bluuebunny/crossref_metadata_2025 huggingface dataset:
Flowering of Crownvetch as Affected by Thermo‐Inductive Treatment, Photoperiod, Plant Age, and Genotype1
Authors: McKee G. W. , Risius M. L. , Langille A. R.
Published: July 2010

Since crownvetch (Coronilla varia L.) does not flower under conditions conducive to flowering in alfalfa, (Medicago sativa L.), red clover (Trifolium pratense L.), and birdfoot trefoil, (Lotus corniculatus L.), four hypotheses were developed concerning flowering in this species. These included: (i) crownvetch requires exposure to cool or cold conditions (thermo‐induction) before flowering can occur; (ii) Thermo‐induction can occur under either long or short photoperiods, but long photoperiods are subsequently required for the initiation and development of floral primordia; (iii) A certain plant age is required before thermo‐induction can occur; and (iv) Crownvetch genotypes and cultivars differ in their need for thermoinduction. A series of field, greenhouse, and growth chamber studies indicated that all or nearly all 4‐ to 8‐week‐old plants of ‘Penngift’ crownvetch exposed to effective thermo‐inductive treatment (minimum temperatures of 10 or less for 12 to 15 hr per day) subsequently flowered in 5 to 7 weeks when tested under warm conditions (20 C or above) and long photoperiods (16 hr or longer). Plants weeks old when subjected to thermo‐inductive treatment required longer exposure (8 weeks) than 8‐week‐old plants, which required only 4 weeks of thermo‐inductive treatment. In these studies thermo‐induction occurred under both long (16‐ to 24‐hr) and short (9‐ to 12‐hr) photoperiods, but thermo‐induced plants flowered only when subsequently exposed to photoperiods of 15 hr or more. Nearly all 5‐ to 8‐week‐old plants of the cultivar Penngift could be thermo‐induced in 4 weeks. Plants of ‘Chemung’ and ‘Emerald’ cultivars needed to be both older (8 to 16 weeks) and thermo‐induced at 10 C or below for longer periods (8 weeks or more) for a comparable response. addition, some genotypes within different cultivars differed somewhat in their response to thermo‐inductive treatment. By using the above techniques, we were able to cause most plants of Penngift crownvetch to flower 13 to 16 weeks after seeding; plants of Emerald and Chemung, however, generally require 7 to 8 weeks longer.
Diurnal Change in Specific Leaf Weight of Medicago sativa L. and Zea mays L.1
Authors: Chatterton N. J. , Lee D. R. , Hungerford W. E.
Published: July 2010

Diurnal changes in SLW (specific leaf weight) and TNC (total nonstructural carbohydrates) were observed in alfalfa (Medicago sativa L.) and corn (Zea mays L.). In addition to the diurnal pattern of increasing SLW and TNC during the day, immediate changes in SLW and TNC were induced by fluctuations in incident light intensity. Since diurnal change in SLW of fully expanded leaves reflects the photosynthate production‐translocation balance, investigation of the use of change in SLW is suggested as a measure of productivity potential.
Low Light Intensity Effects on Grain Sorghum at Different Stages of Growth1
Authors: Pepper G. E. , Prine G. M.
Published: July 2010

‘Georgia 615’ grain sorghum (Sorghum bicolor (L.) Moench) was shaded for weekly periods in three field experiments to determine if periods exist during the life cycle of the sorghum plant when low light intensities are deleterious to grain yield components. Black plastic fabric with 25% light transmission was used to shade plants. Grain yield per ha and per panicle, seed number per panicle, seed weight, and heat units from seeding to 50% anthesis were determined.

Two stages of plant development most adversely affected by low light intensity were found. The first stage occurred from pre‐boot vegetative, when the last leaf was just visible in the whorl to full panicle expansion or during approximately the two‐week period just before 50% anthesis. Shading during this period resulted in reduced number of seed per panicle. The second stage was during the milk and dough stages of grain development or during approximately the three‐week period just after 50% anthesis. Shading during this period resulted in lighter sed with little or no change in number of seed per panicle. When number of seed per panicle was reduced by shading, heavier seed weight compensated for part, and sometimes all, of the potential yield decrease. Grain yields per panicle and per ha of shaded sorghum were generally lower than for the unshaded check.
Commercial Utilization of the Products of Recurrent Selection for Specific Combining Ability in Maize1
Authors: Horner E. S. , Chapman W. H. , Lundy H. W. , Lutrick M. C.
Published: July 2010

Commercial maize (Zea mays L.) hybrids can be generated rapidly from a program of recurrent selection for specific combining ability when the tester is a seed parent already in commercial use. The pollen parent can be an inbred line, a single cross, or a synthetic derived from lines selected in a given cycle. A study was made to compare the three types of parents listed above. Six lines, selected in the fifth cycle of selection for combining ability with the single cross F44 ✕ F6, were evaluated as pollen parents individually (three‐way crosses), in singlecross combinations (double crosses), and as a six‐line synthetic (top cross). These types of crosses averaged 48.7, 47.7, and 47.6 quintals/ha, respectively, at five locations over a 2‐year period. There was no statistically significant difference for average grain yield or lodging among types of hybrids nor between the top cross and any of the three‐way or double crosses. The top cross was as uniform for silking date and ear height as a single cross and a commercial double cross. Since a top cross of this type can be released more quickly and economically than a three‐way or double cross, we conclude that its use in commercial hybrids would be justified.
Influence of Light and Temperature Environments Preceding and During the Dark Period on Floral Initiation in Pima Cotton (Gossypium barbadense L.)1
Authors: Pinkas Leonard L. H.
Published: July 2010

Floral induction in American Pima cotton, (Gossypium barbadense L.), cultivars ‘Pima S‐3’ and ‘Pima S‐4’, occurred earlier (at lower node levels on the main stem) under short winter days than under long summer days when plants were grown under natural light and a controlled temperature program.

