bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Analysis of Resistance to the Corn Virus Disease Complex1
Authors: Naidu B. , Josephson L. M. 
Published: July 2010

Five highly resistant (R) and five highly susceptible (S) inbred lines of corn (Zea mays L.) were evaluated in a diallel set of 45 single crosses to study the inheritance of resistance to the corn virus disease complex. The entries were evaluated under conditions of mechanical inoculation at Knoxville and natural infection at Waverly, Tenn. Evaluations were made prior to flowering and again on fully grown plants.Highly significant differences for mean severity ratings among genotypes were obtained in all experiments. Correlations between ratings in the two locations and for both times of rating were highly significant for both the inbreds and the hybrids. R ✕ R crosses were highly resistant in all evaluations while S ✕ S crosses were highly susceptible. Mean ratings for R ✕ S crosses were significantly lower than the mean of R ✕ R and S ✕ S crosses and the mean of all crosses indicating partial dominance of resistance. General combining ability (gca) and specific combining ability (sea) mean squares were highly significant in all evaluations but gca mean squares were substantially larger than the sea mean squares. Inbred T232 had the largest negative gca effect with both times of rating, followed in order by Tx601, Ky226, Ga209, and Mo18W. By contrast, inbred CI872 had the largest positive gca effect on susceptibility while inbred T105 had the least at both times of rating.Vr, Wr graphs and components of variance analyses of the data provided similar results to those with combining ability analysis. Among the resistant inbreds, T232 indicated the most dominant genes for resistance when tested in both locations and with both times of rating while Mo18W indicated the least number. Inbreds Tx601, Ga209, and Ky226 varied in the two locations and time of rating. As many as four major genes for resistance were indicated to be present in the parental inbreds. Hybrids having high resistance are obtainable from crosses involving these resistant inbreds. Since some degree of dominance was indicated, a backcrossing procedure to transfer the resistance factors into elite lines is suggested. Some form of recurrent selection in populations having a degree of resistance also is suggested.Host reaction and the nature of the genetic variation governing resistance showed that the inbreds used in this study reacted in a similar manner to the virus complex under all conditions of testing. The data also indicate that evaluations for virus resistance can be made prior to flowering and that breeders can make pollinations concurrent with evaluation.
Variation in RuDPCase Activity in Barley1
Authors: Frey Nicholas M. , Moss Dale N. 
Published: July 2010

Seasonal patterns of ribulose 1,5‐diphosphate carboxylase (RuDPCase), EC4.1.1.39, activity from leaves and awns, specific leaf weight, and total above‐ground dry matter accumulation rate were determined for two barley (Hordeum vulgare L.) genotypes. In general, RuDPCase activity was greatest in young, fully expanded leaves and was lower in each subsequent leaf down the culm. for a given leaf, RuDPCase activity also decreased sharply with increasing age. Specific leaf weight (SLW) did not change with leaf age but upper leaves on a culm had greater specific leaf weights than did lower leaves. The RuDPCase activity in the total plant canopy and in the youngest expanded leaf for both varieties was significantly and positively correlated with the rate of aboveground canopy dry matter accumulation.Twelve barley cultivars chosen to sample a relatively broad genetic background were grown in two controlled environments and a greenhouse. Genotypes differed significantly in RuDPCase activity (dm2 leaf) −1 and (g dry wt) −1 and in SLW. Only RuDPCase activity (dm2 leaf) −1 and SLW were significantly affected by environment. There were no significant genotype by environment interactions for RuDPCase activity (dm2 leaf) −1, for activity (g dry wt) −1, or for SLW. Heritability estimates using the components of variance method were 0.67, 0.56, and 0.74 for RuDPCase activity (dm2 leaf) −1, for activity (g dry wt)−1, and for SLW, respectively. The correlation coefficients for SLW vs. RuDPCase activity (dm2 leaf) −1 and vs. activity (g dry wt)−1 were 0.83, and 0.06, respectively. It was concluded that RuDPCase activity of barley leaves might be increased in two ways: 1. by selecting for high RuDPCase activity (g dry wt) −1 and 2. by selecting for high SLW.
Suppression of Standard Forage in vitro Dry Matter Disappearance by Acetone, Methanol, and Aqueous Extracts from Crownvetch Leaflets1
Authors: Burns J. C. , Cope W. A. , Wildonger K. J. 
Published: July 2010

