bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection Criteria for Yield and Quality in Big Bluestem Grass1
Authors: Ross J. G. , Thaden R. T. , Tucker W. L. 
Published: July 2010

AbstractAgronomic characters (e.g., vigor, leafiness, height, seed set, proportions of plant parts, and in vitro dry matter digestion, IVDMD, of plant parts) were studied in a breeding nursery of big bluestem (Andropogon gerardii Vitman), a native warm season grass. Significant differences were found among 23 families for all characters studied except seed weight from five aggregates of racemes and leaf IVDMD. Seedling height was not highly correlated with plant weight at the end of the second and third growing season. Since seed set was not correlated with vigor or leafiness, selection for seed set should not affect forage yield potential.Lack of significant differences among families for leaf IVDMD indicated that selection for IVDMD would have questionable value, because summer grazing would be the only use for a cultivar from this species. High production of seed should be a realizable objective of a breeding program in this species.
Effectiveness of Early‐generation Yield Selection of Heterogeneous Lines in Soybeans1
Authors: Boerma H. R. , Cooper R. L. 
Published: July 2010

AbstractF2−derived, heterogenous soybean [Glycine max (L.) Merr.] lines (HL) were selected for high seed yield by the early‐generation yield‐testing procedure (EGT), based on F3, F3−F4, and F3−F4−F5 combined generation means in four soybean crosses. Pure lines (PL) were selected for high seed yield from these same four crosses by the pedigree selection (PS) and single‐seed‐descent (SSD) procedures.Selection of superior‐yielding HL in the F3, F4, and F5 generations decreased the coefficient of genetic variability in each generation of selection. The yield performance of the selected HL in the 1970 uniform preliminary test II also suggested that the HL were uniform among lines in yielding ability and the HL from one cross were equal in yield to the reference varieties.The results indicated that in one of the four crosses PL selected by the SSD procedure were significantly higher in yield and earlier in maturity than the HL. In the other crosses, no significant yield differences existed between PL and HL, although the PL were usually earlier in maturity than the HL. These results suggested that pure lines from a cross will be equal to or higher in yield than F2−derived heterogeneous lines.
Combining Ability Analysis of Anatomical Components of the Dry Fruit in Chili Pepper1
Authors: Omar Marin V. , Lippert L. F. 
Published: July 2010

AbstractPercentages and combining abilities for five fruit components in dry chili peppers (Capsicum annuum L.) were analyzed in a diallel cross involving nine parental entries. Endocarp comprised approximately 52% of the total dry fruit, seed 25%, exocarp 12%, placenta 6%, and stem 5%. Increases in endocarp percentage were generally associated with decreases in seed content. Variability in fruit components among F1 hybrids were predominantly attributable to general combining ability (GCA), suggesting additive gene action. Neither mean heterosis in hybrids nor mean squares for specific combining ability (SCA) were significant for any of the fruit components. GCA effects and GCA variances of parents for endocarp and seed components compared favorably with parental performance. Procedures for improving endocarp percentage and reducing seed and exocarp percentages are discussed. Parental lines are evaluated for incorporation into base population development for recurrent selection breeding programs. Information from this study is integrated with previously reported information on yield and fruit quality characteristics from the same diallel study.
Inheritance of Stalk Quality Characteristics in Maize1
Authors: Arnold J. M. , Josephson L. M. 
Published: July 2010

AbstractThe inheritance of percentage senescent stalks, crushing strength, and rind thickness, was studied in six maize (Zea mays L.) crosses by the generation mean analysis method. Heritability estimates also were obtained for crushing strength and rind thickness. Additive genetic effects were more important than non additive effects for the three characters. Heritability estimates ranged from 0.28 to 0.53 for crushing strength and from 0.33 to 0.62 for rind thickness for the six crosses. Results indicate that a selection procedure that takes advantage of additive genetic effects and variance would be effective in improving these characters.
General and Specific Combining Ability for Several Agronomic Traits in Diallel Cross Progenies of Cicer Milkvetch1
Authors: Townsend C. E. 
Published: July 2010

