bluuebunny/crossref_metadata_2025 huggingface dataset:
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 acceptability

Ample variability existed within each population for improvement by selection of any of the traits studied.
Inheritance of Leaf Rust Resistance in Three Durum Wheats1
Authors: Rashid G. , Quick J. S. , Statler G. D.
Published: July 2010

We investigated the inheritance of resistance to culture 70‐1 (race 1) of Pucciniu recondita Rob. ex Desm f. sp. tritici in three durum wheats (Triticum durum Desf.). The cultivar ‘Ramsey’ and selections D561 and D6733 were each crossed reciprocally with susceptible selection D6618. Resistance was recessive in all three crosses, and segregation ratios indicated that two recessive genes conditioned resistance in Ramsey. One recessive gene conditioned resistance in D561 and in D6733.
Leaf Area Index and Grain Yield for NonProlific and Prolific Single Crosses of Maize1
Authors: Prior C. L. , Russell W. A.
Published: July 2010

Leaf area indexes (LAI) were obtained for seven elite, nonprolific and seven elite, prolific single crosses of maize (Zea mays L.) in six plant densities ranging from 20,500 to 72,000 plants/ha in one high yield environment. Differences in LAI among hybrids were highly significant, but there was no significant hybrids ✕ densities interaction. LAI increased linearly with increasing plant densities and was greater for the prolific hybrids than for the nonprolific hybrids at each density. Maximum yields for the two groups of hybrids were obtained at similar LAI's (4.0 and 4.1), which occurred at plant densities of 61,700 plants/ha for the nonprolific hybrids and 51,400 plants/ ha for the prolific hybrids. One prolific hybrid yielded most (120.0 quintals/ha) at 30,800 plants/ha where the LAI was 2.9. The linear responses of grain yield to increasing plant densities differed significantly (b1 = 1.18, prolific and b1 = 3.14, nonprolific) for these groups of hybrids. LAI appears unrelated to the differences in linear responses for yield.
Recurrent Selection for Yield in the F2 of a Maize Single Cross1
Authors: Genter C. F.
Published: July 2010

Recurrent selection for intracross progeny yield in the F2 of a maize (Zea mays L.) single cross was continued through four cycles to measure population changes and to interpret the genetics of those changes. Because there are no multiple alleles in single crosses and gene frequencies are 0.5 at all heterozygous loci, gene shifts might be more clearly interpreted in such a population than in heterogeneous ones. Pairs of F3. plants were crossed and yield‐tested; the population was advanced by diallel crossing the most productive crosses each cycle. Tests were conducted of 208 CO, 190 C1, 105 C2, 62 C3, and 101 C4 crosses. Over the four cycles, increases in percent of F1 yield were from 59.9 to 80.4 for mean yield, from 91.6 to 99.8 for maximum progeny yield, and from 31.6 to 58.8 for minimum progeny yield. In both C8 and C4 the lowest progeny yield exceeded that of the F2 check, although not significantly. It seems apparent from the data that the overall frequency of desirable genes increased, but some deleterious genes must have been maintained or increased in frequency sufficiently to suppress the maximum potential among the genotypes. The cumu. lative depressive effect of homozygous deleterious genes on homozygous dominant or heterozygous loci in the F2 was estimated to be 26.7% or greater, assuming complete dominance. A negative correlation was found between date of F2 plant pollination and yield of their progeny, suggesting that the earlier segregates may have carried a lighter load of deleterious genes. If so, selection of earlier segregates may be an additional useful breeding tool.
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 measurements

Specific 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.
Effect of Anhydrous Ammonia and Organic Matter on Components of Nitrogen Fixation and Yield of Soybeans1
Authors: Criswell J. G. , Hume D. J. , Tanner J. W.
Published: July 2010

