bluuebunny/crossref_metadata_2025 huggingface dataset:
A Rapid Colorimetric Method for Epicuticular Wax Contest of Sorghum Leaves1
Authors: Ebercon Adelina , Blum A. , Jordan W. R.
Published: July 2010

Epicuticular wax deposition on sorghum [(Sorghum bicolor) L. Moench] leaf blades imparts drought resistance. Screening of a large number of sorghum genotypes for increased leaf epicuticular wax content, utilizing the available gravimetric method, is impractical. A more rapid colorimetric method was developed and evaluated against the current gravimetric method. The colorimetric method is based on the color change produced due to the reaction of wax with acidic K2Cr2O7 reagent. Wax content determined by the colorimetric method was highly correlated (r = 0.984) with that determined by the gravimetric method. Leaf epicuticular wax content in 11 fieldgrown grain sorghum cultivars did not vary between growth stage #4 (tip of flag leaf showing) and #7 (soft dough), at which stages comparable wax readings were obtained among the four top leaf blades. A CK 60 ‘bloomless’ (bmbm) genotype had only half of the epicuticular wax content of the CK 60 ‘normal’ (BmBm) genotype. Ten cultivars, all of the BmBm genotype, significantly differed in epiculticular wax content, ranging from 1.14 to 1.99 (SE = 0.006) mg/dm2 of leaf.
Multivariate Analysis and the Geographical Distribution of the World Collection of Finger Millet1
Authors: Hussaini S. H. , Goodman M. M. , Timothy D. H.
Published: July 2010

Analysis of variance of 640 genetic stocks from the world collection of finger millet, Eleusine coracana (L.) Gaertn., indicated highly significant differences among entries for the 18 characters selected. Most of the vegetative characters measured were environmentally labile in contrast to reproductive characters, which were little affected by environment. Some vegetative characters, such as stem width and blade length, were found to be relatively little affected by the environment. The characters under study, in general, did not show high mutual correlation.

The data were subjected to principal components analysis. Twelve broad groups have been identified as a result of plotting the first two standardized principal components. Indian material showed clinal variation, with southern and eastern samples forming the extremes. The pattern of variation in African material was distinctly different from that found in India. Ugandan material exhibited distinct separation and isolation from the rest of the material studied.

Canonical variate analysis not only supported the above findings, but also distinctly separated the Ethiopian material (which the principal components analysis grouped with some Indian material) into a distinct group of its own.
Probabilities of Selecting Genotypes When Testing at Several Locations1
Authors: Hinz P. N. , Shorter R. , DuBose P. A. , Yang S. S.
Published: July 2010

When lines are grown in each of several locations in a plant breeding program the rankings will seldom agree. The extent of the disagreement depends on the heritability of the trait being measured. Probabilities of any given line being selected in at least one location are presented. Use of these probabilities to aid in making decisions about resource allocation concerning the number of lines to be selected per location, the number of replications to be used, and the number of locations to use in a plant breeding program is discussed. These probabilities are correct even in the presence of genotype‐environmental interactions involving changes in magnitudes of means but not rankings.
Ten Cycles of Progress from Modified Ear‐to‐Row Selection in Corn1
Authors: Compton W. A. , Bahadur Khan
Published: July 2010

A modified ear‐to‐row selection program in corn Zea maya L.) was initiated in Nebraska by Dr. J. H. Lonnquist in 1961. This paper describes results through the 10th cycle. Grain yields have continued to increase through the 10th cycle, but there is some evidence of curvilinearity. Part of this might be the result of a change in the selection criterion after the seventh cycle. At that time we began using a selection index that included lodging and dropped ears in addition to yield. The authors feel that it is unlikely that the selection study is plateaulng and therefore feel that linear regression estimates of gain are still appropriate. Gains in yield reported here from such an estimate are at the rate of 5.26% per cycle. Correlated responses in lodging, moisture at harvest, ear height, and number of ears per plant are discussed. Yield gains, though not very large, are still larger than those from mass selection in the same cultivar.
Causes for Anomalous Wet‐dry Season Yield Differences in Lowland Rice1
Authors: Leihner Dietrich E. , Cock James H.
Published: July 2010

Field research in the Llanos Orientates (Eastern Plains) of Colombia confirmed the existence of an abnormal yield pattern in lowland rice (Oryxa saliva L.). With uniform irrigation and cultural practices throughout the year, grain yields were consistently lower during the dry than during the wet season. The constant tropical climate was of minor influence; shorter daylength during the dry season was the only factor that had a small negative effect on yield. High fertilizer applications did not raise dry season yields to wet season levels, hence major elements were not considered deficient. Low yielding dry season crops suffered major stress at early stages of growth. Depression of leaf area development and growth were possibly greater during the dry season due to toxic Fe levels in the plants. This resulted in small sink sizes and low yields. Iron toxicity was probably more serious during the dry than during the wet season due to differences in physico‐chemical status of soil at planting.
Effect of Growth Temperature on Leaf Nitrate Reductase, Glutamine Synthetase and NADH‐Glutamate Dehydrogenase of Juvenile Maize Genotypes1
Authors: Amos J. A. , Scholl R. L.
Published: July 2010

