bluuebunny/crossref_metadata_2025 huggingface dataset:
Response or ‘Chippewa 64’ Soybean Scions to Roots of Different Genotypes1
Authors: Cardwell V. B. , Polson D. E.
Published: July 2010

The objective of this study was to determine if the root system is a limiting factor in the productivity of soybeans [Glycine max (L.) Merr.]. The effect of soybean root genotypes on agronomic characteristics of ‘Chippewa 64’ scions was determined by hypocotyl grafts. The scion was dominant in determining seed weight, oil, protein, and maturity, while the root altered lodging, height, and seed yield. Most rootstocks increased lodging and reduced height and seed yield of grafted Chippewa 64 scions. Grafted and ungrafted Chippewa 64 plants were not significantly different in height, lodging, seed weight, oil, protein, maturity, or yield.
Genetic Control of Leaflet Number in Soybeans1
Authors: Fehr W. R.
Published: July 2010

The genetic control of leaflet number in soybeans [Glycine max' (L.) Merr.] was studied using a seven‐leaflet mutant (T255) found in the commercial three‐leaflet cultivar ‘Hawkeye’ and a five‐leaflet strain (T143) in the soybean genetic collection. The F1, F2, and F3 generations of the crosses Hawkeye ✕ T255, T143 ✕ Hawkeye, and T143 ✕ T255 were evaluated.

The seven‐leaflet character was controlled by a single major gene (Lf2). Dominance of the Lf2 allele controlling trifoliolate leaves was complete in the Hawkeye ✕ T255 cross, but partial dominance was present in other genetic backgrounds. Multifoliolate leaves in T143 were controlled by a single major gene with partial dominance for the Lf1 allele controlling the five‐leaflet character. There was independent assortment of the two genes controlling leaflet number. Homozygous Lf1Lf1lf2lf2 individuals with up to 15 leaflets per leaf have been observed.

Leaves of T255 with seven leaflets had a longer rachis by 8 mm and 9.4% greater leaf area than trifoliolate leaves of Hawkeye. No difference in seed yield was observed between Hawkeye and T255, indicating no yield advantage for plants with leaves with more than three leaflets.
Influence of Root‐zone Temperature and P Supply on Total and Inorganic P, Free Sugars, Aconitate, and Soluble Amino N in Corn1
Authors: Patterson R. P. , Grunes D. L. , Lathwell D. J.
Published: July 2010

Corn (Zea mays L.) plants were grown for 4 and 6 weeks in sand culture at root‐zone temperatures of 15, 20, and 25 C and P levels of 2, 9, and 30 ppra P to test the hypothesis that increased P could overcome the effects of low root‐zone temperature. Growth of roots, sheaths, and blades was restricted when plants were exposed to rootzone temperatures of 15 or 20 C and P levels of 2 or 9 ppm P, compared to growth at 25 C and 30 ppm P. Concentration of total P in all plant parts was as great at 15 as at 25 C. The harmful effects of low root‐zone temperature were not overcome by the application of higher P rates. Concentration of inorganic P and the fraction of total P that was inorganic P were higher at the lower temperature for shoots and P‐deficient roots. Free sugar levels in roots were lower at 25 than at 15 C at all P levels. Sugar levels in sheaths and blades, however, were lower at the higher temperature only under P‐deficient conditions. Concentrations of aconitate and soluble amino acids were highest at 15 C, irrespective of P supply. Since metabolism of photosynthate to the level of organic and amino acids was not impeded by low root‐zone temperature, it is suggested that low temperature stress was depressing growth by restricting incorporation of amino acids into protein.
Factors Affecting the Tannin Content of Sorghum Grain As Determined by Two Methods of Tannin Analysis1
Authors: Maxson E. D. , Clark L. E. , Rooney L. W. , Johnson J. W.
Published: July 2010

The ferric ammonium sulfate and modified vanillin‐hydrochloric acid methods of tannin analysis were used to measure the tannin content of samples of sorghum [Sorghum bicolor (L.) Moench] grain. The overall correlation between the two methods was good when all samples were considered. Samples of ‘Ga 615,’ a brown‐seeded hybrid, were grown at each of six locations for 3 years. Both methods of tannin analysis showed a significant environmental effect on tannin content. The genes, B1B2S, that control pericarp color and presence or absence of a pigmented testa significantly affected tannin content. The major effect was a high tannin content associated with the pigmented testa. Tannin content was higher in grain with a red pericarp than grain with a white pericarp in both nonrelated material and in near‐isogenic lines. This pericarp pigmentation is controlled by genes other than the B1B2S genes.
Growth Response of Corn to Changes in Root Temperature and Soil Water Suction Measured with an LVDT1
Authors: Barlow E. W. R. , Boersma L.
Published: July 2010

The rate of corn (Zea mays L.) leaf elongation was continuously monitored with a Linear Variable Differential Transducer (LVDT) which accurately measures the rapid changes in leaf elongation rate that occur after a plant is released from stress. Short‐term measurements of leaf elongation rate at varying root temperatures gave qualitatively similar results to those obtained by other workers in long‐term experiments. The leaf elongation rate increased rapidly when plant roots were released from low temperature or water stress. The maximum leaf elongation rate achieved after the the release from stress was higher than the maximum rate of unstressed plants.
Diploid Interspecific Hybrids of Tripolium pratense L., T. diffusum Ehrh., and Some Related Species1
Authors: Schwer J. F. , Cleveland R. W.
Published: July 2010

Pollen from Trifolium hirtum All., T. diffusum Ehrh., and T. pallidum Waldst. & Kit. on pistils of T. pratense L. germinated and the tubes grew through the styles to the vicinity of the ovules. Likewise, pollen from T. pratense on pistils of T. diffusum and T. pallidum germinated, and the resulting tubes grew to the vicinity of the ovules. Compatible matings within T. pratense resulted in vigorous pollen tube growth, similar to that of the interspecific combinations.