Experiments were conducted in 1972 on ‘Vansoy’ soybeans [Glyclne max (L.) Merr.] to investigate the effects of deep‐placed nitrogen fertilizer and organic matter additions on seed yields, nodule dry weights, and seasonal amounts of nitrogen fixed/ha. Treatments included applying 112 kg NH3‐N/ha, (N); passing the anhydrous applicator tines through the soil without added N, (T); applying 4.5 metric tons/ha of shredded corn cobs as an organic matter source (OM); N+OM; T+OM; and control, (C). Seed yields were not affected by treatments, but seasonal amounts of N2 fixed, estimated by an acetylene reduction assay, were stimulated by OM, T, and T+OM and decreased by applied N. Regression analyses were used to separate N2 fixation responses into effects on nodule mass/plant and fixation/unit of nodule mass. Increased fixation following OM and T+OM treatments could be fully accounted for by larger amounts of nodule mass/plant, which fixed less N2/unit of nodule mass than control plants. NH3‐N reduced N2 fixed/ha by 39 to 48% below control plots, by reducing both nodule mass and nodule efficiency. Application of N+OM increased nodule mass slightly but reduced nodule efficiency and seasonal N2 fixation. The attempt to maintain nodule mass in the presence of deep‐placed NH3‐N through the addition of organic matter was successful but a seed yield response was not obtained.
Leaf Growth in Relation to ATP Levels in Water Stressed Corn Plants1
Authors: Barlow E. W. R. , Ching T. M. , Boersma L.
Published: July 2010

The cell water potential, turgor potential, leaf elongation rate, adenylate energy charge, and concentrations of ATP and free amino acids of elongating corn leaves were monitored during a 48 hour period after the induction of water stress to investigate early physical and metabolic changes. A decrease in cell turgor and rate of leaf elongation induced by the gradually decreasing leaf water potential from −2.6 to −18.0 bars over the 48 hour period under continuous light resulted in a 40% decrease in the ATP concentration of the elongating zone within 3 hours, and a 25 percent decrease in the adenylate energy charge within 12 hours. The concentration of free amino acids increased about 20% during the first 6 hours and over 250% during the 48 hours. The possible significance of the decrease in ATP concentration of the elongating leaf induced by water stress during a diurnal stress cycle is discussed.
Endogenous Growth Regulators and Summer Tillering of Tall Fescue1
Authors: Yeh Richard Y. , Matches Arthur G. , Larson Russell L.
Published: July 2010

In the southern Corn Belt, tall fescue (Festuca arundinacea Schreb.) produces most of its vegetative growth during the spring and autumn. Generally little growth or new tiller initiation occurs during midsummer, even though the potential sites (buds) for tiller production are present. Failure of buds to elongate into tillers may be controlled by endogenous growth regulators. We investigated the influence of endogenous plant auxins on the elongation of buds into new tillers for tall fescue grown under field and growth chamber conditions. High temperature in the field and growth chamber (31/17 C) favored the accumulation of endogenous auxin in stem bases, and this appeared related to the inhibition of tiller initiation in early summer. Low temperature in the field and growth chamber (22/11 C) favored the accumulation of auxin in shoots and a high level of shoot auxin appeared related to active tiller development. Endogenous auxin levels in both shoots and stem bases were low in late summer.
Terminology Pertaining to Photosynthesis1
Authors: Shibles Richard
Published: July 2010

Terms, recommended by the CSSA Committee on Crop Terminology, for the expression of photosynthetic energy and photosynthetic capacity are defined. These are: Photosynthetically Active Radiation (PAR), Photosynthetic Photon Flux Density (PPFD), Photosynthetic Irradiance (PI), Apparent Photosynthesis (AP), and CO2‐Exchange Rate (CER).
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.
Changes in pH of Corn Stover Following Grain Maturity1
Authors: Leask W. C. , Daynard T. B.
Published: July 2010

