bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurrent Selection for Specific Combining Ability for Yield in Two Maize Populations1
Authors: Russell W. A. , Eberhart S. A. , Urbano A. Vega O.
Published: July 2010

This study evaluated recurrent selection for specific combining ability for yield in two maize (Zea mays L.) populations and provided information on the types of gene action involved in the yield improvement. The populations for the recurrent selection program were an open‐pollinated variety, ‘Alph,’ and the F2 of WF9 ✕ B7. Inbred B14 was the tester for both populations. The principal basis of selection was grain yield, and the selection intensity was 10 to 13% in each of five cycles. Ten S1 lines were selected in each cycle and recombined to give a new population in each source. We evaluated progress by measuring yield in B14 ✕ Alph Cn and B14 ✕ (WF9 ✕ B7)Cn populations, Cn populations per se, related and unrelated testers ✕ Cn populations, and Cn ✕ Cn population crosses in six environments. In all types of populations the rates of gain per cycle were significant, and the gains were greater in Alph than in WF9 ✕ B7. Rates of gain per cycle (q/ha) in some comparisons were: B14 ✕ Alph Cn, 3.09; B14 ✕ (WF9 ✕ B7)Cn, 1.32; BSBB ✕ Alph Cn, 3.63; BSBB ✕ (WF9 ✕ B7)Cn, 1.51; and Alph Cn ✕ (WF9 ✕ B7)Cn, 4.09. In all types populations except B14 ✕ (WF9 ✕ B7)Cn, the number ears per 100 plants increased. There were no significant changes for date of silk emergence or lodging, but there were some significant increases for percentage moisture at harvest and plant and ear heights. We concluded that overdominance and overdominant types of epistasis were relatively unimportant in the changes in yield potential of the two populations because the BSBB topcrosses improved as rapidly as the BI4 topcrosses, the Cn ✕ Cn crosses increased more rapidly than the B14 topcrosses, and the heterosis of the Cn ✕ Cn Crosses increased.
Water Requirement, Yield, and Tolerance to Clipping of Some Cool‐Season, Semiarid Range Grasses1
Authors: Bleak Alvin T. , Keller Wesley
Published: July 2010

A water requirement study was conducted for 689 days with 8 accessions of cool‐season Agropyrons and a single accession of Elymus junceus grown in 3.8‐liter cans in a greenhouse. Five plants of A. desertorum Nordan were cloned. Other accessions, including A. desertorum Nordan, were grown from seed. All accessions were subjected to 11 successive harvests. A. sibiricum PI‐314056 was most efficient in water use and also had the highest yields. Mortality of A. inerme was high beginning with the fifth harvest. One‐fifth of the plants of A. desertorum Nordan and commercial A. cristatum were dead or nearly dead by the llth harvest. Only E. junceus Vinall and A. sibiricum PI‐314056 had no mortality throughout the 11 harvests. A comparison of clones of Nordan with plants from seed indicated that 62% of the total variance was genetic. Differences in water requirement within the cloned Nordan suggest that it would respond to selection for efficiency of water use. The first harvest was not a good indicator of the mean yield or water requirement for the other 10 harvests.
Nutrient‐Nitrate Levels and the Accumulation of Chloride in Leaves of Snap Beans and Roots of Soybeans1
Authors: Weigel R. C. , Schillinger J. A. , McCaw B. A. , Gauch H. G. , Hsiao E.
Published: July 2010

The concentration of chloride in leaves of ‘Encore’ snap beans (Phaseolus vulgaris var. humilis) and in roots of ‘S‐100’ soybeans (Glycine max (L.) Merr.) varied inversely with nitrate concentration in the nutrient solution. Plants were grown in a greenhouse in perlite cultures automatically irrigated with complete nutrient solution. Although the concentrations of chloride and other anions were varied in some experiments, accumulated chloride was more closely related to nutrient nitrate than to nutrient chloride.
Inheritance of Test‐Weight Components in Normal, Opaque‐2, and Floury‐2 Corn (Zea mays L.)1
Authors: Paez Alix V. , Zuber Marcus S.
Published: July 2010

Diallel mating systems were used to study kernel‐endosperm properties in normal corn (Zea mays L.) and its opaque‐2 and floury‐2 endosperm mutants. Seven parental lines were involved. Each line had five endosperm versions: original normal, opaque‐2, normal derived from opaque‐2 backcross population, floury‐2, and normal derived from a floury‐2 backcross population. All 21 possible single crosses and reciprocals were made among the seven lines within each of the five groups. The opaque‐2 and floury‐2 groups gave similar responses, each decreasing test weight, 500‐kernel weight, and kernel density; and increasing number of kernels per 100 g and percent kernel breakage. Addition of opaque‐2 and floury‐2 genes changed the means of the kernel traits but did not change appreciably the combining ability of the lines. Additive gene effects accounted for a larger part of the variation among crosses than nonadditive effects in the inheritance of the kernel traits. Phenotypic and genetic correlations among test weight, kernel density, and kernel breakage were high; chemical components were correlated poorly with physical kernel traits.
Selection of High Lysine Corn Using a Scanning Electron Microscope1
Authors: Wassom C. E. , Hoseney R. C.
Published: July 2010

Several inbred sources of corn (Zea mays L.), including high‐lysine modified opaque‐2 lines with hard, translucent endosperm and normal hard, translucent endosperm phenotypes were examined with a scanning electron microscope. Zein bodies were observed in the protein matrix of the normal corn phenotype. Placing samples in 70% ethanol and observing voids produced confirmed that the bodies contained zein. Samples from modified opaque2 lines known to be high in lysine did not show elaborate patterns of voids in the rotein matrix after ethanol treatment. It was concluded that a scanning electron microscope is an excellent tool to identify endosperms with low zein and potentially more lysine.
Indirect Mass Selection for Grain Yield in Oat Populations1
Authors: Chandhanamutta P. , Frey K. J.
Published: July 2010