Matings of T. pratense with T. pallidum and T. hirtum produced no mature seeds. Embryos were collected at 7 days of age, but no hybrids were satisfactorily grown in embryo culture. Many hybrids were produced by mating T. pratense ✕ T. diffusum, but none were obtained from the reciprocal mating. Hybrids were generally chlorotic in the seedling stage, and chlorosis was observed on young leaves in older plants. Most floral and vegetative characteristics of hybrids were intermediate to the parents.

All F1 hybrids of T. pratense ✕ T. diffusum were 2n = 15 and meiosis was very irregular. Univalents and bivalents at MI averaged 1.6 and 1.3 per cell, respectively. The remainder of the chromosomes were associated in complex multivalents of 3 to 15 members. Most multivalents were chains, and bivalents were rods. Up to three bridges with fragments were found at AI, and bridges were also seen at All. These chromosomal abnormalities indicate the presence of translocations and paracentric inversions. It was concluded that T. pratense and T. diffusum had complex differences in chromosome structure.

The F1 of T. pratense ✕ T. diffusum was nearly sterile. However, backcrosses to T. pratense produced a few plants that may have been polyploids. The BC1 plants flowered and were partially fertile.
Frequency Changes of Isozyme Alleles in a Selection Experiment for Grain Yield in Maize (Zea mays L.)1
Authors: Stuber C. W. , Moll R. H.
Published: July 2010

Frequencies of alleles associated with three peroxidase isozyme systems and one acid phosphatase system were monitored through nine cycles in a maize (Zea mays L.) selection program for grain yield that originated from (NC7)✕ CI21) syn 2. The same isozymes were also evaluated in an unselected population following 20 generations of random mating of (NC7)✕ CI21) syn 2. for the three peroxidase systems the dominant alleles became fixed in both the unselected and selected populations.

Two codominant alleles (F and S) were found in the acid phosphatase system with the heterozygote exhibiting two parental bands and an intermediate hybrid band. Frequency of the F allele increased from 0.50 to 0.76 in the first six cycles of selection; however, it now appears that the population is approaching a stable intermediate frequency (0.60). Although the changes in frequencies suggest an association of this acid phosphatase locus with yield, close linkage with another "yield" locus cannot be ruled out.
Variation in Leaf Development and Dry Matter Yield Among Kenaf Varieties and Introductions1
Authors: Adamson W. C. , White G. A. , Higgins J. J.
Published: July 2010

Eight kenaf (Hibiscus cannabinus L.) entries, including five Russian introductions and three Western Hemisphere varieties, were compared in two planting dates at two locations for difference in leaf accumulation and dry‐stem yield. One introduction, P.I. 343142, produced more leaves than any Western Hemisphere variety at both locations for both early and late planting dates. No entry ✕ planting date interaction for leaf accumulation was found. Western Hemisphere varieties produced greater stem yields at both locations and for both planting dates. Stem yields were correlated with leaf accumulation only in the late planting at the northernmost location.
Competition for Environmental Resources by Component Characters1
Authors: Grafius J. E.
Published: July 2010

Do component traits such as numbers of heads/area, seeds/head and weight/kernel compete for the same environmental resources? If so, how can this competition be measured objectively? The general case of two trait competition was examined. When each trait competes more severely with itself than with others, stable equilibria will be found. At some point in development it becomes more difficult for the plant to add, say, another head than to add more seeds per head. The conclusions regarding two competing traits were extended to three traits and applied to the components of yield in oats (Avena sativa L.). The findings seemed to Imply that stable equilibria existed for the three environments and the 36 lines tested. The analysis showed that the component traits shared a common pool of environmental resources but that also certain resources were trait specific. The practical aspects of these findings were discussed.
Maize Fodder—Influence of Barrenness on Yield and Quality1
Authors: Marten G. C. , Westerberg P. M.
Published: July 2010

Our objective was to establish the relative yield potential and quality of high‐sugar, male‐sterile (barren) vs. normal, male‐fertile (fruited) maize (Zea mays L.) for silage crops. We produced fodder from a male‐sterile and a male‐fertile cultivar by procedures causing both barren and fruited plants of both cultivars during each of two years. Feed quality, dry matter yield, and digestible dry matter yield were determined for husked ears, stover, and fodder.

Barrenness reduced in vitro digestibility of fodder from the male‐fertile cultivar, but it did not affect digestibility of the male‐sterile. However, total non‐structural carbohydrate concentration of the fodder was greatly reduced by barrenness of both cultivars. Crude protein of the fodder was not affected by barrenness.

Fruited plants yielded 20% more fodder dry matter than barren plants of both cultivars. The fruited plants also yielded more digestible dry matter (22 to 27% more than barren plants).