Ten F1 hybrids of maize (Zea mays L.) grown at two day/night temperatures (35/25 C and 40/28 C) in controlled‐environment chambers were assayed for in vitro nitrate reductase (NR) to compare the relative effect of high temperature on nitrate reductase activity (NRA) among hybrids. High temperature response of nitrate reductase was tested by assaying glutamine synthetase (GS) and NADH‐glutamate dehydrogenase (GDH) from temperature‐treated seedlings in a set of genotypes that differed for the degree of high temperature stability of nitrate reductase. The NRA of most hybrids was reduced approximately 35% by high temperature, and the overall genetic variability of NRA for temperature stability was low. However, the NRA of some hybrids, such as ‘A632Ht × B37Ht’, was depleted less by high temperature (22 and 17% reduction in two experiments, respectively) than others, such as ‘Oh51A × Oh551× (54 and 31% reduction), indicating that genotypic differences can occasionally be large. Genotypic variability for NR response to temperature was not correlated with that for GS or GDH, neither of which activities were reduced significantly by high temperature in any of six genotypes. The effect on NR of the addition of protein to the NR extraction medium was tested using tissue from seedlings grown at high and low temperatures. This addition had no detectable influence on the apparent temperature stability of genotypes. Protein addition, however, did slightly increase NRA of some of the genotypes. Increases of NRA due to addition of bovine serum albumin ranged from 0 to 30%
Mechanisms of Canopy Development of Tall Fescue Genotypes1
Authors: Nelson C. J. , Asay K. H. , Sleper D. A.
Published: July 2010

Little is known regarding the genetic control of yield components of forage grasses. We conducted four experiments to determine if genotypes of tall rescue (Festuca arundinacea Schreb.) differed in number of tillers and weight/tiller. The relationship between those traits and yield/plant was also investigated under low‐competition conditions.

Genotypes selected for high number of tillers exhibited lower yield/tiller, and often a lower yield/plant than those with a low number of tillers, when cut following 18 to 24 days of regrowth. Among 225 plants from a 6×6 diallel series diallel series, tillers/plant was negatively correlated (r = —0.55) with yield/tiller. Path coefficient analyses revealed that the direct effect of tillers/plant on yield/plant was about 1.5 times greater than that of yield/tiller.

Rate of leaf area expansion was related closely to yield/tiller among genotypes that were selected to represent a broad range in number of tillers/plant. The relationship was not as close (r = 0.43) among progenies of the diallel. Path coefficient analysis of the diallel progeny indicated that leaf elongation rate had 1.6 to 1.8 times more influence than did leaf width on leaf area expansion rate. Leaf area expansion rate may be an acceptable criterion for selection for yield/tiller. Concentration of water‐soluble carbohydrates in leaves and CO2 exchange rate of leaves were not related to number of tillers/plant, yield/tiller, or leaf area expansion rate.
Monogenic Resistance to Red Clover Leaf Rust Associated with Seedling Lethality1
Authors: Engelke M. C. , Smith R. R. , Maxwell D. P.
Published: July 2010

Monogenic dominant resistance to leaf rust (caused by Uromyces trifolii (Hedw. f. ex De.) Lév var. fallens (Desm.) Arth.) in a red clover (Trifolium pratense L.) clone, KyCL 75, was studied to determine its value as a source of resistance for cultivar development. KyCL 75, reported to be heterozygous for rust resistance, was crossed with a rust susceptible clone, L12, and the F1's were intercrossed and backcrossed to the parents. Equal segregation of the F1 population into resistant and susceptible types indicated L12 was homozygous recessive for rust susceptibility. When resistant F1's were intercrossed or backcrossed to the resistant parent, the F2 and BC populations segregated 2 resistant:l susceptible rather than the expected 3:1. When susceptible F1's were intercrossed, all progenies were susceptible. Resistant plants selected from the F2 and BC populations were backcrossed to the susceptible parent L12, and all populations segregated for leaf rust. The unexpected genetic ratios and failure to obtain homozygous resistant genotypes were attributed to a close linkage between a dominant allele conditioning rust resistance and a recessive allele causing seedling mortality. Hence, the homozygous resistant genotypes die in the seedling stage. Unless this linkage can be broken, KyCL 75's rust resistance cannot be used in developing a rust‐resistant cultivar of red clover.
Inheritance of Pollen Fertility Restoration in Cytoplasmic Male‐Sterile Upland Cotton1
Authors: Weaver David B. , Weaver J. B.
Published: July 2010

Information regarding the inheritance of fertility restoration in cytoplasmic male‐sterile cotton will be a valuable tool in commercial production of F1 hybrid cotton seed. F1, F2, and testcross populations were planted in 1975 at two locations to determine the inheritance of the fertility‐restoring factor in cytoplasmic male‐sterile Upland cotton (Gossypium hirsutum L.). Fertility restoration in cytoplasmic male‐sterile cotton is controlled by a single gene probably expressing partial dominance. Either some of the F2 plants were misclassifled or some minor modifying factor(s) was slightly deleterious to the growth and development of fertile plants in segregating populations. G. barbadense L. apparently has a factor that enhances pollen production in the F1 hybrid. A breeding program is underway to transfer this factor(s) into Upland stocks. Fertile plants in segregating F2 populations showed a significantly higher lint percentage than corresponding sterile plants. Higher micronaire was found for sterile plants than fertile plants.
Effects of Partial Defoliation on Petiole Phloem Area, Photosynthesis, and 14C Translocation in Developing Soybean Leaves1
Authors: Sanders T. H. , Ashley D. A. , Brown R. H.
Published: July 2010