The effectiveness of mass selection for heavy panicle weight in a heterogeneous oat (Avena sativa L.) population was evaluated using an F6 bulk oat population composed by mixing seed samples from 160 crosses. To initiate the selection procedure, 6,000 samples of 30 seeds were sown, each in a hill in the center of a 0.09‐m2 land area. After harvest, the three heaviest panicles (10%) were selected from each hill and bulk‐threshed. Two cycles, of this type of mass selection were carried out, and subsequently, 390 lines from the original and first cycle mass‐selected populations, 360 lines from the second cycle mass‐selected population, rand 30 check cultivars were tested for grain yield and other traits in replicated experiments.

The mass‐selection procedure increased panicle weight 7.5% and grain yield 5.6% per cycle. These shifts were associated with taller plant heights and later heading dates. The increase in grain yield was attributed 80% to increased seeds per panicle and 20% to increased seed weight. Tillering was decreased 2.5%.
Hybrids Between Diploid and Hexaploid Crested Wheatgrass1
Authors: Dewey Douglas R.
Published: July 2010

Thirty‐seven unemasculated spikes of hexaploid Agropyron cristatum (L.) Gaertn., 2n=42, pollinated by diploid A. cristatum, 2n=14, yielded seven tetraploid hybrids, 2n=27‐29. The reciprocal cross was unsuccessful. The hybrids were morphologically intermediate between the parent plants, but they had a closer overall resemblance to the hexaploid. Chromosome pairing was almost complete in the 28‐chromosome hybrids which averaged 0.40I, 7.51II, 0.41III, 1.07IV 0.22V, 0.18VI, 0.01VII, 0.31VIII, 0.04IX, 0.09X, and 0.09XII in 72 metaphase‐I cells. Multivalent associations were attributed to a combination of heterozygous interchanges and autoploidy. The genomes of diploid and hexaploid A. cristatum are homologous except for structural rearrangements, primarily interchanged chromosome segments. Three 28‐chromosome hybrids produced 35 to 75% stainable pollen and averaged 11.2, 12.8, and 20.9 seeds per spike under open pollination. The hybrids averaged 9.4 and 10.1 seeds per spike when pollinated by A. desertorum (Fisch. ex Link) Schult., 2n=28, and induced‐tetraploid A. cristatum, 2n=28, respectively. The gene pools of diploid, tetraploid, and hexaploid crested wheatgrass can be merged into a single breeding population at the tetraploid level. This approach is recommended to crested wheatgrass breeders.
Influence of Tissue Drying on o‐Hydroxycinnamic Acid Content in Sweetclover1
Authors: Haskins F. A. , Gorz H. J.
Published: July 2010

A fluorometric procedure was used to study changes in levels of the free and bound forms of the cis and trans isomers of ο‐hydroxycinnamic acid (ο‐HCA) associated with drying sweetclover (Melilotus) tissues under various conditions of time and temperature. Leaves, or leaves and stems, of three sweetclover varieties, ‘Spanish,’ ‘Evergreen,’ and ‘Goldtop,’ and two closely related, highly inbred lines (CuCuBB and CuCubb genotypes) were used. Drying temperatures of 30 and 40 C were used most extensively. When dried at 30 C, leaves lost more than half of their bound cis‐ο‐HCA, and a small amount of free cis‐ο‐HCA (coumarin) was produced. In leaves dried at 40 C, up to 90% or more of the bound cis‐ο‐HCA was converted to the free form by the enzyme, β‐glucosidase, and little loss of total ο‐HCA occurred. Thus, levels of free and bound cis‐ο‐HCA were appreciably modified by the drying treatments imposed. Content of trans‐ο‐HCA, on the other hand, was not greatly changed by drying. The results obtained may have application in the drying of leaves of deer's tongue [Trihsa odoratissima (Walt, ex J. F. Gmel.) Cassini], an ο‐HCA‐containing plant used in the tobacco (Nicotiana tabacum L.) industry.
Heritability of Oat Caryopsis Percentage and Other Grain Quality Components1
Authors: Wesenberg D. M. , Shands H. L.
Published: July 2010

Three oat (Avena sativa L.) crosses involving parents with a wide range of caryopsis percentage and other grain quality components were studied in F2, F3, and F4. A single backcross was studied in BCF1 and BCF2. Primary caryopsis percentage of parents averaged 80.3% for ‘Q.O.30.28,’ 77.1% for ‘RL 2123.38,’ 73.1% for ‘Beedee,’ and 71.5% for ‘Coker 61‐13.’

Progeny caryopsis percentages were generally within observed parental values with mean values approximating those of the midparents. The mean of the backcross progenies approached the high caryopsis percentage of the recurrent parent.