Residues from crownvetch (Coronilla varia L.) leaflets were obtained from evaporation of acetone, methanol, and aqueous extracts and added to standard forages to evaluate a previously observed negative relationship between crownvetch in vitro dry matter disappearance (IVDMD) and anti‐quality substances. The activity of the residue was characterized by changes in the IVDMD of the standard forages. Leaflets were selected to represent forage that previously showed high IVDMD and low total phenols (clone 2); low IVDMD and high total phenols (clone 4) and intermediate IVDMD and high total phenols (clone 6). When equal volumes of the residues (dissolved in water) were added to standard forages, only those from methanol significantly reduced the standard forage IVDMD. These residues also ranked the standard forage IVDMD identical to that of the leaflet IVDMD (clone 4 less than clones 6 or 2 and clone 6 higher than clone 4, but less than clone 2).The addition of increasing quantities of each residue to a standard forage revealed that all residues, when added in sufficient concentration, contained the anti‐quality substance(s). When changes in the IVDMD of the standard forage were related to the total phenol concentrations of the methanol residues a high, negative correlation was obtained. The total phenol fraction appeared to be a good index to anti‐quality substance(s) in the methanol residues.Breeding programs with objectives to improve persistence and yield of crownvetch should consider the negative relationship between certain total phenol fractions and IVDMD. Variation exhibited among clones in this character may provide a useful tool for selecting varieties low in anti‐quality substances as reflected by total phenol concentrations.
Evaluation of Greenbug Resistance in S2 Progenies of Grain Sorghum1
Authors: Kofoid K. D. , Ross W. M. , Hackerott H. L. , Harvey T. L. , Kindler S. D. 
Published: July 2010

The relationship of greenbug [Schizaphis graminum (Rondani)] resistance to various agronomic traits was evaluated by testing 100 greenbug.resistant and 100 greenbug‐ susceptible S2 progenies derived from the same grain sorghum [Sorghum bicolor (L.) Moench] random‐mating population. Data collected in the absence of greenbug infestation indicated that no differences existed between the two populations for any of the traits studied.The same entries tested in the presence of a greenbug infestation showed the mean of the resistant population to be significantly greater for height, grain yield, grain wt/plant, grain wt/head, and live leaves/plant; and significantly less for greenbug mummies/plant, dead leaves/ plant, and damaged leaves/plant. Thus greenbug resistance had no deleterious effects upon any of the agronomic traits studied; and in the presence of greenbug feeding, resistance enhanced the agronomic acceptabilityAmple variability existed within each population for improvement by selection of any of the traits studied.
Leaf Morphology and Anatomy in Relation to CO2‐exchange Rate of Soybean Leaves1
Authors: Dornhoff Gary M. , Shibles Richard 
Published: July 2010

To learn more about factors limiting leaf photosynthesis of soybeans [Glyclne max (L.) Merr.], we examined the relationships among leaf morphological and anatomical characteristics and CO2‐exchange rate (CER). Infrared gas analysis of the most recent, fully expanded, attached leaf of outdoor, pot‐cultured plants was measured in the laboratory under saturating irradiance, after which stomatal impressions were taken and leaf sections were prepared for anatomical measurementsSpecific leaf weight (SLW), which seemed a function of thickness and not deusity, and leaf thickness (LT), itself, were correlated with CER. The thickness differeuces were most strongly expressed in the upper palisade and paraveinal mesophyll layers. Vapor phase diffusion resistance to CO2 accounted for 22 and 13% of the variation in CER in each of 2 years, and only in the former year, when aperature on the adaxial surface was strongly correlated with resistance and CER, were stomatal characteristics related to CER. Residual (mesophyll, carboxylation) resistance accounted for 15 and 53% of the variation in CER the 2 years. Both CER and residual resistance were related to the thickness and cellular volume of the several leaf tissue layers, but they were poorly related to cell diameters, exposed cell surface area, and cell surface to volmne ratio. We conclude that characteristics internal to the cell, as opposed to resistances related to stomata, intercellular space, or cell surfaces, were regulating CER in these soybean leaves.
Inheritance of Genic Sterility in Cultivated Safflower1
Authors: Carapetian Jirair , Knowles P. F. 
Published: July 2010