The effect of altered photosynthate supply on crosssectional phloem area in soybean [Glycine max (L.) Merr.l leaf petioles was examined. Leaf. and leaflet removal were used to alter photosynthate production by a given leaf. Measurements of CO2 exchange rate (CER), 14C translocation, and phloem area were made over a period of 21 days as the first trifoliolate leaf developed. CER and translocation were maximum near day 10 then decreased while petiole phloem area increased throughout the 21‐day period. When unifoliolate leaves and cotyledons were removed from young plants, leaf area and phloem area of the first trifoliolate leaf were less than those of controls although a higher CER on a leaf area basis occurred in leaves of plants previously defoliated. Reduction in photosynthetic area by removal of one or two leaflets from a young unfolding leaf had no effect on petiole phloem area. The lack of changes in phloem area in the petiole in response to changes in photosynthesis rate or leaf area indicates that photosynthate supply does not affect the phloem area.
Expression of the Vestigial Glume Character in Adapted Sweet Corn Inbreds1
Authors: Keys N. A. , Andrew R. H.
Published: July 2010

Use of the vestigial glume gene (Vg) is a means of increasing kernel cut‐off percent in processing sweet corn (Zea mays L,) if pollen production problems can be mastered. In this experiment, effect of the vestigial glume gene on amount of pollen shed and on length of tassel glume in a range of adapted Wisconsin inbreds was studied. Pollen production by Vg vg plants ranged from 0.65 to 15.95 ml/tassel for different inbreds, and tassel glume length from 0.65 to 5.20 ml. There was a highly significant relationship between pollen volume and length of tassel glume. Tassels of Vg Vg plants were very small and did not produce pollen. These results indicate that it should be possible to develop vestigial glume (Vg vg) hybrids with adequate pollen for commercial production.
Number of Plants Necessary to Recover a Trait1
Authors: Sedcole J. R.
Published: July 2010

Four methods are presented for calculating the number of plants needed, with a specified high probability, to recover a given number of plants possessing a trait, given that the trait occurs with a known probability.
Combining Ability in I1 Single Crosses of Red Clover1
Authors: Cornelius P. L. , Taylor N. L. , Anderson M. K.
Published: July 2010

A diallel cross involving 10 I1 red clover (Trifolium pratense L.) clones was evaluated for survival on four dates over a 3‐year period, 1973‐75, and vigor of growth on three dates in 1973 and 1974. Significant nonadditive genetic variance was found for survival in 1974 and 1975 and for vigor in 1973. This nonadditive portion of genetic variance was substantially greater than in a previous study involving I0 clones and strengthens the case for production of hybrid red clover. Significant reciprocal effects were found for all traits except vigor in 1974. GCA effects of I1 clones failed to agree with GCA effects of their I0 parents in the previous study, possibly owing to chance selection of inferior I1‐ segregates from superior I0 clones, or to genotype ✕ environment interactions.
Evaluation of Free Proline Accumulation as an Index of Drought Resistance Using Two Contrasting Barley Cultivars1
Authors: Hanson Andrew D. , Nelsen Charles E. , Everson Everett H.
Published: July 2010

The two barley [Hordeum vulgare L.] cultivars, ‘Proctor’ and ‘Excelsior’, differ in their stability of grain yield under dryland conditions; Proctor produces a low yield in drought seasons and Excelsior a relatively high yield. This varietal difference in drought resistance was clearly expressed at the three to four‐leaf stage, both in soil‐grown plants in greenhouse tests and in perlite‐grown plants in growth chamber experiments. Water deficits were imposed either by withholding water from the soil, or by flooding the perlite rooting medium with polyethylene glycol 6000 (PEG) of osmotic potential –19 bars. Under both conditions the drought‐susceptible Proctor sustained more severe leaf kill than the resistant Excelsior.

Leaf water potentials (ψleaf) and free proline concentrations in various zones of the second leaf blade were determined during the development of PEG‐imposed stress. In both cultivars, a gradient of decreasing ψleaf was established from the base to the tip of the blade; a ψleaf value lower than –30 to –40 bars in any leaf zone indicated leaf kill, i.e. failure of that zone to recover on relief of stress. The ψleaf at the mid‐blade zone always fell more rapidly in Proctor than in Excelsior, and consequently reached the critical –30 to –40 bar value earlier. In both varieties, free proline accumulated in leaf tissue as ψleaf fell, and reached the highest concentration as leaf kill became severe; at this stage much of the free proline was localized in the non‐viable leaf zone. Under stress, Proctor leaves always accumulated free proline more rapidly than Excelsior leaves. On relief of water stress, free proline levels declined in viable leaf tissue, but remained very high in the drought‐killed, desiccated leaf zone.