The intensities of red and far red light in natural sunlight were measured to determine if there were daily or seasonal changes in spectral quality that might be related to variations in floral initiation. Red light predominated during the day, but the balance shifted to a predominance of far red light between sunset and darkness. This relationship was not seasonal.

Total exclusion of all light from plants during the 1.5‐hour period before sunset accelerated floral induction if the temperature during this period was above 30 C, but either had no effect or retarded induction if the temperature was below 30 C. Shortening or interrupting the natural dark period with low intensity lights of different spectral composition retarded induction. The intensity of blue light, but not red or far red light, appeared to be related to induction. The increase in the node number of the first fruiting branch was almost directly proportional to the time interval between sunset and the interruption of the dark period.

Floral induction was most sensitive to photoperiod and to high temperatures during sunset during the 2nd week of development after germination.
Suboptimal Temperature and Assimilate Accumulation in Leaves of ‘Pangola’ Digitgrass (Digitaria decumbens Stent.)1
Authors: Garrard L. A. , West S. H.
Published: July 2010

This study was conducted to determine the effect of metabolic sink activity on mobilization at low temperature of chloroplast starch in a tropical grass. Entire plants or partially shaded plants of ‘Pangola’ digitgrass (Digitaria decumbens Stent.) accumulated photosynthate during a 12‐hr period of illumination of 30 klux at 30C. Plants were then either entirely or partially subjected to a suboptimal temperature of 10C for a dark period of 12 hr. Temperature treatments provided metabolic sinks at 30C in locations proximate to areas containing low temperature‐ immobilized assimilate. Distribution of reducing sugar, sucrose, and starch was determined. No evidence was found that the presence of active metabolic sinks negated the influence of suboptimal temperature in causing assimilate immobilization. Further, the action of suboptimal temperature in causing assimilate immobilization appeared to be located at the area of accumulation, the leaf or perhaps the chloroplas.
Combining Ability Estimates for Weather Fleck in Nicotiana tabacum L.1
Authors: Aycock M. K.
Published: July 2010

Seven cultivars of Nicotiana tabacum L. (four Maryland and three cigar types) and 21 F1 hybrids were grown at three locations for 2 years. During August, data were collected on leaf damage caused by air pollutants, primarily ozone. This condition was referred to as weather fleck. Ozone causes small necrotic lesions usually 0.2 to 0.5 cm in diameter. Plants were scored on a scale of 1 to 5 (1 = no damage, 5 = severe damage). Comparison of parent (2.34) and F1 hybrid (2.37) performance indicated no significant amounts of heterotic resistance to weather fleck. Diallel analyses of variance of the F1 hybrid generation suggested an appreciable amount of variance due to general combining ability (GCA) and the absence of variance due to specific combining ability (SCA). Genetic effects were stable with respect to locations and years. The genotype × environment interactions for the six environments were small. The predominance of additive genetic variance in this material suggests that progress could be made through selection.
Isogenic Barley Lines for Reaction to Erysiphe graminis F. Sp. Hordei1
Authors: Moseman J. G.
Published: July 2010

The procedure is described for developing 10 pairs of barley (Hordeum vulgate L.) lines, each isogenic except for a specific pair of alleles conditioning resistance and suspecptibility to culture CR3 of Erysiphe graminis (DC.) Merat hordei Em. Marchal. Each pair of lines was selected after four backcrosses to the cultivar ‘Manchuria,’ followed by 12 to 15 selfed generations. Four pairs of lines, developed from cultivars ‘Goldfoil,’ ‘Hanna,’ ‘Kwan,’ and ‘Psaknon’ differ by the resistance genes Ml‐g, Ml.h, Ml‐k, and MI‐p and their recessive alleles, respectively. Six pairs of lines differ by genes at the complex Ml‐a locus. The fines developed from cultivars ‘Algerian,’ ‘Franger,’ and ‘Durani’ differ by the resistance genes Ml‐a, Ml‐a6, and Ml‐a10 and their recessive alleles, respectively; and those developed from cultivars ‘Multan,’ ‘Long Glumes,’ and ‘Rupee’ each differ by one resistance gene and its recessive allele.
Grain Filling Period of Sorghum Parents and Hybrids1
Authors: Quinby J. R.
Published: July 2010

The length of the grain‐filling period was determined for three female parents of Sorghum bicolor (L.) Moench, four male parents, and their 12 possible hybrids. All entries reached maximum kernel weight between 30 and 40 days after flowering. Mature kernels of male parents were heavier than those of the hybrids. Differences in duration of dry weight accumulation between parents and hybrids were not significant. Hybrid vigor appeared not to lengthen the period of dry weight accumulation in the endosperm.
Designation of Two Genes for Resistance to Puccinia Recondita in Triticum Aestivum1
Authors: Browder L. E.
Published: July 2010

A gene for resistance to Puccinia recondita in Triticum aestivum derived from Agropyron elongatum is designated as Lrl9. This gene occurred on chromosome 7D in an irradiated translocation line, T4, and is present in the wheat line ‘Agatha’ (C. I. 14048). Another gene for resistance, on chromosome 7A in ‘Thew’ (W203) is designated Lr20.
Cross Breeding Male‐Sterile Wheat (Triticum Aestivum L.) and Rye (Secale Spp.)1
Authors: Porter K. B. , Tuleen N. A.
Published: July 2010

