bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection for Resistance to Four Races of Phytophthora megasperma var. sojae in Soybean1
Authors: Kilen T. C.
Published: July 2010

Phytophthora rot is a serious disease of soybean [Glycine max (L.) Merr.] incited by the fungus Phytophthora megasperma Drechs var. sojae Hildeb. Screening for resistance to this disease is complex because of the genetic variability for virulence in the pathogen. The cultivar ‘Tracy’ was used as the resistant parent in crosses with a very susceptible breeding line, D55‐1492, and the cultivar ‘Forrest’. These crosses were used to study the genetics of resistance to physiologic races 1, 2, 3, and 4 of the pathogen in order to find more efficient screening methods. F3 lines from the crosses Tracy ✕ D55‐1492 and Forrest ✕ Tracy and F2 populations from 50 backcross families of Forrest (2) ✕ Tracy were evaluated. The plants were grown hydroponically and were infested with race 1, 2, 3, or 4 of the pathogen. Data from the Tracy ✕ D55‐1492 and Forrest ✕ Tracy crosses indicated a two‐gene segregation ratio when challenged by races 1, 3, and 4 and a one‐gene ratio with race 2. The reaction of the backcross families suggests that testing with race 2 and any one of the other three races would have been sufficient to select the 22 families that were segregating for all four races and would thus be an efficient screening method.
Arrangement of Sympodia and Earliness Potential of Cotton1
Authors: Namken L. N. , Heilman M. D. , Dilday R. H.
Published: July 2010

Field studies were conducted in 1975 and 1976 to determine if short vertical flowering intervals (VFI) of cotton (Gossypium hirsutum L.) are associated with the arrangement of sympodia. In a random population of ‘Tamcot SP‐37’, 24% of the plants had one or more side‐by‐side (S‐S) sympodia with no discernable internode, 27% had one or more close (C) internodes, and 49% had all normal (N) internodes. Ninety‐four and 81% of the S‐S and C internode‐type plants, respectively, had a 0‐ or 1‐day VFI. At 97 days from planting, the average boll load of the plants with at least one S‐S or C internode‐type was 47 and 33% greater, respectively, than plants with all N internodes. At 124 days from planting, there were no significant differences in average boll load; however, the S‐S and C internode‐type plants had more than twice as many open bolls as did N plants. In 1976, we compared a Tamcot SP‐37 population that had 100% of the plants with at least one S‐S or C type internode (obtained by selective thinning at the five and six true leaf stage) with a random population (randomly thinned), and we verified the earliness potential demonstrated by the individual plant studies in 1975.
Analyses of a Dominant Male‐Sterile Character in Upland Cotton. II. Genetic Studies1
Authors: Bowman D. T. , Weaver J. B.
Published: July 2010

A plant in an okra leaf, frego bract, nectariless strain of upland cotton (Gossypium hirsutum L.) had one branch bearing male‐sterile flowers. Crosses between male‐sterile and male‐fertile plants resulted in populations segregating 1:1 for fertile and sterile plants. Populations from selfed F1 and F4 fertile plants contained only fertile plants. These data suggested that a dominant gene controlled the sterility expression. Viability tests disclosed that a few viable pollen grains were produced in male‐sterile flowers. Six male‐sterile plants produced self‐pollinated seed; the resulting progenies gave a ratio of one sterile to one fertile plant, rather than 3:1 as expected. It was theorized that the pollen grains carrying the dominant gene for male sterility were less competitive than pollen grains carrying the recessive allele or non‐viable. Testcross populations of sterile plants in the F2 generation segregated 1 fertile:1 sterile, indicating that no plant was homozygous dominant for male sterility. Cytological observations had revealed that the new dominant gene differed from Ms4 and Ms7, is microsporogenesis breakdown. The gene symbol Ms10 is proposed for this new dominant gene conditioning male sterility.
Frost‐Hardiness in Relation to Leaf Anatomy and Natural Distribution of Several Solanum Species1
Authors: Palta J. P. , Li P. H.
Published: July 2010

The objective of this study was to determine anatomical and morphological differences related to the frost‐hardiness of tuber bearing Solanum species. Observations were made on about 2‐month‐old plants of 24 species including seven cultivars of potato (Solarium tuberosum L.). These species vary in frost‐hardiness from −2.5 to −5.5 C.

No consistent relationship was found between various gross morphological characteristics of the plants and frosthardiness. However, hardy species (frost killing temperature −4.0 C or colder) usually had short and highly branched stems with smaller and thicker leaves.

Among the various anatomical parameters studied, the number and thickness of palisade parenchyma layers and the stomatal index on the upper leaf surface were closely related to frost.hardiness. All hardy species had two palisade layers and all except three non‐hardy accessions (frost killing temperature ‐3.5 C or warmer) had one palisade layer. On the average, hardy species had a three times greater stomatal index (26.7%) than non‐hardy species. (8.8%), on the upper, surface of. the leaf, which. is probably due to two palisade layers m hardy species. The palisade parenchyma occupied a larger portion of the leaf cross section in hardy species (62.8%) compared to non‐hardy species (51.2%). No significant differences in cell size and intercellular space were detected between these two types of species. Ploidy was not related to leaf anatomy or frost‐ hardiness. Among the hybrid plants examined, hardy hybrids had two palisade parenchyma layers.

