bluuebunny/crossref_metadata_2025 huggingface dataset:
Inheritance of Drying Rate in “Mature” Corn (Zea mays L.)1
Authors: Purdy J. L. , Crane P. L.
Published: July 2010

Three “fast” drying and three “slow” drying corn inbreds, whose hybrids demonstrate various rates of drying after physiological maturity, were used to study the genetics controlling differential drying rates among hybrids. Drying rate was estimated by the moisture loss from husked ears in a forced‐air dryer at 38 C for 18 hours. Initial moisture range was 30 to 40% while dried ears had a range of 20 to 30%.

Correlations in this population indicate that selection for faster drying rate would most likely result in smaller ears, later silking date, and lower moisture content at 60 days after silking. Phenotypic and genotypic correlations were moderately high and similar. Most environmental correlations were nonsignificant.

Diallel analysis indicated significant differences for both general and specific combining ability effects with the additive component more important than the non‐additive; therefore, drying rate is fixable.

Broad sense heritability estimates obtained by the F2 variance method were moderately high, while higher estimates were obtained by genetic components of variance from F1 replication means. High heritability was also indicated by the genetic correlations. Estimates of HMb were between 52% and 95%.

Xenia effect on differential drying rates was generally found to be non‐significant.

Determination of drying rate by use of forced‐air dryers offers a good approach for the plant breeder in selection for faster drying rates.
Meiosis and Pollen Stainability in Switchgrass, Panicum virgatum L1
Authors: Barnett F. L. , Carver R. F.
Published: July 2010

Chromosome number, meiotic behavior, and pollen stainability were studied in switchgrass plants originating mainly in Kansas and Oklahoma. Tall, coarse, glabrous plants, referred to as “lowland”, were tetraploid (2n =36). Shorter, finer plants, featuring varying amounts of leaf blade pubescence and referred to as “upland,” were mostly octoploid. One upland plant was hexaploid, however, and four were aneuploid near the 72‐chromosome level.

Tetraploids were more regular meiotically and exhibited a higher frequency of well‐stained pollen than either octoploids or aneuploids. Octoploids and aneuploids were similar in meiotic behavior, but the former exhibited a higher frequency of well‐stained pollen.

Genetic distinctness of upland and lowland populations was suggested. Asexual reproduction seemed unlikely in tetraploids. It appeared more likely at higher levels of polyploidy where extreme meiotic irregularity suggested materially reduced sexual fertility in occasional plants.
Relative Efficiency of Experimental Designs With Systematic Control Plots for Alfalfa Yield Tests1
Authors: Melton Bill , Finkner M. D.
Published: July 2010

The relative efficiencies were determined for the randomized complete blocks and two lattice designs with systematically arranged control plots. All experimental data were analyzed with and without covariance, first as randomized blocks and then as lattices. The average of the two control plots lying adjacent to each entry was used as the concomitant variable in the covariance analysis.

The use of systematic controls in a covariance analysis resulted in increased efficiencies from 38 to 528%. The effectiveness of the covariance models increased with the age of the stand. Coefficients of variability and F‐values were also compared. Other advantages in the use of systematic controls were the small size of experimental area required, small amount of seed per entry and the value of control plots in making subjective evaluations of entries.
Improving Forage Quality in Bermudagrass by Breeding1
Authors: Burton Glenn W. , Hart Richard H. , Lowrey R. S.
Published: July 2010

Twenty‐three clones of bermudagrass, cut at 2‐, 3‐, 4‐, and 6‐week intervals, differed significantly in crude‐protein content and nylon bag dry‐matter digestibility. These quality measurements decreased as age of forage increased. Genotype ✕ age interactions were not significant. F1 hybrid ‘Coastal’ ✕ ‘Kenya 56 #14’ (the best‐quality hybrid) averaged 12.3% more digestible dry matter than Coastal bermuda over a 4‐year period. With the same forage intake, 1,760‐kg (800‐lb) steers should gain 30% more per day with this hybrid than with Coastal bermudagrass. Fiftyseven F1 ‘Midland’ ✕ ‘Kenya 61’ hybrids cut at 33 days of age ranged from 45.2 to 59.6% in dry‐matter digestibility with a 5% LSD of 2.8%. Midland and Kenya 61 parents included in this test gave dry‐matter digestibilities of 49.7 and 60.5%, respectively. Dry‐matter digestibility, determined by a special nylon‐bag technique (the most precise of eight methods used for estimating forage quality at Tifton, Ga.), appears to be well suited for screening many genotypes in a forage‐breeding program directed toward quality improvement.
Inter‐Genotypic Competition in Soybeans. I. Evaluation of Effects and Proposed Field Plot Design1
Authors: Schutz W. M. , Brim C. A.
Published: July 2010

The effect of inter‐genotypic competition on yield andother attributes was evaluated in both hill and row plots utilizing four diverse adapted varieties. The experimentaldesign permitted the measurement of competition dosage effects as well as compensatory effects on adjoining genotypes. There was a drastic effect of competition in hills and rows on seed yield, seed number, and efficiency (expressed as a ratio of seed yield to straw yield). Certain genotypic combinations exhibited overcompensatory effects, a result which suggests that genotypic behavior in a competitive situation may be a reliable criterion for predictlng superior varietal blends. The data further suggest a nine‐hill field plot which should be effective in evaluating large populations for superior yield genotypes. The ninehill plot removes about 70% of the competition bias exhibited by an unbordered hill and would require much less land area and seed for testing than standard row plots.
Influence of Density on Plant Variation in Fiber Flax, Linum usitatissimum L.1
Authors: Obeid M. , Machin D. , Harper John L.
Published: July 2010