We examined changes over time in the pH of various component parts of maturing corn plants (Zea mays L.). In 1972, representative plants of a single hybrid were sampled at weekly intervals, beginning at 39% grain moisture, and subdivided into several vegetative components. The pH and percent dry matter (PDM) of leaf, stalk, and husk components increased exponentially with decreasing grain moisture content. The pH of all components was initially about 5.5 and began to increase, at grain physiological maturity, to values greater than 8.0. The pH of lower stalk segments was positively correlated (r = 0.677, P ≤ 0.01) with visual pith‐condition ratings. Across the data for 14 hybrids grown at three locations in 1973, stalk pH was linearly correlated over tune with stalk PDM. Both pH and stalk PDM were correlated, over time, with transformed Log 10 X + 1) percent broken stalks (PBS) (r = 0.482 and 0.647, respectively, P ≤ 0.01). Hybrid effects for pH, PDM and PBS were statistically significant (P ≤ 0.01) at all locations. However none of the hybrid by time‐of‐harvest interactions were significant for pH, PDM, or PBS, indicating that rates of change over time in the three parameters were similar for all 14 hybrids.
Peanuts: Genetic Vulnerability and Breeding Strategy1
Authors: Hammons Ray O.
Published: July 2010

Peanuts (Arachis hypogaea L.), grown on 600,000 ha, rank ninth in area among major U.S. crops. Seven states produced 98% of the 1,707,000 metric tons grown in 1974 for a farm value of $576 million. The ‘Florunner’ cultivar was grown on over half the land area and yielded 60% of the total crop output. Two other cultivars, ‘Starr’ and ‘Florigiant,’ accounted for 16% and 12% of the crop area, respectively. None of the present cultivars grown in the USA has genetically identified resistance to the pests and pathogens that plague the peanut here. Pressures for monocultural production and uniformity exist throughout the food chain from farmer to consumer. However, the alloploid genetic structure of A. hypogaea and modified breeding procedures provide greater genotypic diversity for the economically dominant cultivars than that existing in the pure line varieties they replaced. Further widening of the genetic base will require changes in variety seed certification standards and market grading criteria.
Distribution of 14C‐labeled Assimilates in Rape Plants1
Authors: Major D. J. , Charnetski W. A.
Published: July 2010

Turnip rape (Brassica campestris L. ‘Span’) grown in the greenhouse and Argentine rape (B. napus L. ‘Zephyr’) grown in the field at Lethbridge, Alta., were exposed to 14CO2 in the lower or upper portion of the plants and sampled up to 48 hours after treatment. Stems and leaves exported 14C‐labeled assimilates. High levels of radioactivity suggested that photosynthesis occurred in pods. Roots, pods, beaks, seeds, apices, and barren pods were sinks for assimilates. Lower leaves and lower portions of the stems were the primary sources of assimilates exported to the roots. More 14C‐labeled assimilates were detected in plant components sampled from the portions of the plants that were exposed to 14CO2 than from plant components sampled above or below the portion exposed to 14CO2.
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.
Sorghum Vulnerability and Germplasm Resources1
Authors: Webster O. J.
Published: July 2010

The first sorghums [Sorghum bicolor (L.) Moench] introduced into the Western Hemisphere were the tropical cultivars, ‘Milo Maize’ and Guinea corn, later called ‘Guinea Kafir.’ These were tall in plant height and short‐day in photoperiod response but by a series of mutations short‐statured, day‐neutral types evolved. The kafirs and milos, and to a more limited extent the hegaris, feteritas, and shallus have formed germplasm base for the grain sorghum breeders in the USA. Most grain sorghum cultivars are derivatives from crosses between milos and kafirs. Sterile cytoplasm was first found in the milos and the nonrestorer genes in the kafirs. The parent lines of most grain sorghum hybrids are kafirs, milos, or hybrid derivatives from the two. A breeding scheme is in operation designed to transfer the germplasm from tropical cultivars into short, day‐neutral genotypes. The present breeding programs are based on this new source of germplasm. The World Sorghum Collection of over 17,000 items is now being managed by the International Crops Research Institute for the Semi‐arid Tropics. Grain quality is receiving attention since much of the grain sorghum in the world is used directly for human food.
Cytogenetics of Introgression from Saccharum into Sorghum1
Authors: de Wet J. M. J. , Gupta S. C. , Harlan J. R. , Grassl C. O.
Published: July 2010