The natural distribution patterns of many wild growing hardy and non‐hardy Solanum species were analyzed. A difference in the geographical distribution of hardy and non‐hardy wild species was found. The hardy species (except S. commersonii Dunal ex Poir.) are found in the high Andes of southern Peru, in central and southern Bolivia, northern Chile, and northwestern Argenina. Non‐hardy wild species are primarily distributed in Mexico, Guatemala, Venezuela, Colombia, Ecuador, and northern and central coastal Peru. A close relationship was found between the altitude of origin of a species or collection and its frost‐hardiness.

It appears that anatomical features of hardy species are the results of their adaptation to environmental stress (primarily low temperature and in some cases together with water stress) under natural selection.
Abscisic Acid Levels in the Grain of Wild Rice1
Authors: Albrecht K. A. , Oelke E. A. , Brenner M. L.
Published: July 2010

Prolonged grain dormancy hinders wild rice (Zizania palustris L.) domestication. The purpose of this research was to determine if the inhibitor, abscisic acid (ABA), may be responsible tor wild rice grain dormancy.

Nondormant wild rice grains (stored in water at 3 C for 330 days) were dehulled, scarified, and placed in ABA solutions ranging in concentration from 0 to 20 mg/liter for 7 days. Germination decreased as ABA concentrations increased. No germination was obtained at or above 5 mg/liter of ABA. Washing the ABA‐treated grains with water did not reverse the inhibition.

Free and conjugated ABA were determined chromatographically in dehulled grains during a storage period of 146 days in water at 3 C. Free ABA per grain decreased from 12.29 ng to 4.27 ng, and conjugated ABA from 7.14 to 4.86 ng during 146 days of storage.

The ABA contents of hulls, pericarps, embryos, and endosperms were determined in dormant and nondormant (120 days after storage) grains. Total ABA per gram dry weight of embryo and pericarp tissue exceeded that of hulls and endosperms by a factor of 50 in both dormant and nondormant grain. Total ABA per gram dry weight of embryos, pericarps, and hulls was significantly less in nondormant grain. The high concentration of ABA in dormant grain, especially hi the embryo and pericarp, may be one cause of dormancy in wild rice grain.
Soil Water Depletion Patterns under Dryland Field Conditions of Closely Related Height Lines of Winter Wheat
Authors: Pepe John F. , Welsh James R.
Published: July 2010

Dryland soil water depletion patterns of closely related height lines of three adapted hard red winter wheat (Triticum aestivum L. em Thell.) cultivars were studied. Gravimetric soil water measurements were made at 30‐cm increments to a depth of 240 cm at 3‐week intervals in 1975 and 1976. Two single dwarf gene near‐isogenic lines and the tall parents were studied in the cultivars ‘Scout’ and ‘Wichita’. A two‐dwarf gene line and tall parent was used from ‘Trapper’. Although moisture stress varied considerably between years, no relationship could be established between‐soil water depletion and dwarfing genes and root development or activity. This was true when the individual time increments and depths were considered and also when total water losses from the profiles in each year were investigated.
Light in Early Plant Development: Influence on Leaf and Floral Initiation in Tobacco1
Authors: Thomas Judith F. , Raper C. David
Published: July 2010

Quantitative effects of accumulated PAR (photosynthetically active radiation) on apical meristem and leaf development were investigated using a cultivar of flue‐cured tobacco (Nicotiana tabacum L.) grown in controlled‐environment rooms at day/night temperatures of 22/18 and 26/22 C. Times of floral initiation and days between emergence of successive leaves were determined over a PAR range of 10.5 to 40.5 E m‐2day‐1. The total numbers of leaves and leaf primordia at the time of floral initiation and the days between initiation of successive leaf primordia were determined over a PAR range of 10.5 to 25.5 E m‐2day‐1. There was an interaction between temperature and all measured responses. In general, the times of floral initiation, final number of leaves and leaf primordia, and time between initiation of leaf primordia were only slightly affected by PAR at 22/18 C. At 26/22 C, however, floral initiation was delayed, final number of leaves and leaf promordia were increased, and the time between initiation of leaf premordia decreased as PAR decreased. The days between emergence of successive leaves increased as PAR decreased at 22/18 C but decreased at 26/22 C. These results will be used in developing an onogenetic simulator for a dynamic model of tobacco growth and development.
Comparison of Winter‐ and Spring‐Type Safflower1
Authors: Yazdi‐Samadi Bahman , Zali A. A.
Published: July 2010

Winter and spring types of safflower (Carthamus tinctorius L.) were compared in three tests. Two separate tests, one of 26 winter‐type lines and the other of 25 winter‐type lines, each compared winter types with five spring‐type cultivars developed in Iran. Both tests were sown in the fall and in the spring in the 1973–74 season. A third test, which included selected materials from the first two tests, was sown in October, April, and May of the 1974–75 season. A two‐replicate split‐plot design was used for each test, with planting dates the main plots, and lines and cultivars as subplots.