Plants of fiber flax develop a log normal frequency distribution of dry weight with age and increased density. Capsule number per plant shows an even more skewed frequency distribution. Mean seed number per capsule and individual seed weight are less sensitive to density but frequency distributions are not normal.
Induction of Aneuploids in Hexaploid Oats, Avena sativa L., Through X‐Irradiation1
Authors: Mannephong C. , Sadanaga K.
Published: July 2010

Aneuploids were induced in the hexaploid oat variety ‘Cherokee’ through X‐radiation (300r, 500r, 700r) of panicles in the pre‐anthesis stage. The X1 and control plants were examined for abnormal tetrads (micronuclei in tetrads), and plants with more than 15% abnormal tetrads were classified abnormal and saved as potential sources of aneuploids and translocations. The percentage of abnormal plants was related to the X‐ray treatments. Although the percentage (6.4) of monosomics was highest in the 700r treatment, we conclude that the 300r treatment (4.9%) was most efficient in producing monosomics since it was associated with the lowest percentage of translocations
Net Photosynthesis of Barley Seedlings as Influenced by Leaf Area Index1
Authors: Pearce R. B. , Brown R. H. , Blaser R. E.
Published: July 2010

Net photosynthesis of barley seedlings increased to an optimum leaf area index. This optimum was hard to define since net photosynthesis remained maximal over a wide range of leaf areas. Net Photosynthesis was adversely affected only by very high leaf areas.
Reciprocal Recurrent Selection and Modifications in Simulated Populations1
Authors: Cress C. E.
Published: July 2010

Computer simulation was conducted by the Monte Carlo method for a bisexual organism with two allels at each of 40 independently segregating loci. Reciprocal recurrent selection and two modifications were performed for the completely dominant and purely overdominant models at a number of starting gene frequencies. Genetic divergence is an unsound basis for selecting starting populations when the goals of selection are long term. A short term increase in the means of the recurrent populations cannot be used as evidence for a predominance of partially or completely cominant gene effects.

Two modifications are important for the improvement of genetic potential and rate of progress for types of recurrent selection using progeny testing. 1) A synthetic variety should be made from all material entered into a moderate to long term recurrent selection program. 2) One generation of selling (or other inbreeding) should precede the test crosses in each cycle, where the progress per unit time indicates this is more efficient.
Effect of Clipping and Nitrogen Fertilization on Yield and Stands of Tall Fescue1
Authors: McKee W. H. , Brown R. H. , Blaser R. E.
Published: July 2010

Two experiments were conducted in the field during spring and summer to study effects of nitrogen level, time of fertilization, and defoliation, and their relationships on yield and tillering and on carbohydrate and nitrogen content of the stubble.

Stand reduction by N and defoliation in ‘Kentucky 31’ fescue appears to be related to morphological stage of growth and season. Stands were reduced at high N levels in spring when grass was cut at flowering stage but not if cut frequently. Stands and regrowth during summer were reduced only slightly by high N. Soluble carbohydrates in stem bases were reduced with high N fertilization and N content was increased. Differences in chemical constituents due to treatments disappeared 20 to 30 days after regrowth.

Faster regrowth was obtained when N was applied 5 days before clipping or at time of clipping as compared with 7 days later. Fast regrowths were associated with decreases in organic reserves.
Cyto‐Histological Investigations of Pollen Abortion in Male‐Sterile Sudangrass1
Authors: Alam Sultanol , Sandal P. C.
Published: July 2010

Comparative morphological and cytological studies were made of anthers from a male‐sterile and male‐fertile line and a male‐sterile and a male‐fertile Ft hybrid of Sudangrass, Sorghum vulgare var. sudanense. Meiosis was normal in both male‐fertile and male‐sterile lines and normal tetrads were formed. Pollen abortion in male‐sterile lines was associated with non‐degeneration of the tapetal cells during the maturation of the young microspores, whereas, tapetal cells degenerated during similar maturation stages with production of normal pollen in malefertile lines.
Influence of Plant Residues on Sclerotium rolfsii and Inhibitory Soil Microorganisms1
Authors: Mixon A. C. , Curl E. A.
Published: July 2010

Effects of certain dry‐plant residues on Sclerotium rolfsii and inhibitory soil microorganisms were investigated with regard to the potential value of these residues in biological control of the pathogen. Average daily growth rates of both S. rolfsii and Trichoderma sp. in sterilized soil containing oat‐residue substrate were reduced in comparison to growth rates with residues of clover, peanut, vetch, or corn. However, the least growth of Trichoderma always exceeded the best growth of the pathogen. Sclerotium production by S. rolfsii and sporulation by Trichoderma were greatly increased in sterilized soil amended with either oat or corn residue. Additions of oat residue to natural soil resulted in severe mycelial degradation and an inhibitory effect upon sclerotial germination. Experiments with sterilized soil inoculated with known inhibitory microorganisms revealed that the biological control effect in oat‐amended soil may be attributed primarily to Trichoderma sp. and certain bacteria.
An Evaluation of Modified Ear‐to‐Row Selection in a Population of Corn (Zea mays L.)1
Authors: Webel O. D. , Lonnquist J. H.
Published: July 2010

Four cycles of modified ear‐to‐row selection have been applied to the open‐pollinated variety, ‘Hays Golden.’ The objective of this research was to evaluate the effectiveness of combined selection for yield of grain. The method entails selection among and within half‐sib families. The family selection was based on the average performance in three replications, one at each of three locations. The selection of individuals within selected families was based upon phenotypic performance in a natural crossing block isolation.