Seed set on male‐sterile wheat (Triticum aestivum L.), T. timopheevi cytoplasm, pollinated by rye (Secale) in field crossing blocks was less than 2%. Seed set on male sterile wheat/rye F1's was negligible when backcrossed to rye, 0.37% when backcrossed to wheat, and 0.96% when crossed to 6X Triticale. The partial fertility of two 56‐ chromosome amphiploids arising spontaneously on malesterile wheat/rye F1's pollinated by rye indicate that some ryes possess fertility restoration factors that interact with those of male‐sterile wheat to restore pollen fertility. F1 progenies of cytoplasmic male‐sterile wheat‐rye F1's crossed to 6X Triticale were frequently partially fertile. Malesterile wheat may be a useful breeding tool for making interspecific crosses involving rye.
Scissor Emasculation of Sorghum1
Authors: Crook W. J. , Casady A. J. , Campbell L. G.
Published: July 2010

Sorghum bicolor (L.) Moench was emasculated by clipping the spikelets with scissors. The amounts of seed set from crossing and selfing were similar for tweezer and scissor emasculation. Scissor emasculation produced 3.6 times as many crossed seed per unit of time as did tweezer emasculation. An acceptable percentage of seed set was obtained as late as 7 days after scissor emasculation.
Effects of Row and Plant Spacings on Verticillium Wilt of Cotton1
Authors: Minton Earl B. , Brashears A. D. , Kirk I. W. , Hudspeth E. B.
Published: July 2010

The effects of row and plant spacings on percent Verticillium wilt (Verticillium albo‐atrum Reinke and Berth.) in ‘Gregg 35,’ a wilt‐susceptible cotton (Gossypium hirsutum L.) adapted to a wide range of row and plant spacings, were studied in single‐ and double‐row planting patterns. Percent wilt was decreased slightly in double‐row and significantly in single‐row patterns by close row spacings. In both planting patterns percent wilt decreased as plant populations (seeding rates) increased from low to medium levels, but percent wilt remained constant or decreased slightly at higher plant populations. The interaction of row widths ✕ seeding rates was significant only for the single‐row patterns.
Variation and Heritability of Protein Concentration in Various Alfalfa Plant Parts1
Authors: Gengenbach B. G. , Miller D. A.
Published: July 2010

Significant estimates of genetic and nongenetic variances were obtained for the protein concentration of top leaves and stems, midleaves and stems, and the total herbage (above 5 cm) of alfalfa (Medicago saliva L.) plants. Broad‐sense heritability estimates indicated that clonal selection for higher protein concentration in all plant parts was possible. Heritability estimates for the total herbage were consistently equal to or greater than estimates for plant parts. The protein concentration in each plant part generally was significantly correlated with the protein concentration of the total herbage. The relationships were not strong enough, however, to suggest that analysis of a plant part could be used as a predictor of the protein concentration of the total herbage. Thus, selection of high‐ or low‐protein plants may be accomplished best on the basis of protein analysis of the total herbage.
Hybridization of Desmodium canum (Gmel.) Schin. and Thell. and D. uncinatum (Jacq.) DC.1
Authors: Chow Kuan‐how , Crowder L. V.
Published: July 2010

Three F1 hybrids were obtained from the cross of Desmodium canum (Gmel.) Schin. and Thell. and D. uncinatum (Jacq.) DC. The parents differ considerably in morphology, light response, floral biology, and flowering behavior. The three F1 plants were morphologically identical. They had the semi‐decumbent growth habit of D. canum did not show the silver leaf‐marking of D. uncinatum, displayed less plant growth than the parents, and developed certain intermediate characteristics. The hybrids did not produce flowers under 11‐ and 14‐hour (or longer) periods of light. Apparently, this is the first report of successful hybridization.
Differential Stomatal Response Between C3 and C4 Species to Atmospheric CO2 Concentration and Light1
Authors: Akita Shigemi , Moss Dale N.
Published: July 2010

Transpiration measurements were made on attached leaves of potted plants or on excised leaves of native plants of three C3 species—wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and dandelion (Taraxacum officinale L.) — and three C4 species — maize (Zea mays L.), green foxtail (Setaria viridis L.), and pigweed (Amarranthus retroflexus L.) — in different CO2 concentrations and light intensities. The experiments were begun with leaves in CO2‐free air in light (0.4 cal cm−2 min−1, 400–700 nm) to open the stomata.

Stomata of C3 species were less prone to closure than were stomata of C4 species as the light intensity was decreased or as the CO2 concentration was increased. The greater water use efficiency of C4 species may be due in part to the better control of water loss because the stomata are more responsive to environmental changes than are the stomata of C3 species.
Effect of Infection by Cephalosporium gramineum on Winter Wheat1
Authors: Johnston R. H. , Mathre D. E.
Published: July 2010

Under greenhouse conditions inoculum density studies with Cephalosporium gramineum Nisikado and Ikata indicated that at least 106 conidiospores per winter wheat plant (Triticum aestivum L.) were required to affect yield components and that maximum disease was obtained with 108 conidiospores per plant. Inoculation was accomplished by slicing the root system of vernalized plants with a knife and pouring a predetermined concentration of conidia into the soil slice. Infected plants were stunted, had reduced yield, and had higher levels of protein than healthy plants. The yield components most affected by this disease were number and weight of seeds (kernels) per head. Shriveling of kernels reduced the carbohydrate present and resulted in a relative increase in percent protein. The number of heads produced by infected plants was never significantly different from the number of heads produced by healthy plants. Yield losses were as high as 78%, thus giving an indication of the potential destructiveness of this pathogen under severe disease conditions. Symptom expression was found to be of little value in accurately estimating the degree of susceptibility to the pathogen. No relationship was found between the number of minor genes present for stripe rust (Puccinia striiformis west.) resistance and susceptibility to C. gramineum.