The tests showed that, on the average, winter types survived better and yielded more seed and oil than did spring types in fall plantings during 1973–74, when the minimum temperature recorded during the growing season was –14.4C, but in 1974–75, when the minimum temperature recorded during the growing season was –7.6C, yield and survival were similar. Winter types flowered about the same time as spring types when both were sown in the fall, but were about 3 weeks later than spring types when sown in the spring; winter types were taller than spring types; yields of seed/ha were higher for whiter types than for spring types in fall plantings in 1973–74, but not in 1974–75; and winter types were distinctly inferior to spring types in spring plantings. Fall‐planted winter type safflower yielded more than spring‐planted safflower and exceeded fall‐planted, spring‐type safflower in yield during the cold (–14.4 C) winter.
Inheritance of Testa Color Variegation in Peanut1
Authors: Branch W. D. , Hammons Ray O.
Published: July 2010

The inheritance of testa color variegation was investigated in reciprocal crosses between the variegated (red on white) PI 274191 ✕ solid red PI 371965 peanut (Arachis hypogaea L.) genotypes. F2 phenotypic segregation was consistent with that of a genetic model for incomplete dominance at one locus, designated V. Microscopic examination showed that the V gene inhibited full cellular development of the outer red epidermal layer of the testa in certain regions. This inhibition exposed the underlying white cellular layer resulting in a variegated pattern. The homozygously recessive locus, v, does not prevent the r2 locus from producing phenotypes with solid red color testa.
Protein‐Oil Relationships in Oats1
Authors: Youngs V. L. , Forsberg R. A.
Published: July 2010

Oil and protein relations in oat groats were studied with location‐year data from the USDA‐coordinated Uniform Early and Midseason Oat Performance Nurseries. Ranges, means, and correlations between protein and oil in oat genotypes were calculated (i) by location and across genotypes, (ii) by genotype and across locations, and (iii) by genotype and location and across years. Of 277 correlations calculated, only 36 were significant at the 5 or 1% level, and 20 of these occurred in comparison (iii). A majority of the correlations were positive in comparison (i) but, conversely, were negative in comparisons (ii) and (iii). A possible cause of these contrasting results is a blending of relationships in comparison (a) because of the independence of protein and oil levels in the many genotypes compared on a location basis. Within an individual genotype across locations (comparison b) and in specific locations (comparison c), changes in concentration of one seed component probably were associated with changes in concentration of other components (negative correlations).

Variation among oil concentrations generally was less than that among protein concentrations because of the greater effect of environment on protein. Homogeneity of variance ratios (protein/oil) were greater in comparison (b) than in comparison (a). Variation in protein and oil concentrations among oat genotypes provides breeders with great latitude in pursuing their goals.
Root Characteristics of Black Beans. I. Relationship of Root Size to Lodging and Seed Yield1
Authors: Stoffella P. J. , Sandsted R. F. , Zobel R. W. , Hymes W. L.
Published: July 2010

The relationship of root size to seed yield and lodging of two black bean (Phaseolus vulgaris L.) cultivars, ‘Black Turtle Soup’ (BTS) and ‘Strain 39,’ was compared with that of four black‐seeded lines (70001, 70002, 70003, and 70004) under both field and greenhouse conditions at different growth stages. Root weight was significantly higher for the four lines than for the two cultivars in the field, but not in the greenhouse. Shoot:root ratios were significantly lower for all the lines than for BTS in both environments and for Strain 39 under field conditions.

Combined field data for 2 years showed all four lines had significantly higher seed and biological yields than the two cultivars, although no differences were measured for harvest index. In both years the four lines lodged less than the two cultivars.

Uprooting resistance of all lines was significantly higher than for BTS and Strain 39. None of the parameters measured showed a stage ✕ genotype interaction, except for shoot:root ratio in the greenhouse.

Our results suggest that a larger root biomas may be an important component of lodging resistance in black beans. Erect plant types would result in decreased yield losses by direct harvesters.
Microscopy of the Pericarp and the Testa of Different Genotypes of Sorghum1
Authors: Blakely Mary E. , Rooney L. W. , Sullins R. D. , Miller F. R.
Published: July 2010

Scanning electron and light microscopy were used to determine the location and structure of the pigment containing tissues in kernels of six sorghum [Sorghum bicolor (L.) Moench] genotypes. The genotypes included kernels with white pericarp with and without a testa, red pericarp with and without a testa, and a brown pericarp (genetically red) with a testa and dominant spreader (S‐) gene. The sixth sorghum genotype had a partial testa. The polyphenollc pigments were located m the epicarp and endocarp of sorghums with a red pericarp (R‐Y‐). Sorghums with dominant B1‐B2‐ genes had a pigmented testa.

The testa did not always appear as a noncellular band. The testa was often composed of two overlapping layers, which were usually different colors. In some kernels, the testa appeared as blocky subunlts, while in other kernels the testa was a single, structuxeless layer. Thickness of the testa was measured around the kernel at eight locations. The thickest region of the testa occurred directly under the style and the thinnest areas on the sides of the kernel. We found no differences in thickness among the different genotypes with a testa. Greater differences in testa thickness appeared within a given kernel than between kernels of the different sorghum genotypes with B1‐B2‐ genes. Kernels with a dominant S‐ and B1‐B2‐ had brown pigments in the epicarp and endocarp.
Seasonal Variation of Hordenine and Gramine Concentrations and Their Heritability in Reed Canarygrass1
Authors: Woods D. L. , Hovin A. W. , Marten G. C.
Published: July 2010

The antiquality tryptamine alkaloids and their β‐ carboline derivatives in reed canarygrass, Phalaris arundinacea L., are under relatively simple genetic control and can be eliminated by breeding. The nontryptamine alkaloids (hordenine and gramine) are more difficult remove because they can only be controlled genetically by lowering their concentrations. The objectives of this study were to determine seasonal variation of hordenine concentration, its heritability, and relationship to gramine concentration in reed canarygrass.