These data demonstrate that reports of a simple positive correlation between proline‐accumulating potential and drought resistance in barley may be in error. Therefore, proline‐accumulating potential should not be utilized as a positive index of drought resistance in screening methods for cereal breeding programs.
D‐Genome Substitution‐Monosomics of Durum Wheat1
Authors: Joppa L. R. , Williams N. D.
Published: July 2010

Each of the D‐genome chromosomes was substituted for its homoeologous A‐ and B‐genome chromosomes in Triticum turgidum L. cv. durum ‘Langdon’. All 14 possible substitution‐monosomics were obtained by crossing the appropriate ‘Chinese Spring’ nullisomic‐tetrasomic (Triticum aesthium L.) with Langdon. Selfing these F1's and selecting for 14 chromosome pairs in the F2 and F3 resulted in the disomic substitution of a D‐genome chromosome pair for a homoeologous A‐ or B‐geuome chromosome pair. When these disomic substitutions were backcrossed to Langdon, the BC1 progenies were substitution‐monosomics with 13 pairs plus two univalents (13″ + 2′). One of the univalents was an A‐ or B‐genome chromosome and the other univalent, the homoeologous D‐genome chromosome. In repeated backcrosses to Langdon durum, the D‐genome chromosomes were transmitted through the female gametes 33% of the time on the average. The substitution‐monosomics were more fertile, more vigorous, and the D‐genome chromosomes were transmitted through the female gamete at a higher rate than the durum monosomics. They can be used for many of the same genetic studies as the monosomics in hexaploid wheat.
Variation Among Alfalfa Genotypes for Rate of Acetylene Reduction1
Authors: Seetin M. W. , Barnes D. K.
Published: July 2010

Alfalfa (Medicago sativa L) cultivars with increased symbiotic N fixation potential would be useful in many agricultural systems for supplying N for grain and pasture crop production. This paper describes a greenhouse procedure for evaluating alfalfa for rates of acetylene reduction and characterizes genetic variation of traits that may influence nitrogen fixation in alfalfa. Two thousand plants of six alfalfa cultivars were scored for nodulation when inoculated with a mixture of Rhizobium meliloti strains. Seventy‐seven plants, representing extremes in nodulation, were selected and vegetatively propagated (cloned). Clones differed significantly for nodulation, root type, and acetylene reduction in replicated tests. Crosses were made in all possible combinations among six clones differing in acetylene reduction potential. Progenies were established in sand benches, allowed to grow to flowering, and then cut off. When the regrowth was at the early bud stage, plants were assayed for acetylene reduction and evaluated for nodulation and root morphology. Crosses between clones with high acetylene reduction values produced progenies with acetylene reduction rates more than twice those of progenies from low ✕ low crosses. Crosses between clones with high acetylene reduction values and clones with low acetylene reduction values produced progenies with intermediate values. Morphological traits associated with high levels of acetylene reduction were: many fibrous roots, many nodules, and high top and root weights. These greenhouse results indicated that significant variation exists among alfalfa genotypes for factors that may be associated with N fixation.
Red and Far‐Red Light Effects on Climbing in Phaseolus vulgaris L.1
Authors: Kretchmer Paul J. , Ozbun J. L. , Kaplan Stuart L. , Laing D. R. , Wallace D. H.
Published: July 2010

Growth habit of some Phaseolus vulgaris L. lines is influenced by geographic and seasonal environment, complicating their geographical adaptation. This study was undertaken to determine if this morphological instability is a photoperiodic or photomorphogenic response. Three P. vulgaris L. lines that changed from indeterminate bush to indeterminate climbing under different environments in Columbia, South America, and one line that did not were grown in controlled environments. Photoperiods of 12 vs. 18 hours did not affect the time at which climbing occurred or the percentage of plants that climbed. However, plants climbed 2 to 4 days earlier and the percentage of climbing plants increased 4.5 to 20‐fold when the dark period of either the 12 or 18‐hourphotoperiod was interrupted with 15 rain of red light. This indicates that the change in morphology was due to the reddight interruption and not to the effective length of the dark periods that such an interruption created, implying a photomorphogenic rather than a photoperiodic response. The morphological instability caused by a night break of red light was nullified when the red light was followed by a far‐red irradiation, suggesting that the morphological instability was controlled by phytochrome.
Inheritance of a Brachytic Character in Soybeans1
Authors: Kilen T. C.
Published: July 2010

An F3 soybean [Glycine max (L.) Merr.] breeding line (D74‐BL‐4) was crossed with the cultivar ‘Tracy’ to study the inheritance of a brachytic character. D74‐BL‐4 was only 59% as tall as Tracy, but had a similar number of nodes. Average plant height and node number of the F1 plants were slightly greater than those of Tracy. Segregation for the brachytic character fit a 3:1 ratio in the F3 population, and F3 lines segregated in a 1:2:1 ratio. The data indicate that the brachytic character is controlled by a single recessive gene. The gene symbol sb is proposed.
Effects on Cottonseed of Immersion in Acetone or Methylene Chloride1
Authors: Halloin John M.
Published: July 2010

Acetone and methylene chloride have been advocated as carrier solvents for incorporation of growth regulators and seed protectants into seeds. The penetration and effects of these solvents on cottonseed (Gossypium hirsutum L.) were studied. Seeds immersed in the solvents had normal germinability, whereas excised embryos and gin‐damaged seeds were killed by immersion in the solvents, apparently due to disruption of lipid systems. Seeds were soaked in solvents containing the dye oil red O; the dye penetrated the seed coat, but none entered the embryos. When excised embryos were immersed in dye solutions, the dye permeated throughout the embryos. Thus, seed coats are permeable to the solvents and the dye, but the nucellar layer surrounding embryos is impermeable, at least to the dye. Acetone and methylene chloride may be suitable for surface application of chemicals to sound cottonseed, but not for introduction of chemicals into embryos.
Effect of Aphid‐Transmitted Soybean Mosaic Virus on Yields of Closely Related Resistant and Susceptible Soybean Lines1
Authors: Ross J. P.
Published: July 2010

The effect of soybean mosaic virus (SMV) resistance on soybean yields during three growing seasons (1974, 1975, and 1976) was determined under circumstances of natural virus transmission by using closely related SMV‐resistant and susceptible lines (27 pairs). They were developed by backcrossing SMV resistance derived from PI 96983 or PI 170893 to cultivars ‘Dare,’ ‘Semmes’, ‘Pickett 71’, ‘Lee 68’, and ‘Ransom’. Susceptible lines in two of four pairs from the Dare backcross family manifested a “field resistance”, i.e., no significant yield reduction (5.2%). Yield reductions in other backcross families averaged from 35 (Semmes) to 20% (Lee 68 and Pickett 71); Ransom was intermediate at 27%.