AbstractCicer milkvetch (Astragalus cicer L.) was evaluated in a six‐parent diallel for vigor score, height, and date of flowering for 2 years and for spread and seed weight for 1 year. F1 progenies, their reciprocals, and parental clones were grown under irrigation. Significant differences occurred among crosses and among parental clones for all characters each year. The variance for these traits was partitioned into general combining ability, specific combining ability, and reciprocal effects. General combining ability was significant for all characters, except vigor score in the seedling year. Specific combining ability was significant for vigor score both years, height in the seedling year, and date of flowering in the second year. Reciprocal effects were significant for vigor score both years, date of flowering both years, and height in the second year. Because most of the genetic variance for all characters except 1971 vigor was caused by the additive component, recurrent selection should be an effective method for improving cicer milkvetch.
Ripening of Sugarcane: Effects of Sunlight, Temperature, and Rainfall1
Authors: Legendre B. L. 
Published: July 2010

AbstractThe effects of incident sunlight, temperature, and rainfall on ripening of sugarcane (Saccharum spp.) were studied with five interspecific hybrids selected for subtropical conditions. Ripening was associated with both incident sunlight and temperature, but not with rainfall. Partial correlations reinforced the independence of ripening on incident sunlight, but showed that the associations of ripening with temperature were spurious. Partial correlation also showed an interacting effect of incident sunlight and temperature on ripening that varied with the cultivar. There was a significant difference between cultivars in the associations between ripening and sampling dates.
Frequency, Size, and Distribution of Stomata in Triticale Leaves
Authors: Sapra V. T. , Hughes J. L. , Sharma G. C. 
Published: July 2010

AbstractBase, middle, and tip part of the abaxial surface of flag and two succeeding lower leaves of 13 cultivars of triticale (× Triticosecale), wheat (Triticum aestivum L.), and rye (Secale cereale L.) with varying ploidy level were studied for stomatal frequency and size (guard cell length). Significant differences existed among cultivars within species, among leaves within cultivars, and among positions within leaves for both frequency and size. Hexaploid triticale ‘Rosner’ had significantly greater number of stomata/unit area than ‘Blueboy’ (wheat) while ‘Snoopy’ (rye) had significantly less. Stomatal frequency and size were negatively correlated (r = −0.80, significant at the 1% level).‘6TA 204’ had the lowest number and largest stomata size of 6x triticales. With increasing ploidy level within a species, the number of stomata/unit area decreased and stomata size increased.
Associations Among Traits in Progenies from Avena sativa L. ✕ A. sterilis L. Crosses1
Authors: Lyrene P. M. , Shands H. L. 
Published: July 2010

AbstractThe relationships between groat protein percentage and several other agronomic traits were studied in F2 and F3 progenies of six Arena sativa ✕ A. sterilis crosses. Groat protein percentage was negatively correlated with groat plumpness, groat percentage, and grain yield. High groat protein was associated with several undesirable spikelet characteristics inherited from A. sterilis, including spikelet shattering, lemma awns and pubescence, and brown lemma color. The association between shattering spikelets and high groat protein percentage was especially pronounced. F2 plants with shattering spikelets averaged 3.0% higher in groat protein than those with nonshattering spikelets. The comparable difference for F3 lines was 3.8%.Development of useful cultivars from A. sativa ✕ A. sterilis progenies will require selection for groat plumpness, high grain yields, A. sativa spikelet type, and several other agronomic traits in addition to high groat protein percentage. The unfavorable associations noted, undoubtedly will reduce the rate of progress in increasing protein percentage.
Effect of Helminthosporium maydis, Race T, Pathotoxin on Growth and Ribonuclease Levels of Corn Roots1
Authors: Wilson C. M. , Apel G. A. 
Published: July 2010