Our studies showed high broad sense heritability estimates for hordenine and gramine of first growth and regrowth forage, a statistically significant but low positive correlation between the two alkaloids, and similar seasonal variation in their concentration. Concentration of gramine (7,000 µg/g dry wt) in regrowth forage was 10 times greater than that in first growth; concentration of hordenine (3,200 µg/g dry wt) in regrowth was twice greater than that in first growth (mean of 155 plants). Leaf blades contained higher concentrations of gramine than did leaf sheaths, whereas the converse was true for hordenine. The upper portion of the canopy contained 69% and 48% of mean herbage concentrations of gramine and hordenine, respectively. Improved techniques for extraction and colorimetric determination of the alkaloids are detailed, and the presence of nor‐gramine is reported.
An Ineffective Nitrogen Fixation Trait in Alfalfa1
Authors: Viands D. R. , Vance C. P. , Heichel G. H. , Barnes D. K.
Published: July 2010

An alfalfa (Medicago sativa L.) plant designated MnPL‐ 480 formed large, white nodules incapable of fixing atmospheric N when grown in association with five strains of Rhizobium meliloti Dang. in nil‐nitrate greenhouse sand culture. Under the same conditions, control plants capable of fixing atmospheric N were vigorous, dark green, and had pink corraloid nodules. To verify the ineffectiveness of the rhizobium‐MnPL‐480 association, cuttings from control plants and from MnPL‐480 were compared for both physiological and histological characteristics. MnPL‐480 was self‐pollinated and cross‐pollinated with control plants having functional nodules to determine if the ineffective association was a heritable trait.

Acetylene reduction rates and nodule leghemoglobin concentrations were zero in MnPL‐480. Forage and root dry weights of control plants were both about fivefold greater than those of MnPL‐480. Nitrogen concentrations in forage and shoots of control plants were 1.5 fold greater than those of MnPL‐480. However, nodule fresh weight and .root nonstructural carbohydrates were greater in MnPL‐480 than in controls. Histological examinations of MnPL‐480 nodules showed only a few cells that contained bacteroids. Bacteroids that were found in MnPL‐480 nodules cells appeared to undergo rapid senescence. Nodules collected from MnPL‐480 showed larger numbers of starch granules than nodules from control plants. MnPL‐480 formed white, ineffective nodules with five Rhizobium strains tested in Leonard jar culture.

Progenies from self‐pollination of MnPL‐480 produced only ineffective nodules. F1 progenies from crosses of control plants and MnPL‐480 produced functional nodules, thereby indicating that the ineffective association was a heritable (probably recessive), host‐conditioned trait.

The MnPL‐480 ineffective trait should be useful in studying the morphogenesis of alfalfa nodules, the genetic control of N fixation by the host, and the N economy of the alfalfa plant.
Relative Yields of Mixtures and Monocultures of Oat Genotypes1
Authors: Shorter R. , Frey K. J.
Published: July 2010

We evaluated relative yields of mixtures and monocultures of eight cultivars and 20 random F9‐derived oat (Avena sativa L.) lines from a bulk population at two locations for 2 years. Three diallel sets of two‐component mixtures were constructed: 378 1:1 mixtures among 28 lines, as well as 105 1:3 mixtures among 15 lines (four cultivars and 11 random lines). The 28 oat lines also were mixed in a 1:1 frequency with each of six testers (homogeneous and heterogeneous at low, medium, and high grain yield levels) to identify lines forming high yielding mixtures.

General mixing ability was significant (P ≤ 0.01) for grain and straw yields and specific mixing ability was not. Of the 1:1 mixtures, 321 for grain yield and 305 for straw yield were not significantly different (P ≤ 0.05) from their component means. Only 15 1:1 mixtures for grain yield and .10 for. straw yield, significantly (P ≤ 0.05) outyielded thexr higher yielding component (by up to 11% for grain and 15% for straw). Cultivar mixtures exceeded their component means by up to 7% for grain or straw yield whereas random line mixtures were superior to their component means by up to 13% for grain yield and 17% for straw yield. Grain or straw yield differentials between mixtures and their components in monoculture generally had repeatability of 0 to 32% over environ. ments.

Seven (for grain) and five (for straw) mixtures out of 105 used in the component.frequency experiment had significant (P ≤ 0.05) linear effects across component frequencies, and none had significant quadratic effects for either trait, indicating that mixture components interacted additively. Line performances in monoculture and in 1:1 mixtures were significantly correlated (r = 0.91 for both grain and strawyield (P ≤ 0.05). For both traits, the highest yielding mixtures were not superior to either their higheryieldin.g component or the fine with the highest monoculture yield. Therefore, use of mixtures of oat cultivars or lines to obtain a yield advantage over monocultures would not be justified.
Responses to 10 Cycles of Mass Selection in an Inbred Population of Grain Sorghum1
Authors: Foster K. W. , Jain S. K. , Smeltzer D. G.
Published: July 2010

Retention of genetic variability within highly inbred populations of predominantly self‐pollinating plant species suggests that response to directional selection within such populations may be significant. Ten generations of bidirectional mass selection for seed weight, plant height, and days to flower were conducted within a foundation seed lot of ‘Double Dwarf Yellow Milo 38’ (DD38) grain sorghum (Sorghum bicolor (L.) Moench) to evaluate this possibility. Selection gains were evaluated by comparing nonselected and tenth cycle selected populations grown in replicated experiments at three locations in 1978.