The relationship of SMV infection to seed quality was examined by scoring seed from 1975 visually and by plating out seed from 1976 on agar to determine the percent infection by Phomopsis sp. Seed of susceptible lines appeared inferior to seed of resistant lines in 16 of 26 comparisons; in 17 of 26 pairs, Phomopsis sp. was isolated with greater frequency from SMV‐susceptible lines than from SMV‐resistant lines (18.7%) vs. 4.5%).
Early Generation Bulk Hybrid Yield Testing of Adapted Hard Red Spring Wheat Crosses1
Authors: Cregan P. B. , Busch R. H.
Published: July 2010

The parents, F1, F2 through F5 bulks, and 519 F5, lines from 28 crosses of a diallel produced from adapted high‐yielding hard red spring wheats (Triticum aestivum L.) were grown in standard nursery plots at two locations in 1975. Our objective was to determine the value of 1975 midparent, F1, and bulk generation yields and 1971‐73 midparent and bulk generation yields as predictive criteria for identifying crosses producing high proportions of superior‐yielding F5 lines in 1975. Except for the 1971‐73 midparental performance, all predictive criteria were significantly correlated with mean cross yield of F5 lines. The highest correlation (r=0.81. P≤ 0.01) was between F5 line means and the 1975 F2 bulk performance.

Of the F5 lines which yielded at least two standard deviations above the overall line mean, 67 and 56% were derived from sets of seven crosses (upper 25%) chosen on the basis of the 1975 mean F2 + F3 bulk yields and the 1971‐73 mean F2 + F3 bulk yields, respectively. This compared with 37 and 43% respectively, when 1975 and 1971‐73 midparental performances were used to choose sets of seven crosses. While bulk yields were more useful than midparent yields in identifying superior crosses at the 25% selection intensity, the superiority of the bulks was not as great at a cross selection intensity of 50%.
Effect of Planting Density on Correlations among Yield and Its Components in Two Corn Populations1
Authors: Ordas A. , Stucker R. E.
Published: July 2010

Forty‐eight S1 lines of corn (Zea mays L.) from each of two synthetic populations were grown at three planting densities at two Minnesota locations to estimate genotypic and phenotypic correlations between yield and its components (ears per plant, ear length, and kernel depth). A second objective was to assess predicted genetic gain for yield under S1 testing assuming direct selection for yield compared to progress for yield from selection for the components individually. A split‐plot arrangement in a randomized complete block design with two replications per location was used. Planting densities formed whole plots and split plots were S1 lines (arranged as blocks‐in‐replicates within whole plots).

Phenotypic and genotypic correlations were, in general, of the same magnitude and tended to increase with increased planting density although there were exceptions to this trend. All genetic variance estimates were significantly different from zero. Only the variances for ears per plant were different from each other at the high and the low density. Predicted genetic gains from direct yield selection were greater than correlated responses. The correlated responses for yield with ears per plant as the selection criterion were important in both populations at the high planting densities. Ear length appeared to be a satisfactory selection criterion for yield progress at the high density in one population.
Variety‐Specific Electrophoretic Variants of Four Soybean Enzymes1
Authors: Gorman M. B. , Kiang Y. T.
Published: July 2010

The purpose of this study was to examine the possible use of electrophoresis in soybean (Glycine max (L.) Merr.) variety identification. Seeds from 113 commercial soybean varieties were examined with polyacrylamide slab gel electrophoresis. Distinct variety‐specific electrophoretic zymogams were observed for acid phosphatase (AP), alcohol dehydrogenase (ADH), amylase (AM), tetrazolium oxidase (TO). The varieties displayed one of three banding patterns (zymograms) for each of the four enzymes. In the 4,411 seeds tested for these four enzymes, only four seeds yielded zymograms which were atypical of their respective variety. An additional nine seeds were probably of heterozygous genotype based upon the observed zymograms. Thus, the electrophoretic zymograms were stable varietal characteristics and could be used in varietal identification. Varietal pedigrees constructed from the available records indicated that variant dectrophoretic zymogram patterns were heritable, and that all variants could be traced back to an area of origin.
Growth and Maintenance Requirements of Subterranean Clover1
Authors: McCree K. J. , Silsbury J. H.
Published: July 2010

