproductive stages can be approximated from research involving only three of the stages. The objective of our study was to test the validity of the assumptions by comparing the response of indeterminate and determinate soybean cultivars to 100% defoliation and 100% half‐plant cut‐off at six reproductive stages from R2 to R7. Two indeterminate cultivars, ‘Hark’ and ‘Beeson’, were studied at Ames, Iowa, and Lafayette, Ind., and two determinate cuitivars, ‘Hill’ and ‘Lee’ were evaluated at Stuttgart, Ark.The determinate cultivars had significantly greater yield reduction from 100% defoliation than did the indeterminate cultivars at all reproductive stages, except R7. Average yield reduction from defoliation for all stages was 59% for the determinate cultivars, compared with 39% for the indeterminate cultivars. Maximum yield loss from 100% defoliation occurred at R4 (86%) and R5 (88%) for determinate cultivars and at R5 (82%) for indeterminate cultivars. Average yield loss from half‐plant cut‐off was similar for indeterminate (34%) and determinate (33%) cultivars, but there was a significant interaction with stages. Yield loss for indeterminate cultivars increased from R2 to R5, then remained constant from R5 to R7. The yield loss from half‐plant cut‐off with determinate cultivars increased progressively rom R2 to R7. The determinateness of a cultivar should be considered when assessing yield reductidn from defoliation and half‐plant cut‐off during reproductive development. Damage from hail, insects, and other factors will be most accurately estimated by establishing separate loss values for indeterminate and determinate types.There was no significant difference between Iowa and Indiana in the percentage of yield loss from 100% defoliation. For the cultivars and locations studied, location effects were not important in the estimation of yield loss from plant injury.Yield loss from 100% defoliation at the six reproductive stages did not follow the relationship predicted from previous studies. Our data indicated that maximum loss for indeterminate cultivars occurred at R5, not R4 as has been assumed. Some yield loss occurred at R7 indicating that the description used to identify plants at physiological maturity was incorrect. A new description based on pod or seed maturation is needed to identify plants that have reached physiological maturity.
Flag Leaf Physiological Analysis of Oat Isolines That Differ in Grain Yield from Their Recurrent Parents1
Authors: Brinkman M. A. , Frey K. J. 
Published: July 2010

An early and a midseason series of oat (Avena sativa L.) isolines were developed for resistance to crown rust Puccinia coronata Cda var. avenae Frazier and Ledingham), but they were significantly higher or lower yielding than their recurrent parent in each series. The purpose of this study was to determineif the isolines in each series had significant differences in physiological characteristics of flag leaves from their respective recurrent parent that may have contributed to the deviant grain yields.Plants were grown in field plots and CO2 exchange rates (CER) and transpiration (T) were measured on intact leaves. In the early series, the two high yielding isolines had higher CER, and in the midseason series the low yielding isoline had a lower CER than the respective recurrent parent. Rates of T and specific leaf weights (SLW) were similar to the recurrent parent T and SLW in each series.Differences in CER between isolines and their recurrent parent were attributable primarily to differences in residual (mesophyll) resistance (rr) to CO2 diffusion in both series. There was no association between CER and SLW within the two sets of closely related lines.
Anatomical Study of Seed Shattering in Bahiagrass and Dallisgrass1
Authors: Burson Byron L. , Correa Jario , Potts Howard C. 
Published: July 2010

Seed shattering is a major problem in ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) and dallisgrass (P. dilatatum Poir.) which often reduces availability and quality of seed of these species. An anatomical investigation of the abscission layer formation in the pedicel of Pensacola bahiagrass, common dallisgrass, and yellow‐anthered dallisgrass was conducted to determine the sequential histogenesis of the layer, and to relate its development to different morphological stages of the developing infloresences for each species. The abscission layer was located in the pedicel just below the glumes in both species. In bahiagrass it became distinguishable while the infloresence was in the boot stage, and by anthesis it was fully developed. The layer appeared as a ribbon of thick walled cells, five to seven cells wide, extending across the pedicel. Eight to 10 days after anthesis the abscission cells elongated and collapsed. Small lacunae were initiated adjacent to the vascular strands and continued to increase in size until the crushed vascular and pith cells had completely disintegrated. Spikelets remained attached to the pedicels by the epidermal cells until abscission occurred approximately 13 days after anthesis.In both dallisgrass biotypes the layer became distinguishable when the inflorescence was intermediate between early boot and boot stages, and was fully developed by anthesis. The layer appeared as a slightly wedge‐shaped band of thick walled cells, six cells wide at the epidermal edge and four cells wide at the vascular bundles, extending across the pedicel. Six days after anthesis, abscission layer cells in yellow‐anthered dallisgrass became elongated, and 9 days after anthesis a similar behavior was observed in common dallisgrass. In both biotypes, cells in the layer collapsed, leaving a crushed mass of cells. This and the remaining events were similar to those observed in bahiagrass. Abscission occurred on the 15th day after anthesis in the yellow‐anthered biotype, and on the 18th day in common dallisgrass. It appears that the abscission process in these three grasses is primarily biochemical in nature. These findings are probably indicative of the abscission process in other Paspalum species.
Performance of Anther‐Derived Dihaploids and Their Conventionally Inbred Parents as Lines, in F1 Hybrids, and in F2 Generations1
Authors: Arcia M. A. , Wernsman E. A. , Burk L. G. 
Published: July 2010