Divergence of population means of plus and minus selected strains was significant (p ≤ 0.01) for all three traits, while asymmetry of response was significant (p ≤0.01) for seed weight and days to flower only. Mean per cycle selection response expressed as a percentage of nonselected population mean over 10 generations ranged from 0.25% for the early flowering population to 3.40% for increased seed weight. Realized heritabilities ranged from 0.06 in the early population to 0.17 in the late population. Correlated selection responses were observed for each character selected, but the magnitude and direction of correlated responses were inconsistent.

The results suggest that sorghum populations may respond to directional selection despite apparently restrictive mating systems. Population structure and response to selection in a mixed selfing and random mating species like sorghum should be investigated more extensively in relation to the current discussions of population improvement methods.
Leaf Conductance and Osmoregulation of Field‐grown Sorghum Genotypes1
Authors: Ackerson R. C. , Krieg D. R. , Sung F. J. M.
Published: July 2010

The relationship between stomatal activity and leaf water potential components was examined for several sorghum [Sorghum bicolor (L.) Moench] genotypes as a function of growth stage under semi‐arid field conditions. During vegetative development, prior to flowering, genotypic differences were observed in the leaf water potential required to initiate stomatal control of transpirational water loss and the rate of change in conductance per unit change in leaf water potential. No significant genotypic differences existed in conductance when leaf water potential was high. After flowering and attainment of maximum leaf size, conductance remained high even when the leaf water potentials declined to −24 to −26 bars.

The relationships between leaf water potential components were examined to help explain the leaf conductance observations. Genotypic differences were observed in the leaf water potential‐leaf turgor potential relationships at each growth stage. Prior to flowering, as leaf water potential declined, leaf turgor declined accordingly with little evidence of osmoregulation, and all genotypes reached calculated 0 turgor at essentially the same leaf water potential (−18 to −20 bars). Genotypic differences were also observed in the leaf turgor‐stomatal conductance relationships.

After flowering, during the grain filling stage, significant genotypic differences were observed in the degree of osmotic adjustment. The genetic range in osmotic adjustment represents a potentially important adaptive mechanism to water stress which allows for maintenance of turgor and thus of metabolic functions dependent on turgor. Apparently, water conservation through stomatal control is practiced to some extent in sorghum prior to the onset of reproductive development; however, after flowering photosynthetic productivity is apparently maintained at the expense of water conservation.
Effects of Locations and Years upon Relative Yields in the Soft Red Winter Wheat Region1
Authors: Campbell L. G. , Lafever H. N.
Published: July 2010

Yields of entries in the Uniform Eastern Soft Red Winter Wheat (Triticum aestivum L. em Thell) Nursery at 12 locations were correlated with corresponding yields at each of the other locations for 7 years to access the relative yield response at various locations and to determine the influence of years upon relative yields at locations. All but one of 66 location pairs (Madison, Wis. Blacksburg, Va.) exhibited a significant positive correlation in at least 1 year and only one location pair (Lafayette, Ind.‐South Charleston, Ohio) showed a significant positive correlation for all 7 years. Sixteen location pairs were significantly correlated (positive) in 5 or more years. A cluster analysis based upon the 7‐year mean correlation coefficients indicated that relative yields were similar at Lafayette, Ind., Urbana, Ill., and Columbia, Mo. and that Keiser, Ark., Madison, Wis., and Blacksburg, Va. were most unlike other locations in the region. An average of correlation coefficients including all location pairs with a common location indicated that Lafayette, Ind. and South Charleston, Ohio would be favorable sites for breeding and testing for wide adaptation; whereas, Madison, Wis. and Blacksburg, Va. may require traits not generally needed for adaptation throughout the region. Averages of correlation coefficients within a year indicated that relative yields were more uniform throughout the region in some years (1970, 1972, and 1975) than in others (1971). An examination of ‘Knox 62’ yield relative to the mean yield in individual environments was used as an indicator of the reliability of cultivar characterization based upon 3 years of testing. Regression coefficients (Knox 62 vs. environment mean) were consistently lower in combinations of years including 1972 while 1974 produced higher values. Coefficients of determination (r2) were lower in periods including 1975 and higher in combinations including 1974. Neither measure of yield stability appeared to be related to yield level. The data supported an extensive testing program and makes apparent the need to test over years to adequately characterize cultivars.
Effect of Stage of Growth, Temperature, and N and P Levels on the Hydrocyanic Acid Potential of Sorghums in the Field and Growth Room1
Authors: Gorashi A. M. , Drolsom P. N. , Scholl J. M.
Published: July 2010

Variation in hydrocyanic acid potential (HCN‐p) was studied in three sudangrass [Sorghum sudanense (Piper) Stapf] strains and S. almum Parodi. Under field conditions, nitrogen application did not result in a significant change in HCN‐p, but strain and stage of growth when sampled had highly significant effects. ‘Sweet’ sudangrass and S. almum were high in HCN‐p, while ‘Piper’ and Line 109 (L109) sudangrasses were low in HCN‐p. Forty‐five days after planting HCN.p peaked, then dropped sharply during the following 15‐day interval.