Heritability estimates for primary caryopsis percentage by variance components were high with the exception of Q.O.30.28/RL 2123.38 where both parents were high in caryopsis percentage. Heritability estimates ranged from 0.36 for Q.O.30.28/RL 2123.38 to 0.93 for Q.O.30.28/Coker 61‐13. Estimates of genetic advance ranged from 0.51 to 3.95%, suggesting that increases above midparent and near high parent values could be attained by selecting for high caryopsis percentage. The data suggest difficulty in isolating segregates with more than 80% caryopsis.
Influence of Temperature on a Partially Male‐Sterile Soybean Strain1
Authors: Caviness C. E. , Fagala B. L.
Published: July 2010

Temperature during flowering and pod set influenced degree of sterility in a partially male‐sterile soybean strain [Glycine max (L.) Merr.]. Growth chambers, set for 14.5/ 9.5, light/dark sequences in each 24‐hour period, were used to present varying day/night temperatures to the growing plants. No pods were set on the male‐sterile strain when the day temperature was 35C and the night temperature was either 21 or 27C. Plants were partially fertile, however, when grown 'at a day temperature of either 21 or 29C with a night temperature of 16 or 21C. The largest number of pods was produced on the partially male‐sterile strain when the day temperature was 29C followed by a night temperature of 21C. Temperature did not affect number of seeds per pod on the partially male‐sterile strain at temperature regimes where pods were formed.
Influence of Succinic Acid 2,2‐Dimethylhydrazide on Yield and Morphological Characteristics of Starr Peanuts (Arachis hypogaea L.)1
Authors: Brown R. H. , Ethredge W. J. , King J. W.
Published: July 2010

Succinic acid 2,2‐dimethylhydrazide (SADH) was applied to “Starr” peanuts (Arachis hypogaea L.) at the rate of 1.43 kg/ha in 1968, 1969, and 1970. Data were obtained on pod yield; stem length; peg and pod lengths; pod, stem and leaf weights; and leaflet area. The most consistent effect of SADH was a reduction of plant height. Stem lengths were reduced 30 to 40% by SADH application. Pod length was reduced by 6 to 10% in 1969 and 4% in 1970 when plants were treated with SADH. Peg length in 1970 was 2.7 cm on SADH‐treated plants compared to 3.4 cm for controls.

Pod yields were increased in 1968, but not in 1969 or 1970. The increase in yield in 1968 was similar for irrigated and nonirrigated peanuts. Stem weight per plant was decreased by SADH in 1970 but not in 1969, and the pod‐vegetative ratio was increased in 1969 and 1970. Specific leaf area and area of leaflets were reduced in some cases by SADH applications. Dry weight per leaflet was not affected. Reduction of top growth may be beneficial because ground machinery can be used later than usual in the season to apply insecticides and fungicides without damage to the peanut plants.
Plant‐Water Measurements on Soybeans Sheltered by Temporary Corn Windbreaks1
Authors: Radke J. K. , Hagstrom R. T.
Published: July 2010

Double rows of corn (Zea mays L.) spaced at regular intervals in a soybean (Glycine max (L.) Merr.) field served as temporary windbreaks at two locations in western Minnesota. In 1969 at Dumont, Minnesota, corn windbreaks were placed between every 14 rows of soybeans (every 11.4 meters), and in 1970 at Lamberton, Minnesota, 22 rows of soybeans (17.5 meters) separated the corn windbreaks. Moisture stress was high in 1969, but moisture was adequate in 1970.

Small, white evaporimeters provided estimates of potential evaporation, soybean plant potometers furnished information on potential transpiration, and the stomatal resistances of the soybean leaves were measured by a porometer and from leaf impressions. Windspeed and potential evaporation were reduced significantly over the first seven or eight soybean rows on the lee side of the windbreaks. Potential transpiration and stomatal resistance varied significantly among rows between corn windbreaks and in some cases showed cyclic trends over rows. Potential transpiration and stomatal resistance appeared to be directly related when moisture stress was low, but were inversely related when moisture stress was high.

Sheltered soybean yield increases and variations over rows were largely an accumulation of the variations that occurred in the plant‐water relations during the growing season.
Breeding for Improved Dry Matter Digestibility in Smooth Bromegrass (Bromus inermis Leyss.)1
Authors: Sleper D. A. , Drolsom P. N. , Jorgensen N. A.
Published: July 2010

A diallel cross involving six smooth bromegrass (Bromis inermis Leyss.) clones was used to gain information on the inheritance of digestibility as measured by the acidpepsin dry matter disappearance (APDMD) technique. APDMD was evaluated on the whole forage at two harvest dates in 1971 and 1972. Plant fractions (blades, sheaths, and stems) were also evaluated for APDMD in 1972 on diallel progenies, excluding reciprocals. Progenies differed significantly for the whole forage APDMD at first and second harvest and for the APDMD of the blades. No significant differences were found for APDMD of the sheaths and stems. General combining ability was significant for APDMD of the whole forage at both harvest dates and for APDMD of the blades. Maternal effects were significant for the whole forage APDMD at the second harvest. Progenies ✕ year interactions were not significant for the whole forage APDMD. Heritability and gain from selection values indicated that improvement of whole forage and blade APDMD is possible through breeding.
Leaf Chamber to Measure Photosynthesis and Transpiration of Intact Grass Leaf Sections
Authors: Chatterton N. J. , Lee D. R.
Published: July 2010

A leaf‐chamber design that uses two air seals to facilitate measurements of photosynthesis and transpiration of sections of intact grass leaves is described. A leaf port in either end allows a leaf to be inserted in one end and moved through the chamber, and out the opposite end. The chamber can be moved along the leaf to measure photosynthesis of any section of the leaf. The chamber length dictates the length of leaf section that is measured.
Cytogenetics of a Crown Rust‐Resistant Hexaploid Oat with 42 + 2 Fragment Chromosomes1
Authors: Dherawattana A. , Sadanaga K.
Published: July 2010

Twenty‐two bivalents were observed in X117 oat (Avena sativa L.), a isogenic line resistant to crown rust (Puccinia coronata Cda. avenae Fraser and Led.), and with 42 + 2 fragment chromosomes. The homologous fragment chromosomes are either telocentric or acrocentric. Transmission through the egg, calculated from the backcross data, was 18.2%. A dominant gene, Pc‐15, conferring resistance to races 264 and 290 of crown rust of oats is located on each of the fragments.
Prediction of Semidwarf Culm‐Length Genotypes in Wheat1
Authors: Allan R. E. , Pritchett J. A.
Published: July 2010