We confirmed the hypothesis that preventing grain formation in maize reduces its efficiency in producing fodder dry matter. Our results show that maize breeders are likely to produce higher yielding, high quality silage cultivars by developing male‐fertile, fruited genotypes instead of male‐sterile, high‐sugar genotypes.
Seasonal and Canopy Variation in Nitrate Reductase Activity of Soybean (Glycine max L. Merr.) Varieties1
Authors: Harper J. E. , Nicholas J. C. , Hageman R. H.
Published: July 2010

An in vivo assay was used to determine if differences existed in nitrate reductase activity among 16 soybean (Glycine max L. Merr.) varieties within four maturity groups. Canopy and seasonal profiles of nitrate reductase activity were determined. All varieties exhibited highest nitrate reductase activity per leaf ✕ nr in upper leaves of the plant canopy during growth stages up to mid pod fill. Activity levels were similar throughout the plant leal canopy following mid pod fill. Nitrate reductase activity per leaf × hr at a given node was generally highest the initial date at which the leaf was sampled and activity declined with leaf age. Mean nitrate reductase activity (µmoles NO‐2 formed per g fresh wt × hr) for the entire leaf canopy was highest in the seedling stage for all maturity groups and declined as the plants matured. Activity of the total plant (µmoles NO‐2 formed per plant × hr) was maximal at approximately the full bloom stage with all maturity groups, irrespective of the calendar date at which the maturity groups attained full bloom. Thus, enzyme activity appeared to be closely associated with physiological growth stage. Genetic variation (up to 1.8 fold) in enzyme activity (seasonal means of µmoles NO‐2 formed per plant × hr) was found within maturity groups II, III, and IV. However, enzyme activity did not correlate with either seed yield or seed protein content.
Combining Ability for Grain Yield, Percent Protein, and g Lysine/100 g Protein in a Nine‐parent Diallel of Sorghum bicolor (L.) Moench1
Authors: Collins F.C. , Pickett R.C.
Published: July 2010

Parents and one set of F1 hybrids from a nine line diallel of Sorghum bicolor (L.) Moench were evaluated for combining ability for grain yield, percentage protein, and g L/100g P using the Griffing analysis. The ranges in performance were 31 to 159 q/ha for yield, 9.2 to 18.2% for protein and 1.74 to 2.74% for lysine in the protein. General (GCA) and specific (SCA) combining ability were found to be important for all three characters. The GCA:SCAra tio of mean squares indicated that additive gene action was more important for protein and less important for yield and g L/100g P. One parent had large GCA effects for all three characters. Several hybrids exhibited heterosis for yield, but only a few hybrids showed heterosis for percentage protein while no positive heterosis was observed for gL/100gP. Protein was negatively correlated with gL/100gP and yield. Yield and gL/100gP were positively associated.
Delayed Flowering of Saccharum spontaneum L. and Related Hybrids
Authors: James Norman I.
Published: July 2010

Artificial light from 12 midnight to 2 a.m. each night for various periods prior to floral initiation drastically reduced intensity of flowering of most Saccharum spontaneum clones and delayed emergence of those panicles that did emerge in some clones as much as 105 days.

A 12.5‐hr photoperiod for 3 or 4 weeks after floral initiation occurred naturally delayed flowering of backcross progeny of S. spontaneum ✕ commercial‐type Saccharum sp. hybrids an average of 12.4 days with a range from 0 to 25 days among clones.
Influence of Temperature at Various Growth Stages of Oat Cultivars. I. Utilization of Controlled Environment Chambers, Climatological Data and Developmental Growth Stages1
Authors: Taylor G. A. , Frey K. J.
Published: July 2010

An approach is discussed that permits an evaluation of genotype ✕ temperature and growth stage ✕ temperature interactions in oats (Avena sativa L.). Methods were developed that permitted the assay (a) of genetic differences for tolerance to temperature stress among four oat cultivars and (b) of reactions of four oat cultivars when stress temperatures were applied at several growth stages.

Controlled environment chambers were programmed to simulate climatological data for the Iowa oat‐growing season of April through June. Three temperature levels (high, control, and low) were imposed at five growth stages (initiation and differentiation of tillers, differentiation of floral reproductive structures, elongation of shoot apex, anthesis, and grain filling) on four diverse oat cultivars.

Even though an experimental unit consisted of only one plant per 4‐inch pot, the precision of experimentation, measured by coefficients of variation (CV), was quite acceptable. The CV's for seed yield varied from 8.2 to 9.6%, similar to oat yield trials in the field where the sample size is about 500 plants.
Modification of Flowering in Pima Cotton with Ethephon1
Authors: Pinkas Leonard L. H.
Published: July 2010

In greenhouse experiments 2‐chloroethylphosphonic acid (ethephon) was applied to American Pima cotton (Gossypium barbadense L.) plants, cultivar ‘Pima S‐4,’ to determine if the first‐formed (lowest) floral buds could be easily removed. At altitudes above 762 m (2,500 feet) this cultivar may set fruit too low on the plant for efficient mechanical harvesting when it is grown on soils of less than average productivity. Spray applications of 0.032M Ethephon raised the node level of the first flower about four nodes. The timing of the application did not appear to be unreasonably critical.
Performance of Diallel Cross Progenies for Certain Morphological Traits in Bromus inermis Leyss.1
Authors: Mishra S. N. , Drolsom P. N.
Published: July 2010

A diallel cross including reciprocals was performed on six random clones of smooth bromegrass (Bromus inermis Leyss.) to investigate differences for certain morphological traits. Differences among crosses were significant for plant height, leaf length, leaf width, panicle length, number of spikelets per panicle, number of florets per spikelet, number of panicles per plant, vigor, and plant type. for these traits the variance was partitioned info general, specific, maternal, and nonmaternal reciprocal effects. General combining ability was more important than specific combining ability for all traits except leaf width. Maternal effects were significant for plant height, leaf length, and panicle length. None of the nonmaternal reciprocal effects were significant. Both narrow and broad sense heritabilities were estimated.
Cyanogenesis: Its Inheritance in Sorghum bicolor, Sorghum sudanense, Lotus, and Trifolium repens—A Review1
Authors: Nass Hans G.
Published: July 2010