In the first experiment performed under controlled environmental conditions, HCN‐p differences among the four strains were highly significant. When P concentration in Hoagland’s solution was increased from 0.0 ppm to 31.0 ppm, HCN‐p was reduced significantly. Lowering the temperature from 30 C day/20 C night to 20/10 C resulted in a highly significant increase in HCN‐p. In the second growth room experiment, a low HCN‐p strain, L109, was significantly lower in HCN‐p than the cultivar, Piper, under three N levels. HCN‐p was associated with N‐level, being lowest at the low N rate. Under both 30/20 C and 20/10 C temperature regimes, HCN‐p was higher when the plants were 30 days old, than when they were 45 days old. Also, HCN‐p was lower at 30/20 C than at 20/10 C. When both temperature regimes were lowered to 10/10 C for 10 days, the HCN‐p in 55‐day old plants was greater than in the 45‐day old plants. On the other hand, further reduction of temperature to −5/−5 C for one day at day 55, resulted in the lowest HCN‐p 56 days after planting.
Soil‐Water Use by Semidwarf and Tall Winter Wheat Cultivars under Dryland Field Conditions1
Authors: Holbrook Fredrick S. , Welsh J. R.
Published: July 2010

An experiment was conducted to evaluate soil‐water extraction patterns among two tall and three semidwarf winter wheat (Triticum aestivum L. em Thell.) cultivars in 1972 and 1973 under field conditions in eastern Colorado. Change in soil‐water content was used as the indicator of root development and activity. Soil water was determined using neutron scattering at 2‐week intervals at 30‐cm increments to a depth of 270 cm during the growing season. The cultivars did not differ significantly for total amounts of water used or for water extraction patterns over tune and profile depths. Consequently, there was no relationship between semidwarfing genes and amounts and pattern of water uptake in the dryland winter wheat cultivars investigated.
Paternal Influence on F1 Seed Size in Soybean1
Authors: Kilen T. C.
Published: July 2010

Heterosis for seed yield in soybean [Glycine max (L.) Merr.] has been large enough to stimulate research on efficient methods of obtaining cross pollination in this highly self‐pollinated crop and on techniques for detecting and separating the crossed seed. The objective of this study was to determine if cross‐fertilized seed could be distinguished from self‐fertilized seed on the basis of differences in seed size when a large‐seeded type was used as the pollen parent. Large‐seeded and small‐seeded parents used in the study differed in seed weight by at least 30 g/100 seeds.

The study showed that the weight of the crossed seed was no greater than that of the selfed seed on the same plant when the number of pods at a node were about equal, preventing any physical separation on the basis of seed size.
Response of Barley, Spring Wheat, and Oats to Atrazine1
Authors: Brinkman M. A. , Langer D. K. , Harvey R. G.
Published: July 2010

Frequent inquiries about the response of small grains to atrazine (2‐chloro‐4.ethylamino‐6‐isopropylamino‐s‐triazinc) have been made, but research in this area has been very limited. If atrazine carryover is expected, harley (Hordeum vulgate L. emend Bowden) and spring wheat (Triticum aestivum L. em Thell) might be more suitable small grains to grow if they produced more grain and straw in residual atrazine than oats (Avena sativa L.). The objectives of this research were to evaluate the response of barley and spring wheat to atrazlne, to compare the response of these two small grains to the response of oats, and to test for genotyplc differences for grain yield response to atrazine in barley and spring wheat.

Atrazine applications of 0, 1.12, 2.24, 3.36, and 4.48 kg/ha were applied postemergence to corn (Zea mays L.) in 1975, and the small grains were sown during the spring of 1976. This procedure was repeated in 1976 and 1977. The soil was a silt loam (Typic Arguidoll, finesilty, mixed, mesic) with 3.5 to 4.0% organic matter.

Grain and straw yields of all genotypes were reduced by atrazine carryover, and species differences were evident. Barley produced higher grain and straw yields in residual atrazine than spring wheat in both 1976 and 1977. Oats, which were not included in 1976 comparisons, also had higher grain and straw yields than spring wheat in 1977. Oats did not yield as much grain and straw as barley in high levels of residual atrazine in 1977, but on the basis of tolerance (yield in soil containing atrazine/yield in soil with no atrazine), there was little difference between barley and oats. However, barley was significantly more tolerant of atrazine than spring wheat on the basis of seedling dry matter production in a greenhouse test. Variation among genotypes for response to atrazine in the 2 years of testing was limited in both barley and spring wheat.

The results of this research indicate that if small grains are grown in soil with an anticipated atrazine carryover problem, barley would be preferable to oats. and both harley and oats would be preferable to spring wheat.
Growth, Flowering, and Fruiting Responses of Peanut Plants to Ethrel1,2
Authors: Ketring D. L. , Schubert A. M.
Published: July 2010

The stage of fruiting subsequent to flowering of peanut plants is called pegging. Pegs naturally produce ethylene during initial stages of growth. This study was done to test whether an exogenous source of ethylene, Ethrel [(2‐ chloroethyl) phosphonic acid], could affect growth, pegging, and yield of peanut plants. Spanish‐type peanut (Arachis hypogaea L.) plants grown in the greenhouse were sprayed to runoff with different Ethrel concentrations. Dry weight of the shoots was not reduced. Concentrations below 5 × 10−4M did not inhibit flowering, but all concentrations except 10−5M reduced production of mature pods and seeds. Three applications of 5 × 10−4M Ethrel at 2‐week intervals beginning 2 and 3 weeks postemergence (PE) caused prolonged inhibition of the onset of flowering, and there was eventual cessation of flowering in treatments beginning at 4 weeks PE. All treatments reduced production of mature pods and seeds. Only a single application of 5 × 10−4M Ethrel at 6 weeks PE did not reduce yield.