The mean yield increased an average of 9.44% per cycle relative to the parental variety. The predicted gain from selection based upon estimates of genetic and geneticenviromnental variances in the original Hays Golden variety was in good agreement with the observed response for grain yield. A comparison with results published earlier using mass selection in the same variety indicates that the modified ear‐to‐row procedure is more effective than mass selection alone in improving yield in the Hays Golden varietal population.

Modified ear‐to‐row selection may be used to obtain a more rapid increase in the frequency of favorable genes prior to the extraction of inbred lines. The method can be used to advantage after some reduction in the additive genetic variance has resulted as a consequence of effective mass selection and a more precise measure of the genotypic effect is needed.
Induced Sterility and Assiciated Effects of Dimethylarsinic Acid Treatment of Pearl Millet1
Authors: Powell Jerrel B. , Taylorson R. B.
Published: July 2010

We have further investigated dimethylarsinic acid because of its possible gametocidal activity, using the prolific‐seeding pearl millet, Pennisetum typhoides (Burm.) Stapf and C. E. Hubb. Seed set, pollen stainability, chromosome pairing, length of tillers, and other characteristics were evaluated. Foliar‐spray applications (183 grams per hectare) at early growth stages selectively modified floral structures, the gynoecium being the most sensitive. Multiple and intermediately modified pistils were observed in single spikelets. A significant increase in number of chromosome univalents in microsporocytes was associated with treatment dose and seed set was markedly reduced. No one causal factor was found to have a dominant influence on sterility, although selective interference with normal tissue differentiation and retarded cell elongation of floral structures played an important part.
Heritability of Three Soft Wheat Quality Characters in the F2 and F3 Generations1
Authors: Briggle L. W. , Yamazaki W. T. , Hanson W. D.
Published: July 2010

Use of early generation testing procedures for quality has a direct effect on the efficiency of any wheat breeding program. Soft wheat breeders now have access to three micro tests (tests involving small samples of grain) which can be used as early in varietal development as the F2 or F3.

Heritabilities and expected genetic advance for the quality characters measured by micro AWRC, micro pearling index, and micro flour yield, are high based on data from F2 and F3 progenies of one cross, ‘Blackhawk’ X ‘Kharkof’. Results, though limited, indicate that a wheat breeder may expect to make significant gains through early generation selection for any one of the three quality characteristics measured by the micro tests. Growing breeding lines at one location, at least under conditions expected in an average season, is sufficient for evaluation based on these three micro tests.
A Leaf Abnormality for the Identification of a Genetic Male Sterile in Gossypium hirsutum L.1
Authors: Quisenberry J. E. , Kohel R. J.
Published: July 2010

We found a leaf abnormality associated with male‐sterile‐2 in Gossypium hirsutum. Male‐sterile‐2 is completely male sterile and inherited as a monogenic recessive. A study was conducted to determine whether the observed leaf abnormality was a pleiotropic effect or linkage. Male‐sterile‐2 and the leaf abnormality showed no recombination. Pleiotropv was assumed, althoueh very close linkage could not be ruled out. We tested for allelism between the leaf abnormality and the previously reported abnormal palisade mutant (because they were phenotypically similar) but they were not allelic.
Mapping of Stem‐Rust Genes Sr9 and Srl6 of Wheat1
Authors: Sears E. R. , Loegering W. Q.
Published: July 2010

The stem‐rust genes Sr9a from Red Egyptian and Srl6 from Thatcher, previously known to be located on chromosome 2B with little or no linkage between them, were mapped by means of telocentric chromosomes. Both genes lie on the long arm, and they showed 10.6% and approximately 50% crossing‐over, respectively, with the centromere. Male transmission of telocentric 2BL in competition with the entire 2B from Red Egyptian and Thatcher was 23.6% and 16.0%, respectively, as compared with only 0.4% and 4.1% for telo‐2Bs.
Physiological and Chemical Differences in Aged Seeds1
Authors: Ching T. M. , Schoolcraft Isabelle
Published: July 2010

Moisture content, germination percentage, seedling length and contents of sugars, amino acids, inorganic. phosphate, starch, and insoluble protein were determined in new and 10‐year‐old canned crimson clover and perennial ryegrass seeds. Conductances,u gars, aminoa cids, and phosphatew ere measuredi n the leachate of these seeds. Loss of viability and vigor was not due to depletion of food but appeared to be related to the activity of proteases, phytase, and phosphatases since an increase of permeability, amino acids, and inorganic phosphate was observed in the aged material. The magnitude of these increases was related to species, seed moisture and to a lesser degree storage temperature.
Pollen Production and Pollen Shedding of Hard Red Spring (Triticum aestivum L. em Thell.) and Durum (T. durum Desf.) Wheats1
Authors: Joppa L. R. , McNeal F. H. , Berg M. A.
Published: July 2010

We have investigated the relative pollen‐shedding abilities of 11 hard red spring and 3 durum wheat varieties and the relationships between pollen‐shedding and other varietal characteristics.