Two major independent genes, Sd1 and Sd2, control semidwarf culm length in wheat (Triticum aestivum L.) and singly produce very similar culm‐length phenotypes. Culm‐length genotypes of semidwarf lines have normally been determined by evaluating culm‐length distributions for F2 populations of test crosses to known Sd1 and Sd2 lines. In the present study, test crosses of eight semidwarf lines of unknown genotype were made to Sd1 and Sd2 tester lines to test the premise that the magnitudes of variance for coleoptile length and culm length varied directly with one another in F2 populations. The results verified that variance of coleoptile length closely corresponded with the variance of culm length in all F2 populations. The culm‐length genotypes of the eight semidwarf lines were accurately predicted using the F2 coleoptile‐length variance values. The coleoptile test is particularly valuable because measurements can be obtained in 8 days, and the test requires little space and much less labor than the F2 culm‐length method. Identification of culm‐length genotype is a necessary first step before the association of these specific genes with seedling vigor, winter survival, grain yield, quality criteria, and other important traits can be determined.
Breeding for Soybean Hypocotyl Length at 25 C1
Authors: Fehr W. R.
Published: July 2010

The effectiveness of breeding for soybean (Glycine max (L.) Merr.) hypocotyl length at 25 C was evaluated by examining segregation from crosses between long, intermediate, and short hypocotyl cultivars and performance of the parent cultivars. Progeny were evaluated in F1 and F2 as individual seedlings and in F3 as the mean of 24 seedlings for each F2 line. All tests for hypocotyl length were conducted in the dark in growth chambers maintained at 25 ± 1 C.

Evaluation of individual seedlings for the parent cultivars indicated that there was an environmental influence on hypocotyl length, particularly for the intermediate cultivars. There was little overlap in the single plant distributions for long and short hypocotyl cultivars, but the distributions for intermediate cultivars had considerable overlap.

Progeny from crosses between long hypocotyl cultivars were similar to the parents in hypocotyl length. Crosses of long ✕ intermediate and long ✕ short parents had segregation typical of a major gene with dominance for long hypocotyls. The F2 lines in F3 generally were within the range of the parents for intermediate ✕ intermediate, intermediate ✕ short, and short ✕ short crosses.

Selection for genetic differences in hypocotyl length at 25 C is possible. To select for long hypocotyl genotypes, crosses should include at least one long hypocotyl parent. In crosses involving only intermediate and short hypocotyl parents, transgressive segregates may be found that exceed the length of the best parent; however, the frequency of superior segregates in such crosses probably will be low.

Selection for hypocotyl length on a single plant basis is hampered by environmental effects. In a segregating population, selection for long hypocotyl genotypes on a single plant basis will eliminate many of the short hypocotyl genotypes, but will include some of the intermediate genotypes. A progeny test is the best way to evaluate a genotype's genetic potential for hypocotyl length.
Vigor Determination in Soybean Seed by Multiple Criteria1
Authors: Abdul‐Baki Aref A. , Anderson James D.
Published: July 2010

A multiple criteria approach is presented by which vigor was evaluated in 16 lots of soybean (Glycine max L., cv. ‘Lee‐68’) seed by determining O2 uptake, CO2 production, uptake of labeled glucose or leucine, conversion of isotopes into 14CO2 and polysaccharides or proteins, and leaching of metabolites through membranes of excised embryonic axes after 5 hours of imbibition. The concept upon which this approach is based is that excised embryonic axes from vigorous seed lots take up more sugars and amino acids from imbibing media, incorporate these metabolites faster into polysaccharides and proteins, and permit less leaching of nonused metabolites into surrounding aqueous media than axes from less vigorous seed lots. These measurements focus on the biosynthetic capacity of the axis and the integrity of its cellular membranes.
Inheritance and Association of Subcrown‐Internode Length with Coleoptile and Culm Length in a Winter Wheat Cross1
Authors: Allan R. E. , Pritchett J. A.
Published: July 2010

The inheritance of crown depth was determined by measurement of subcrown‐internode length in a winter wheat (Triticum aestivum L.) cross between the semidwarf selection C.I. 13253 (‘Norin lO’/Brevor 14) and the standard height cultivar ‘Brevor.’ Cultivars and selections that form deep crowns have been reported to show less winter injury. Broad sense heritability estimates for subcrown‐internode length ranged from 38.4 to 49.7%, and F4 lines of the cross followed a discontinuous segregation pattern. Subcrown‐internode length and coleoptile length were correlated closely (r = 0.79), which suggested that the two traits are governed by closely linked genes or are related pleiotropically. Similarly, subcrowninternode length closely correlated with culm length (r = 0.77). The growth mechanisms for short subcrown‐internode length, short coleoptile length, and short culm length of C.I. 13253 are related closely. The genetic associations between coleoptile and subcrown‐internode length with culm length were somewhat divergent. Results implied that one‐gene semidwarf types could be selected with long or short subcrown internodes. Unrestricted selection among semidwarf types for short subcrown‐internode or long coleoptile length may produce poor emerging types or shallow crown types, respectively.
Cytology of Obligate Sexual Plants in Panicum maximum Jacq. and Their Use in Controlled Hybrids1
Authors: Hanna Wayne W. , Powell Jerrel B. , Millot Juan C. , Burton Glenn W.
Published: July 2010

We isolated 18 obligate sexual plants of guineagrass (Panicum maximum Jacq.) from 2 plant introductions, PI 277922 and PI 277946, by analysis of morphological variation and cytological studies. Megasporogenesis and embryo sac development was typical of the Gramineae family. Sixteen controlled crosses involving 10 sexual plants ✕ robust short day apomictic plants produced 156 progenies. Fifty‐nine of the progenies were hybrids.