Associations of HCN potential with many plant characteristics have been reported for Sorghum bicolor and Sorghum sudanense. In the literature dominance or partial dominance for genetic control of both high and low HCN potential is indicated in these crops. The number of genes regulating HCN production in sorghum and sudangrass has not been established. Cyanogenesis in Trifolium repens is governed by the interaction of two independently segregating pairs of genes: (i) Ac:ac — for the presence or absence of the cyanoglucoside lotaustralin; and (ii) Li:li — for the presence or absence of the enzyme linamarase. A similar mechanism appears to be operating in Lotus with additional modifier genes. Several environmental factors play an important role in regulating cyanoglucoside and enzyme frequencies in Trifolium repens. A part of the mechanism by which the polymorphism of the cyanoglucoside of L. corniculatus is maintained under natural conditions may be through feeding on the acyanogenetic forms by several animals.
X Y Z System of Producing Hybrid Wheat1
Authors: Driscoll C. J.
Published: July 2010

A chromosomal recessive male‐sterility factor and a corresponding fertility factor on a homoeologous alien chromosome make available a system of producing hybrid wheat, Triticum aestivum L. era. Thell. Three lines, X, Y, and Z, are homozygous for the male‐sterility factor and contain 2, 1, and 0 doses of the alien chromosome, respectively. Limited roguing of plants possessing an alien trait is involved in the first stage only. Acquisition of required genetic stocks appears feasible.
Inheritance of Resistance to Isolates of Fusarium oxysporum var. batatas in Burley Tobacco1,3
Authors: Jones J. L. , Gupton C. L. , Terrill T. R.
Published: July 2010

Two genetic experiments designed for diallel analysis and generation means analysis were utilized to study the nature of gene action conditioning resistance to four isolates of Fusarium oxysporum var. batatas in burley tobacco (Nicotiana tabacum L.). Plants were evaluated for their reaction as seedlings in the greenhouse. The diallel experiment, consisting of all possible crosses among five burley tobacco parents, was analyzed according to the procedures of Griffing and Jinks‐Hayman. The generation means experiment included the P1, P2, F1, F2, P1F1, and P2, F1 generations of the cross between ‘Kentucky 12’ and ‘Judy's Pride.’

General combining ability mean squares and Hayman's D (additive component) were highly significant for each isolate. There was close association between the ranking of the parental entries for general combining ability effects and parental performance per se, indicating that predictions of Fl hybrid performance can be made from parental performance. The generation means analyses showed additive gene effects to be most important and dominance and epistatic effects to be relatively unimportant in the inheritance of resistance to each of the isolates and their mixture. Narrow‐sense heritability estimates indicated that rapid genetic advances through selection could be made for resistance to Fusarium wilt.
Identification of Hybrids from Alfalfa Crosses by Electrophoresis of Single Seed Proteins1
Authors: Miller M. K. , Schonhorst M. H. , McDaniel R. G.
Published: July 2010

A simple procedure far distinguishing hybrids from selfed alfalfas (Medicago spp.) by extraction and separation of proteins from single alfalfa seeds using disc‐gel electrophoresis is described. One protein band was consistently light in three S1 (first generation selfed) lines, consistently dark in another S1 line; and varied in two other S1 lines. Hybrids of parents with light and dark protein bands contained the protein at an intermediate concentration. Hybrids could thus be differentiated from selfs and crossing percentages determined. Variation in number and density of protein bands among plants within cultivars tested was very pronounced. Better extraction resulting in enrichment of bands was obtained when seeds were crushed rather than cut in half. Embryos and whole seeds produced similar bands.
Temperatures in Early Post‐Transplant Growth: Effect on Shape of Mature Nicotiana Tabacum L. Leaves1
Authors: Raper C. David , Thomas Judith F.
Published: July 2010

Tobacco plants (Nicotiana tabacum L. ‘Coker 319’) were grown in controlled environment rooms under a simplified simulation of seasonal temperature progression. The temperature simulation was differentially modified only during the first 10 days of post‐transplant growth. The temperatures during this period were effective in determining the final shape of leaves from the upper half of the plant. In addition to the generally accepted role of night temperature, day temperature during this initial post‐transplant period was critical in determination of final leaf shape.
Genetic Effects Estimated from Generation Means in Four Diallel Sets of Maize Inbreds1
Authors: Darrah L. L. , Hallauer Arnel R.
Published: July 2010

Genetic parameters were estimated from generation means in four types of maize (Zea mays L.) inbred lines: first cycle lines, isolated from open‐pollinated varieties; second cycle lines, isolated from either planned pedigree crosses or synthetic varieties; good lines per se; and poor line per se. Nine generations were available for each cross: parents, F1, F2, F3, backcrosses, and backcrosses selfed. Parameters estimated were additive, dominance, and digenic epistatic effects.

Second‐cycle inbreds demonstrated significantly more epistasis for yield than did first‐cycle inbreds. Good and poor inbreds were similar and intermediate to first‐ and second‐cycle inbreds in the occurence of epistasis, which occurred in 30% of the crosses. Interactions of environments ✕ additive and dominance effects were significant in more than two‐thirds of the crosses. The environments ✕ epistasis interactions were significant in 25% of the cases for the poor inbreds.