The varieties differed in amount of pollen shed, number of pollen grains/anther, percent anthers extruded, tillers/plot, fertile florets/plot, fertile florets/tiller, yield, and kernel weight. Anther extrusion varied from 72% for ‘Thatcher’ spring wheat to 22% for ‘Lakota’ durum wheat. Number of pollen grains/anther varied from 3,867 for ‘Rescue’ to 2,687 for ‘Fortuna’ spring wheat.

The amount of pollen shed was positively correlated with percent anthers extruded and tillers/plot but negatively correlated with fertile florets/tiller. Path coefficient analysis indicated that percent anther extrusion had the largest direct effect on pollen shedding. Pollen shedding ability of a variety was predicted on the basis of percent anther extrusion, pollen grains/anther and fertile florets/plot.
Effects of Frost and Freezing on Hydrocyanic Acid Potential of Sorghum Plants1
Authors: Wattenbarger D. W. , Gray Elmer , Rice J. S. , Reynolds John H.
Published: July 2010

The effects of frost and freezing on hydrocyanic acid potential (HCN‐p) of plants of ‘Greenleaf’ and ‘Piper’ sudangrass and ‘Suhi‐1’, a sorghum ✕ sudangrass hybrid, were studied.

The HCN‐p of plants of all plant heights and cultivars decreased during the autumn until frost occurred. Significant increases in HCN‐p were measured after most frosts. These increases were most evident from 1 to 6 days after frost. The response of HCN‐p to frost was greater in shorter than in taller plants. Plants of Suhi‐1 had a greater increase in HCN‐p than plants of Greenleaf or Piper. Freezes (−5 C or lower) resulted in death of the plants and caused a decrease in HCN‐p which continued until little or none was detected. This decrease in HCN‐p was observed for plants of all heights and cultivars.
Effect of Temperature on Germination and Seedling Development of Ladino Clover (Trifolium repens L.) and Salina Strawberry Clover (Trifolium fragiferum L.)1
Authors: Olusuyi Samuel A. , Raguse Charles A.
Published: July 2010

Germination and seedling development of Ladino and 'Salina' strawberry clovers at 10, 15, and 20 C were studied. Little growth occurred in either species at 10 C. Ladino clover had a lower percentage of normal seedlings when germinated at 15 C as compared to 20 C. The cumulative average leaf index number differed little between species at 15 and 20 C. Petiole elongation was retarded more than blade development at 15 C in both species.
Effect of Nitrogen Fertilization on Protein Quality and Quantity and Certain Other Characteristics of 19 Strains of Sorghum bicolor (L.) Moench1
Authors: Campbell A. R. , Pickett R. C.
Published: July 2010

Eighteen inbred lines from the world sorghum collection and RS610 were tested with three levels of nitrogen fertilization. The same 18 inbred lines were grown under high fertility conditions. Significant differences among lines existed for height, lodging, maturity, weight of 100 seeds, grain weight per panicle, protein, lysine in protein, and protein ✕ lysine within each test. Nitrogen fertilization affected the protein production significantly, but variation among lines was much greater. Genotypic range for protein production was 11.7 to 16.3%. Lysine as percent of protein was not affected significantly by nitrogen fertilization, but genotypes ranged from 1.64 to 2.52%.

A comparison of a very high fertility treatment with three nitrogen fertilization levels showed that there were significant differences among fertility levels and among genotypes for grain weight per panicle, protein, lysine in protein, and protein ✕ lysine. Protein was 0.6% higher for high fertility while lysine was 0.47% lower, grain weight per panicle was 10.7 g lower, and protein ✕ lysine was 5.68 units lower for this location. There was a significant interaction between genotype and location for lysine, protein ✕ lysine, and grain weight per panicle, but not for protein production.
Analysis of A Diallel Set of Early Flint Varieties of Maize1
Authors: Troyer A. Forrest , Hallauer Arnel R.
Published: July 2010

We evaluated a diallel set of 10 early flint varieties of maize (Zea mays L.) for yield and seven other traits at two planting rates (85.8 and 128.7 M plants per ha) and dates (May 3 and June 14). Dates and rates showed differences; however, except for erect plants, the interactions of entries with the two planting rates and dates were not significant. The analyses showed that the initial evaluation of the varieties and their crosses could have been made in one cultural environment for this group of varieties.

Highest average yields were obtained on the early planting date (May 3) at the high rate (128.7 M/ha). Average yields for both dates and rates were 2,536 and 4,167 kg/ha for the 10 varieties and 45 variety crosses, respectively. Saskatchewan was the highest yielding variety (3,119 kg/ha). ‘Syzldecka’ ✕ ‘Motto’ was the highest yielding variety cross (5,309 kg/ha). The crosses that included Motto as one of the parents had the highest average yields (4,312 kg/ha).

Average heterosis was 43% relative to the high parent and 72% relative to the midparent. Only two of the crosses (‘Alberta’ #x2715; ‘Rutherford’ and ‘Morden’ ✕ ‘Pervenets’) were lower yielding than one of the parents. Average variety heterosis (mean of parents vs. mean of crosses) was 71%. The amount of heterosis observed in the variety crosses indicates that the parent varieties were genetically diverse.
Maternal Control of Oil Synthesis in Soybeans, Glycine max (L.) Merr.1
Authors: Singh B. B. , Hadley H. H.
Published: July 2010