Grain sorghum [Sorghum bicolor (L.) Moench] crosses with sugarcane (Saccharum officinarum L.) when the latter species is the female parent. These hybrids are male sterile but produce offspring when pollinated with either parent. Four backcrosses, the first and second with diploid (2n=20) and then with tetraploid sorghum (2n=40), produced plants that are male and female fertile even though they combine 40 Sorghum + 4–10 Saccharum chromosomes. Selfing or further backcrossing with sorghum for one or more generations, results in complete elimination of Saccharum chromosomes, and essentially pure or morphologically modified sorghums are recovered. Modified sorghums have various combinations of Saccharum characteristics superimposed on a basic Sorghum morphology. The study was initiated in an attempt to transfer shoot fly resistance from sugarcane to grain sorghum. Whether this aim was achieved is now being investigated.
Cell Wall Constituents of Reed Canarygrass: Genetic Variability and Relationship to Digestibility and Yield1
Authors: Hovin A. W. , Marten G. C. , Stucker R. E.
Published: July 2010

Objectives of this study were to obtain estimates of combining ability and gene action for cell wall constituents (CWC) and to ascertain the relationships among CWC, in vitro digestible dry matter (IVDDM), and forage yield in a diverse germplasm source of reed canarygrass (Phalaris arundinacea L.). Ramets of 12 randomly selected clones and an incomplete diallel cross consisting of 30 crosses obtained by mutual pollination of each clone to five of the remaining 11 were grown for 2 years at two locations with two replicates arranged in randomized complete blocks. Each 1.25 m2 plot consisted either of 15 F1 plants or ramets of the parents. General (GCA) and specific combining ability (SCA) regrowth forage were estimated by least squares analysis. Mean squares among parents for CWC and yield for IVDDM and GCA were highly significant (P < 0.01). Parent mean square for IVDDM and GCA mean square for CWC were significant (P < 0.05). Mean squares of SCA for traits were nonsignificant. Estimated variance components were interpreted assuming disomic inheritance. Estimates of total genetic variance (s2p), covariance of parent‐off‐spring () and GCA variance (s2g) were obtained. Estimates of s2g were larger than estimates of 2 (and 4s2g for CWC) indicating that non‐additive genetic variance was important for CWC and yield. Broad and narrow sense heritabilities for CWC were 0.83 and 0.33, respectively. Phenotypic correlation (r = 0.87) for CWC between parent clone performance and GCA effect suggested that clone performance could be used in initial selection for CWC. Phenotypic and genotypic (in parentheses) correlations between CWC and IVDDM were r = 0.77 (−0.75) and r = −0.68 (−0.90) for parents and crosses, respectively. Phenotypic correlations between CWC and forage regrowth yield were nonsignificant. The multiple phenotypic correlation of forage on cell solubles (100 − CWC) and IVDDM was R = 0.47 and R = 0.50 for parents and crosses, respectively. The relatively small coefficients of determinations (22% and 25%) suggested that progress could be made in selecting for lower concentration of CWC and higher concentrations of IVDDM without adversely affecting forage yield.
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.
Flag Smut Reaction in Wheat: Its Genetic Control and Associations with Other Traits1
Authors: Allan R. E.
Published: July 2010

The reaction to flag smut [Urocystis agropyri (Preuss) Schroet.] of F3 and F4 lines of 10 wheat (Triticum aestivum L. em Thell.) crosses involving the parents ‘Spinkcota’, ‘lowin’ (highly resistant); ‘Games’, ‘Hurt’, ‘Golden’, ‘Dickson 114’ (resistant); ‘Ridit’ (moderately resistant); and CI 13749 (susceptible) was studied in a field near Bickleton, Wash. Segregation ratios in five crosses between highly resistant and resistant parents suggested that different large‐effect genes governed resistance to flag smut; no completely susceptible lines were recovered, which indicated that the parental combinations tested had one or more small‐effect genes for resistance in common with one another. Evidence suggested that lowin has two large‐effect genes for resistance that differ from those possessed by Spinkcota, Dickson 114, and Gaines. Ridit probably has one gene for moderate resistance that is not common to Spinkcota, Dickson 114, and Gaines. The segregation patterns for reaction of two crosses involving the susceptible parent, CI 13749, suggested complementary resistance. Results indicated that a minimum of four different large‐effect and three small‐effect genes for flag smut resistance were represented among the eight parents studied. No associations were found between percentage of flag smut and plant height, stripe rust reaction, maturity, and spike type. Percentage of flag smut was associated with chaff color in two of seven crosses and with awn expression in one of five crosses.
Variability Within Gossypium hirsutum L. for Seedling Isocitratase Activity1
Authors: Scholl R. L.
Published: July 2010