Dominance effects were several times larger than additive effects for all crosses. Pooling of effects over loci is discussed as the reason for disagreement with results of variance analyses. Additive ✕ additive and dominance ✕ dominance interactions were present in half the crosses of the poor inbreds. Significance of epistatic effects and additive effects was found in about the same frequency in the other types of inbreds.

Correlation analyses indicated the nonepistatic model sufficient to describe the gene action, since all r values exceeded 0.9**. The full model including epistatic terms was of value in describing a particular environment, but the epistatic terms were of no value when predicting yield in one environment from trials in a different environment.
Recurrent Selection for Lodging Susceptibility and Resistance in Corn1
Authors: Thompson D. L.
Published: July 2010

Recurrent selection was practiced for two corn synthetics, Syn 8 and Syn 9 (Zea mays L.), for lodging susceptibility (6 cycles) and lodging resistance (7 cycles) counting erect plants at maturity. Selection progress was evaluated using crosses between comparable cycles of the two synthetics and determining changes for the following traits: erect plants; ratings for root clump, rind puncture, and stalk rot; stem section dry weight, crushing strength, rind thickness, specific gravity, water content, and pith ratings; and yield and other agronomic characters. Compared with the cross of the original synthetics as 100%, the last cycle for susceptibility (cycle 6) had 28% as many erect plants and the last cycle for resistance (cycle 7) had 228% as many. Observed means for these comparisons were 40.3, 11.3, and 91.9% erect plants, respectively. All possible simple correlation coefficients among the stalk and root quality traits were significant at the 1% level except for pith ratings. The use of a single selection criterion (erect plants) insured that associated changes in other traits were not confounded by other conscious selection.
Effect of Timing of Irrigation on Total Nonstructural Carbohydrate Level in Roots and on Seed Yield of Alfalfa (Medicago sativa L.)1
Authors: Cohen Y. , Bielorai H. , Dovrat A.
Published: July 2010

This study was undertaken in order to assess the effect of certain soil moisture regimes, manipulated by timing of irrigation, on the seed yield of alfalfa (Medicago sativa L.)

Sprinkler‐irrigated alfalfa (cv ‘Hairy Peruvian’) was cut once and the regrowth was left for seed production or cut periodically for forage during the spring to midsummer period. Seed plots were irrigated either at day 10 or 23, or both (following cutting) to 180‐cm soil depth. Forage plots were irrigated once immediately after each cutting.

Irrigation at day 23 resulted in a considerably lower rate of foliar regrowth during the 1st 3 weeks following cutting than when irrigation was applied at day 10. Slow regrowth was conducive to greater accumulation of total nonstructural carbohydrate (TNC) in roots than quick regrowth. High TNC level in the roots was associated with high percentage of pods set and with high seed yield. Irrigation both at day 10 and also at day 23 increased the flowering intensity that was associated with a lower percentage of pods set than the other treatments. The seasonal decline of TNC in the roots of plants harvested for seed was smaller than that in the roots of plants cut for forage.

It was concluded that timing of irrigation that leads to an increase in the root reserves during the period of initial regrowth is likely to increase the seed yield potential of alfalfa.
Influence of Temperature on Germination and Elongation of the Radicle and Shoot of Corn (Zea mays L.)1
Authors: Blacklow W. M.
Published: July 2010

Radicle and shoot elongation of seedlings of corn (Zea mays L. cv ‘UH108’) grown in wet, freely drained vermiculite were approximated by linear functions of time. The rates of elongation were greatest at about 30C and effectively ceased at 9 and 40C. The time for initiation of a radicle and a shoot decreased to a minimum at 30C with the radicle preceding the shoot. The water content of the seeds at initiation of the radicle were 57% at 30C and increased at less favorable temperature to as much as 75% at 12C. Shoot initiation occurred at 7 to 10% higher water contents than radicle initiation. The rate of radicle elongation was independent of the shoot but removal of the radicle reduced shoot growth by 15% at 20C. The apical meristem of an emerged seedling at 20C remained below the soil surface and was a function of the depth of planting. The equations derived for the processes and events have been incorporated into a mathematical model to predict germination and emergence of corn.
Effects of Herbicides Applied Preplant or Preemergence on Weeds and Sunflowers1
Authors: Johnson B. J.
Published: July 2010

Herbicides applied preplant or preemergence were evaluated on weeds and sunflowers (Helianthus annuus L.) over a 3‐year period at Experiment, Georgia. Alachlor (2‐chloro‐2',6'‐diethyl‐N‐(methoxymethyl) acetanilide) applied in combination with either chlorpropham (isopropyl m‐chlorocarbanilate) or prometryne (2,4‐bis(isopropylamino)‐ 6‐(methylthio)‐s‐triazine) were the only herbicide treatments that satisfactorily controlled both grasses and broadleaf weeds in sunflowers planted in April and June from 1969 through 1971. A higher percentage of broad leafweeds was controlled with herbicides applied preemergence to sunflowers planted in April than when applied to sunflowers planted in June. Sunflower plants were severely injured from incorporated treatment of nitralin (4‐(methylsulfonyl)‐2,6‐dinitro‐N,N‐dipropylaniline) in 1 year and from incorporated or injected treatments of EPTC (S‐ethyl dipropylthiocarbamate) in 2 years. Herbicides applied preemergence to sunflowers planted in April did not affect achene yields when compared with the untreated check, whereas, alachlor applied alone or in combination with chlorpropham or prometryne to sunflowers planted in June produced higher yields than did the untreated check. None of the herbicide treatments caused sunflowers to have a higher achene oil content than did untreated sunflowers.
Interaction of Initial Seed Moisture and Imbibitional Temperature on Germination and Productivity of Soybean1
Authors: Hobbs P. R. , Obendorf R. L.
Published: July 2010

This study compared the interaction of seed moisture and imbibition temperature of soybean [Glycine max (L.) Merr.] to (i) optimum survival and seedling growth, (ii) soaking injury to seeds, (iii) quantity of organic leachates from germinating seeds, and (iv) growth and yield under field conditions.