Seeds of F1, F2, and backcross populations resulting from crosses between high oil (21‐22%) and low oil (13‐16%) soybean Glycine max (L.) Merr., lines were analyzed NMR for oil content both on an individual seed and on an individual plant basis. On the average, oil content of F1 seeds was 1.1% lower than the oil contents of seeds resulting from self‐fertilization of the high line female parents and 1.3% higher than that from the low line females. Heritability estimates based on single seed values were negligible and the correlation between oil content of F2 seeds and F3 seeds on the resulting F2 plants was +0.25. On a plant basis the oil content of F1 plants was intermediate between the oil contents of seeds produced by self fertilization on the two parents. About 60% of the total variability among F2 plants was due to additive genetic effects. No cytoplasmic effect was detected. It was concluded that oil synthesis in soybean seed is determined largely by the genotype of the plant producing the seed. Thus, selection for oil contents among individual seeds on the same plant likely will be ineffective even though the plant is heterozygous for genes affecting oil content.
Screening Sugarcane Populations for Cold Tolerance by Artificial Freezing1
Authors: Irvine J. E.
Published: July 2010

Results of artificial freezing of young, potted sugarcane plants for 6 hours at —3 C were similar to field experience when plants were preconditioned in an unheated greenhouse. Precision control of freezer temperatures permitted the detection of levels of cold tolerance in the progeny of two cold tolerant parents. The method has been adapted to routine screening of seedlings for cold tolerance.
Leaf Pubescence in Common Wheat, Triticum aestivum L., and Resistance to the Cereal Leaf Beetle, Oulema melanopus (L.)1
Authors: Ringlund Kåre , Everson Everett H.
Published: July 2010

Plant materials were derived from crosses between glabrous and pubescent wheat varieties. A technique for evaluating pubescence density on photomicrographs of cleared leaf samples was developed. Individual plants from parental and segregating populations were evaluated for leaf pubescencea nd tested for resistance by a larval feeding test. Correlation coefficients between larval weight and pubescence density were highly significant with highpubescence, density associated with resistance.

The original data for both larval weight and pubescence density were transformed to square roots to make variances independent of the means. The square root transformation also made the frequency distributions for segregating populations more normal.

Analyses of the pubescence data of F1, F2, and BC progenies from crosses between glabrous and pubescent varieties show this character to be quantitatively inherited. The gene action estimated on the square root scale is mainly additive. Partition of variance shows only additivity, but analysis of population means reveals a partial dominance for pubescence density. Heritability in the F2 was approximatdy 50%.
Peroxidase Activity in Seeds of Soybean Varieties1
Authors: Buttery B. R. , Buzzell R. I.
Published: July 2010

Varieties of soybean (Glycine max (L.) Merr.) were separated into two main groups on the basis of high or low peroxidase activity in the seed coat. Differences in peroxidase activity were detected following electrophoresis of extracts on polyacrylamide gel and by quantitative determinations. Seed‐coat extracts from the high level group exhibited more than 78 tunes the peroxidase activity of seed‐coat extracts of the low level group. A survey of peroxidase activity of soybean varieties was carried out by using a specially developed spot test. Pedigree relationships among the varieties indicated that high and low activity is highly heritable and that it is not a case of ‘extra‐nuclear’ maternal inheritance.

Disc electrophoresis using suitable amounts of seedcoat extracts resulted in a major band of isoperoxidase which was common to both groups. Two minor bands of isoperoxidase were also identified in all high‐level varieties and in two of the five low‐level varieties tested. Between the two groups, isoperoxidases appeared to be qualitatively identical but quantitatively different.
Inheritance of Pubescence Type in Soybeans: Glabrous, Curly, Dense, Sparse, and Puberulent1
Authors: Bernard R. L. , Singh B. B.
Published: July 2010

F2 and F3 data from crosses of soybean strains with five aberrant pubescence types and strains with normal pubescence showed that each of the five differs from normal by a single gene pair and that the five loci segregate independently. Four of these genes occur in varieties from eastern Asia: P1 (glabrous), pc (curly pubescence), Pd (dense, three to four times the normal number of hairs), and Ps (sparse, a third to a fourth of the normal concentration of hairs); and the fifth originated as a mutant found in Iowa in 1924: P2 (puberulent). P1 (glabrous) appears to be epistatic to the other types, although Pd and Ps affect the density of the hair stubs visible on close inspection of glabrous plants. The genes pc and p2, affect the form of the hairs independently of the density effects of Pd and Ps. Pd and Ps interact with each other in an additive fashion in controlling hair density. The reported linkage between P1 p1 and R r (seed color) was confirmed.
Combining Abilities and Relative Dominance among Maize Inbreds for Resistance to Earworm Injury1
Authors: Widstrom Neil W. , Hamm John J.
Published: July 2010

General combining ability effects for corn earworm, Heliothis zea (Boddie), resistance were highly significant and accounted for approximately two‐thirds of the genetic variability measured in two sets of diallel crosses among sweet corn, Zea mays (L.)> inbreds. Specific combining ability estimates were generally low, though significant in one case. Highly significant genotype‐environment mean squares were attributed to the interaction of general combining ability with location and years. The relative importance of location effects was essentially equivalent to those for years.

