bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Chloroplast and Nuclear DNAs of Zea mays L.1
Authors: Shah D. M. , Levings C. S. 
Published: July 2010

Highly purified chloroplasts and nuclei were isolated from two hybrids of maize (Zea mays L.), ‘McNair X210N’ containing normal and ‘X210 cms T’ containing Texas‐type male‐sterile cytoplasm. Chloroplast and nuclear deoxyribonucleic acids were obtained from their respective organelles and purified by CsCl density gradient centrifugation. These DNAs were compared with respect to thermal denaturation temperature (Tm), buoyant density (ρ) and the guanine‐plus‐cytosine content (molar % GC).Nuclear DNA (nDNA) had a mean buoyant density in CsCl of 1.7019 g/cm3 and a Tm of 86.9 C. Mean molar GC was calculated to be 43.3%. In contrast, Chloroplast DNA (cDNA) had a lower buoyant density in CsCl (1.6998 g/cm3) and a lower Tm (85.9 C). Mean molar GC was determined to be 39.5%. Thus, cDNA was distinguishable from nDNA by its lower buoyant density, lower Tm, lower GC content, and the absence of 5‐methylcytosine, which was present in significant amounts (6.9%) in nDNA. GC content, Tm, and buoyant density values of cDNAs did not differ between normal and Texas cytoplasms, and therefore, cannot account for their cytoplasmic differences.
Light‐Induced Leaflet Orientation in Phaseolus vulgaris L.1
Authors: Wien H. C. , Wallace D. H. 
Published: July 2010

The effect of light on change of leaflet angle of attached and detached leaves of four cultivars of dry beans (Phaseolus vulgaris L.) was measured. Light receptor and response site were both found to be the pulvinule at the base of each leaflet. All three pulvinules of the trifoliolate leaf responded. Light impinging on the top of pulvinules of all varieties caused them to bend upward, i.e. toward the light. This rotated attached leaflets upward, orienting them more parallel to the overhead source‐direction of the light. Light from the side also caused the pulvinules of all four varieties to bend toward the light. However, the more prominent response to light impinging upon the side of pulvinules was a twisting of the pulvinule which, with reference to the light source, rotated the far side of the leaflet upward and the near side downward. This positioned the leaflets more perpendicular to the horizontal source‐direction of the light. Thus, light from the side caused the leaflets to orient themselves so that they would intercept more light energy, whereas light from above oriented them so that they would intercept less. The four varieties differed in amount and type of leaf orientation under a given light intensity. For one variety only, in addition to causing the pulvinule to bend toward the light, light impinging upon the top of the pulvinule also caused it to twist. With this variety, both responses oriented leaflets more parallel to the overhead source‐direction of the light, with the result that the leaflets would intercept less light energy.It is hypothesized that leaf characters maximizing both pulvinule exposure to light and the leaf‐orientation response would maximize light penetration into the leaf canopy and lead to higher photosynthetic rates, especially at close spacings with high leaf area index.
Modification of Saponin Characteristics of Alfalfa by Selection1
Authors: Pedersen M. W. , Berrang Bertold , Wall M. E. , Davis K. H. 
Published: July 2010

Recurrent phenotypic selection for low‐ and high‐saponin concentration in alfalfa (Medicago sativa L.) was practiced in each of six alfalfa varieties for up to five generations. In the last cycle of selection the low series did not differ significantly from one variety to another, and the saponin index averaged 0.34%. In the last cycle of the high series the saponin index averaged 3.14% and ranged from 1.12% for ‘Lahontan’ to 4.72% for ‘Uinta.‘ The saponin concentrations of leaves and stems were correlated (P < 0.01). Concentrations of saponin in first and second crops were also correlated (P < 0.01). There was a low correlation between saponinconcentration index and leaf percentage (P < 0.05). With the exception of high‐saponin Uinta, selection for saponin‐concentration did not significantly change the leaf percentage from that of the original variety. Changes in leaf percentage accounted for only a small part of the change in saponin concentrations. Yield and protein concentration were not affected by low‐ or high‐saponin selection.Evidently a shift occurred towards an increase of saponins that contain carboxylic acid‐type aglycones in the high‐saponin selection and towards saponins that do not contain carboxylic acid‐type aglycones in the low‐saponin selections. This conclusion was supported by 1) chromatographic separations, 2) bioassays of butanol extracts, and 3) bioassays with water extracts with added cholesterol. Apparently more toxic fractions of saponins were increased by selection for high saponin and decreased by selection for low saponin.
Effects of Temperature and Method of Pollination on the Frequency of Aborted Seed in Alfalfa1
Authors: Dane Fenny , Melton Bill 
Published: July 2010