Thirteen to 14% seed moisture (dry weight basis) was the lowest moisture content resulting in optimum protection against chilling temperatures during imbibition in both ‘Chippewa 64’ and ‘Acme’ soybean varieties. With seed moisture at 5%, exposure to chilling during imbibition or during seed soaking resulted in decreased survival and seedling vigor. The combination of anaerobically soaking 5%‐moisture seeds at 5 C was nearly fatal. Transverse cracks and yellowing and browning of cotyledons were observed after cold or warm imbibition of 5 but not 13% moisture seeds. Soaking of 5% moisture seeds increased the visible injury to cotyledons. The loss of survival after soaking low‐moisture seeds at 5 C was greater than the additive effects of chilling and soaking. Loss of sugars and ninhydrin positive materials as leachate was primarily a function of cold temperature during imbibition, but 13% initial seed moisture gave little protection against loss of leachates. After a severe reduction in survival from imbibitional chilling of 5% moisture seeds, surviving plants of the Acme variety were shorter, produced fewer fruits and seeds, and yielded less grain and stover under field conditions. Losses were avoided by equilibrating seeds to 13% moisture before imbibition.
Effect of Gibberellic Acid on Alfalfa (Medicago sativa L.)1
Authors: Cole D. F. , Dobrenz A. K. , Massengale M. A.
Published: July 2010

The objectives of this investigation were to evaluate the effects of gibberellic acid (GA) on yield, photosynthesis, respiration, specific leaf weight (SLW) and carbohydrate root reserves in alfalfa (Medicago sativa L.) grown under irrigated field conditions at Tucson, Ariz. Data showed that GA significantly increased forage yield on treated plants; regrowth on these plants, however, was reduced. Increases in forage production from GA‐treated plants were due to increased stem production. Photosynthesis, respiration, and SLW were significantly decreased by GA application, and roots from plants sprayed with GA had lower percentages of free and acid‐hydrolyzable (A‐HC) carbohydrates. The results indicate GA affected the ‘source‐sink’ relationship in trans‐location and carbohydrate storage in alfalfa.
Protein, Oil, and Fatty Acid in Developing Soybean Seeds1
Authors: Rubel A. , Rinne R. W. , Canvin D. T.
Published: July 2010

We followed the deposition of protein, oil and fatty acids in developing seeds of ‘Acme,’ ‘Chippewa,’ and ‘Harosoy 63’ soybeans [Glycine max (L.) Merrill] to gain a better insight to the accumulation of these components. Nonprotein N and protein N were estimated by micro‐Kjeldahl procedure. Oil was determined by NMR, while fatty acids were analyzed by gas liquid chromatography.

At approximately 25 days after flowering the composition of the seeds was about 30% protein and 5% oil; however, this represents only 2% of the total protein and 1% of the oil in the mature seed.

From 24 to 40 days after flowering, oil percentage increased rapidly to 20%, which represents 30% of the total oil in the mature seed. The percentage of palmitic, stearic, and linolenic acid in the oil decreased, while the percentage of oleic and linoleic acid increased during this period. Although the percent values of the fatty acids changed markedly, actual amounts of all fatty acids increased. Percent nonprotein N decreased slightly, while percent protein N showed a concommittant rise from 24 to 40 days after flowering.

During the remainder of the deevlopment (about 25 days) of the soybean seed, percent values of the components remained essentially constant. During this time, however, 70% of the total protein, oil, palmitic acid, oleic acid, and linoleic acid were synthesized, and 65% of the total stearic acid and 50% of the total linolenic acid also were synthesized.
Effect of Temparature Preconditioning and Cultivar on Ryegrass (Lolium sp.) Seed Dormancy1
Authors: Wiesner Loren E. , Grabe Don F.
Published: July 2010

This study was conducted to determine if cultivar differences in seed dormancy existed in ryegrass (Lolium sp.), and whether seasonal differences in dormancy could be related to temperature during the seed development period.

Field‐grown ryegrass cultivars differed in degree of seed dormancy when grown under the same field environment. ‘Gulf,’ ‘Florida Rust‐Resistant,’ and ‘Magnolia’ annual and ‘NK‐100,’ ‘Manhattan,’ ‘Atempo,’ ‘Petra,’ and ‘Pelo’ perennial ryegrass cultivars were considered dormant. ‘Obahikari’ annual and ‘Verna Pajdjerg’ and ‘Linn’ perennial ryegrass cultivars were nearly nondormant.