Trends among constant parent regression coefficients were essentially absent, suggesting a low level of dominance for resistance to earworm injury. Dominance estimates for individual inbreds and average estimates as obtained from variance component ratios for diallel sets were also in the partial dominance range. Estimates of heritability for selection of half‐sib families were .340 and .398 for the nine‐line and 12‐line sets, respectively. Although heritabilities of this size should make reasonable selection gains possible, culling F1's with large noncomplementing specific combining ability effects from selected half‐sib families of high general combining ability would further enhance potential selection gains.
Stability of Attractiveness of Alfalfa Clones to Honeybees under Varying Locations, Seasons, and Years1
Authors: Kauffeld Norbert M. , Sorensen Edgar L. , Painter Reginald H.
Published: July 2010

The honeybee (Apis mellifera L.) attractiveness of five highly‐preferred and five relatively nonpreferred clones of alfalfa (Medicago spp.) as selected during 2 years in two locations, remained consistent for 2 additional years (summer and fall, with and without a cage), one additional location, and with differing total numbers of bees present. The 10 clones were associated with a total of 6,825, 45, and 25 different clones at locations 1, 2, and 3, respectively, but this did not greatly alter their rank in respect to each other. Only eight of 110 attractiveness ranks disagreed with the grouping, highly preferred and least preferred. The coefficient of concordance of 15 clonal rank values was +O.702 (P < .01).

Honeybee attractiveness of 45 clones studied varied differentially with locations and years. Attractiveness of certain clones remained high and that of others low. Conversely, other clones were characterized by conspicuous attractiveness alterations over seasons, years, and locations.

The preference of honey bees for alfalfa clones in a cage paralleled that in the field (r = +0.946, P < .001).
Interpretation and Use of Estimates of Heritability and Genetic Variances in Plant Breeding1
Authors: Dudley J. W. , Moll R. H.
Published: July 2010

Estimates of genetic variance and heritability provide useful guidelines for answering many questions which arise in a plant breeding program. In this paper we have attempted to (a) delineate appropriate questions which can be answered by estimation of genetic variance components and heritabilities (b) examine the assumptions necessary for estimation and (c) clarify the limitations imposed on interpretation of the estimates by the assumptions.
Comparison of Planting Arrangements and Time of Evaluation for Peas (Pisum sativum L.)1
Authors: Gritton Earl T.
Published: July 2010

Eight cultivars of processing peas (Pisum sativum L.) were grown under both nursery and commercial conditions during 1965 and 1966. They were evaluated for yield and other characters at the normal green pea processing stage and at the mature plant dry seed stage. The relationship between values measured under the two different planting arrangements and at the two tunes of harvest were examined through simple correlation coefficients and analyses of variance. Values obtained under nursery conditions for plant height, total number of nodes, lowest pod node, and number of ovule initials per pod were highly correlated with values obtained under commercial growing conditions. Large and highly significant “r” values were likewise obtained for these same traits when the comparison was between the normal processing stage and the dry seed stage. Yield per plot, pods per plant, and peas per pod were not consistently correlated between planting arrangements nor between tunes of harvest. Significant variety ✕ planting arrangement and variety ✕ harvest interactions indicate that some cultivars differed markedly for some characters from the general similarities of performance. Too much reliance upon evaluations made under nursery conditions, or at the mature plant stage, would results in misclassification of these cultivars relative to their performance under normal processing renditions.
Sources of Tolerance to Soil‐Borne Oat Mosaic Virus from the World Oat Collection1
Authors: Graham Doyce , Byrd W. P. , Kingsland G. C.
Published: July 2010

The World Oat (Avena spp.) Collection (4,533 entries) was evaluated in replicated experiments in 1963‐64 for tolerance to soil‐borne oat mosaic virus, Marmor terrestre var. typicum and M. terrestre var. oculatum McK. In 1964‐65, 601 entries were repeated that scored less than 4 on a 0 to 10 rating (0 = no visual symptoms and 10 = completely susceptible or dead plants). Of these 601 entries, the 37 that scored less than or equal to 2.5 are listed.

From this evaluation several excellent divergent sources of tolerance to soil‐borne oat mosaic virus were noted.
Organic Acids from Leaves of Several Crop Plants by Gas Chromatography1
Authors: Clark Ralph B.
Published: July 2010

Organic acids from leaf extracts of Hordeum vulgare L., Zea mays L., Avena sativa L., Secale cereale L., Sorghum bicolor (L.) Moench, Triticum aestivum L., Medicago sativa L., Glycine max (L.) Merr., Phaseolus vulgaris L., and Lycopersicon esculentum, Mill, were separated by gas chromatography. Good chromatographic separation of trimethylsilyl‐derivatives of the organic acids were obtained using N,O‐bis(trimethylsilyl)acetamide as the esterifying reagent. Trans‐aconitic acid was one of the predominant acids in the cereal crops, but not in the dicotyledonous plants. Relatively high amounts of malonic acid were found in the legumes. The Krebs cycle acids were found in all the plants studied.
Effect of Anthracnose (Colletotrichum trifolii) Infection on Yield, Stand, and Vigor of Alfalfa1
Authors: Barnes D. K. , Ostazeski S. A. , Schillinger J. A. , Hanson C. H.
Published: July 2010

Relatively high levels of field resistance to anthracnose, Colletotrichum trifolii, were observed in the alfalfa variety ‘Cherokee’ and in an experimental line MSHp6. Severe anthracnose infection on susceptible varieties, ‘Saranac’ and ‘Iroquois,’ caused 25 to 30% losses in forage yield and stand, as well as losses in plant vigor the following spring. We believe that the importance of anthracnose injury in warm humid areas has been underestimated. Resistance in Cherokee and MSHp6 was attributed to recurrent cycles of field selection in North Carolina and Maryland, respectively, where anthracnose often occurs.
Relationship of Tannin, Dry Matter Digestibility and Crude Protein in Sericea lespedeza1
Authors: Donnelly E. D. , Anthony W. B.
Published: July 2010