AbstractThe growth of corn (Zea mays L.) roots with Texas male‐sterile cytoplasm is inhibited by. a pathotoxin produced by race T of Helminthosporium maydis Nisik. and Miyake. Application of toxin solutions to the primary root tip for only 20 rain was enough to inhibit root growth. This inhibition formed the basis for a rapid semi‐quantitative toxin assay requiring only small volumes of toxin solution. Also, the geotropic response of roots was affected by the toxin.Changes in ribonuclease (RNase) activity of toxintreated roots were studied to determine whether or not the known corn RNase could be specifically implicated in the processes leading to inhibition of growth. The RNase activity of inhibited root tips was greatly increased over that of untreated controls, but only when growth was drastically reduced. The increase in RNase was concluded to be a secondary reaction occurring after the toxin had damaged the growing regions of the root. Tests for the specific nucleases in corn roots did not detect appreciable differences in the relative amounts of the different enzymes; all increased together. RNase increased in the terminal 15 mm of the tip; the increase could be detected within 6 hours after a brief treatment of the tip with pathotoxin.
Origin, Cytology, and Reproductive Characteristics of Haploids in Pearl Millet1
Authors: Powell Jerrel B. , Hanna Wayne W. , Burton Glenn W. 
Published: July 2010

AbstractPearl millet [Pennisetum americanum (L.) K. Schum.] is an important introduced forage species in the U.S. Thirteen haploid plants with seven chromosomes in somatic cells were studied. Two plants resulted from a twinembryo caryopsis, whereas the others were discovered in field plantings. The rate of spontaneous haploid occurrence was 1 per 10,000 plants in the inbred ‘Tift 23A.’ Seed set on individual haploid plants ranged from 502 to none. No haploids were recovered from progeny of seeds harvested from haploid plants. Spontaneous chromosome doubling occurred in several plants. The doubled sectors in the inflorescences were characterized by good exsertion and good dehiscence of anthers. Haploids were conspicuous because of their small inflorescence diameters, narrow leaves, and poor exsertion and dehiscence of anthers. Meiotic chromosomes of haploids were mostly univalents, but occasional pairing of two or more chromosomes was observed at metaphase I.
Effect of Chilling Duration on Germination of Cottonseed1
Authors: Cole D. F. , Christiansen M. N. 
Published: July 2010

AbstractSeed of genetic selection M‐8 (Gossypiura hirsutum L.) and ‘Pima S‐4’ (G. barbademe L.) were subjected to various levels of chilling (0, 1, 2, 4, 8, 16, and 32 days at 5 C in water) after the seed were preconditioned by inbibition for 6 hours at 30 C in water. Seed for evaluation of chilling injury were germinated over a temperature range of 15 to 30 C on a thermogradient plate and in rolled towels at 30 C. Percent emergence and stand survival were determined for both cultivars.Higher percent germination over the same range of temperatures on the thermogradient plate was obtained with M‐8 than with Pima S‐4. Seed chilled for 16 and 32 days was very low in viability and germinated over a narrower range of temperatures than seed chilled for shorter periods. Preconditioning increased germination of both selections and improved emergence of M‐8. Seed of Pima S.4 inbibed water at a faster rate than M‐8. Selections differed in their responses to different durations of chilling.
Response of Beans to Shading1
Authors: Crookston R. K. , Treharne K. J. , Ludford P. , Ozbun J. L. 
Published: July 2010

AbstractTwo dry bean (Phaseolus vulgaris L.) cultivars were grown in controlled‐environment chambers under standard light [390 μ Einsteins m‐2 sec‐1 (400 to 700 nm) = approx. 22,000 lux] and shaded light [55 μ Einsteins m‐2 sec‐1 (400 to 700 nm) = approx. 3,200 lux] intensities. Experimental observations included measurement of gas exchange and photosynthetic and respiratory enzyme activity along with examination of plant morphology, leaf anatomy, and chloroplast ultrastructure.Shading reduced leaf number, area, and thickness. Photosynthesis/unit area of shaded leaves was decreased by an average of 38%. Transpiration was not significantly affected. Increased intracellular resistance of the shaded leaves was more important in reducing CO2 uptake than was the increase in stomatal resistance. The increase in mesophyll resistance was reflected both in the biochemical reactions of the leaf (activity of all measured enzymes being reduced by 70%) and in the ultrastructure of the leaf chloroplasts (reduced quantities of starch in spite of extensive grana).
Wind Barriers Most Beneficial at Intermediate Stress1
Authors: Skidmore E. L. , Hagen L. J. , Teare I. D. 
Published: July 2010