The growth and maintenance requirements of young communities of subterranean clover (Trifolium subtermneum L.) were determined from CO2 exchange rates, through the equation: N = kD + (l+k)cW, where and D are the nighttime and daytime 12 hour totals of CO2 exchanged, W is the CO2 equivalent of the dry weight, and k and c are growth and maintenance coefficients, respectively. Values of k and c were obtained from steady state tests in which the plant communities were allowed to equilibrate for several days, first with 12 hours of full light and 12 hours of darkness, and then in continuous darkness. The dynamic responses of the plants were determined in other tests, in which D and N were varied by changing the photon flux at 24 hour intervals and a linear regression of N against D was formed. Both sets of experiments were repeated at different temperatures in the range 10 to 35 C. At the lower temperatures the slope of the regression line in the dynamic response tests tended to be lower than the steady state values of k. This was interpreted to mean that the plants were not reaching a steady‐state of substrate production and use within 24 hours of a change in photon flux. A steady‐state condition is implicit in the equation since it does not include a storage term. The steady state values of k were virtually independent of temperature, while the value of c was an increasing exponential function of temperature, with a Q10 of 1.81. The values of k and c at 30 C (0.14 g.g−1 and 18 mg.g−1.12h−1 respectively) were not significantly different from those obtained in parallel experiments with white clover (Trifolium repens L.) (0.15 g.g−1 and 22 mg.g−1.12h−1). for subterranean clover, the value of Thornley's maintenance coefficient m was 48 mg.g−l.24h−1 at 30 C, with a Q10 of 1.85, which is consistent with the idea that the protein turnover rate determines the maintenance loss rate. The yield of new biomass carbon (C) per unit of C used (Thornley's Yg) was 0.75, which is consistent with estimates from quantitative biochemistry.
Effects of Reflectors, Black Boards, or Shades Applied at Different Stages of Plant Development on Yield of Soybeans1
Authors: Schou J. B. , Jeffers D. L. , Streeter J. G.
Published: July 2010

Our objective was to determine the effects of a 2‐week period of light enrichment or reduction at various stages of plant development on the number of pods and on seed yield of soybeans (Glyclne max (L.) Merr.). Soybeans were field‐grown at uniform populations on Wooster silt loam soil (Typic fragiudalf, mixed mesic). In 1973 and 1974 aluminum foil reflectors were positioned at a 45° angle to the ground on the north side of east‐west rows for a duration of 2 weeks. Reflector treatments, which were established weekly, increased the amount of photosynthetically active radiation received by the plants 57%.

In 1973 plants with light enrichment during late flowering and early pod formation, the period of greatest response, had 48% more pods (frults)/plant at maturity than controls. Stem plus fruit weight and total seed weight were increased 50 and 57%, respectively, over controls at maturity.

In 1974, black boards (non‐reflective surfaces), positioned in the same manner as the reflectors, and shades that gave a light reduction of 63%, were included as treatments for 2‐week periods. Reflector and black board treatments imposed at late flowering or early pod formation caused a 31 and 28% increase, respectively, over controls in the number of pods/plant at maturity. Seed yield from plants treated at the same period with reflectors and black boards was 40 and 27%, respectively, greater than controls. The number of pods and seed yield for shaded plants was reduced as much as 16 and 29%, respectively, below that of the controls. All plants aborted a large percentage of pods (27 to 34%) from 12 August to maturity.
Developmental Allometry and Its Implication to Grain Yield in Barley1
Authors: Hamid Zakri A. , Grafius J. E.
Published: July 2010

Five parental pairs of barley selections (Hordeum vulgate L. Emend. Lam) exhibiting differences in leaf area (S) and culm diameter (D) were used in this experiment. The crosses and backcrosses to each parent were allowed to self to the equivalent of the F4 at which time 20 random plant selections were drawn from each of the 15 populations. Seed was increased for two generations and standard nursery plot trials were conducted on the equivalent of the F7. The objectives were to observe the allometric relationships among leaf area, culm diameter, and the yield components, and to relate these relationships to differences in yield between the 15 populations.

Evidence was presented to show that earlier‐developed organs have a profound influence on later‐formed structures. A striking relationship was observed between the number of fertile tillers per unit area (X) and all the other plant organs involved. It was found that X was negatively correlated at a highly significant level with culm diameter (D) and the average leaf area (S). The pattern was clear: when the number of tillers increased, the size of the organs on each tiller tended to decrease. In other words, a genotype with a high number of tillers tended to have smaller culm diameters, smaller leaves and smaller heads. In addition, highly significant correlations were observed among D, S, and Y (number of kernels per head).

Grain yield (W) was not significantly associated with either D or S, although the two traits may be strongly correlated with one or more of the three components of yield. With this gene pool and in this particular growing environment, the components of yield were more limiting than the size of the photosynthetic surface in causing variation of grain yield among these cultivars.
A Possible Role for Leaf Cell Rupture in Legume Pasture Bloat1
Authors: Howarth R. E. , Goplen B. P. , Fesser A. C. , Brandt S. A.
Published: July 2010