This work examines the host‐parasite interaction, a preprequisite to establishing guide lines that could be applied to a screening program for the development of resistant and/or tolerant cultivars.
Inheritance of Brown Pericarp and Subcoat in Sorghum1
Authors: Wanjari M. R. , York J. O.
Published: July 2010

Five grain sorghums [Sorghum bicolor (L.) Moench] were used in this study to determine the inheritance of the brown pericarp and subcoat: (i). 7078,Tx 7078 strain of ‘Combine 7078’ (red pericarp without a subcoat); (ii). CK‐60,Tx 3197 strain of ‘Combine Kafir 60’ (white pericarp with reddish brown speckles without a subcoat); (iii). Hegari, TS 7313 strain of ‘Early Hegari’ (chalky white pericarp with a subcoat); (iv). Schrock, CI 616 strain of ‘Schrock’ (brown pericarp with a subcoat); and (v). Shallu, AK 3001R strain of ‘Double Dwarf Early Shallu’ (pearly white pericarp without a subcoat). All possible crosses (with reciprocals) were made among the five sorghums. The pericarp colors and the presence or absence of a subcoat were noted for the crosses and reciprocals in the F1 generation. The presence or absence of the subcoat was determined by microscopic examinations of cross sections of the grain from the parents and from their crosses and reciprocals, 20 F1's.

The F2 segregating populations were classified for pericarp colors and for the presence or absence of a subcoat. The observed data were tested by chi‐square for goodness‐of‐fit to the theoretical ratios. The F3 populations were used to confirm the F2 segregating ratios.

It was confirmed that two complementary factors B1 and B2 are responsible for the presence of a subcoat. Brown pericarp resulted when factors B1, B2, and S were dominant and these brown grains possessed a subcoat. Additional factors R and Y were responsible for red pericarp when any of the factors B1, B2, or S were homozygous recessive. Brown grain containing the dominant R and Y factors had a deeper brown color. When either of the subcoat factors were homozygous recessive and homozygous recessive R or Y factor, regardless of the S factor, a white pericarp resulted. Pericarp and subcoat genotypes for the five sorghums were determined.
Opaque‐2 Effects on Single‐Gene Inheritance Of Maize Oil Fatty Acid Composition1
Authors: Poneleit C. G.
Published: July 2010

Opaque‐2 and translucent kernel versions of the maize (Zea mays L.) inbred ‘Oh7N’ were found to have different percentages of linoleic acid in their grain oils. Kernels of the parent lines and F1, F2, F3, and BC1 generations were examined to determine if opaque‐2 or other genes determined the large differences in linoleic acid percentages. Individual kernels were separated into germ and endosperm oil fractions and their fatty acids were esterified with boron‐trifluoride prior to analysis by gas chromatography. A single gene was found to control 10 to 15% of the linoleic acid in the germ oil. The opaque‐2 locus also affected linoleic acid percentage of the oil. Opaque‐2 kernels had from 4 to 6% less linoleic acid in their germ oil and from 7 to 9% less linoleic acid in their endosperm oil than did translucent kernels. Endosperm oil of opaque kernels was higher in palmitic acid percentages than translucent kernels. The opaque‐2 locus effects were independent of control effects exerted by the linoleic acid control locus.
Utilization of Soybean Germplasm Strains in a Soybean Improvement Program
Authors: Hartwig Edgar E.
Published: July 2010

Selected strains from the soybean [Glycine max (L.) Merrill] germplasm collection were hybridized with the cultivar ‘Hill’ and evaluated in bulk in F3, F4, and F5 generations. Mean seed yields of bulk F5 populations averaged 15% of the field for Hill.

Material was selected from four crosses for further study. Degree of susceptibility of the susceptible parent to the diseases phytophthora rot or bacterial pustule influenced the percentage of resistant types found among Fn lines. The lines selected on the basis of disease reaction or chemical composition produced yields which averaged 70 to 80% of the yield for Hill.
Field Performance of Cotton Grown from Filled and Partially Filled Seeds1
Authors: Turner John H. , Ferguson David
Published: July 2010

The influence of seed fullness (degree to which kernels fill the space within the seed coat) upon emergence, vigor, maturity, and yield of cotton (Gossypiun hirsutum L.) was studied under field conditions in 1971. Each of four lots of ‘Acala SJ‐1’ cottonseed, was sorted by X‐ray inspection into three classes: check (or unsorted), full, and partially filled seed.

Plants from filled seeds were superior to those from partially filled seeds for all emergence and vigor measurements. Plants from the filled class were also superior to those of the check seeds for vigor as measured by dry weight accumulation during 8 weeks of seedling growth.

An earlier‐maturing cotton was produced from plants grown from filled seeds as measured by blooming rate and by first picking weights.

The four lots of seeds differed significantly for emergence rate and final number of plants, but no significant differences among lots could be detected for seedling vigor and maturity. No significant lot ✕ class interactions were found.

No significant differences for final yield were detected, but in each of the four lots the mean yields were highest for the full seed class.