Seedlings of 23 accessions of Gossypium hirsutum L. were examined for isocitratase activity and fresh weight of plant axes. An eight‐fold range of isocitratase activity was observed for these accessions (40 hours after germination); less variability was found among older seedlings (112 hours after germination). Isocitratase activity and the percentage of seedling fresh weight in the axis were very closely associatetd at 40 hours after germination (r =;0.866, significant at the 0.01 level).
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.
Effect of Moisture Stress on Photosynthesis and Some Related Physiological Characteristics in Peanut1
Authors: Bhagsari A. S. , Brown R. H. , Schepers J. S.
Published: July 2010

Two experiments were conducted to assess the effects of water stress on net photosynthesis (Pn) in peanut (Arachis hypogaea L.), since indications from earlier reports were that peanut photosynthesis might be less affected by water stress than in other crop species. Three genotypes of peanut were grown in pots in the greenhouse in 1973 (Experiment 1) and two were grown outside pots in 1974 (Experiment 2). Soybean [Glycine max (L.) Merr.] was included in Exp. 2 for comparison. Net photosynthesis and transpiration were measured on single leaves during a 5 or 6‐day drying cycle with assimilation chambers and relative leaf water content (RLWC) was determined by floating leaf discs on water. Diffusive resistance was calculated from transpiration data and also measured with a diffusion porometer. Water potential was determined on leaves and immature pods on the last 2 days of Exp. 2. Decreases in Pn of stressed plants during the drying cycle were closely related to decreases in RLWC and transpiration. The relationship between Pn and RLWCw as similar for peanut and soybean in Exp. 2. The diffusive resistance determined with a porometer or from transpiration varied between 0.5 and 2.5 sec cm‐1 for control plants, while the diffusive resistance of stressed plants reached maximum values of 18 to 20 sec cm‐1 in Exp. 1 and between 30 and 35 sec cm‐1 for peanut and soybean in Exp. 2. No differences appeared among genotypes of peanut in the response of Pn to water stress. Water potential of immature pods was equal to, or slightly higher than that of leaves at the end of Exp. 2. Comparison of the data for peanut with that from soybean and also with published data indicates that Pn of peanut is controlled by water stress in a manner quantatively similar to that of other crop species.
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.
Influence of Distance from Pollen Plant on Seed Produced by Male‐Sterile Cotton
Authors: Moffett Joseph O. , Stith Lee S. , Shipman Cahrles W.
Published: July 2010

Because of increasing interest in hybrid cotton, Gossypium hirsutum L. a study was made in southern Arizona in 1973 and 1974 to determine a planting pattern of pollinator and male‐sterile rows that would give satisfactory yields of hybrid seed. In 1973 two rows of pollen plants were alternated with 14 rows of male‐sterile plants. The two male‐sterile rows closest to the pollen plants produced 49% more seeds per flower than were produced in the remaining male‐sterile rows. In 1974 an alternating pattern of 2 rows of pollen parents and 6 rows of male‐sterile parents was planted in 12 replications. There were no significant differences in number of seeds produced per flower among these male‐sterile rows. In both years the seeds were a higher percentage of the total boll weight in bolls from the male sterile plants than in bolls from the pollen plants (68.2 to 60.6 in 1973 and 68.2 to 62.0 in 1974).