Dihaploid lines of tobacco (Nicotiana tabacum L.) were developed from anther cultures of two long‐term, conventionally inbred cultivars. Ten dihaploids from ‘Coker 139’ and 10 dihaploids from ‘NC 95’ were selfed and randomly crossed to produce 10 dihaploid F1's. Each F1 was selfed to produce a dihaploid F2. The conventional cultivars were crossed to produce a conventional F1, which was selfed to produce an F2. All genetic materials were evaluated for agronomic performance and chemical composition.Dihaploid lines grew more slowly, yielded approximately 15% less, and were agronomically inferior to their conventional pure‐line parents. Dihaploid F1's and F2's yielded less than the conventional F1 and F2. Enforced complete homozygosity in tobacco may not be entirely responsible for the reduction in yield of dihaploid lines developed by anther culture methods. The dihaploid technique as presently employed may be mutagenic.Reduced yields of dihaploid lines produced by the anther culture technique and the inferiority of crosses of dihaploid lines compared to conventional entries, suggest that this technique may not be suitable for a tobacco breeding program, where increased yield is of primary interest.
Genetic Variation Within Cotton For Seed N and Amino Acid Content1
Authors: Meredith William R. , Elmore C. D. , King E. E. 
Published: July 2010

The objective of this study was to investigate the genetic variability for seed N and amino acid content among currently available cottons (Gossypium hirsutum L.). In 1974 and 1975, 35 cultivars and strains were grown in two replications at Stoneville, Miss. Significant genetic variability was detected for N and eight amino acids in dehulled cottonseed. Seed N ranged from 5.0% for ‘Delfos 9169’ to 6.1% for ‘Q1’. Significant genotype ✕ year interactions were detected for lysine, histidine, and phenylalanine. Significant phenotypic correlations of N with lysine, threonine, glycine, alanine, and leucine were –0.36, –0.85, –0.66, –0.72, and –0.64 respectively. Genotypic correlations were generally of the same sign and magnitude as the phenotypic correlations.Results of the study indicated a modest amount of genetic variability within G. hirsutum for N and amino acid content. Old cultivars and new strains originating from interspecific hybridizations appeared to be the most promising sources for useful breeding material. There were little differences in N and amino acid contents among the commonly used cultivars regardless of their geographic use patterns.
Dormancy of Kentucky Bluegrass Seed in Relation to the Color of Spikelets and Panicle Branches at Harvest1
Authors: Phaneendranath Bangalore R. , Duell Robert W. , Funk C. Reed 
Published: July 2010

One of the most important factors affecting germination of Kentucky bluegrass (Poa pratensis L.) seed is maturity at harvest. This study evaluated degrees of seed dormancy in 10 cultivars and selections of Kentucky bluegrass harvested at various stages of change in color of spikelet and panicle branches from green to brown.Significant differences in the degree of dormancy at different stages of change in color of panicle branches existed among the entries. ‘Merion’ exhibited the most prolonged dormancy of seed during this period of change in color. The reduction in dormancy was generally accompanied by changes in color, of the panicle branches in particular, from green to brown. A color index was, therefore, proposed to determine the right time for harvesting Kentucky bluegrass seed to obtain maximum germination.
Inoculation of Detached Cotyledons For Screening Soybeans Against Two Races of Phytophthora Megasperma Var. Sojae1
Authors: Morrison R. H. , Thorne J. C. 
Published: July 2010

A non‐destructive method was used to evaluate the resistance of soybean (Glycine max (L.) Merr.) to Phytophthora megasperma. Drechs. var. sojae Hildeb. based on the reaction of detached cotyledons inoculated with the pathogen. Cotyledons from soybean seedlings were placed on moist filter paper and inoculated with an agar culture homogenate of the pathogen using a hypodermic needle. Disease reactions were determined 72 to 96 hours after inoculation. Cotyledons of resistant genotypes showed only a slight discoloration at the inoculation site; cotyledons of susceptible genotypes became severely necrotic.Similar results were obtained with cotyledon and hypocotyl inoculation when soybean genotypes differing in their reaction to races 1 and 3 were tested. The same plant could be tested simultaneously with both races by using a mixture of races, or by inoculating each cotyledon with a single race. The method was effective for greenhouse and field grown plants. Cotyledon inoculation is non‐destructive so that susceptible germplasm may be conserved and field‐grown plants can be tested without introducing the pathogen into an area.