A general advantage in emergence, seedling vigor, and crop maturity was indicated for the full seed. Thus, cotton planting seeds that are completely filled should be desirable for obtaining and maintaining a stand of healthy seedlings and for earlier fruit production.
A Single Cone Multiple‐Row Plot Seeder1
Authors: Marshall H. G.
Published: July 2010

A plot seeder has been constructed on a light‐weight 14 hp crawler‐type tractor so as to minimize soil compaction problems. Seeds are dispensed into five rows by means of a cone and a slotted base plate. Planting is nonstop and a two‐man operation. The unit can be transported on a one‐half ton truck.
Maturity Index as a Measure of Vegetative Development of Sudangrass and Related Sorghum Crosses1
Authors: Summer D. C. , Holmes R. L.
Published: July 2010

To develop a method for establishing indices of vegetative development harvests were made twice weekly during the vegetative growth phase of ‘Piper’ and ‘Sudan 23’ sudangrass [Sorghum sudanense (Piper) Stapf.] and the cross ‘Sweet Sioux’ and ‘SX‐12’ [Sorghum bicolor (L.) Moench × Sorghum Sudanese (Piper) Stapf.]. Heights from ground level to the uppermost exposed leaf collar (tiller height) and to the apical meristem were recorded for all tillers over 16.5 cm. The sum of meristem heights divided by the sum of tiller heights and the quotient multiplied by 100 describes a mean point, termed maturity index, of morphological development for each sample. This figure may be used to compare qualitative or quantitative measurements among cultivars, seasons, locations, or treatments at the same degree of morphological development.

Cultivars at the same morphological degree of development differed in stand height and percentage crude protein. Flag leaves were first evidenced at an index of approximately 70. At this stage of development there is a rapid increase in dry matter and lignin percentages, and a rapid decrease in crude protein concentration. The data indicate that harvesting at a maturity index of 70 (first evidence of flag leaves) may be a good compromise between maximizing quantity and quality of these forage crops.
A Six‐Parent Diallel Cross Analysis for Protein in Avena sterilis L.1
Authors: Ohm H. W. , Patterson F. L.
Published: July 2010

Six Arena sterilis L. introductions were crossed in a diallel to study groat protein level and to estimate heterosis and types of genetic effects for percent protein and protein yield. Parents, one set of Fl's, and two adapted commercial check cultivars were grown for three seasons (1969‐1971) along with reciprocal Fl's in 1970 and with F2's in 1970 and 1971. The A. sterilis parents averaged 25.6% groat protein and the two check cultivars, 17.9% groat protein. The adapted check cultivars produced twice as much seed yield, which resulted in a higher yield of protein. Percent groat protein in the F1 and F2 was similar to the midparent values. Heterosis for protein yield averaged 10.7% in the F1 but was much reduced in the F2 generation. Reciprocal F1 hybrids did not differ for percent groat protein or protein yield. General combining ability predominated for all characters. Partial dominance occurred for percent groat protein in this group of genotypes. Epistasis and environmental factors were important for protein yield. The relationship between protein and protein yield was generally not significant, but tended to be negative.
Effects of Recurrent Seed Irradiation on Genetic Variability and Recombination in Cotton (Gossypium hirsutum L.)1
Authors: Fotiadis N. A. , Miller P. A.
Published: July 2010

The effect of five cycles of seed irradiation with 10 kr of γ‐rays per cycle on the means, variances, and covariances of a synthetic variety of cotton (Gossypium hirsutum L.) was studied.

Means were lower after the treatment for the traits previously selected for high values and were higher for the traits previously selected for low values. Means of traits previously selected for intermediate values remained unaffected. Variances were generally but moderately increased. The effect on correlations between traits was rather small. Expected gains from selection were higher in the treated population, but the increased gain could hardly, if at all, compensate for the lower means of that population.

The changes effected by the treatment are deemed rather small. The reason is thought to be the low doses of radiation used.
Histological Examination of Fresh Forage Leaves After in vitro Digestion1
Authors: Hanna W. W. , Monson W. G. , Burton G. W.
Published: July 2010

All anatomical components except the cuticle, trichomes, xylem, fibers, and bundle sheaths were digested after in vitro leaf digestion of Avena sativa L., Secale cereale L., Lolium multiflorum Lam., Poa pratensis L., Dactylis glomerata L., and Festuca elatior L. for 24 hours; Pennisetum typhoides (Burm.) Stapf and C. E. Hubb. for 48 hours; and Cynodon dactylon (L.) Pers. for 96 hours. Some breakdown of the bundle sheath in bermudagrass occurred. The outer thin‐walled parenchymatic bundle sheath but not the inner sheath of the cool‐season grasses was digested. The larger cells, less compact arrangement, and larger intercellular spaces of the mesophyll of cool‐season grasses as compared to bermudagrass or pearl millet appeared to allow the microorganism to be in contact with a larger surface area in a given time. These mesophyll characteristics may explain why the rate of digestion was faster in the cool‐season grasses than in pearl millet and bermudagrass.