Leaves from seven forage crop species were crushed in a mortar and pestle to demonstrate a relationship between susceptibility to mesophyll cell rupture and the tendency to cause bloat in ruminant animals. The bloat‐causing forages were alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and white clover (T. repens L.). The bloat‐safe species were cicer milkvetch (Astragalus cicer L.), birdsfoot trefoil (Lotus corniculatus L.), sainfoin (Onobrychis viciaefolia Scop.), and bromegrass (Bromus inermis Leyss.). Two grams of fresh leaves were crushed between two layers of 100‐mesh nylon cloth in a mortar and pestle. The leaf material which passed through the nylon cloth was suspended in 0.2 M sodium maleate buffer (pH 6.9) and allowed to separate into sediment and supernatant fractions by standing at 4 C for 45 min. The sediment fraction contained intact mesophyll cells and the supernatant fraction contained fragments of chloroplast lamellae which had been released from ruptured mesophyll cells. Compared to the bloat‐causing legumes, the bloat‐safe legumes had 10 to 20 times more whole mesophyll cells released from the leaf tissue. Conversely, the supernatant fractions from the bloat‐causing legumes contained 6 to l0 times more chlorophyll than supernatant fractions from the bloat‐safe legumes. These data showed that mesophyll cells in the bloat‐safe forage legumes were more resistant to mechanical rupture compared to mesophyll cells in the bloat‐causing forage legumes. Disruption of sainfoin leaves in buffer containing 10% polyvinylpyrolidone did not affect the number of whole mesophyll cells in the filtrate fraction. Hence the presence of tannins and leaf cell resistance to rupture are two separate and complementary explanations for the bloat‐safe nature of sainfoin. The bloat‐safe nature of cicer milkvetch, which does not contain tannins, was attributed to the resistance to rupture of the mesophyll cell walls.
Tannin Content and Inheritance in Common Bean1
Authors: Ma Yu , Bliss F. A.
Published: July 2010

Estimation of tannin in common bean (Phaseolus vulgaris L.) seed using a modified vanillin‐HC1 procedure revealed that white‐seeded strains contained no detectable amounts, and that, when present in colored seeds, tannin was located in the testae. Although dark‐colored seeds contained the highest amount, we did not find a strong relationship between tannin content and seed coat color. Analyses of four F2 populations, resulting from crosses between parents that differed in testa color and tannin content, revealed a high broad‐sense heritability for tannin content. The segregation patterns were similar in three of the four F2 populations, and a few genes seem to be responsible for genetic differences. In the F2 populations, seeds with black testae contained the most tannin, but recombinant types having black and other colors and relatively low tannin were identified. Low tannin strains may be obtained either by selecting among existing pure lines or by crossing and selecting for appropriate recombinants.
Accelerated Aging Studies of Normal and Segregating Chlorophyl Deficient Isolines of Pearl Millet1
Authors: Roos E. E. , Sowa S. , Burton G. W.
Published: July 2010

Pearl millet (Pennisetum americanum (L.) Leeke) seeds were subjected to accelerated aging for various periods at temperatures of 21 and 32 C and relative humidities (RH) of 70 and 90%. Seeds stored at 32 C‐90% RH rapidly lost germination capacity, while seeds stored at 21 C‐70% RH lost viability more slowly. Seedlings apparently passed through an abnormal stage before dying. Isogenic lines heterozygous for six different chlorophyl deficiency genes were allowed to self‐pollinate and the resulting seeds were tested to determine the effects of rapid aging on the ratio of normal to chlorophyl deficient seedlings. No differences in the genetic ratio were observed following accelerated aging.
Relationship of Photosynthetic Rate to Growth and Fruiting of Cotton, Soybean, Sorghum, and Sunflower1
Authors: Mauney J. R. , Fry K. E. , Guinn G.
Published: July 2010

Cotton (Gossypium hirsutum L.), sorghum (Sorghum bicolor L.), soybean (Glycine max L.), and sunflower (Helianthus annuus L.) plants were exposed during daylight hours to an atmosphere enriched with CO2 to 630 ppm (v:v) (HiCO2) in a glasshouse. Temperature was trolled continuously to produce a daily maximum of 35 C and a minimum of 21 C. Days were cloudless and long, May to August, in Phoenix, Ariz. Average CO2 exchange rate (CER) increased 15% for cotton, 2% for sorghum, 41% for soybean, and 7% for sunflower compared to the CER of these species at 330 ppm CO2 (LoCO2). The increase in CER was not statistically significant for sorghum and sunflower. Measurements of relative growth rate and net assimilation rate showed the growth rate of all species increased during the juvenile stage (10d‐30d) in the enriched atmosphere. and were not higher in the enriched atmosphere after the juvenile stage, but cotton and soybean plants maintained their larger size and greater absolute growth.

Final dry weights of cotton and soybean increased 110 and 380%, respectively, in HiCO2 compared to LoCO2. Lint yield of cotton was increased 180% by HiCO2 on a per‐plant basis and 88% on a unit leaf area basis. Became of growth fimitations imposed by terminal flowers, the final size of sorghum and sunflower plants in HiCO2 was not significantly larger than in LoCO2 These results imply that selection for CER will not effectively increase yield of determinate species such as sunflower and sorghum, but may effectively increase yield of indeterminate species such as cotton and soybean, if a sensitive assay for CER can be found.
Genetic Variability in Post‐harvest Respiration Rates of Sugarbeet Roots1
Authors: Wyse R. E. , Theurer J. C. , Doney D. L.
Published: July 2010

Post‐harvest respiration rates were measured on whole sugarbeet (Beta vulgaris L.) roots from 97 inbred and hybrid breeding lines to determine the magnitude of the genetic variability. Measurements were made between 50 and 160 days of storage at 5 C on 19 hybrids and inbreds grown at two locations; on eight hybrids and inbreds in 2 successive years; and on 76 inbreds.