Effects of temperature and method of pollination on the frequency of normal and aborted seeds were determined for five selected alfalfa clones, Medicago sativa L. Numbers of normal seeds were greatest at 21 to 27 C and lowest at 32 C. Aborted seeds were more frequent at 32 C.Self‐pollination resulted in lower numbers of normal and aborted seeds than crossing; however, the ratio of normal to aborted seeds was the same under self‐or cross‐pollination.Abortion of “mature” seeds appeared to be independent of factors conditioning embryo abortion in the early stages of seed development.
Symbiotic Nitrogen Fixation in Soybeans. II. Interrelationship Between Carbon and Nitrogen Assimilation1
Authors: Lawn R. J. , Fischer K. S. , Brun William A. 
Published: July 2010

Reciprocal intervarietal grafts were made in all root: shoot combinations using seedlings of eight soybean (Glycine max (L.) Merr.) genotypes, grown in sandfilled pots in the greenhouse. After grafting, the plants were inoculated with Rhizobium japonicum (USDA strain #138) and watered with a low‐nitrogen nutrient solution. Two replicate plants of each root:shoot combination were sampled at each of four times, 28, 38, 50, and 58 days after grafting, for photosynthetic rate of leaves; leaf area, shoot and root dry weight; and number, fresh weight, and acetylene reduction activity of nodules.Significant shoot genotype, sampling date, and shoot genotype ✕ sampling date effects occurred for all traits measured. Root genotype effects, independent of the shoot genotype, occurred for all root traits measured, except nodule fresh weight. No overall root effects occurred for any of the shoot traits. Shoot genotype effects were small at the first two sample dates relative to root genotype effects, but were large at the last two sampling dates due to differences in stage of physiological development. Shoot genotype effects on total nodule activity (TNA) per plant were strongly and positively associated with shoot effects on nodule fresh weight, but showed no association with shoot effects on specific nodule activity (SNA). Shoot genotype effects on nodule fresh weight per plant were, in turn, strongly and positively associated with shoot effects on photosynthesis per plant and shoot dry weight. Root genotype effects on TNA per plant were due to inherent differences in SNA.
Predictions of GCA Model Estimates of Total Leaf Area and Leaf Area Distribution from Leaf Area of Parental Inbreds1
Authors: Johnson G. R. 
Published: July 2010

The relationships of GCA (general combining ability) for total leaf area per plant and leaf area at leaf positions somewhat distal to the ear leaf to parental total leaf area per plant and leaf area at individual leaf positions were investigated by means of multiple regression procedures applied to data obtained from 10 homozygous inbred lines of corn (Zea mays L.) and the diallel set of crosses among them. In the multiple regression analyses, GCA model estimates of leaf area at leaf positions —4 and 6 (the fourth leaf position below and sixth leaf position above the ear, respectively) and total leaf area were used as dependent variables, while midparent values of leaf area at individual leaf positions and total leaf area were used as independent variables. The regression equations were then appraised for their ability to predict F1 leaf area, based on a GCA effects model, from midparent leaf area values.The results indicated: 1) GCA model estimates of total leaf area could readily have been predicted from midparent total leaf area; 2) GCA model estimates of leaf area at leaf position 6 could have been predicted by a linear function of midparent observations of total leaf area, leaf area at the upper leaf positions, and leaf area at leaf positions near the ear; and 3) GCA model estimates of leaf area at position —4 could have been predicted by a linear function of midparent values including leaf area at and below the ear leaf. However, since GCA model estimates of leaf area at leaf position —4 were poorly and mostly negatively correlated with parental leaf area, prediction of F1 leaf area at the lower leaf positions might generally be tenuous.
Seasonal Variation in Photosynthesis, Respiration, and Growth Components of Nondormant Alfalfa (Medicago sativa L.)1
Authors: Delaney R. H. , Dobrenz A. K. , Poole H. T. 
Published: July 2010

