bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developmental Studies on the Panicle Initiation in Sorghum1
Authors: Lee Kit‐wah , Lommasson Robert C. , Eastin Jerry D. 
Published: July 2010

A study of the morphology and development of the sorghum (Sorghum bicolor (L.) Moench) panicle was made from photographs of fresh apices and from stained sections of fixed material. From periodic collections, the transition from vegetative to reproductive stages indicated an acropetal initiation of primary branch primordia. Higher orders of branch primordia are commonly found on lower branch primordia. Differentiation of spikelets in the panicle is basipetal and is marked by the appearance of glume primordia. Both fertile and sterile spikelets of a pair are morphologically similar during their early development, but the floret parts of the latter degenerate as the inflorescence matures. A developmental stage system evaluating the degree of panicle development is proposed.Three factors considered to be of importance in the control of yield, which are associated with the development of the inflorescence, are number of primary branch primordia, number of branches arising from each primary branch, and the timing of spikelet differentiation. Of these, the time sequence of acropetal differentiation of primary branch primordia followed by basipetal differentiation of spikelets may be the most important in controlling yield.
Correlations Among Chemical and Agronomic Characteristics in Certain Oat Cultivars and Selections1
Authors: Forsberg R. A. , Youngs V. L. , Shands H. L. 
Published: July 2010

Correlations among several chemical and agronomic characteristics were determined in 1970 and 1971 for 10 Avena sativa L. cultivars and for 46 F4‐F6 backcross “N” lines derived from a complex interspecific cross involving a 6x amphiploid. In 1971, groat protein percentage was significantly and negatively correlated with yield in both series, but in 1970 a nonsignificant positive r of 0.37 existed in the A. sativa series. A strong negative association existed between groat protein percentage and kernel weight in the A. sativa and 46 “N” line series in 1971 (−0.71** and −0.28*, respectively), when kernel weights were considerably higher than in 1970. Correlation coefficients between groat protein and lipid percentages were negative, though nonsignificant, for the A. sativa series in both years, but were near zero or positive in the “N” series. ‘Dal’ was high in both groat protein and lipid percentages, illustrating that departures from the general relationship exist. Lines such as ‘Lodi,’ with higher lipid and lower protein percentages, contribute strongly to a negative association.The correlation between lipid percentage and grain yield was significant and positive only in 1971. While r values between lipid percentage and kernel weight were significantly positive in the A. sativa series in both years, the relationship in the “N” series was significant and negative in 1970 and near zero in 1971. Groat protein percentages varied more from year to year within selections than did lipid percentages.The association between groat protein percentage and four of the six fatty acids differed in the A. sativa series from that in the “N” series. The relationship between lipid percentage and the fatty acids were considerably more in agreement for the two series. Lipid percentage was positively associated with percentages of stearic and oleic acids, but negatively correlated with myristic, palmitic, and linoleic acids.
Production of Inhibitory Compounds in Corn Inbreds with Monogenic and Multigenic Resistance to Helminthosporium turcicum1
Authors: Calub A.G. , Long B. J. , Dunn G. M. 
Published: July 2010

Utilizing the drop diffusion technique the sixth or seventh leaf of corn (Zea mays L.) seedlings was inoculated with drops of a spore suspension of Helminthosporium turcicum Pass. in a humid chamber at 100% RH, 21C, and 3230 lux. Drops of the suspension were then withdrawn from 1 to 6 days after inoculation and centrifuged. The supernatant or diffusate, then free of spores and germ tubes, was mixed with a drop of fresh spore suspension. Diffusates that inhibited spore germination or delayed the growth of germ tubes were assumed to contain a phytoalexin or other inhibitory substance.Percent leaf infection was determined within 6 to 9 days from seedlings inoculated at the third leaf stage and left in the humid chamber at 100% RH for 18 hours.Multigenic lines produced inhibitory substances similar in effect but in significantly larger amounts than monogenic inbred lines. Percent leaf infection was also significantly lower on multigenic than on monogenic inbred lines. Percent spore germination in bioassays was significantly correlated with percent leaf infection. The addition of monogenic (Ht) resistance to two multigenic resistant inbreds diluted their ability to produce inhibitory substances.
Mass Selection and Mating Systems in Cereals1
Authors: Redden R. J. , Jensen N. F. 
Published: July 2010