AbstractA slat‐fence wind barrier, installed midfield and oriented east‐west, was used to investigate leaf‐water potential and stomatal resistance of winter wheat (Triticum aestivum L.) as influenced by barrier‐induced microclimate in a semiarid macroclimate. Leaf‐water potential, stomatal resistance, and micrometeorological parameters indicated that shelter affected neither leaf‐water potential nor stomatal resistance when stress was low. At intermediate stress, leaf‐water potential was significantly higher in the sheltered area than in open field. Under high stress, leaf‐water potentials of plants hi the two areas did not differ significantly; however, stomatal resistance was higher in the open field than in the sheltered area.
Inter‐row Competitive Effects among Four Cotton Cultivars1
Authors: Moran‐Val Cesar A. , Miller P. A. 
Published: July 2010

Inter‐row competition among cotton (Gossypium hisutum L.) genotypes may cause major biases in the estimation of cultivar performance. The objective of the present study was to evaluate the nature and importance of such effects among four cotton cultivars and relate the results to field evaluation techniques.Four cultivars, representing the extremes of vegetative growth habit among the strains currently being tested in North Carolina, were grown. Inter‐row competition was measured using each cultivar as a test cultivar subjected to all possible pair wise combinations of the same four entries as competitors. Thus, there were 10 competitor combinations for each test cnltivar, for a total of 40 treatments. A randomized block design of six replicates was grown at each of three locations in North Carolina. Six traits were measured including seed cotton yield, lint yield, lint percent, boll weight, plant height, and plant width.The four cultivars differed significantly in competitive ability. Although effects on all traits were noted, fiber and seed cotton were the only traits which were modified sufficiently to be of major concern in an evaluation program. Both additive (average) and specific inter‐row competitive effects were observed for yield. Mean squares for average effects were consistently larger than those for specific effects. Averaged over the three locations, biases expected from the use of nonbordered single‐row plots ranged up to 13.2% for lint yield. Competition effects of this magnitude suggest the need to use bordered plots for measuring yield, at least in advanced trials.
Cephalosporium Stripe of Winter Wheat: Procedures for Determining Host Response1
Authors: Mathre D. E. , Johnston R. H. 
Published: July 2010

Techniques were evaluated for determining the response of winter wheat (Triticum aestwum L.) to infection by Cephalosporium gramineum Nisikado and Ikata. The objective was to develop a system that would allow large scale field screening for resistance to this pathogen. Use of a root inoculation technique indicated that cultivars differed in the severity of symptoms that developed but the technique was laborious and difficult to use. An oat kernel inoculum, added with the seed at the tune of planting, produced high levels of infection and closely approximated a natural inoculum situation. Early fall seeding accompanied by the use of 10 to 20g of oat inoculum per 3.6 m of row maximized disease development. Thirty entries were evaluated for their response to this disease using the oat kernel technique. A few entries, including 'Trader,' PI 178383, and PI 347737, appeared to have a low degree of susceptibility. Counts of white heads were positively correlated with degree of yield reduction.The oat kernel technique should be of use to plant breeders and plant pathologists interested in a screening program to develop resistant and/or tolerant cultivars.
Selection of T‐Cytoplasm Maize Callus Cultures Resistant to Helminthosporium maydis Race T Pathotoxin1
Authors: Gengenbach B. G. , Green C. E. 
Published: July 2010

Texas male‐sterile cytoplasm (cms‐T) maize (Zea mays L.) is susceptible to Helminthosporium maydis (Nisikado and Miyake) rate T and its pathotoxin; whereas nonsterile (N) cytoplasm maize is resistant. Callus cultures of cms‐T and N versions of A619 maize were established to study the effect of the toxin on maize callus and to select for toxin‐resistant cms‐T callus. Toxin in the culture medium inhibited cms‐T growth, while N grew normally. The percent inhibition of cms‐T callus growth depended on the toxin concentration. Complete inhibition was obtainable.Selection of toxin‐resistant A619(cms‐T) callus began with cultures grown on sublethal toxin concentrations. The fastest growing callus or callus sectors were subeultured for additional selection. After four subculture cycles (160 days on toxin), 14 callus clones were selected for growth analysis in the absence and presence of toxin concentrations lethal to unselected A619(cms‐T) callus. Growth rates at these toxin concentrations were 53 to 111% of the growth without toxin. This high degree of toxin resistance remained stable for 127 days growth in the absence of toxin.The in vitro effects of toxin on NADH oxidation, oxidative phosphorylation, malate‐driven 2,6‐dichlorophenol indophenol reduction, and swelling of mitochondria isolated from unselected A619(N) and A619(cms‐T) callus and from resistant A619(cms‐T) callus were determined. These four activity parameters of mitochondria from susceptible A619(cms‐T) callus were significantly affected by toxin added to the reaction medium. Mitochondria isolated from A619(N) and resistant A619(cms‐T) callus were not affected by toxin addition. This association of mitochondrial insensitivity to the toxin with resistance at the callus level may help clarify the role of mitochondria in resistance to this disease.
Photosynthetic Characteristics of Panicum milioides, a Species with Reduced Photorespiration1
Authors: Brown R. H. , Brown W. V. 
Published: July 2010