Vegetatively normal but reproductively sterile safflower (Carthamus tinctorius L.) plants were observed in segregating generations (F2, F3, BC1F2, and BC1F3) of crosses involving the cultivar ‘US‐10’ and an introduction from India, 57‐147. Seed heads appeared pinched because of shorter florets at anthesis and an absence of seeds.Different methods of classification, namely, the morphological appearance of flowering heads, seed set under self‐ and open‐pollination, and the morphology and stainability of pollen grains were used to identify the sterile plants under field and greenhouse conditions. Data strongly support the involvement of three unlinked nuclear genes in the inheritance of sterility. It is proposed that US‐10 and 57‐147, respectively, have the genotypes AAbbcc and aaBBCC. Sterility occurs when a homozygous recessive allele at the A locus interacts with a homozygous recessive allele at either the B or C locus. As expected, F2 families segregating at the three loci gave a good fit to a 57:7 (fertile:sterile) ratio in which the sterile genotypes are aabbC‐, aaB‐cc, and aabbcc.
Quantitative Genetic Studies of the NP3R Random‐mating Grain Sorghum Population1
Authors: Jan‐orn Jinda , Gardner C. O. , Ross W. M. 
Published: July 2010

The need for broadening the germplasm base in breeding populations to avoid genetic vulnerability and the availability of the genetic male‐sterile genes have prompted the development of random‐mating grain sorghum [Sorghum bicolor (L.) Moench] populations and the use of recurrent selection systems to improve those populations. The objectives of this study were to investigate the inheritance of grain yield and other quantitative traits in one such population and to utilize the information to make decisions as to which breeding systems are the most likely to be successful in achieving population improvement.Nine quantitative traits were measured in 196 half‐sib, 196 full‐sib, and 196 S1 randomly developed families derived from the NP3R random‐mating grain sorghum population and grown in intermixed 14 ✕ 14 simple lattice designs at Mead and Lincoln, Neb. Genetic and environmental components of variance, heritabilities, phenotypic correlations, and expected gains from selection were estimated for each trait in each type of family.Dominance variance () exceeded additive genetic variance () for grain yield per plant and per unit area and for kernels per plant, but the reverse was true for other traits. The trend in grain yield with full‐sib family means > half‐sib family means > S1 family means indicates that heterosis and inbreeding depression are important for this trait. Heterosis is also indicated for plant height and number of kernels per plant. In total genetic variance, S1 families tended to exceed full‐sib families which in turn tended to exceed half‐sib families. The S1 family component of variance does not appear to be suitable for estimating additive genetic variance in the NP3R population. Heterogeneous half‐sib families tended to be most stable over environments, and the S1 families were least. Heritability estimates on an individual plant basis were high for days to flower (0.88) and plant height (0.71), very low for grain yield (0.09), and quite for heads per plant (0.16) and kernels per plant (0.15).Predicted response from single trait selection was highest for S1 family selection for most traits, particularly grain yield. Highly heritable traits, days to flower and plant height, could easily be improved by mass selection. If selection is for yield alone, correlations indicate that the population would become later maturing and taller; therefore, selection procedures must take expected correlated responses into account.
Flavonol Glycoside Genes and Photosynthesis in Soybeans
Authors: Buttery B. R. , Buzzell R. I. 
Published: July 2010