In 1976 field trials, Ethrel was applied at 0, 0.14, and 0.28 kg active ingredient/ha in 374 liters of water/ha. Three applications of each rate were made to separate plots at 2‐week intervals beginning 2 weeks PE. There was no significant effect on yield or value for ‘Start,’ ‘Tanmut 74,’ and ‘Florunner’ cultivars. In 1977, two separate field trials were conducted with single PE Ethrel treatments of 0, 0.28, and 0.56 kg active ingredient/ha at 4 weeks (early flowering) and 0 and 0.56 kg/ha at weeks. The 4‐week application at both rates reduced yields, but did not affect value. However, treatment at 10 weeks did not affect yields, but reduced value, indicating delayed fruit maturation in addition to inhibition of late flowering.

Although flowering of peanut plants was readily regulated by Ethrel treatment, it had either no effect or its effect(s) was deleterious to yield and value of peanuts over a range of concentrations and times of application.
Effects of Row Spacing and Cotton Cultivars on Seedling Diseases, Verticillium Wilt, and Yield1
Authors: Minton Earl B.
Published: July 2010

Cotton (Gossypium hirsutum L.) cultivars ‘Rilcot 90’ (susceptible to Vertkillium wilt) and ‘Paymaster 266’ (resistant to Verticillium wilt) were grown in one, two, and four rows per bed spaced 100 cm apart to determine the effects of cultivars and row spacings on seedling diseases, Verticillium wilt, and yield. Each treatment was applied to the same plot for 3 consecutive years. Plant stands increased with close row spacings but were not directly related to the seeding rates. The prevalence of foliar symptoms of Verticillium wilt was higher in Rilcot 90 than in Paymaster 266, but the percentage decreased with close row spacing. The number of diseased plants of each cultivar was higher with closer row spacing but did not increase directly with plant populations. Lint yield was highest in plants having two rows per bed and lowest in those having one row per bed, but the differences were not significant. The high moisture level maintained during the growing season provided good conditions for disease evaluations but probably reduced lint yield.

In the 4th year, each plot was halved. Seeds of the wilt‐susceptible ‘Lockett 4789A’ and of the wilt‐resistant ‘Paymaster 909’ were planted in one half of each plot in rows 100 cm apart. Stands were reduced slightly by seedling diseases. The prevalence of Verticillium wilt was lower when each cultivar was grown after Paymaster 266 rather than Rilcot 90. Close row spacing during the previous 3 years did not significantly increase the prevalence of Verticillium wilt. A disease‐resistant cultivar should be grown at high plant populations to minmize losses from Verticillium wilt and to maximize lint yields.
Relationships between Morphological Characters above the Flag Leaf Node and Grain Yield in Spring Wheats1
Authors: Briggs K. G. , Aytenfisu Attinaw
Published: July 2010

A study of the effects of seeding rates and dates on four morphological characters above the flag leaf node and on the yield components of seven spring wheat (Triticum aestivum L. aestivum group) genotypes indicated that interaction effects among genotypes, dates, and rates were as common for the morphological characters as for the yield components. In addition, the relationship between yield per unit area and each of the morphological characters was affected greatly by date and rate of seeding and by genotype. The most consistent general relationship across the range of genotypes was obtained between yield and extrusion length and was negative. It is suggested that, in breeding for higher yield, the use of early seeding dates and intermediate seeding rates (60 to 120 kg/ha), combined with selection for short extrusion length, long heads and large flag‐leaf lamina area and flag‐leaf sheath area, would be useful.
Vegetative Propagation of Temperate Forage Grasses through Callus Culture1
Authors: Lo P. F. , Chen C. H. , Ross J. G.
Published: July 2010

Five temperate forage grass species, creeping foxtail (Alopecurus arundinaceus Poir.), crested wheatgrass (Agropyron cristatum (L.) Gaertn.), green needlegrass (Stipa viridula Trin.), smooth bromegrass (Bromus inermis Leyss.) and western wheatgrass (Agropyron smithii Rydb.) were cultured in vitro. Callus was initiated from segments of young inflorescences of each species cultured in the dark at 25 C on Linsmaier and Skoog (RM) or Gamborg, Miller, and Ojima (BS) medium supplemented with 5 mg of 2,4‐dichlorophenoxyacetic acid (2.4‐D) combination with 0 or 0.2 mg kinetin/liter. All of the calluses subcultured on RM medium unsupplemented with hormones in the dark at 25 C developed plantlets via organogenesis. An addition of 1 mg kinetin/liter to the basal medium enhanced shoot initiation in calluses of western wheatgrass, green needlegrass, and creeping foxtail. Regenerated plants were subsequently established in soil.

Albinism was noted among the regenerated plantlets of smooth bromegrass, creeping foxtail, crested wheatgrass, and green needlegrass. The relative frequency of albino plantlets emerging from a callus tended to increase with age of the subculture. Albinism was reduced in calluses differentiating on RM medium containing 1 mg kinetin/ liter, possibly due to improved plastid formation.