Ten low‐tannin sericea plants (Lespedeza cuneata [Dumont] G. Don) were higher in digestible dry matter than 10 high‐tannin plants, as indicated by the in vivo nylon bag technique. Dry matter digestibility and percentage crude protein were not significantly correlated. Results indicated a significant genetic interaction for tannin and crude protein. In only one of three familiesdid crude protein increase as tannin content decreased. Preliminary data indicate that nutritive value of sericea forage can be increased significantly by developing varieties low in tannin.
Carbon Dioxide Uptake in Nitrogen‐Deficient Plants1
Authors: Ryle G. J. A. , Hesketh J. D.
Published: July 2010

Carbon dioxide uptake at the leaf surface in air and in oxygen‐free air was examined in maize (Zea mays L.), cotton (Gossypium hirsutum L.), and bean (Phaseolus vulgaris L.) plants exposed to an increasing deficiency of nitrogen. Carbon assimilation in these conditions was then related to the stomatal and apparent mesophyll resistances to CO2 transfer.

Lack of nitrogen decreased carbon assimilation in all three species. Assimilation was enhanced in oxygen‐free air in cotton and beans, but little affected in maize. The inhibition of assimilation in nitrogen‐deficient plants was accompanied by an apparent increase in mesophyll resistance to CO2 transfer, but some increase in stomatal resistance was also measured. Enhancement of carbon assimilation in oxygen‐free air was negatively associated with the apparent mesophyll resistance to CO2 transfer. Such apparent resistances in the mesophyll may be associated with differences in dark reactions, with a light or photosynthetically‐induced respiratory pathway, as well as with CO2 diffusion.
Seed Quality Charaters Associated with the D Locus of Flax, Linum usitatissimum L.1
Authors: Comstock V. E. , Ford J. H. , Gimore E. C.
Published: July 2010

Comparison of agronomic and seed quality characters of 17 near‐isogenic pairs of flax lines showed that the d locus was not associated with seed yield, maturity, height, or seed germination. Lines homozygous for the recessive d allele (yellow seed and pink flowers) had significantly smaller seed and higher iodine value than lines homozygous for the dominant D allele (brown seed and blue flowers). Percent oil of the two seed color classes differed significantly in each of four trials, but the differences were not consistent. High oil content was associated with the recessive allele in half the trials, but with the dominant allele in the other 2 trials. The analyses of variance strongly suggests that the chromosomal segment adjacent to the d locus is active in determining oil content and seed size, and that the d locus has a pleiotropic effect upon iodine value.
Carbohydrate Accumulation of Coastal Bermudagrass and Kentucky Bluegrass in Relation to Temperature Regimes1
Authors: McKell C. M. , Youngner V. B. , Nudge F. J. , Chatterton N. J.
Published: July 2010

Cynodon dactylon (L.) Pers., ‘Coastal,’ and Poa pratensis L., ‘Newport,’ were grown in four different temperature regimes to study the effect of temperature upon the accumulation of carbohydrate.

Plants were harvested at two‐week periods for 8 weeks and the stem bases were analyzed for alcohol soluble sugars, fructosan, and starch.

The highest concentration of carbohydrate occurred at the coolest temperature for both Kentucky bluegrass and Coastal bermudagrass. Carbohydrate accumulation generally increased as a function of time. Alcohol soluble sugar levels were approximately equal for both species at each temperature regime with the exception of a high amount in bluegrass grown at the coolest temperature.
Differential Seed Production of Northern Alsike and Red Clovers at Southern Latitude1
Authors: Dovrat A. , Waldman Miriam
Published: July 2010

Almost all plants of the original and increase lots of ‘Iso’ and ‘Tammisto’ alsike clover (Trifolium hybridum L.) contributed to the seed harvests at Rehovot, Israel (approx. 32°N). Seed yields per plant and total seed production of increase lots were similar to the original in spite of a considerable increase in the varietal population of plants contributing to the early seed harvests. Very little relationship was found between early flowering and high seed yield in these two varieties of alsike clover.

About half of the plants of ‘Tepa’ and ‘Alaskland’ red clover (Trifolium pratense L.) derived from the original seed lot produced seed. Varietal populations of first and second generation increase lots of Alaskland had a higher percentage of early‐flowering plants than the original seed ]tot. Varietal populations of second generation increase lots of Tepa also had a higher percentage of early flowering plants, but the first generation increase seed lots were similar to the original seed of Tepa. Total seed production of second generation increase lots of Alaskland was higher than of first generation lots. Early flowering and the contribution of seed from early‐flowering plants to the total seed yield showed some relationship in Alaskland but not in Tepa.
Effects of Nitrogen Fertilization on Polyphenol Content and Oxidase Activities in Tobacco Seedlings1
Authors: Sheen S. J. , Calvert J. , Rebagay G. R.
Published: July 2010