Soybean [Glycine max (L.) Merr.] cultivars and strains vary in leaf content of flavonol glycosides which are controlled by the nonallelic genes Fg1, Fg2, Fg3, Fg4, T, and Wm. This study was undertaken to see if certain combinations of these genes or their products were associated with alterations in photosynthetic activity of the leaves.Chlorophyll concentration, specific leaf weight (SLW), and photosynthetic rate (P) were measured in field‐grown soybean plants differing in flavonol glycoside genes. Similar measurements were made in the growth chamber in an Fg2 population segregating for Fg1/fg1 and for T/t.The Fg1fg2Fg3t genotype had high concentrations of kaempferol 2G‐glucosylgentiobioside (K9) in the leaves, and low levels of chlorophyll, P, and SLW. In the presence of Fg2 instead of fg2, or of T instead of t, the level of K9 was reduced and chlorophyll concentration, P, and SLW were increased. The recessive wm gene was associated with very low levels of flavonol glycosides in the leaves, and this also appeared to reduce P, but not chlorophyll nor SLW.Bean yield and P were highly correlated. Cultivar surveys indicate that there has been a tendency in breeding programs either to eliminate Fg1 while maintaining Fg3 at a high frequency, or to reduce the frequencies of both Fg1 and Fg3. In the future, soybean breeders could eliminate some crosses which would produce a high proportion of low yielding material by avoiding parents which result in complementary gene action of Fg1 and Fg3.
Effects of Geographic Origin and Seed Production Environments on Apomixis in Kentucky Bluegrass1
Authors: Hovin A. W. , Berg C. C. , Bashaw E. C. , Buckner R. C. , Dewey D. R. , Dunn G. M. , Hoveland C. S. , Rincker C. M. , Wood G. M. 
Published: July 2010

The objectives were to determine whether the frequency of atypical aberrant plants of Kentucky bluegrass (Poa pratensis L.) was affected by geographic origin of genotypes and by seed production environments. An increase in frequency of aberrants may adversely affect seed certification of production fields established outside the area of geographic origin of apomictic cultivars. Seed was produced in seven states for open‐pollinated progeny tests of highly apomictic and diverse clones. Progenies were grown at Beltsville, Md., and near State College, Pa. Plants of each progeny were classified as typical apomictic, aberrant, or weak. The frequency of aberrant plus weak plants (13.6%) was higher at locations (Alabama and Kentucky) with wide overall anthesis range (at least 4 weeks) and short photoperiod than the frequency (7.2%) at locations (Maryland, New Hampshire, and Vermont) with narrow anthesis range (6 to 9 days) and long photoperiod (> 14.5 hours). The frequency of aberrant and weak plants was considerably higher for four clones (13.6%) than for the remaining five (5.0%). Clones with high frequency of aberrants traced to widely diverse origin. The results indicate that the frequency of aberrant progeny of Kentucky bluegrass is not adversely affected when seed is produced outside the area of geographic origin of a cultivar.Seed produced on 40 plants scored as weak was used to ascertain whether weak plants were typical or aberrant. Only two plants produced typical progeny; the remaining 38 produced segregating apomictic or sexual progenies. Although most weak plants were aberrant and would probably not become established under competitive conditions with typical apomictic progeny, aberrant and weak plants should be rogued from space‐planted fields that are used for the production of breeder seed.Cytological examination of megasporogenesis was inconclusive in regards to the hypothesis that environments influence the initiation of aposporous nucellar cells. Examination of embryo development failed to distinguish possible effects of either genotype or environment on relative frequency of apomictic and sexual reproduction of ovules.
Effect of Parental Component Complementation on Yield and Components of Yield in Barley1
Authors: Grafius J. E. , Thomas Roger L. , Barnard John 
Published: July 2010