In both years production of hybrid seed was satisfactory. The male‐sterile plants produced 98% and 79% as many seeds per flower as the pollen plants in 1973 and 1974, respectively. The mean number of bees observed visiting cotton flowers at any given time varied from 0.45 to 10.13 per 100 flowers. Honey bees (Apis mellifera L.) made 38% of the total bee visits in 1973 and 84% in 1974.
Gene Effects for Resistance to Kernel Shattering in a Barley Cross1
Authors: Chapman S. R. , Hockett E. A.
Published: July 2010

Yield losses from shattering have necessitated the development of shatter resistant cultivars, and breeding procedures depend on the type of gene action conditioning the trait under study. Shatter resistance was measured in barley (Hordeum vulgare L.) as the force required to free a spikelet from the rachis. Measurements were made on single random plants of four generations representing six populations (parents, F1, F2, and single backcrosses) from a cross between two parental lines. All populations were grown near Bozeman, Mont. in both 1968 and 1969. In both years, dominance for shattering susceptibility as well as additive gene effects separating the parents were detected. In 1969, a significant additive ✕ additive epistatic effect was detected, and the dominance effect was more than twice as large as it was in 1968. These results suggest that the inheritance of shattering resistance is complex and the expression of gene effects appears to be sensitive to environmental (year) conditions. However, because shatter resistance is recessive and because only the additive ✕ additive epistatic component was significant, in this cross direct selection for shattering resistance in early generations should be effective. More crosses must be evaluated before a general breeding scheme can be proposed.
Effect of Leaf and Pod Removal on the Distribution of 14C Labeled Assimilate in Soybeans1
Authors: Egli D. B. , Gossett D. R. , Leggett J. E.
Published: July 2010

The effect of varying source‐sink ratios on the distribution of 14C labeled assimilate in soybeans (Glycine max (L.) Merr.) was investigated in a greenhouse experiment. Varying source‐sink ratios were created by pod (approximately 50%) or leaf removal (two side leaflets from each trifolioliate) at the end of flowering. A single leaf was exposed to 14CO2 17 days after application of the treatments. Pod removal reduced seed yield/plant and increased seed size, whereas leaf removal reduced yield, the number of seed/plant, and seed size. Seven hours after labeling a greater percentage of 14C remained in the leaf in the pod removal treatment (72%) than in either the leaf removal (55%) or the control (59%), and specific leaf weight was higher in the pod removal treatment.

The distribution of 14C 24 hours after labeling was not greatly affected by the treatments. The pod removal treatment had a greater percentage of 14C in the labeled leaf, in the stem both above and below the node of the labeled leaf, and less in the seed. Removal of the leaves did not affect the percentage of 14C in the labeled leaf after 24 hours or the distribution of the 14C in the plant, probably because the source‐sink ratio was similar to that of the control. The primary effect of altering the source‐sink ratio was on the movement of 14C labeled assimilate out of the leaf.
Abscisic Acid Content of Barley Grains During Ripening as Affected by Temperature and Variety1
Authors: Goldbach H. , Michael G.
Published: July 2010

The Abscisic acid (ABA) content of grains of two varieties of barley (Hordeum vulgare L.) was investigated during their development. ABA was determined by the Lemna minor‐bioassay after extraction and purification similar to Milborrow's 1967 method. In the first days after pollination ABA content was low, and reached a maximum at the same time as the fresh and dry weight of the grains. The subsequent decrease in ABA levels coincided with drying of the grains. The cultivar ‘Kristina,’ characterized by a very short dormancy and a low resistance to sprouting, showed a distinctly lower ABA level during grain development compared to the more resistant ‘Oriol’. After reaching its maximum, the decrease of ABA in the grains of ‘Kristina’ was, under the same environmental conditions, more pronounced than in Oriol. Barley grains of plants grown at 26 C compared to those grown at 18C, matured sooner and reached an earlier ABA maximum followed by a sharper decrease in ABA content. In mature grains a relatively high proportion of the total ABA amount was found in the embryo. A possible relationship between ABA and the ripening process is discussed.
Cytological, Morphological, and Agronomic Characteristics of Tall ✕ Giant Fescue Hybrids and Their Amphiploid Progenies1
Authors: Buckner R. C. , Webster G. T. , Burrus P. B. , Bush L. P.
Published: July 2010

F1 hybrids (2n = 42) of tall fescue (Festuca arundinacea Schreb.) (2n = 42) ✕ giant fescue [Festuca gigantea (L.) Vill.] (2n = 42) were male‐sterile, had poor seed‐set when backcrossed to tall fescue, and generally were intermediate between parental species for most morphological characters. Sterility of the F1 hybrids was attributed to meiotic irregularity resulting from lack of chromosomal association of one genome of each parent. Frequency of mean univalents per cell and in mean micronuclei per quartet of F1s varied from 10.1 to 13.7 and from 2.9 to 6.5, respectively.