The inheritance data, based upon progeny of selfed sexual plants and sexual ✕ apomictic hybrids indicated that sexuality is dominant. Sexuality appears to be controlled by at least two loci and conditioned by a dosage effect of two or more dominant alleles.

This research demonstrates that it is possible to release the “stored” variability in this apomictic species through controlled sexual ✕ apomictic hybrids.
Cotton Fiber Development‐Kinetics of Cell Elongation and Secondary Wall Thickening1
Authors: Schubert A. M. , Benedict C. R. , Berlin J. D. , Kohel R. J.
Published: July 2010

The development of lint fibers of field‐grown ‘Stoneville 213’ cotton (Gossypium hirsutum L.) was studied from anthesis to maturity with reference to lint fiber elongation, dry lint weight per seed, and dry lint weight per seed per unit of length. These variables were plotted against boll age and fitted to appropriate best‐fit curves by computer curvilinear regression analysis. The curve‐fitting procedures yielded mathematical equations which were differentiated to give accurate growth rate curves. The elongation rate curve showed that lint fiber elongation ceased at 27 days after anthesis. At that time, dry fiber weight and dry fiber weight per unit length had reached 40% of their final values. Splining analysis of the data shows that fiber dry weight per unit length ceased to be constant at 16 to 19 days after anthesis; theoretically, this is the age at which secondary wall thickening began. These data strongly suggests that the elongation and secondary wall thickening phases were not separated in time and that a substantial portion of secondary wall thickening occurred before fiber elongation ceased.
Effects of Ethephon on Growth of Grasses1
Authors: Poovaiah B. W. , Leopold A. C.
Published: July 2010

Applications of ethephon (2‐chloroethylphosphonic acid) to bluegrass (Poa pratensis L. ‘Sydsport’) result in marked inhibitions of leaf elongation, but concomitantly cause large stimulations of stem growth. Ethephon at 10,000 ppm brought about a 75% inhibition of leaf elongation but increased stem length more than twenty‐fold. Exposure to 5,000 ppm ethylene brought about qualitatively similar responses. Similar ethephon applications to wheat (Triticum aestivum L. ‘Waldron’) decreased both leaf and stem elongation and promoted tillering.
Analysis of Several Morphological Traits and Their Associations with Digestibility in Bromus inermis Leyss.1
Authors: Sleper D.A. , Drolsom P.N.
Published: July 2010

Several morphological traits were examined in smooth bromegrass (Bromus inermis Leyss.) Significant differences were found among genotypes for leaf length, leaf width, culm diameter, plant height, and plant color. General combining ability was significant at the 1% level for leaf width, culm diameter, and plant color. Specific combining ability was significant at the 5% level for leaf length and plant height.

Leaf width, culm diameter, and dark green color were associated positively, and plant height negatively, with acid‐pepsin dry matter disappearance.
Tolerance of Phalaris tuberosa L. and Festuca arundinacea Schreb. to Preemergence Herbicide Treatment1
Authors: Berry Charles D. , Buchanan Gale A.
Published: July 2010

The phytotoxic response of the cool‐season perennial forage grasses phalaris (Phalaris tuberosa L.) and tall rescue (Festuca arundinacea Schreb.) to several herbicides was evaluated in greenhouse and field tests. Phalaris was more tolerant than tall rescue to dimethyl tetrachloroterephthalate (DCPA) and 0,0‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl) benzenesulfonamide (bensulide). DCPA and bensulide treatments of at least 1.68 and 1.12 kg/ha in the greenhouse and 3.36 and 5.60 kg/ha in the field, respectively, did not cause measurable injury to phalaris. Phalaris and tall rescue tolerated up to 5.60 kg/ha of l‐(2‐methylcyclohexyl)‐3‐phenylurea (siduron). Goosegrass (Eleusine indica (L.) Gaertn.) was controlled with all siduron treatments, whereas siduron and 3,6‐dichloro‐o‐anisic acid (dicamba) gave the best control of several broadleaf weeds
Independent Inheritance of Resistance to Corn Stunt and Maize Dwarf Mosaic in Corn1
Authors: Scott Gene E. , Rosenkranz Eugen E.
Published: July 2010

Inbred lines of corn (Zea mays L.), resistant to corn stunt (CS) but susceptible to maize dwarf mosaic (MDM), were crossed with inbreds of the opposite genotype. The parent, F1, and F2 populations were grown in a field experiment. Plants were inoculated with maize dwarf mosaic virus and allowed to be naturally infected with the corn stunt agents. Notes were taken on severity of symptom expression for each disease on each plant. Notes were taken 7 and 14 weeks after planting for MDM and CS, respectively. Data from F2 plants did not indicate the number of genes conditioning resistance to either of these diseases. Coefficients of correlation between CS and MDM ratings obtained on individual F2 plants were extremely small and not significant. Therefore, we concluded that the resistance to these two diseases was independently inherited.
Herability of Resistance to Cercospora Leaf Spot in Sugarbeet1
Authors: Smith G. A. , Ruppel E. G.
Published: July 2010

Narrow‐sense heritability estimates, adjusted to account for inbreeding of parental lines, were compared with realized hcritabilitles obtained by actual selection for high and low resistance to Cercospora beticola in sugarbeet (Beta vulgaris). Parental, F1, F2, F3, and polycross populations from high and low selections were field grown under an artificially induced leaf spot epidemic. Heritability estimates, in percent were 24.3±2.9 and 24.3±2.4 for each of two resistant ✕ susceptible crosses. These values were compared with realized heritabilities of 20.47 and 26.71 for the same two resistant ✕ susceptible crosses. Environmental variation accounted for 44 to 62% of the total variation for leaf spot resistance.
Antitranspirant Action of Carbon Dioxide on Intact Sorghum Plants
Authors: van Bavel C. H. M.
Published: July 2010