The effects of three levels of N fertilization on polyphenol content and polyphenoloxidase and peroxidase activities in the juvenile plants of hurley and dark tobaccos, Nicotiana tabacum L. were studied in solution culture. Large amounts of polyphenols were accumulated in the leaf; smaller amounts accumulated in the root. Chlorogenic acid and two isomers were the predominant fractions of polyphenols in the leaf, but the isomer neochlorogenic acid was absent in the root. Roots contained high concentrations of scopolin and scopoletin. The latter was not detected in seedling leaves. The amount and kind of N fertilizer greatly influenced the accumulation of polyphenols. Polyphenols were lowest on medium N, whereas they accumulated in large concentrations on both high and low N solutions. As a result, quantitative difference between the high and low polyphenol strains became less significant. Plants grown in high nitrate N solution contained more polyphenols than those fed with high ammonium nutrition. Polyphenoloxidase and peroxidase activities were higher in root than in leaf extracts and in plants cultured under medium N rate than in either extreme N environment. However, in high ammonium N fertilization the activity of both oxidases increased in the leaf but polyphenoloxidase decreased in the root. The results suggest that a medium rate of N fertilization increases oxidase in roots, polyphenoloxidase in particular, accompanied by a decrease of soluble polyphenol content in leaves, and produces a maximal phenotypic contrast for leaf polyphenol concentration among tobacco strains.
Induction of a Nonflowering Mutant in Sugarcane (Saccharum sp.)
Authors: Walker D. I. T. , Sisodia N. S.
Published: July 2010

Two sugarcane clones were treated with a range of doses of gamma rays. After one propagation, a number of subclones differed from untreated controls in their flowering propensity. Several subclones showed a high degree of uniformity. The recovery of nonflowering mutants from irradiated material of heavy flowering, but otherwise good sugarcane varieties may therefore be easy, enabling this ceiling on production to be removed.
Choice of Population Size and Use of Variation Between Replicate Populations in Plant Breeding Selection Programs
Authors: Baker L. H. , Curnow R. N.
Published: July 2010

Some factors which influence the choice of population size in selection aimed at improving composite populations of maize as sources of inbred lines are considered. The consequences of different effective population sizes on progress from selection within a population with a specific genetic model are examined, using a new mathematical approach described by Curnow and Baker (1968) [but see correction and Curnow and Baker (1969) and later errata notice]. The results obtained suggest that reasonably rapid progress from selection can be expected with small effective population sizes. Substantial added progress may be obtained if selection can be practiced within each of a number of replicate lines developed out of the same original population, followed by selection of the best replicate lines.

The results obtained also suggest that the selected lines should be tested in all possible combinations to identify outstanding lines which can then serve as sources of new inbred lines or as foundation material for new crosses in which selection can then be practiced.

The effect of departures from the assumed genetic model are discussed. However, the work reported reflects results expected with a specific genetic model. The most important finding is that conditions can exist where recommendations on population size, at present basic in the planning of a selection program, should be reconsidered.
A Laboratory Method of Determining Cold Hardiness in Bermudagrass, Cynodon dactylon (L.) Pers.1
Authors: Ahring R. M. , Irving R. M.
Published: July 2010

Differences in cold resistance among bermudagrass varieties can be detected by the triphenyl tetrazolium chloride (TTC) test. The TTC test has a limited potential as a tool in screening and predicting survival in areas where certain varieties are not recommended. The freezing technique which supplemented the TTC test showed that: 1) temperatures between –2.2 and –4.4 C caused significant injury to rhizomes of ‘Coastal;’ 2) –6.6 C caused significant injury to common, ‘Midland,’ and ‘Greenfield;’ 3) introductions A‐9957 (Yugoslavia) and A‐8153 (Afghanistan) were not injured at –6.6 C and occasionally will survive with some freeze injury at –9.4 C; 4) a 25% reduction in TTC absorbance following freeze treatment correlated closely with visual survival checks and served as a good index of viability; 5) cold hardiness may be induced in certain strains of bermudagrass in response to short‐day lengths and further conditioned by low temperatures under field conditions; and 6) rhizomes acclimated to fall and winter field conditions are more cold resistant than those grown under short day lengths and warm temperatures.
Seedling Difference Among Agrostis Species and Varieties1
Authors: Nittler L. W. , Kenny T. J.
Published: July 2010

Seedlings of four Agrostis species, two represented by two varieties each, were grown with continuous light and supplied with a complete nutrient solution. Within 5 weeks significant differences developed among species in several characteristics. A. alba L. plants had large leaves and stems, whereas those of A. canina L. were small in leaf size and stem diameter. A. palustris Huds. and A. tenuis Sibth. were intermediate in leaf size and stem diameter, but differed from each other in stem length and growth habit. A. alba and A. tenuis were upright in growth habit, but most plants of A. canina and A. palustris were decumbent. Plants could be classified easily as to species. Significant differences were not found between the varieties of A. palustris, ‘Penncross’ and ‘Seaside,’ but varieties of A. tenuis, ‘Exeter’ and ‘Highland,’ differed in several characteristics.
Production of Protoplasts from Plant Cells in Liquid Culture Using Purified Commercial Cellulases 1
Authors: Shenk Roy U. , Hildebrandt A. C.
Published: July 2010

Viable protoplasts were obtained from cells of 19 higher plant species grown in liquid shake culture utilizing purified commercial celluiases. Crude commercial cellnlases produced dead protoplasts. Viable protoplasts were obtained after purification by extraction with acidified acetone, fractional precipitation with ethanol, gel‐filtration, and charcoal adsorption. Results suggested that, in addition to cellulase, other enzymes present in commercial celluiases may be required for release of protoplasts from the cell walls. Protoplast formation from living unstained cells was observed in microcultures using phase microscopy. Protoplasts of some species survived only a few hours, but others survived for as long as 2 weeks. The routine production of protoplasts from a consistent source of enzyme is considered to be the first step toward the goal of producing somatic hybrids.