Four generations of colchicine‐induced amphiploid progenies were male‐fertile, and seed‐set per panicle was equivalent to that of tall fescue. First‐generation progenies varied in chromosome number from 2n = 80 to 84, and in mean micronuclei per quartet from 1.15 to 2.57. Chromosomal pairing of the colchicine‐induced progenies was largely bivalent as evidenced by relatively few micronuclei. Chromosome numbers of fourth‐generation progenies varied from 2n = 53 to a maximum of 84. Ths occurrence of dodecaploids as the most frequent number in fourth‐generation progenies indicates that with rigid selection, rapid progress might be made in securing meiotically stable populations at the 2n = 84 chromosome level.

Although hay yields of fourth‐generation progenies compared favorably with ‘Kentucky 31’ tall fescue, both stand and yield declined rapidly after first hay harvest. Poor agronomic performance of the fourth‐generation progenies could have been attributed to their narrow gene base. Because the forage quality of the fourth‐generation progenies was markedly superior to that of tall fescue cultivars, dodecaploid tall fescue ✕ giant fescue populations appear to have promise as a valuable forage crop.
Contributions of Vegetative Growth Rate and Harvest Index to Grain Yield of Progenies from Avena sativa ✕ A. Sterilis Crosses1
Authors: Takeda K. , Frey K. J.
Published: July 2010

The relative importance of growth rate and harvest index in determining grain yield of oats was studied in various backcross generations of all possible matings between two strains of Avena sativa and eight collections of A. sterilis. Eight interspecific matings evaluated in 1972 showed maximum heterosis for growth rate in Bc0 (original cross), whereas the eight tested in 1974 showed maximum heterosis for this trait in Bc3. Pooled correlations for growth rate and harvest index with grain yield were 0.76 and 0.54, respectively. The associations of harvest index and growth rate were nearly equal in Bc0, but with repeated backcrosses the association between growth rate and yield intensified, whereas that between harvest index and yield diminished. Variation for grain yield within backcross.mating combinations was determined almost completely by growth rate and harvest index (R2 from 0.92 to 0.97). An increase of 0.1 g/day/plot (0.09 m2) in growth rate gave the same grain yield improvement (14%) as a 4% increased in harvest index.
Breeding Potentials of Noncultivated Cottons. III. Inheritance of Date of First Flower1
Authors: Wilson F. D. , Wilson R. L.
Published: July 2010

Date of first flower was analyzed in parental, F1 F2, and backcross generations of two cultivars and three Texas race stocks of cotton (Gossypium hirsutum L.). The cultivar ‘Deltapine 16’ (DPL) differed from Texas 203 (T‐203) by an additive component and from Texas 40Y (T‐40Y) by an additive and an epistatic component. T‐203 and T‐40Y were similar phenotypically but showed slight genetic differences from one another in flowering response. Both differed from the third race stock, Texas 711 (T‐711), by at least two genetic factors. DPL‐16 differed from T‐711 by more factors for flowering response than T‐203 or T‐40Y. The other cultivar, ‘Stoneville 7A’ (St 7A), seemed closely related phenotypically to DPL‐16. However, the hybrid combination between the two revealed significant additive, dominance, and epistatic effects. St 7A differed genetically from T‐40Y but not from T‐203 for date of first flower. St 7A, like DPL‐16, was quite different from T‐711. Favorable F1‐midparent heterosis was exhibited by two of the 10 hybrid combinations, DPL‐16 ✕ T‐711 and St 7A ✕ T‐711.