Responses to two cycles of mass selection under two mating systems were compared in the F2 and F3 generations of one cross each of spring wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.). The number of green tillers prior to head emergence was used as the critical character. Additional characters, time from sowing to flowering and fertility number at maturity, were measured also in the evaluation of selection response for green tillers. The mean response for increased tillring, evaluated at two sites against unselected control generations, was higher in the wheat at 10.3%cycle than in the barley at 6.3%/cycle. Broad sense hentability estimates for tillering were between 10 and 25% for each cross.In both species the selection responses were greater in the hybrid than in the selfed selection series. The hybrid series was obtained by random mating among the selections in each cycle. The respective responses in barley realized over two selection cycles, were 17.1% with outbreeding and 8.7% with inbreeding at site 1, and 13.9% with outbreeding and 10.3% with inbreeding at site 2. In wheat at site 1, the responses were 22.6% with outbreeding and 18.5% with inbreeding. (Site 2 of the wheat had poor establishment.) Since the same F2 selection generated the hybrid and selfed series, the differences in response were attributed to the second cycle only. Asso. ciated selection responses for time to flowering and tiller number at maturity were detected only in the wheat.The results showed that mass selection with concurrent random mating could be a useful breeding stratcgy in self‐pollinated crops.
Genetic and Environmental Effects on Production of Inhibitory Compounds in Corn Resistant to Helminthosporium turcicum1
Authors: Calub A. G. , Dunn G. M. , Routley D. G. , Couture R. M. 
Published: July 2010

By utilizing the leaf drop diffusate technique, seedling leaves of corn (Zea mays L.) were inoculated with a spore drop suspension of Helminthosporium turcicum Pass, in a humid chamber at 21 C and light intensity of 3,230 lux. The drop suspensions were then withdrawn from 1 to 7 days after inoculation and centrifuged. The supernatant or diffusate, now free of spores and germ tubes, was mixed with a drop of fresh spore suspension. Diffusates which inhibited spore germination or delayed growth of the germ tube were assumed to contain phytoalexin or other inhibitory substances.The four homozygous combinations of the genes Ht and Bx were bioassayed plus the heterozygote HthtBxBx. The HtHtBxBx genotype, treated with drops of distilled water only, served as control. Greatest to least inhibition was produced by the double dominant HtHtBxBx, followed by the single dominant genotypes and then the double recessive hthtbxbx. Both Ht and Bx had a significant inhibitory effect. A significant amount of inhibition occurred within 24 hours after inoculation, increased to a maximum on the second or third day following inoculation, and continued at this high level until the sixth day. Inhibition was decreased significantly by leaf detachment, low spore concentration, and high preconditioning temperature.
Heterosis, Inbreeding Depression, and Combining Ability in Diallel Crosses of Cigar‐Wrapper Tobacco1
Authors: Dean C. E. 
Published: July 2010

Seven varieties and breeding lines of cigar‐wrapper tobacco (Nicotiana tabacum L.) and the 21 possible hybrids between them, excluding reciprocals, were evaluated in terms of 8 important characters. Heterosis above the midparent was observed for number of 40‐cm (16‐in) leaves, total leaf number, lateral vein angle, yield, No. 1 string, grade index, crop index, and blue mold index. One hybrid, 1128✕5058, yielded significantly more than the highest‐yielding parent, ‘Florida 20.’ Inbreeding depression was observed for number of 40‐cm leaves, lateral vein augle, yield, crop index, and blue mold Peronospora tabacina Adam) index.Estimates of general combining ability were significant for all characters investigated; specific combining ability was significant for number of 40‐cm leaves, total leaf number, and lateral vein angle. The data indicate the predominance of additive genetic variance in the material investigated, but also suggest that nonadditive components may be important, especially for certain leaf characteristics. Inferences from the data are that development of pure lines from segregating material would, in general, be preferable to the development of F1 hybrids as a breeding procedure to produce commercial varieties. If F1 hybrids are to be used commercially for any reason, intensive development of inbreds for specific contributions to particular F1 hybrids and evaluation of combining ability could result in superior hybrids for specific situations.
Equations for the Rate of Dark Respiration of White Clover and Grain Sorghum, as Functions of Dry Weight, Photosynthetic Rate, and Temperature1
Authors: McCree K. J. 
Published: July 2010