Twenty‐day‐old hybrid sorghum (Sorghum bicolor (L.) Moench) plants of the ‘Oro’ variety were grown in a closely controlled environment in which the air temperature was 30 C, the humidity about 80%, the horizontal air flow about 1 m s−1, and the incident, photosynthetically active radiation close to the maximum daylight level in clear weather. The ambient carbon dioxide level was varied to induce varying degrees of stomatal aperture and internal levels of carbon dioxide. This manipulation affected transpiration and carbon assimilation simultaneously, decreasing the former and increasing the latter.

The results were compared with a mathematical model of leaf action in which assumptions had to be made as to the mathematical form of the relations and the value of the constants. The effect of the carbon dioxide level upon stomatal aperture was well predicted by the model, as originally conceived, regarding both the nature of the functional relation and the value of the constant required.
Effects of Drought Stress and Succinic Acid‐2,2‐Dimethylhydrazide Treatment on Water Relations and Photosynthesis in Pea Seedlings1
Authors: Lee K. C. , Campbell R. W. , Paulsen G. M.
Published: July 2010

Physiological effects of drought were studied in two pea (Pisum sativum L.) cultivars to determine their relative ability to withstand this stress. Drought stress decreased dry weight and relative turgidity, reducing sugar, sucrose and starch concentrations, ribulose‐l,5‐ diphosphate carboxylase (E.CA.l.l.39) activity, and net photosynthesis in both drought‐susceptible ‘Alaska’ and drought‐resistant ‘Hardy’ peas. Decreases in dry weight, carbohydrate concentration, enzyme activity, and net photosynthesis were greater in the drought.susceptible cultlvar, but respiration rate, determined by infrared analysis, was decreased more in the tolerant cultivar. SADH (succinic acid‐2,2‐dimethylhydrazide) treatment increased relative turgidity and ribulose‐l,5‐diphosphate carboxylase activity under drought stress, but decreased respiration and rate of water uptake in both cultivars under nonstress conditions. Sucrose concentration increased in Alaska peas whereas net photosynthesis decreased in Hardy peas after SADH treatment. SADH had no effect on reducing sugar and starch concentrations. It was concluded that SADH treatment probably enabled plants to tolerate stress longer by decreasing energy requirements and metabolic degradation rates.
Nitrate Reductase Activity in Sudangrass Cultivars1
Authors: Eck H. V. , Hageman R. H.
Published: July 2010

Seventeen sudangrass [Sorghum sudanense (Piper) Stapf] varieties and sudangrass‐sorghum (Sorghum color L. Moench) crosses were evaluated for nitrate reductase activity by both in vitro and in vivo procedures. They were also evaluated for total cyanide concentration. Measurements were made on leaf tissue of 10‐, 14‐, and 18‐day‐old growth chamber‐grown seedlings. Nitrate reductase activity ranged from 9.6 to 3.3 µmoles NO−2.g fresh wt−1.hr−1 for the in vitro assay and from 3.9 to 0.8 µmoles NO−2.g fresh wt−l.hr−1 for the in vivo assay. Significant differences in nitrate reductase activity among genotypes were detected by both assays. While the in vivo activity was only 30% that of the in vitro assay, the range and relative rankings of the genotypes were similar as shown by the overall correlation, r = 0.6 (significant at the 1% level). Total cyanide concentration in the leaf tissue ranged from 16.4 to 1.5 µmoles.g fresh wt−1 and significant differences were noted among the 17 genotypes. Both nitrate reductase activity and cyanide concentration decreased with plant age.

Maximum recovery of nitrate reductase activity was obtained with an extraction medium containing 20 mM gluthathione and 4 mM NiCl2 The optimum tissue: extraction medium ratio was 1:20. The NiCl2 protected nitrate reductase from exogenous cyanide up to 7.2 µmoles/g, which is higher than is likely to be produced in the extracts by hydrolysis of the cyanogenic glucoside found in sudangrass.
Growth and Productivity of Cotton Grown from Seed Produced Under Four Night Temperatures1
Authors: Quisenberry J. E. , Gipson J. R.
Published: July 2010

The seeds used in this study were produced by growing cotton (Gossypium hirsutum L.) plants from first flower through boll maturation in growth chambers where tire night temperatures were 11, 15, 21, and 27 C. These seeds were used to evaluate the effect of seed quality on the growth and productivity of matured plants. The cultivars used were ‘Acala 1517 Br2,’ ‘Stoneville 7A,’ ‘Lankart Sel 57,’ ‘Stripper 31,’ and ‘CA 491.’ Characters or traits measured were 1) seed weight and percentage of germination of the seed produced in the temperature controlled growth chambers; and 2) rate of seedling emergence, vegetative growth rates, seed cotton per plant, bolls per plant, and production rate index of the plants grown from the seed produced in the chambers.

Low night temperatures during the seed maturation period had a detrimental effect upon seed quality (seed weight and percentage of germination). In field plantings, seedlings from seeds produced under low night temperatures (11 and 15 C) emerged more slowly than those from seeds produced under high night temperatures (21 and 27 C). The plants that developed from seeds produced under low night temperatures (11 C) grew more slowly and were less productive than plants from seeds produced under high night temperatures (21 and 27 C).
Effect of Normal Cytoplasms on Resistance to Southern Corn Leaf Blight and on Other Traits of Maize1
Authors: Good R. L. , Horner E. S.
Published: July 2010

Maize (Zea mays L.) hybrids having Texas male‐sterile cytoplasm are much more susceptible to Race T of Helminthosporium maydis Nisikado and Miyake than normal cytoplasm hybrids. This has raised questions about the effects of different normal cytoplasms on resistance to Race O of H. maydis.