Temperature preconditioning during seed development and maturation affected the degree of dormany present in freshly harvested seed. These studies were conducted using a detached culm technique in growth chamber and greenhouse facilities. The dormancy response of Gulf seed produced on detached culms was similar to that of seeds from intact plants, lending validity to the use of this technique. Gulf seeds developed at low temperatures were dormant, but those developed at high temperatures were nondormant. The duration of exposure to different temperatures and the stage of development at which the seeds were exposed to high or low temperature also influenced the degree of dormancy. Exposure to 1 week of low temperature during ripening increased seed dormancy, but at anthesis reduced dormancy. Extended periods of low temperature during seed development increased seed weight. Seed weight was reduced when seeds were exposed to high temperatures during the 2nd week of seed development.

A multi‐temperature technique was used to characterize the degree of dormancy present in the seeds.
Comparison of S1 and Open‐Pollination Progenies of Astragalus cicer L. for Certain Agronomic Characters1
Authors: Townsend C. E.
Published: July 2010

Self‐ (S1) and open‐pollination (O.P.) progenies of 24 self‐compatible S0 plants of cicer milkvetch (Astragalus cicer L.) were evaluated in the field for forage yield, height, spread, vigor score, and date of flowering. One generation of inbreeding had such a deleterious effect on plant vigor that paired S1 and O.P. progenies could be differentiated visually. Forage yields of the S1 progenies were approximately 50% of the forage yields of O.P. progenies. Considerable variation occurred among S0 plants for inbreeding depression. Inbreeding delayed flowering approximately 10 days in the seedling year, but there was little difference between the S1 and O.P. progenies for mean date of flowering in subsequent growth periods. There was no relationship between the self‐compatibility of the S0 parents and forage yields of their S1 and O.P. progenies.

There were significant differences among S0 parents for general combining ability. Open‐pollination progenies of several S0 plants with average vigor performed better than similar progenies of S0 plants with excellent vigor.

Simple correlation coefficients between forage yield, height, spread, vigor score, and date of flowering were highly significant. The associations between vigor score and forage yield were the highest with coefficients of —0.93, —0.91, and —0.92 for the one harvest in 1970 and the first and second harvests in 1971, respectively.
Multiple Cottonseed Treatments: Effect of Sequence of Application of Pesticides on Germination, Seedling Growth, and Survival1
Authors: Ranney C. D. , Heartley W. H.
Published: July 2010

This study evaluates the effect of the sequence of application of pesticides used as seed treatments on germination, seedling growth, and field survival of cotton (Gossypium hirsutum L.). In separate tests three protectant fungicides, 2‐(thiocyanomethylthio)benzothiazole (Busan 72), pentachloronitrobenzene + 5‐ethoxy‐3‐trichloromethyl‐ l,2,4‐thiadiazole (Terracoat L21), or bis(dimethylthiocarbamyl) disulfide (thiram) were used with the systematic fungicide l,4‐dichloro‐2,5‐dimethoxybenzene (chloroneb) and the systemic insecticide 0,0‐diethyl S [2‐(ethylthio)ethyl] phosphorodithioate (disulfoton), and were applied in all feasible combinations of the various pesticides. Evaluations included germination tests at standard conditions, at constant 20 C, and a constant 30 C. Dry weight transfer (DWT) determinations were made at 20 and 30 C, and seedling survival in the field at Stoneville, Miss. 42 days after planting.

In all three studies the results indicated that the sequence of pesticide treatment affected subsequent performance of cottonseed. In the case of Terracoat L21, only seedling survival in the field was not significantly affected by the sequence of pesticide application. ‘Traditional’ sequence of application — protectant fungicide followed by the systemic fungicide and then by the systemic insecticide — was the best sequence with these pesticides. When Busan 72 was used, alternative sequences proved to be more effective. When thiram was used, application of disulfoton first, irrespective of the application sequence of the other pesticides, reduced seedling survival and germination values at 20 C. Our results indicate that any change in pesticide usage, where multiple pesticides are used for seed treatment, may require a change in the sequence of pesticide application to obtain optimum results. In some instances, germination values may be affected to the point that treated seed would be rejected for certification and possible sale because of substandard germination, whereas untreated seed would have been acceptable.
Physiologic Maturity in Grain Sorghum1
Authors: Eastin Jerry D. , Hultquist Joe H. , Sullivan C. Y.
Published: July 2010

External visualization of the apparent dark closing layer in the placental area near the sorghum [Sorghum bicolor (L.) Moench] kernel attachment point coincides closely with the cutoff of radioactive assimilate translocation to the kernel. Dark layer determination permits identification of physiologic maturity or date of maximum dry weight accumulation. This judgment is meaningful because yield is a function of both time and metabolic efficiency. Genotypes can be characterized in terms of grain filling‐period duration by noting the dates of bloom and dark layer formation. Yield data plus physiologic maturity data permit direct field quantitation of the time and metabolic efficiency components of Grain dry weight accumulation.
Dry Matter Accumulation Patterns in Determinate and Indeterminate Soybeans1
Authors: Egli D. B. , Leggett J. E.
Published: July 2010

Comparisons were made of the accumulation of dry matter in the various plant components of a determinate (D66‐5566) strain had an indetermate (‘Kent’) soybean [Glycine max (L.) Merrill] cultivar using field‐grown plants for 2 years at Lexington, Ky. Kent and D66‐5566 are of similar maturity and yielding ability.

At initial flowering D66‐5566 had reached 84% of its maximum height, compared with 64% for Kent. At this point the stem dry weight of D66‐5566 was 67% of the maximum compared with 30% for Kent. Although stem elongation of the determinate type was nearly complete when flowering began, it continued to increase in dry weight.