A high correlation (r=0.90**) existed between the loss of sucrose and respiration rate. The respiration rate of the entries varied between years and between locations, but relative rankings remained consistent (rs=0.87** and 0.81**, respectively). The Spearman's coefficient for respiration rates between locations was similar to those for yield (rs=0.77**) and sucrose content (rs=0.89**). Single‐cross hybrids respired at a lower rate than the midparent mean and, in several cases, lower than the lowest component inbred. A range of 2.5‐fold in respiration rate was found within the 76 inbreds. No correlation existed between sucrose content or root size and respiration rate. Sufficient genetic variability exists within sugarbeet genotypes to sustain a breeding program designed to develop low‐respiring breeding lines.
Fertility of Eight Bermudagrass Clones and Open‐Pollinated Progeny from Them1
Authors: Richardson W. L. , Taliaferro C. M. , Abring R. M.
Published: July 2010

We determined the percent of open‐pollinated (OP) seed set for eight bermudagtass (Cynodon dactylon (L.) Pers.) clones and for 420 of their OP progeny in 1969 and 1970, respectively. After selecting 30 of the most fertile of the 420 progeny, we determined their percent of OP and self‐pollinated (SP) seed set for 3 and 2 years, respectively. Objectives of the studies were to characterize the seed‐set potential of the clones and their progeny, thereby estimating the variation that exists among bermudagrass genotypes for cross and self‐fertility, and to provide information pertinent to the genetic improvement of bermudagrass seed production.

The OP seed set was significantly different (P < 0.01) among the eight clones, ranging from 2.8 to 43.2%. Seed set of the 420 OP progeny ranged from 0 to 78.8%. Mean OP seed set of progeny families paralleled rather closely that of the maternal parent. Standard deviations for OP fertility of progeny clones increased as the OP fertility of the maternal clone increased.

The 30 selected clones differed significantly in both OP and SP seed set each test year and for the combined averages. The seed set percentages averaged over clones differed significantly between years for OP but not SP seed set. The year ✕ clone interaction was not significant for either OP or SP seed set. The OP seed set of the 30 progeny clones averaged over 3 years ranged from 15 to 57%, most values being considerably lower than the initial ones used as indices for their selection. The 2‐year averages for SP seed set ranged from 0.10 to 8.09%. The selffertility of 24 of the clones was, however, less than 1%.
Factors Influencing Development of Wheat‐Rye Hybrid Embryos in Vitro1
Authors: Tiara T. , Larter E. N.
Published: July 2010

Using Norstog's medium as a basic formulation, specific conditions were modified to improve its properties as a nutrient culture for 12 to 14‐day‐old triploid wheat‐rye hybrid embryos. Maximum normal embryo development was found to occur at a pH of 5.5, a sucrose concentration of 0.15 M, and a casein hydrolysate level of 2,500 rag/liter (equivalent to 400 rag/liter actual N).
Variability in Soybean Progenies Developed by Single Seed Descent at Two Plant Populations1
Authors: Martin R. J. , Wilcox J. R. , Laviolette F. A.
Published: July 2010

Progenies from three soybean (Glyelne max (L.) Merr.) crosses were advanced four generations by single seed descent in the greenhouse. Plants were grown at two populations, three plants/15 cm pot and nine plants/15 cm pot. Plant losses averaged 19% of the original population at the low density and 55% of the original population at the high density at the end of the four generations.

Gene frequencies for flower and pubescence color did not deviate from theoretical frequencies in the low density populations. At the high density population, significant deviations from expected values occurred for flower color in two crosses andf or pubescencceo lor in all three crosses. In two crosses the incidence of plants heterozygous for the gene controlling reaction to race 1 of Phytophthora megasperma Drechs. var. sojae Hildebrand was higher than expected.

A two replicate field test was used to evaluate progenies from the low and high density populations for maturity, lodging, plant height, and seed size. Progenies advanced from the high density population averaged 0.5 to 3.6 days later in maturity, 0.I to 0.2 higher in lodging score, and 0 to 4.3 cm taller than progenies advanced from the low density population.
Irradiance Response of Tall Fescue Genotypes with Contrasting Levels of Photosynthesis and Yield1
Authors: Wilhelm W. W. , Nelson C. J.
Published: July 2010

The purpose of this study was to determine if genotype by irradiance interactions or genetic variation in diurnal trends of CO2 exchange rate (CER) influenced the CER‐yield relationship in tall rescue (Festuca arundinacea Schreb.). Genotypes were selected in the field for high CER‐high yield, high CER‐lowyield, low CER‐high yield, and low CER‐Iow yield. Responses of CER to photosynthetic photon flux density (PPFD) of these genotypes were determined using both growth chamber‐ and field‐grown material. The shapes of the PPFD response curves were similar for all genotypes, and saturation occurred at approximately 1,200 μE m‐2 sec‐1 (400 to 700 nm) under both growth conditions. In a growth chamber at 25/20 C (light/dark), all genotypes achieved near maximal CER and photorespiration within 1 hour of the beginning of the photoperiod and maintained these rates throughout the rest of the photoperiod, with high CER genotypes exhibiting about 30% higher rates than low CER genotypes. Photorespiration rates were significantly correlated (r = 0.80) with CER. Leaf diffusive resistance were similar for all genotypes throughout the photoperiod.

Genotypic differences did not occur in PPFD‐response curves or diurnal patterns of CER. This suggests that differences in these two factors among genotypes are not the underlying cause of the poor relationship reported between short term measurements of leaf photosynthesis on recently collared leaves and forage yield. Other factors must be limiting genetic expression for CER in terms of yield.