Alfalfa (Medicago sativa L.) plants were grown under field conditions to determine causes of yield fluctuation throughout the growing season. Photosynthesis, dark respiration, forage yield, specific leaf weight (SLW), leaf size, leaf:stem ratio, and leaf area index (LAI) were measured for six harvests.High atmospheric temperatures during periods of reduced forage yield resulted in a maximum decrease of 38% in apparent photosynthesis and a 19% decrease in dark respiration. This reduction in photosynthesis may contribute to the “summer slump” in yield of alfalfa grown in warm climates. Specific leaf weight decreased with increased temperatures and followed a similar seasonal pattern under two plant densities.Leaf area index continued to decrease throughout the season in a pattern similar to forage yield. The data suggest that the decline in leaf area index was not a result of a decrease in leaflet size.
Sources and Inheritance of Resistance to Brown Planthopper in Some Breeding Lines of Rice1
Authors: Martinez C. R. , Khush Gurdev S. 
Published: July 2010

The inheritance of resistance to the brown planthopper (Nilaparvata lugens Sial.) in three breeding lines of rice (Oryza sativa L.), IR747B2‐6, IR1154‐243, and IR4‐93, was studied. Seven‐day‐old seedlings were infested with second‐ and third‐instar nymphs of brown planthopper and seedling injury was recorded 7 to 8 days after infestation.The resistance of IR747B2‐6 was conditioned by a single dominant gene which was allelic to the dominant gene of the variety ‘Mudgo’ (Bph 1). The resistance of IR1154‐243 and of IR4‐93 was governed by the same recessive gene which was also allelic to the recessive gene conditioning the resistance of ‘ASD 7’ (bph 2). IR4‐93 inherited its resistance from ‘H‐105.’ But both parents of IR747B2‐6 and of IR1154‐243 were susceptible. We concluded that ‘TKM 6,’ one of the parents of IR747B2‐6, is homozygous for Bph 1 but is also homozygous for a gene, I‐Bph‐1, which inhibits Bph 1. ‘Zenith,’ one of the parents of IR1154‐243, may also have a similar inhibitor gene.
Abscission of Cotton Floral Buds and Bolls as Influenced by Factors Affecting Photosynthesis and Respiration1
Authors: Guinn Gene 
Published: July 2010

The effects of some environmental factors on abscission (shedding) of young cotton (Gossypium hirsutum L.) fruits were investigated because excessive shedding is sometimes a problem in cotton production. Increasing the concentration of CO2 in the atmosphere from 350 to 1,000 ppm decreased shedding, increased the glucose and fructose contents of leaves, and lowered the average node number of the first bolls. Increasing the daily photoperiod from 8 to about 14 hours had similar effects. Conversely, shedding was increased by warm nights (30 C) and by low light intensity.These results indicate that factors that decrease photosynthesis or increase respiration may delay fruiting and decrease retention of floral buds (squares) and bolls. Low light intensity could become critical with high plant populations (more than 100,000 plants/ha), cloudy weather, rank growth, or a combination of the above conditions.
Variety Synthesis in Alfalfa1
Authors: Lowe C. C. , Cleveland R. W. , Hill R. R. 
Published: July 2010

We compared performance of conventional synthetics, double‐cross synthetics, and the parental components of the double‐cross synthetics in a series of field experiments of alfalfa (Medicago sativa L.). Nine clones that had been selected for high general combinging ability were used as parents for the nine 4‐clone combinations studied. Synthetics were produced by several methods of synthesis. The forage yield of the synthetics, measured in broadcast‐seeded trials at three locations in New York and Pennsylvania, was used to compare the methods of synthesis. All seeds were produced in cage isolations in California and New York. Honeybees (Apis mellifera L.) were used as pollinators.Conventional 4‐clone synthetics consistently yielded slightly more than the double‐cross synthetics. True double‐cross hybrid varieties from these parents would probably yield about 104% of that of the double.cross synthetics or about equal to the conventional synthetics. Advanced generations of 2‐clone synthetics (components of double.cross synthetics) were consistently lower yidlding than any 4‐clone synthetic which had the same two clones in its parentage. This agrees with theoretical expectations on inbreeding. Permutations of parent clones in synthesis of double‐cross synthetics affected performance but no permutation exceeded the corresponding conventional synthetic. Double‐cross synthetics made from Syn 2 generations of 2‐clone synthetics as parent lines yielded the same as those made from the Syn 1 generations of the parent lines. Differences observed in performance of synthetics produced in California and New York were attributed to differences in methods of establishing the plantings in seed production cages.
Mutations Induced in Vegetatively Propagated Turf Bermudagrasses by Gamma Radiation1
Authors: Powell Jerrel B. , Burton Glenn W. , Young Jonh. R. 
Published: July 2010