We evaluated 222 reciprocal plant‐to‐plant crosses, involving 60 diverse germplasm sources, in a 3‐stage series of tests for cytoplasmic effects on susceptibility to H. maydis and other traits. F2 and F3 crosses were used in the second and third stages, respectively, to eliminate maternal seed effects. The crosses were subjected to both Race O and Race T of H. maydis.

In the second stage of testing one cross was found to have an appreciable reciprocal effect on susceptibility to H. maydis. This cross, along with several others, also showed significant reciprocal differences for such traits as height, maturity, and yield. However, when the three crosses having the largest differences between reciprocals were retested using fresh seed, the differences observed the previous year were not found. We conclude that many, if not all of the apparently significant differences found in the second stage of testing were due to sampling variation or maternal seed effects, and that the normal maize cytoplasms we tested had no measurable effect on susceptibility to H. maydis or on several other traits.
Intergeneric Hybrid Between Pearl Millet and Buffelgrass1
Authors: Read J. C. , Bashaw E. C.
Published: July 2010

Extensive efforts to cross a male‐sterile pearl millet (Pennisetum americanum (L.) K. Schum.) and apomictic buffelgrass (Cenchrus ciliaris L.) produced one F1 hybrid plant. Investigations of megasporogenesis and embryo sac development revealed that the apomictic mechanism (apospory) of the buffelgrass parent was transferred to the F1. In spite of the apparent potential for apomictic reproduction, the F1 plant was completely sterile. Cytogenetic studies indicate that the relationship of the parental species is probably no closer than the tertiary gene pool. Thus, any transfer of characters would be difficult and efforts should be limited to those traits that do not exist in the primary and secondary gene pools.
Quality Characteristics of Tall and Semidwarf Near‐Isogenic Lines of Durum Wheat1
Authors: Joppa L. R. , Walsh D. E.
Published: July 2010

The semidwarf genes derived from ‘Norin‐10’ have been transferred to durum wheat (Triticum turgidum L.). The desired flour quality of durum wheat and common wheat (T. aestivum L. em. Thell.) is very different. The transfer of a gene or genes from common to durum wheat along with the semidwarf genes could be deleterious. Twenty‐six pairs of near‐isogenic lines of durum wheat were grown at two locations in each of 2 years. The semidwarf lines did not differ significantly from the tall lines for any of the 10 quality characteristics studied. We concluded that the semidwarf genes were not associated with any of the 10 quality characteristics and that semidwarf durums with adequate quality can be produced. There were significant differences between pairs of lines for 9 of the 10 characters. Correlations among the various quality characters were significant.
Response of Greenbug‐Resistant Grain Sorghum Lines and Hybrids to a Natural Infestation of Greenbugs1
Authors: Johnson J. W. , Rosenow D. T. , Teetes G. L.
Published: July 2010

Three greenbug [Schizaphis graminum (Rondani)]‐ resistant sorghum [Sorghum bicolor (L.) Moench] lines, 'IS 809,' 'SA 7536‐1,' and 'KS 30,' their F1 hybrids with greenbug‐susceptible A lines, three susceptible hybrids, and one susceptible line were planted in yield tests subjected to a natural infestation of greenbugs at Lubbock, Texas in 1971 and 1972. In untreated plots, the mean number of greenbugs per plant was higher and leaf injury from greenbug feeding was greater in susceptible entries than in resistant lines and their hybrids. In greenbug‐infested plots, grain yield was significantly reduced only in the early‐blooming susceptible line. Hybrids with one resistant parent exhibited enough resistance to control greenbug populations and significantly reduce leaf death from greenbugs feeding on adult plants.
Morphological and Anatomical Features of Alfalfa Leaves as Related to CO2 Exchange1
Authors: Delaney R. H. , Dobrenz A. K.
Published: July 2010

Cuttings from alfalfa (Medicago sativa L. cv. ‘Mesa‐Sirsa’) genotypes which exhibited a wide range in leaflet size were grown under spaced‐planted and nonspaced‐planted conditions and used to determine the relation. ships between leaflet anatomy, leaflet morphology, and CO2 exchange. These same relationships were evaluated under controlled environmental conditions using alfalfa population MSE‐6 which has a broad germplasm base.

Area per leaflet and leaflet width were negatively associated with photosynthetic rate per unit leaf area. Specific leaf weight (SLW) was positively correlated with photosynthesis; however, the correlation coefficients were consistently lower than the r values for leaflet size vs photosynthesis. Photosynthesis expressed as total CO2 uptake per plant was not significantly associated with SLW and leaflet size. Plants with small leaves had the greatest SLW, palisade tissue thickness, and leaf thickness. A positive association was observed between palisade tissue thickness and photosynthesis expressed on a leaf area basis. The significance of leaflet size as a selection tool for photosynthetic rate in alfalfa is discussed.
Changes in Free Proline Concentration in Sorghum and Soybean Plants Under Field Conditions1
Authors: Waldren R. P. , Teare I. D. , Ehler S. W.
Published: July 2010

Free proline in the leaves of sorghum [Sorghum bicolor (L.) Moench cv. ‘Pioneer 846’] and soybean [Glycine max (L.) cv. ‘Calland’] was measured in the field under drought stress and adequate soil moisture. Leaf water potential and stomatal diffusive resistance were the measures of drought stress in the plants.