Five parental pairs of barley (Hordeum vulgare L.) were selected on the basis of wide differences in heads/30 cm of row (X), kernels/head (Y), and mg/kernel (Z). The crosses and backcrosses to each parent were allowed to self to the equivalent of the F4 at which time 20 random selections were drawn from each population. Seed was increased for two generations and standard nursery plot trials were conducted on the equivalent of the F7. The objectives were to observe component complementation and to see how it affected predicted yield.We were able to predict progeny mean yields (W) the basis of parental (XY). In only one case was there a significant failure in prediction. The backcross 1 ✕ 42 significantly exceeded the regression estimate and the mean of the higher parent ∗ and this for the selfed unselected progeny. Comparisons via a graph of Y on X showed that parent 4 was an ‘outlier’ and that it somehow relaxed the constraints in X on Y permitting a large (XY) and higher yield which was expressed in the progeny.All parents had an acceptable level of W but differed widely in component values. Mated pairs were selected to complement component values so that these were phenotypically wide crosses. In every case the mean yield of one or the other backcross exceeded that of the cross. Using vector terminology, the backcross narrowed the angle between parents. In terms of developmental physiology and morphology, the backcross tended to preserve the integrity of an already proven system while adding bits and pieces of another system. When the parents are more similar, the advantage of the backcross would be expected to dissipate.
An Inhibitor Gene for Flower Standard Development in Korean Lespedeza1
Authors: Offutt M. S. 
Published: July 2010

Crosses were made between two lines of Korean lespedeza (Lespedeza stipulacea Maxim.) with mutant flower characters. F1, F2, F3, and F4 data were used to determine whether the mutant gene s for small purple flower standard and the mutant gene a for fused accessory wings and no standard (formerly designated narrow white standard nws) were alleles, whether dominance between the two existed, and whether there was any linkage or recessive epistasis involved if the two genes were not alleles.F1 plants from this cross all produced normal flowers, indicating that the two genes >s> and >a were not alleles. Flower data from the F2 plants indicated a segregation ratio of 9 normal standards: 3 small purple standards: 4 fused accessory wings. Flower data from the F3 and F4 generations provided further support for the proposed 9:3:4 F2 ratio. All evidence indicated that the genotypes of the mutant parent with small purple flower standard, the mutant parent with fused accessory wings, and the F2 plants were ss AA, SS aa, and Ss Aa, respectively, and that no linkage was involved. It was concluded that the gene a in the homozygous condition completely inhibits flower standard development (recessive epistasis), regardless of whether the gene for standard is homozygous dominant (SS), homozygous recessive (ss), or heterozygous (Ss). When flower standard development is inhibited by the gene a, it is suggested that fused accessory wings develop in place of the flower standard.
Effects of Plant Density on the Quality of Cobs Used for Corn Cob Pipes1
Authors: Loesch P. J. , Stark C. F. , Zuber M. S. 
Published: July 2010

Special purpose corn (Zea mays L.) cultivars and hybrids have been developed for manufacture of cob pipes. Little information is available concerning cultural practices most suited to the production of pipe corn. The objectives of the present investigation were to 1) determine whether plant density affects cob quality and 2) determine the simple correlations among cob quality traits.Tour corn (Zea mays L.) hybrids characterized by large cob size were evaluated at three densities at two locations in 2 years. Significant differences among hybrids were obtained for every trait studied and interactions among combinations of hybrids, years, locations, and plant spacing occurred frequently. Cob quality, as expressed by length, diameter, weight, and the length of cob exceeding a specified diameter, was improved significantly by reducing plant density. Similarly, crushing strength, weight, and density of 5.1‐cm cob sections increased significantly as plant density was reduced. Increased size, weight, density, and crushing strength would improve cob machinability and presumably increase the life expectancy of the pipes. We concluded that the pipe corn manufacturer would benefit appreciably by contracting pipe corn to be grown at relatively low plant densities to improve the quality and increase the frequency of acceptable cobs. Economic considerations will determine the appropriate plant density to achieve an acceptable balance between high quality cobs and grain yield per unit area.
Inheritance of a Light Seed Coat Color in Safflower1
Authors: Abel G.H. 
Published: July 2010

Information was needed on the inheritance of seed coat color in safflower, Carthamus tinctorius L. Darker seed coats yield darker colored oils whereas the lighter colored ones yield the more desirable lighter colored oils.A cream‐colored seed coat parent was crossed to two dark seed coat parents. The inheritance was studied in the F1, F2, F3, and BC1 progeny. The data corroborate the hypothesis of a previous author that the trait for brown seed coat color, Lt, is dominant over that for light, lt. In addition, minor genes are present which influence color intensity. Current cultivars having dark to intermediate colored seed coats can be converted to light colored ones, however, the interaction of seed coat color to environmental is not known.