Most improved cultivars of turf bermudagrass (Cynodon sp.) are vegetatively propagated because of trlploid‐induced sterility or poor seed‐setting characteristics. Further improvement of these specialized turfgrasses is unlikely because they cannot be hybridized or easily constructed from parental stocks. New techniques are needed to circumvent these breeding barriers. Physical or chemical mutagens offer a practical approach.Rhizomes of two turf bermudagrass cultivars were treated with gamma rays to evaluate the mutation‐breeding technique for these vegetatively propagated grasses. Dosages of 9,000 and 11,300 rads produced 71 distinct mutations in the treated material screened. Mutations to dwarfism and changes in color hue of the stolons were most frequently noted. Gamma‐ray induction of mutations was of such frequency as to recommend use of this approach for the practical and successful breeding improvement of vegetatively propagated turf bermudagrass. Methods reported here also apply to the forage bermudagrasses and other vegetatively propagated grasses.
Amylolytic Activity of Orchardgrass and Starch and Sucrose Contents of Orchardgrass vs Pangola Digitgrass Leaf Blades as Influenced by Night Temperature and Gibberellic Acid1
Authors: Carter J. L. , Garrard L. A. , West S. H. 
Published: July 2010

This study was made to determine differences in sucrose and starch contents and amylolytic activities between Orchardgrass (Dactylis glomerata L.) and ‘Pangola’ digitgrass (Digitaria decumbens Stent.). This information could help explain why growth of tropical grasses is severely reduced by suboptimal night temperature (10C) whereas temperate species are much less affected.Orchardgrass and Pangola were treated with gibberellic acid (GA) and subjected to 30 or 10C 12‐hour nights with SOC days, after which sucrose and starch were determined. The starch‐degrading enzymes of Orchardgrass leaf blades were separated by means of polyacrylamide gel electrophoresis. Amylolytic enzyme activity was determined from densitometer tracings and by a colorimetric assay. In the case of Orchardgrass extracts, densitometer tracings of gels negatively stained by starch‐iodine showed the presence of 18 bands regardless of plant treatment. This was hi contrast to similar data previously obtained for Pangola. The temperate grass was found to contain more amylolytic isozymes and greater total amylolytic activity than Pangola. Neither the 10C night regime nor GA application affected total amylolytic activity or starch content of Orchardgrass, whereas both treatments affected amylolytic activity and starch content of Pangola. GA application did not affect the number of amylolytic isozymes in the leaf blades of either plant. Sucrose appeared to accumulate in leaves of both grasses during 10C exposure, in the presence and in the absence of GA. In the case of Orchardgrass, GA appeared to reduce leaf sucrose content at 30C.
Refractive Index as a Basis for Assessing Fatty Acid Composition in Segregating Populations Derived from Infraspecific Crosses of Cultivated Peanuts1
Authors: Khan A. Rahman , Emery Donald A. , Singleton John A. 
Published: July 2010

Refractive indexes of oil were converted to calculated iodine values (C.I.V.'s) and used to assess the fatty acid composition of hybrid and segregating populations of six crosses of cultivated peanuts (Arachis hypogaea L.). Two subspecies (hypogaea and fastigiata), three botanical types (Virginia, Spanish, and Valencia), and four market types (Virginia, Southeastern Runner, Spanish, and Valencia) were represented in the four parents.Highly significant statistical effects of locations and genotypes on mean C.I.V.'s were noted. Parent by location interactions were statistically significant, but hybrid by location interactions were nonsignificant.The use of a refractometer as a practical, rapid, inexpensive, and objective means of assessing the fatty acid composition of peanut oil was demonstrated. Significant positive correlation coefficients between C.I.V.'s and the actual linoleic acid compositions of oils from 40 F2 plants supported the use of the refractometer method.The wide range of genetic variability for C.I.V.'s in F2 populations of infraspecific crosses indicated selection potential for the improvement of quality and stability of seed oil within specific botanical plant types.C.I.V. appears to be highly heritable, and its expression is controlled by a few additive genes.
Semidwarfness, Stem Solidness, and Tillering of F2 Plants from 17 Spring Wheat Crosses1
Authors: McNeal F. H. , Wallace L. E. , Berg M. A. 
Published: July 2010