Free leaf proline in nonstressed plants changed during the day but seasonal changes were insignificant. Free proline increased with light intensity and varied widely in middle leaves that were shaded or received sunlight. Free proline did not accumulate significantly until plants were severely stressed and visibly wilting (about −20 bars leaf water potential in soybean). Variation was high in both stressed and nonstressed plants. However, factors that affected transpiration demand also affected free proline accumulation.

For irrigation scheduling free proline was not a good indicator of drought stress in the field because it increased after the critical time to irrigate for maximum yield.
Photosynthetic Response of Peanut1
Authors: Pallas J. E. , Samish Y. B.
Published: July 2010

The net photosynthetic rates of nine genotypes of the cultivated peanut (Arachis hypogaea L.) grown under controlled conditions were measured at six different light intensities: 180, 255, 526, 784, 1098, and 1546 µE m−2 sec−1 (E = einsteins). All genotypes evidenced an endogenous, circadian rhythm in photosynthetic rate. No genotype photosaturated at the highest intensity used, which was slightly less than full sunlight. Genotypes differed significantly in photosynthetic rate at similar light intensities; net photosynthetic rates of several of the genotypes exceeded 50 mg dm−2 hr−1. Soybean (Glycine max (L.) Merr., cv. ‘Bragg’) and tomato (Lycopersicum esculentum L., cv. ‘Marion’), grown similarly to peanut in growth chambers, showed considerably lower photosynthetic potential and photosaturated at much lower light levels (~250 to 500 µE m−2 sec−1). The peanut's photosynthetic response can help explain its adaptation to the dissimiliar light conditions in humid, semihumid, and arid regions. Its high rate of photosynthesis at any light level indicates that it is one of the more efficient species in converting solar energy to fixed carbon. Lowering ambient oxygen concentration to 1.5% increased net photosynthetic rate 35%. No correlation between specific leaf weight and net photosynthesis of the peanut was found.
Flat‐Square in Cotton, Acala Type. I. Its Mode of Inheritance and Heritability1
Authors: Khalifa H. , Starmer W. T. , Fisher W. D. , Stith L. S.
Published: July 2010

Flat‐square, an unidentified flower disorder in cotton (Gossypium hirsutum L.) which is manifested at bloom time, appeared on a large scale in Arizona during 1962. Part of this study was designed to verify the mode of inheritance and heritability of this disorder.

Three homozygous inbred lines of Acala‐type cotton known to exhibit flat‐square were intercrossed with a doubled haploid line free from flat‐square. Seeds of the F1, F2, BCDf, and BCf generations were grown simultaneously with the parental populations to evaluate its mode of inheritance and heritability.

Flat‐square was found to be quantitatively inherited, with low heritability. The estimates of the genetic parameters indicate that the inhertance is mostly additive in nature with no evidence of epistasis or maternal effect.
Effect of Row Spacing and Genotypic Frequency on the Yield of Soybean Blends1
Authors: Fehr W. R. , Rodriguez S. R.
Published: July 2010

The effects of row spacing and genotypic frequency on the yield of soybean (Glycine max (L.) Merr.) blends were evaluated for use in establishing testing procedures for new blends. In 1969 and 1970, ‘Chippewa 64,’ ‘Hark,’ ‘Corsoy,’ ‘Provar,’ and ‘Amsoy’ were evaluated in all possible two‐component blends at the frequencies 3:1, 1:1, and 1:3, and in all possible three‐component blends in a 1:1:1 frequency. The blends and pure stands were tested for yield in 70‐ and 100‐cm rows.

The average yield response of blends to narrow rows was similar to that of pure cultivars. The average yield increase in 70‐cm rows over 100‐cm rows was 9.6% for the two‐component blends, 10.2% for the three‐component blends, and 10.0% for the cultivars in pure stand.

Average compensatory responses (deviations of actual blend yields from the weighted means of their component cultivars in pure stand) were similar for both spacings. The average compensatory response was 69 kg/ha or 2.5% for 100‐cm rows and 72 kg/ha or 2.4% for 70‐cm rows.

Although row spacing generally did not influence compensatory responses, there were blends that had significant deviations from the expected yield in one spacing but not in the other. Furthermore, the percentage yield differences in two row spacings for a blend could not be consistently estimated from the percentage row‐spacing response of its component cultivars. It seems that whenever possible, the compensatory response of a blend and its yield response to different row spacings should be evaluated by testing the blend per se in the row spacings of interest.

In 1971 and 1972, genotypic frequencies in four two‐component blends were varied in 10% increments from 100:0 to 0:100. Compensatory responses of the blends were found to be dependent on genotypic frequency. Maximum yields of the blends generally occurred over a limited range of genotypic frequencies. All blends had their highest yields when the highest yielding cultivar made up at least 70% of the blend.
Gene Pm5 for Resistance to Erysiphe graminis f. sp. tritici in Hope Wheat1
Authors: Lebsock K. L. , Briggle L. W.
Published: July 2010

‘Hope’ wheat (Triticum aestivum L.) is known to be resistant to certain cultures of the powdery mildew fungus, Erysiphe graminis DC. f. sp. tritici Em. Marchal. We inoculated parental, F2, and F3 populations from crosses of Hope with four lines near‐isogenic for Pm1, Pm2, Pm3a, and Pm4, with three cultures of the powdery mildew fungus. Our data showed that Hope has a single, recessive gene pan: that conditions resistance to the fungus and that the gene is different from Pm1, Pm2, Pm3a, and Pm4. The symbol Pm5 has been assigned to the Hope locus. The phenotype of pm5 is best expressed when the host is inoculated at the four to five leaf stage of growth. Reaction of Hope is characterized by marked chlorosis surrounding lesions.