A species (Panicum milioides Nees ex. Trin.), has been found which apparently has a reduced rate of photorespiration compared to other C3 plants. It was found in preliminary studies that the response of net photosynthesis (Pn) to O2 concentration was less for this species than for other C3 plants. Therefore, this work was conducted to characterize for five accessions of P. milioides the CO2 exchange related to photorespiration. Panicum maximum Jacq. (C4), P. laevifolium Htack. (C4), and tall fescue (Festuca arundinacea Schreb. (C3) were included for comparison. Leaf cross‐sections of P. milioides were examined for characteristics known to be related to photosynthetic carbon pathways. 13C/12C ratios were determined on P. milioides tissue.P. milioides photorespired less than tall fescue and more than P. maximum as determined by the three criteria: Pn response to O2, CO2 evolution in the light, and CO2 compensation concentration. The change in Pn for each 1% increase in O2 was from −0.36 to −0.48 mg CO2 dm−2 h−1 for five accessions of P. milioides compared to −0.10, −0.13, and −0.61 mg dm−2 h−1 for P. maximum, P. laevifolium, and tall fescue, respectively. P. milioides evolved an average of 0.85 mg CO2 dm−2 h−1 in the light at 20% O2 compared to 0.02 mg dm−2 h−1 for P. maximum and 2.96 mg dm−2 h−1 for tall fescue. CO2 compensation concentrations determined by a Mylar bag technique were 0.4, 15.8, and 54 ppm for P. maximum, P. milioides, and tall fescue, respectively. Determination of CO2 compensation from Pn response to CO2 gave a similar trend, although actual concentrations were different. P. milioides tissue had δ 13C values of about −25 ‰, characteristic of C3 species. A leaf anatomical study showed that P. milioides had enlarged parenchyma sheath cells with centripetally located chloroplasts and mesophyll cells arranged in a radial manner around the parenchyma sheath. The parenchyma sheath cell walls appeared to be thicker than those of most C3 species. It is concluded that while P. milioides exhibits mostly C3 characteristics, its reduced photorespiration rate and some C4‐like anatomical characteristics indicate a degree of intermediacy between C3 and C4.
Rapid Method for Estimating Leaf Area Per Plant in Maize1
Authors: Pearce R. B. , Mock J. J. , Bailey T. B. 
Published: July 2010

We grew four maize (Zea mays L.) genotypes, representing a wide range of leaf area/plant, at two plant densities in 1973 to develop a simple, rapid, and nondestructive method for estimating average leaf area/ plant. Immediately after pollen‐shed, we measured lengths and maximum widths of all leaves on all plants in each plot and subsequently calculated individual leaf areas.Individual leaf areas were summed to give total leaf area/plant. Correlations of individual leaf areas with total plant leaf area revealed that leaf #8 (from the top of the plant) was the most highly correlated (r = 0.95). Therefore, the regression of total plant leaf area on area of leaf #8 was computed and the resulting b‐value (9.39 ± 0.04) used as the leaf area factor for estimating average leaf area/plant.Results indicated average leaf area/plant for normal maize plants can be estimated by measuring length and maximum width of leaf #8 on several competitive plants/ plot, calculating area of leaf jS, and multiplying that leaf area by 9.39. Genotype means can often be obtained across replications by measuring only one plant/plot. This method is rapid, nondestructive, and should allow estimation of leaf area of more genotypes and/or experimental treatments/experiment than is currently feasible with conventional techniques.