Observations on the arrangement of mesophyll in ‘Tift 18’ and ‘Tift 23’ pearl millet and on the patterns of digestion would indicate that digestibility could be increased by breeding for certain cell arrangements.
The Origin of 2n and n Sectors of Chimeral Pima Cotton Plants
Authors: Turcotte E. L. , Feaster Carl V.
Published: July 2010

The tetraploid tissue of American Pima cotton (Gossypium barbadense L.) plants chimeral for tetraploid and haploid tissues was found to be of hybrid origin. We crossed 57‐4, a doubled haploid that is semigametic, as female, with a multiple‐marked stock homozygous for glandless and heterozygous for red plant color. A number of the plants from this cross were chimeral for glanded or glandless tissue, red or green tissue, and tetraploid or haploid tissue. The combinations of tissues in tri‐chimeral plants were such that polyspermy appeared to be involved in the development of their tetraploid tissue. We theorized that a sperm nucleus divided in the egg cell before fertilization. The semigametic tendency of the female parent may be associated with the stimulation of divisions of the sperm nucleus.
Inheritance of Leaf Rust Resistance in Leeds Durum Wheat1
Authors: Statler Glen D.
Published: July 2010

The inheritance of resistance to wheat leaf rust incited by Puccinia recondita Rob. ex Desm. f. sp. tritici, was investigated in ‘Leeds’ durum wheat (Triticum durum Desf.) All F1 plants of reciprocal crosses between Leeds and the rust‐susceptible line ‘D6618’ were susceptible to culture 70‐1 (race 1) P. recondita. The segregation ratio of approximately 15 susceptible plants: 1 resistant plant in the F2 generation suggests that resistance is conditioned by two recessive genes, and this was confirmed when 281 F3 families satisfactorily fit a 2‐factor 7:4:4:1 ratio.
Maternal Control of Oil Content in Oats (Avena Sativa L.)1
Authors: Brown C. M. , Aryeetey Andrew N.
Published: July 2010

Crossed and selfed groats from individual F1, F2, and parental plants of reciprocal oat (Avena sativa L.) crosses between the cultivars ‘Brave’ (approximately 7.5% oil) and ‘Garland’ (approximately 3.5% oil) were analyzed by NMR for oil content. The difference in NMR values between selfed and crossed groats produced on plants of Brave was nonsignificant. The difference between selfed and crossed groats produced on Garland was small but significant. NMR data from individual F1 and F2 plants showed that the similarity between crossed and selfed groats on the same panicle was due to maternal and not cytoplasmic effects. Selection for oil content among individual groats on the same plant would probably be ineffective in oats.
Effect of Seed Treatment and Planting Depth on Germination and Seedling Emergence in Aeschynomene Americana L.1
Authors: Hanna Wayne W.
Published: July 2010

The experiment was conducted to investigate the factors affecting germination of Aeschynomene americana L. seed and the subsequent emergence of the seedlings. Depodding and scarification of Aeschynomene americana L. seed increased germination from 6 to 78% and 2 to 74% for 1968‐ and 1970‐crop seed, respectively. Data indicated that seed coat and seed pod inhibited water inhibition and/or exchange of gases. A planting depth greater than 13 mm significantly reduced seedling emergence.
Diallel Analysis of Resistance of Corn (Zea mays L.) to Corn Stunt1
Authors: Nelson Lloyd R. , Scott Gene E.
Published: July 2010

A diallel analysis was used to evaluate 45 single crosses (10 inbred lines) of maize (Zea mays L.) for resistance to corn stunt. Using a corn stunt rating scale of 1 (healthy) to 6 (dead plants), the R ✕ R crosses had a mean corn stunt rating of 1.6. The R ✕ S and S ✕ S crosses had a mean rating of 2.4 and 3.5, respectively. Mean yields of 3,205, 2,754, and 2,538 kg/ha were produced by the R ✕ R, R ✕ S, and S ✕ S crosses, respectively. General combining ability for corn stunt ratings was highly significant in all experiments and was much larger than specific combining ability. Thus, additive gene action appears to be much more important than dominance gene action in the inheritance of resistance to corn stunt in this material.
Combining Ability in Durum Wheat: I. Agronomic Characteristics1
Authors: Widner J. N. , Lebsock K. L.
Published: July 2010

The parents and 45 F1 and F2 populations from a diallel cross among 10 genetically diverse varieties or lines of durum wheat (Triticum durum Desf.) were evaluated at two locations in North Dakota in 1965. Parental, Fu and F2 populations of 17 of the 45 crosses were evaluated again in 1966 at one location. The traits studied were grain yield, number of tillers per unit area, kernels per spike, kernel weight, test weight, seedling vigor, maturity, height, and lodging.

Heterosis percentages for grain yield in 1965, based on means of the higher parent of each cross, ranged from —19 to 84% for the F1's and from —23 to 26% for the F2's. Seventeen hybrids displayed significant heterosis for yield, but none was significantly higher than the check variety, ‘Wells.’ The best hybrid yielded 16 and 9% more than Wells when Wells was sown at 33 and 67 kg/ha, respectively. Heterosis also occurred for the other character studied. Twenty‐seven F2 populations yielded significantly less than their respective F1's.

An estimate of genotype ✕ environment interaction was calculated for grain yield on the means of the 17 F1's, F2's, and parents for the crosses grown in 1965 and 1966. The analyses were based on mean values from three environments, Fargo 1965, Langdon 1965, and Fargo 1966. Genotype ✕ environment mean squares were significant for the F1 hybrids and parents, but nonsignificant for the F2 populations.

General and specific combining ability mean squares were obtained from F1 and F2 populations grown in 1965. General combining ability mean squares were highly significant among F1's and among F2's for all nine characteristics.