Equations were designed to be used in computer models of photosynthesis and respiration in crops. They were developed from new experimental data on the rates CO2 exchange of whole plants grown under constant conditions. The dark respiratory rate was separated into two components. The “maintenance” component was taken to be the efflux of CO2 after more than 48 hours in the dark at constant temperature. This component was proportional to the dry weight of the plant (W), and was a strong function of temperature (T). The proportionality constant (c) was about twice as great for clover (Trifolium repens L.) as it was for sorghum (Sorghum bicolor L.), at the same temperature. The “growth” component was taken to be the difference between the “maintenance” component and the total efflux during a normal night period (N). This component was proportional to the total influx during the previous daytime period (D), and the proportionality constant (k) was independent of species and temperature. The values of c and k were in good agreement with values calculated by Penning de Vries, using the principles and equations of biochemistry.The experimental data were best fitted by the following equations:

For clover at 30C: N = 0.14 D + 0.0143W

For sorghum at 30C: N = 0.14 D + 0.0054W

Temperature dependence of maintenance coefficient:

cT = c30 (0.044 + 0.0019 T + 0.0010 T2)

where N = night total of CO2 evolved in g•12h‐l•plant‐1,

D = daytime total of CO2 taken up in g•12h‐1•plant‐1,

W = CO3 equivalent of dry weight in g•12h‐1•plant‐1,

T = temperature in °C.
Relationship of Mitochondrial Efficiency to Forage Yield in Alfalfa1
Authors: Schneiter A. A. , McDaniel R. G. , Dobrenz A. K. , Schonhorst M. H. 
Published: July 2010

The utilization of a physiological variable to determine yield potential could serve as a valuable tool for plant breeders. The object of this study was to determine if a relationship existed in ratios of adenosine diphosphate (ADP) to oxygen (mitochondrial efficiency) and forage production in alfalfa (Medicago sativa L.).Significant differences in ADP:O among mitochondria isolated from 5‐day‐old seedlings of several lines of alfalfa were found. When ADP:O means of the seedlings were compared to forage yields obtained from field studies, significant positive correlation coefficients were found. Correlations were highest during cooler portions of the growing season (spring, fall) when yields are normally highest and lower during the summer months when forage production/harvest is low.It would appear that the laboratory determination of ADP:O ratios may have potential as a physiological tool for the selection of high yielding alfalfa genotypes when grown under optimum conditions. When factors such as physical environment, insects, or diseases are the yieldlimiting variables the relationship may not be as valid.
Intraspecific Competition, Competition with Weeds, and Spacing Response in Rice1
Authors: Kawano K. , Gonzalez H. , Lucena M. 
Published: July 2010

Intraspecific‐intergenotypic competition, competition with weeds, and spacing response were studied in 25 rice (Oryza sativa L.) cultivars with different growth habits in Lambayeque, Peru. The actual yield of genetically mixed rice populations was always below the yield of the better component genotype in pure populations. The yield of the mixtures seldom exceeded the average yield of the pure populations of the component genotypes. Thus, yield reduction in one genotype as a result of competition was not compensated by the yield increase in another.Intraspecific competition, competition with weeds, and spacing response were highly intercorrelated with each other, suggesting that these were controlled largely by the same genetic factors through the same physiological process. Vegetative vigor, large leaf area, a high rate of N absorption in early growth stages, and plant height were the most significant characters related to competitive ability. Tillering itself was not related to either competitive ability or to spacing response. Tall, vigorous genotypes with a long growth duration were adapted to extremely primitive agronomic conditions. The evolution of cultivars has been accompanied by the evolution of cultural methods and the loss of competitive ability.
Effect of Blooming Date on Boll Retention and Fiber Properties in Cotton1
Authors: Verhalen Laval M. , Mamaghani Reza , Morrison Walter C. , McNew Ronald W. 
Published: July 2010