All of the calluses were maintained on RM medium supplemented with 5 mg 2,4‐D/liter. Improved growth of green needlegrass callus was obtained by supplementing the above medium with 0.5 mg of kinetin/liter.

Two warm‐season grasses, big bluestem and Indiangrass, have previously been shown to respond to the same general tissue culture methods used in the present study. This suggests that these methods may have general applicability for forage grass species.
Preharvest Desiccants for Rice1
Authors: Eastin E. F.
Published: July 2010

Preharvest desiccation of rice (Oryza saliva L.) would improve timeliness of harvest and allow more efficient and faster combining of the grain. Field studies to determine the suitability of diquat (6,7‐dihydrodipyrido [1,2‐α:2′,1′‐c]pyrazinediium ion), glyphosate [N‐(phosphonomethyl)glycine], paraquat (1,1′‐dimethyl‐4,4′‐bipyridinium ion), and sodium chlorate as preharvest desicants for rice were conducted for 2 years. Diquat at 0.28 kg/ha and paraquat at 0.14 kg/ha resulted in good leaf desiccation in 2 days under the hot cloudy conditions of the studies. Three days were required for desiccation when diquat at 0.14 kg/ha was applied, while 4 days were required when sodium chlorate at 5.04 kg/ha was applied. Glyphosate at rates up to 1.12 kg/ha did not adequately desiccate rice leaves in 7 days under the conditions of this study. When applied to rice with grain moisture of 22%, diquat at 0.56 kg/ha, paraquat at 0.14 kg/ha, and sodium chlorate at 5.04 kg/ha significantly reduced grain moisture 3 days after application. Diquat at 0.14 kg/ha and glyphosate at 1.12 kg/ha required 7 days to reduce grain moisture. Only paraquat at 0.14 kg/ha 7 days after application to 16.5% moisture rice reduced grain moisture.

Whole kernels after milling were slightly reduced by diquat at 0.28 and 0.56 kg/ha, paraquat at 0.14 kg/ha and sodium chlorate at 5.04 kg/ha, all applied to 25% grain moisture rice 7 days before harvest. None of the desiccants evaluated reduced grain yield, seed germination, or 1,000 grain weight. These results indicate that diquat, paraquat and sodium chlorate may have potential as preharvest desiccants for rice.
Inheritance of Rust Reactions and Their Associations with other Traits in Crosses with a Hard Red Winter Wheat1
Authors: Wells Darrell G. , Cowley Craig R.
Published: July 2010

‘Hand’ wheat (Triticum aestivum L.) is immune from leaf rust (Puccinia recondita Rob. ex. Desm. f. sp. tritici) and stem rust (P. graminis f. sp. tritici Eriks. and Henn.), high in seed protein, and of excellent baking and dough handling properties, though weak‐strawed and medium in yield. The putative pedigree of Hand is in doubt. To determine the inheritance of Hand's valuable characteristics, crosses were studied, using single plants and progeny rows, of Hand with ‘Centurk’ and TX62A2522‐8‐2 (semidwarf), both low in protein, and of Hand with NE68513, high in protein. All seedlings were vernalized and transplanted to the field in 1973. Races 15B‐2, 32, and 151 (of Puccinia graminis f. sp. tritici) were inoculated into spreader rows. Centurk was moderately resistant to stem rust and susceptible to naturally occurring races of P. recondita f. sp. tritici. TX62A2522‐8‐2 was susceptible to stem rust and mixed in reaction to leaf rust. NE68513 was moderately susceptible to stem rust and susceptible to leaf rust. Two dominant factor pairs and one factor pair controlled immunity from leaf rust and stem rust, respectively, in Hand. SrTtl was identified as the gene in Hand controlling resistance to stem rust. High protein and resistance to leaf rust were usually associated in inheritance. High protein and resistance to stem rust were not associated except in the F3 of the TX/Hand cross. Leaf rust resistance was usually associated with large seed. Stem rust resistance and lateness were associated in one cross but immune, early lines occurred. Reaction to leaf and stem rust were inherited independently. The results indicated that high yielding, rust resistant, early wheats with high protein and large seeds can be developed from crosses with Hand.
Light and Nitrogen Affect Storage Protein Mobilization in Germinating Cottonseed1
Authors: Elmore C. D. , Paul R. N.
Published: July 2010

Laboratory germination studies to evaluate seed performance and seed quality attributes are routinely conducted in the dark with distilled water used to moisten the seed blotter paper. This study was conducted to determine the effect of light and N on storage protein mobilization during the first 5 days of germination of cottonseed (Gossypium hirsutum L.). Dry weight, hydrolysate amino acid composition, and free amino acid composition of cotyledons and axis were determined. Ultrastructure of cotyledons was examined. In the absence of N, light enhanced the protein body breakdown and coalescence of protein bodies into the central vacuole of cotyledonary cells. The presence of N in the nutrient solution had little effect on the protein body breakdown in the light (as revealed by electron microscopy) but slowed the mobilization process in the dark. Total free amino acid content and individual amino acid composition support this conclusion. Light increases the total free amino acid content of cotyledons at 3 and 5 days in the absence of N and at 5 days in the presence of N. Similar results are seen for the prominently affected amino acids, asparagine, arginine, γ‐aminobutyric acid, and histidine. These results indicate that seed germination is sensitive to environmental factors such as light and mineral nutrients.