At initial flowering Kent had produced 58% of its total vegetative material, compared to 78% for D66‐5566. Both types produced very little vegetative growth after a measurable amount of dry weight had accumulated in the pods and seeds. Kent produced more vegetative material during flowering and pod set, and the potential for competition for photosynthate between reproductive and vegetative growth was greater.

The rate of accumulation of dry matter in the pods and seeds was greater for D66‐5566 than Kent in 1970, but there was no significant difference in 1971. The rates of both types were greater in 1970 than 1971, although grain yields were greater in 1971 than 1970. The length of the effective filling period, i.e., the grain yield divided by the rate of grain filling, was longer for both types in 1971 than 1970, and was thus positively associated with grain yields.
Photosynthetic Responses to CO2 and Light by Maize and Wheat Leaves Adjusted for Constant Stomatal Apertures1
Authors: Akita Shigemi , Moss Dale N.
Published: July 2010

Previously we found that maize (Zea mays L.) leaf stomata were more responsive to changes in light intensity on CO2 concentration than were the stomata of wheat (Triticum aestivum L.). This study was undertaken to determine how the photosynthetic light and CO2 responses were affected by this differential stomatal sensitivity. Measurements of net photosynthesis and leaf diffusive resistances were made in various CO2 concentrations and light intensities on attached, mature leaves on 40‐ to 60‐ day‐old potted maize and wheat plants grown in a glasshouse. The data for each leaf were adjusted to a constant leaf diffusive resistance according to the diffusive equation for photosynthesis as given by Gaastra.

The results showed that “apparent Km's” for CO2 response by whole maize leaves had large errors due to a changing leaf diffusive resistance as the CO2 concentration changed. The initial slope of the light response curves were greater for maize than for wheat when corrected for the changes in stomatal apertures caused by the treatment.
Resistance to Water Flow in Vigna sinensis L. (Endl.) at High Rates of Transpiration1
Authors: Hailey James L. , Hiler Edward A. , Jordan Wayne R. , van Bavel C. H. M.
Published: July 2010

Recent studies support conflicting views concerning the validity of using an Ohm's Law analogy to describe liquid water flow through plants during transpiration. The results of these studies are compared with a common base; however, complete interpretation is difficult because most of the data are in a range of transpiration rates less than could be expected in a normal field environment.

Results of experiments with southern peas [Vigna sinensis L. (Endl.)] are presented in which high rates of transpiration were attained. Plants were studied in both the vegetative and the reproductive stages. In all experiments a linear relation between leaf water potential and transpiration rate was evident. This implies that the plant resistance to flow was constant, and hence, that an Ohm's Law analogy is valid for the transpiration rate range studied. Effects of plant age on the resistance to flow are discussed.
Residual Effects of Germination Temperature in Sugarcane1
Authors: Gascho G. J. , Ruelke O. C. , West S. H.
Published: July 2010

Stalk count, stalk weight, and sugar yield per stool in a first ratoon crop of sugarcane (Saccharum spp.) were reduced by nonoptimum germination temperature in the planted crop. Nearly the same responses were recorded in a crop vegetatively propagated from stalks of the first ratoon and harvested 37 months after the differential temperatures were applied. Total sugar per stool for the 37‐month period (three crops) ranged from 4.3 to 9.0 kg for original germination temperatures of 10 and 31 C, respectively. The ability to produce high stalk and sugar yields after low temperatures at germination decreased with the amount of time that a given variety had been grown under Florida conditions. Data suggest that nonoptimum germination temperatures, whether too high or too low, may be a factor in yield decline.
The Gene for Low Reaction to Puccinia Graminis Tritici in the Thatcher‐3B Substitution Line1
Authors: Loegering W. Q. , Sears E. R.
Published: July 2010

Tests of lines of ‘Chinese Spring‘ wheat (Triticum aestivum L.) with single pairs of chromosomes substituted from ‘Thatcher’ had indicated that chromosomes 2B and 3B carried similar genes for resistance to the stem‐rust organism. Results of crosses between near‐isogenic lines derived from the substitution lines show that the resistance gene in the 3B substitution line is Srl6, which is located on chromosome 2B.
Yield, Yield Component and Fiber Property Variation of Cotton (Gossypium hirsutum L.) Within and Among Environments1
Authors: Meredith William R. , Bridge R. R.
Published: July 2010

We evaluated the performance of four cotton (Gossypium hirsutum L.) cultivars when grown under four environments at Stoneville, Mississippi. Each variety was harvested by hand at approximately weekly intervals, averaging nine harvests per environment. We obtained estimates of yield, seven yield components, and seven fiber properties for each harvest.

Generally for the first two harvest weeks cotton bolls opened at a relatively slow rate, approximately 10 kg/ha per day. This was usually followed by 4 weeks of a greater rate of opening, approximately 24 kg/ha per day. After this period the rate of opening decreased substantially to approximately 7 kg/ha per day.

The most important cultivar ✕ harvest interactions were for yield, number of bolls, and rate of boll opening. These interactions were related most to the distribution of yield within environments. Lint percentage was lowest for the early harvest, whereas boll size and seed index values became smaller as the season advanced. Lint index was highest for the middle harvests. There was no consistent seasonal trend in number of seed per boll.

Cultivars were the most important source of variability for fiber properties. Yarn strength, 50% and 2.5% span length, length uniformity, fiber strength, and Micronaire were usually lower for the last two harvest dates. Lower quality fiber and low yield potential in the last two harvests suggest that early season production would be advantageous to the cotton industry.

The implications of this study pertaining to sampling for yield, yield components, and fiber properties are discussed.