Six cultivars of upland cotton (Gossypium hirsutum L.) were studied to determine the influence of blooming date on boll retention and selected fiber properties in experiments conducted over 3 years at a single location. Flowers were tagged at weekly intervals; and after frost, bolls within plots were harvested by tagging dates. Records were kept by dates of blooms tagged/row, tagged bolls set/row, and percent tagged bolls set/row. Fiber properties (2.5% span length, 50% span length, uniformity index, micronaire, and 1/8‐inch gauge stelometer) were also studied to determine their patterns of variation.In general, blooms tagged increased from the beginning of the flowering season until shortly after mid‐season, then declined to form a fairly symmetrical distribution. Boll set increased rapidly during the first 3 weeks of the season, then gradually decreased. Percentage boll set was highest at the first of each season, then declined fairly continuously. As a consequence, shedding rate increased in a linear fashion as the seasons progressed. In one instance, it appeared that the cotton plant exhibited increased boll retention efficiency when blooms were limited. The 2.5 and 50% span length measurements exhibited similar distributions within each of the 3 years; however, both showed moderately different patterns between years. Their means did decrease fairly steadily, particularly during the latter part of each season. Evidence in 1 year suggested that about a week's delay was required to obtain a response in the longer fibers comparable to that in the shorter ones. Uniformity index was higher at the end of each season than in midseason; and in 2 of ~ years, it was also higher at the first of the season. All cultivars except one displayed lower micronaires at the end of the flowering season than at the beginning. The 1/8‐inch gauge stelometer reading also declined toward the end of the flowering period.Relative performance among cultivars for each trait and their differential response patterns over the season are discussed in the text.
Carbon Dioxide Enrichment Effects Upon Yield and Yield Components in Wheat1
Authors: Krenzer E. G. , Moss Dale N. 
Published: July 2010

Two hard red spring wheat (Triticum aestivum L.) genotypes, the commercial variety ‘Era’ and an experimental genotype ‘8037,’ selected for this work because it had unusually large heads, were grown in normal air and in atmospheres enriched in CO2 to 600 ppm by volume in the field and in growth chambers in two day/night temperature regimes of 25/20 and 13/17 C. The growth period was divided into three stages: a) the vegetative period from germination to floral initiation; b) the floral development stage from floral initiation until anthesis; and c) the grain development stage from anthesis until maturity. Normal or CO2 enriched air was applied during each of these developmental stages in all possible combinations giving eight treatments in each experiment.Both genotypes showed an increase in grain yield in the field and in the 25/20 C temperature regime in growth chambers when CO2 enrichment was applied during stage b or c or both. No effect of CO2 enrichment on grain yield was observed when the enrichment was applied before stage b in any experiment or at any development stage in the 13/17 C temperature regime. For both genotypes in the field and in the 25/20 temperature regime, CO2 enrichment caused an increase in kernel number/plant when applied during stage b, and in kernel size when applied during stage c. This suggests that kernel number and size are both dependent on the supply of photosynthate. Thus, we conclude that a screening procedure, that is effective in classifying genotypes as to their photosynthetic capacity during either stages b or c, might be useful in identifying desirable parental lines for a yield‐oriented wheat breeding program.
Effect of Honey Bees on Yield of Three Soybean Cultivars1
Authors: Erickson Eric H. 
Published: July 2010

The importance of insects in the pollination of soybeans [Glycine max (L.) Merr.] was studied over a year period by comparing the yields from plots caged with honey bees (Apis mellifera L.), plots without bees and without insects (insecticide treatment), and open plots. The pollinating activity of bees resulted in significantly greater yields from ‘Corsoy’ and ‘Hark’ cultivars but not from ‘Chippewa 64.’The foraging activity of bees on soybeans was dependent on the floral response of each cultivar to the environment. Hark had a high percentage of dissolved solids in the nectar and the highest quantity of nectar/floret.
Evaluation of Freezing Hardiness in Winter Wheat1
Authors: Gullord M. , Olien C. R. , Everson E. H. 
Published: July 2010