Specific combining ability mean squares among F1's were significant for kernel weight, test weight, and seedling vigor, and were significant among F2's for kernel weight, test weight, and lodging score. Maximum yields of durum wheat may be attainable only with a system that can exploit both additive and nonadditive genetic effects.
Insolation and Temperature Effects on Maize Growth and Yield1
Authors: Duncan W. G. , Shaver D. L. , Williams W. A.
Published: July 2010

Five hybrid varieties of maize (Zea mays L.) were planted at three rates and two dates for 2 years at Lexington, Ky.; Greenfield, Calif.; and Davis, Calif.; locations with nearly the same latitude and elevation but having climates differing widely in insolation and average daily temperature. Plots were managed to minimize differences other than climate.

Grain yields per hectare were highest at Davis, which had the highest daily insolation, highest daylight temperatures, and second‐lowest night temperatures. Grain yields were lowest at Lexington, which had the lowest daily insolation, moderately high daylight temperatures, and the highest night temperatures. Grain yields and environmental factors at Greenfield presented a more complex picture, which is discussed. Grain yields at each location were positively, and kernel weights, negatively correlated with planting rate.
Epistasis in Maize (Zea mays L.): III. Significance in Predictions of Hybrid Performances1
Authors: Stuber C. W. , Williams W. P. , Moll R. H.
Published: July 2010

The relative significance of epistatic effects and genotype ✕ environmental interaction effects in predictions of hybrid performances was evaluated in 28 sets of single, three‐way, and double crosses. Parental inbred lines originated from two unselected maize (Zea mays L.) varieties and from these two varieties after three cycles of reciprocal recurrent selection. Comparisons between unselected (UNS) and selected (RRS) population means indicate that selection has influenced both the additive and nonadditive genetic contributions to the observed differences.

Comparisons among means over sets show significant epistatic effects, which, on the average, cause underestimates of three‐way and double‐cross performances from predictions based on nonparental single cross means. However, these underestimates appear to be inconsequential except for a few unique combinations of lines. Correlations between predicted and observed performances indicate that both the effects of epistatic deviations and the effects of genotype ✕ environmental interactions cause significant biases in hybrid predictions. Predictions of yield and ear number based on data from a single environment show somewhat greater biases from genotype ✕ environmental interactions than from epistatic effects. However, when predictions are based on data from three environments, biases from the two types of effects differ little in magnitudes.

Except for those unique, apparently infrequent combinations of lines very strongly influenced by epistatic effects, the results indicate that standard single‐cross procedures for predicting three.way and double crosses need not be replaced by more complex procedures. Data from a single environment provide poor discrimination among three‐way or double crosses and somewhat better discrimination among single crosses. It is suggested that preliminary selections for three‐way and double‐cross hybrids are most efficiently performed by utilizing predictions based on nonparental single‐cross means from a few environments. Final testing of reduced numbers of selected hybrids requires several environments for adequate evaluation. Likewise, ascertainment of commercially acceptable unique single‐cross combinations requires several environments.
Performance of 2‐dwarf and 3‐dwarf Grain Sorghum Hybrids Harvested at Various Moisture Contents1
Authors: Windscheffel Jan A. , Vanderlip R. L. , Casady A. J.
Published: July 2010

Experiments were conducted at three locations in Kansas to see if in producing combine (3‐dwarf) varieties the potential grain yield of sorghum [Sorghum bicolor (L.) Moench] had been reduced. Harvesting was done at three moisture contents, and effects on lodging, threshing loss, grain yield, and stover yield were determined. Isogenic (2‐dwarf and 3‐dwarf) ‘RS 650’ and ‘RS 702’ hybrid grain sorghums differing by one gene (Dw3) were used. The tall, 2‐dwarf sorghum was found to yield 12.7% more threshed grain, 11.6% more total grain, and 22.1% more stover than the short, 3‐dwarf plants. The 2‐dwarf sorghum lodged significantly more than the 3‐ dwarf in late season wind storms at three of the locations. Harvesting sorghum at about 26% grain moisture yielded 8.4% more total grain and 7.4% more stover than harvesting at 14% grain moisture. Threshing losses were significantly higher when the grain was harvested at high moisture. Threshing losses were significantly lower for the 2‐dwarf than for the 3‐dwarf grain sorghum.
Performance and Within‐Hybrid Variability of Three‐Way and Single Crosses of Grain Sorghum1
Authors: Walsh E. J. , Atkins R. E.
Published: July 2010

Mean performance and within‐plot variability of parents and hybrids of grain sorghums [Sorghum bicolor (L.) Moench] were evaluated from the results of experiments conducted during 2 years in Iowa. Analyses of the data combined over years indicated that fertile single crosses and three‐way hybrids did not differ significantly for mean grain yield, 100‐seed weight, seeds/head, heads/plant, plant height, and days to midbloom. Mean within‐plot standard deviations for plant height and days to midbloom of the three‐way hybrids were significantly greater (P < 0.01) than those of single‐crosses, but the differences do not seem large enough to be important agronomically.