Combining resistance to the wheat stem sawfly (Cephus cinctus Norton) with semidwarfness and higher grain yields in wheat (Triticum aestivum L.) is a plant breeding objective in Montana. Parental and F2 populations from 17 crosses of 6 standard‐height, solid‐stemmed wheat selections with three semidwarf, hollow‐stemmed selections were evaluated in the field for semidwarfness (plant height), stem solidness, and tillering.Plant height data from crosses with ‘Bonanza’ suggest additive gene action, whereas skewness for tallness from crosses with ‘Shortana’ and MT 6830 suggest either dominance or some type of epistasis. The lack of dominance hi solid‐stemmed by hollow‐stemmed crosses is considered an indication of genetic additivity for stem solidness. All parents except Shortana tillered equally; Shortana had more tillers than standard height parents ND 681, ND 683, and ND 6850. A negative relationship between plant height and stem solidness indicates that selection of solid‐stemmed, semidwarf types should be possible.The variation exhibited by these three plant characteristics offers plant breeders an opportunity to combine desirable features of each.
Genetic Analysis of a New Virescent Mutant in Cotton1
Authors: Kohel R. J. 
Published: July 2010

A spontaneous mutant in cotton (Gossypium hirsutum L.) is described, and the results of its genetic analysis are reported. This mutant was called virescent‐splash‐leaf because it showed a typical virescent expression, and portions of the leaf surface had a splash‐leaf appearance resulting from abnormal palisade cell development. Expression of the virescent phenotype was consistent, but the splash‐leaf expression was variable. The incidence of the splash‐leaf expression was associated with cool temperatures.The mutant was conditioned by recessive alleles at a single locus. Because it was non‐allelic with any known virescent mutants, it was designated as virescent‐8 and assigned the gene symbols v8v8.Linkage analysis of virescent‐8 did not reveal any significant association with the marker loci: cup leaf, glandless‐1, frego bract, cluster‐1, virescent‐1, Okra leaf, Red plant, Pilose, Petal spot, Yellow petals, Pollen color, Brown lint‐1, Naked seed, or Green lint.
Comparative Leaf Area and Dry Matter Accumulation by Maize and Sugarbeet1
Authors: Snyder F. W. 
Published: July 2010

Growth of noncompetitive plants of locally adapted maize (Zea mays L. cv. ‘Michigan 555 3x’) was compared with that of sugarbect (Beta vulgaris L. cv. ‘US H20’) in five experiments, including a 113‐day experiment outdoors.Maize had larger leaf area per plant at emergence and maintained a larger area until the end of the 113‐day experiment; however, sugarbeet had nearly the same leaf area as maize at 113 days from emergence. The rate of leaf‐area accretion for both species was very similar for the first 50 days. Maize had decelerated to zero by 71 days, whereas sugarbeet continued to accrete leaf area.Dry‐matter production per plant was greater for maize, ranging from 11.7‐fold greater at 15 days to 1.6‐fold greater at 113 days when it was mature.The ratio of total dry matter produced per unit leaf area (DM/ULA) for maize:sugarbeet at 15 days was 1.60:1.00 and at 30 days was 1.48:1.00. At 50 days maize had produced no more DM/ULA than sugarbeet; and when the differential rate of leaf‐area accretion between the two species was adjusted, they were about equal at 71 days. At 92 days, maize again produced more DM/ULA than sugarbeet. At 113 days, maize averaged 66.8 mg dry matter cm−2 of leaf area and sugarbeet only 46.4. Thus, in the 113‐day period, the ratio of total DM/ULA for maize:sugarbeet was 1.44:1.00. Individual plants of both species differed markedly in producing DM/ULA. Growth‐rate data are included.
Development of a Nitrogen Balance for Cotton Growth Models: A First Approximation1
Authors: Jones J. W. , Hesketh J. D. , Kamprath E. J. , Bowen H. D. 
Published: July 2010

Daily growth values of cotton (Gossypium hirsutum L.) were calculated based on the carbohydrate balance of SIMCOT II, a simulation model of cotton growth and development. The daily N requirements for new growth of leaves, stems, roots, burrs, and seed were calculated based on maximum and minimum N concentration for these plant parts. Daily N absorption depended on the availability of N in the soil pool and new growth requirements. If the absorbed N was less than the required amount, partitioning functions determined the distribution of available N into each sink. During periods of N shortages, some N reserves were supplied for new growth from the breakdown of N compounds in the older leaves and stems. Depending on the level of N shortage, new growth was slowed, bolls and squares were abscised, and some leaves were shed.The model shows that, based on the N balance, growth can be restricted and reproductive organs aborted after SIMCOT II runs its normal course for a day during the boll setting period. Simulated fruiting characteristics and yield curves were similar to those of real plants.