Freezing hardiness was evaluated for several winter wheat (Triticum aestivum L.) cultivars and eight selections under controlled freezing conditions. High and low intensity freezing was achieved by decreasing the temperature slowly in hardened wheat crowns containing high and low amounts of water respectively. Freezing hardiness was assessed in terms of lower peripheral crown meristem (root) regrowth on a 0 (dead) to 5 (undamaged) scale.The standard deviation for the freezing test was approximately one meristem rating unit when the number of pots/replication were less than four. Standard deviation increased when the number of pots/replication increased.Different genotypes were easily differentiated when freezing hardiness was evaluated in terms of meristem rating and each genotype replicated 50 times.Many tests were required over a wide range of test temperatures to obtain satisfactory LD50 values.Significant interaction in freezing hardiness evaluated either as meristem ratings or as percent survival was found between eight winter wheat selections and freezing condition, but not between 14 wheat cultivars and freezing condition.
Carbon‐14 Assimilate Translocation in Nodulated and Nonnodulated Soybeans1
Authors: Russell W. J. , Johnson D. R. 
Published: July 2010

Nodulating and nonnodulating soybean [Glyclne max (L.) Merr.] isolines were grown for 30 days in silica sand in the greenhouse with 0, 50, and 100 μg N/g sand to evaluate 14C translocation in plants dependent solely on N fixation or nitrate uptake or both.No differences were observed between the two geno. type's translocation patterns at the vegetative stage, when they are totally dependent on soil nitrate up to 120 hours after 14CO2 exposure.Plant leaves, totally dependent on symbiotically fixed N, exported 14% more 14C to the roots and nodules when compared to plants with total inhibition of nodulation. No more than 2% of the total recovered 14C was found in the nodule component at any harvest time.Plants with partial inhibition of nodulation (grown with 50 μg N/g sand) exhibited relatively intermediate characteristics. The stem component contained significantly less 14C than the other treatments and was accompanied by a decrease in stem dry weight.
Factors Influencing the Susceptibility of Male‐sterile Barley to Ergot1
Authors: Cunfer B. , Mathre D. E. , Hockett E. A. 
Published: July 2010

This study was undertaken to determine whether susceptibility of male‐sterile barley (Hordeum vulgare L.) to ergot [Claviceps purpurea (Fr.) Tul.] is influenced by characteristics of the host, fertilization, and inoculum density. A suspension of conidia (106/ml) was atomized into florets in which the lemma and palea had been clipped back to expose the pistil. Most of the 12 lines tested were moderately to highly susceptible with more than 25% of the florets infected.Inoculation at various times after hand pollination showed that 9 of 12 lines were immune to ergot infection by 5 days and all were immune by 8 days after pollination and fertilization. Some lines became immune much faster than others, with ‘Hoodless Beardless’8 msg1 msg1 developing immunity within 24 to 48 hours after pollination.Increasing the inoculum density from 104 to 106 conidia/ml increased the incidence of ergot. All five lines tested showed similar reactions to the different inoculum densities.
Inheritance of Pubescence and Its Use in Outcrossing Measurements Between a Crambe Hispanica Type and C. abyssinica Hochst. ex R. E. Fries1
Authors: Beck L. C. , Lessman K. J. , Buker R. J. 
Published: July 2010

The inheritance of glabrous vs. pubescent leaf type was studied in a plant introduction designated Crambe hispanica L. (PI 279346). Normally the species has densely pubescent leaves, but observations on a small sample of this introduction revealed one selection which segregated with respect to leaf type and another which produced all glabrous leaves. Further selections were made within each of these progenies. Selected plants were paired randomly with other C. hispanica types and crossed reciprocally to determine inheritance and potential of the trait as a genetic marker. Segregation ratios in 44 F2 families involving 4,004 seedlings indicated that pubescent leaf was controlled by a single recessive gene p.Glabrous leaf was used as a dominant marker in measuring percent outcrossing between C. abyssinica Hochst. ex R. E. Fries and C. hispanica types. Four normally glabrous C. abyssinica pollinator lines were planted in a circular row design with a pubescent C. hispanica type line planted in concentric rows outside each pollinator row. Row spacings were 50.8, 76.2, and 101.6 cm from the pollinator row with each spacing in a different subunit. To determine wind affects on pollen dispersal, circles were divided into four segments corresponding to northeast, northwest, southwest, and southeast quadrants.Differences in outcrossing due to pollinators and to row spacings were found. Outcrossing over the various treatment combinations ranged from 0.5 to 7.0% with a mean of 2.7%.