Mean grain yields of single and three‐way crosses and within‐plot standard deviations for the other characters were not highly correlated. Neither the differences between parents of male‐sterile single crosses nor heterogeneity within parental lines was closely associated with level of variability within three‐way hybrids. Male‐sterile single crosses yielded significantly more (19%) than sterile lines as parents for the production of hybrid seed. Superiority of the single crosses resulted primarily from larger numbers of seeds/head.
Northern Anthracnose Resistance in Red Clover1
Authors: Smith R. R. , Maxwell D. P.
Published: July 2010

Resistant and susceptible red clover (Trifolium pratense L.) clones were intercrossed to study the inheritance of resistance to Kabatiella caulivora (Kirchn.) Karak., causal agent of northern anthracnose. Evaluation of F1, F2, and BC progeny reactions to this fungus indicated that resistance was dominant and controlled by more than three genes. Fifty‐one percent of the plants were resistant to K. caulivora after two cycles of recurrent phenotypic selection, whereas 5% of the initial population were resistant. We suggested that breeding for resistance to this disease would best be accomplished by progeny‐testing resistant plants before their inclusion in a recurrent selection program.
Development of a Set of Upland Cotton Lines for Comparisons of Fusarium Wilt‐Root‐Knot Nematode data from Several Tests1
Authors: Kappelman A. J. , Sappenfield W. P.
Published: July 2010

Ten cotton (Gossypium hirsutum L.) cultivars were evaluated under five environments to determine their reaction to Fusarium wilt (Fusarium oxysporum f. vasinfectum (Atk.) Snyd & Hans.) and root‐knot nematodes (Meloidogyne spp.). These tests were conducted in an effort to determine a set of entries with known differential susceptibility to the Fusarium wilt‐root‐knot nematode complex. ‘Auburn 56’ and ‘Auburn M’ were highly resistant, while ‘Rowden’ and ‘Stardel’ were highly susceptible under all environments. The other six cultivars differed over environments but usually were intermediate in resistance.

Although a complete set of differentials was not determined, two distinctively different groupings were observed. Using a cultivar from both the resistant group and the susceptible group as check materials hi Fusarium wilt screening tests will enable investigators to compare results from different areas on a relative basis.
Resistance in Soybeans to a New Race of Root‐Knot Nematode1
Authors: Williams Curtis , Birchfield Wray , Hartwig E. E.
Published: July 2010

A new race of root‐knot nematode, Meloidogyne incognita, found in a field on the Wartelle farm in St. Landry Parish, Louisiana, caused severe yield reductions in soybeans [Glycine max L. (Merrill)]. ‘Bragg’ has produced low seed yields on this field even with soil fumigation. Greenhouse screening trials showed that of the soybean cultivars currently in production in Louisiana, Bragg was the most resistant. Several old cultivars and new experimental lines that had shown root‐knot nematode resistance in other areas of the U. S. were screened in the greenhouse and field for resistance to this new race. Breeding lines were identified which had a low root‐knot index and produced relatively high seed yields. Two breeding lines yielded well but had a moderately high root‐knot index. Basic sources of resistance came from ‘Hill,’ ‘Palmetto,’ and ‘Laredo.’
Monogenic Chlorotic‐Lesion Resistance in Corn to Helminthosporium maydis1
Authors: Smith D. R. , Hooker A. L.
Published: July 2010

Chlorotic‐lesion resistance in corn (Zea mays L.) to Helminthosporium maydis race O was inherited as a single recessive gene. Resistant plants in both normal and cms‐T cytoplasm expressed small chlorotic lesions whereas suceptible plant exhibited large tan to brown, oval to rectangular lesions.
Analysis of Several Types of Gene Action Controlling Resistance to Bacterial Blight of Cotton by Means of a Generalized Computer Model1
Authors: Davis D. D. , Jackson J. , Cross H. Z.
Published: July 2010

A computer program has been written having the capability to fit three‐ or four‐gene models to F2 segregation data divided into ten or fewer phenotypic classes. The various types of gene action analyzed are known to occur in the determination of bacterial blight resistance in cotton. The genes in any specific model may be independent or dependent, unequal in effect, and either dominant, partially dominant, additive, or recessive. Successive increments of gene values were limited to integers. Linkage was in five increments from 0 to 50% recombination inclusive, coupling or repulsion, and restricted to two genes in any particular model. The X2 criterion was used to select those models printed out as possible solutions. Exact data based on hypothetical three‐gene models were solved satisfactorily by the computer program. To provide a “live” test, a strain of cotton (Gossypium hirsutum, L.) resistant to the bacterial blight pathogen (Xanthomonas malvacearum [(E. F. Smith) Dowson], was crossed to susceptible strain. Data from the segregating progenies were analyzed by the program, and feasible models for the gene action accounting for resistance were proposed. Classification into eight grades of resistance‐susceptibility were shown to be statistically satisfactory for resistant and susceptible parents and for a segregating progeny in a specified environmental range of temperature and humidity. Conclusions regarding gene action are restricted to the specified environmental range. The program is best adapted for analysis of samples of 200 to 350 individuals.
Performance of Crosses Within and Between Two Diverse Sources of Birdsfoot Trefoil, Lotus corniculatus L.1
Authors: Conje A. M. , Carlson I. T.
Published: July 2010

Nine clones derived from the cultivar ‘Empire’ and nine clones derived from two Russian introductions of birdsfoot trefoil (Lotus eorniculatus L.) were crossed in a partial diallel fashion, both within and between sources, to evaluate the influence of genetic diversity on expression of heterosis, to study combining ability of the parent clones, and to study interrelationships among characters that affect forage yield, seed size, and seed production. Sibmating was practiced in 16 F1 progenies to study breeding behavior in the second generation.

In a space‐planted test, intersource F1 progenies yielded 14% more forage than intrasource progenies; however, they did not outyield crosses within the Russian source. General combining ability mean squares usually were considerably larger than specific combining ability mean squares. Full‐sib progenies derived from intersource crosses were superior to those from intrasource crosses in forage yield, winterhardiness, spring vigor, and pod production.

High forage yield was closely associated with spring vigor and winterhardiness in F1 and full‐sib progenies and tended to be associated with a more prostrate growth habit and good pod production. Large seed size showed a low but significant association with low forage yield. Seed size was independent of pod production.