bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission of the Transec Wheat‐rye Translocation Chromosome1
Authors: Bielig L. M. , Driscoll C. J.
Published: July 2010

The pollen transmission of the ‘Transec’ wheat‐rye translocation chromosome was examined in two different genetic backgrounds, viz, ‘Chinese Spring’ and a line extracted from ‘Cornell Wheat Selection 82al‐2‐4‐7.’ The percentage of resistant progeny (%R) which resulted from crossing individuals heterozygous for the translocation chromosome into these two genetic backgrounds provided an index of male transmission. When heterozygotes were backcrossed to Chinese Spring, differential male transmission was observed in two different populations, I and II, which showed a low and high transmission rate, respectively. Transmission in Population I was not significantly affected by crossing to Chinese Spring, and was similar to transmission in a BC9 of Transec to Chinese Spring. However, the transmission showed a seasonal fluctuation, always being relatively higher in winter (23.3%R) than in summer (14.1%R). In Population II, transmission was initially significantly higher than in Population I (65.2%R cf. 18.2%R), but the rate of transmission decreased progressively with additional crosses to Chinese Spring, until transmission in the two populations became identical. Since crossing to Chinese Spring resulted in reduction of transmission in Population II, it can be concluded that Chinese Spring impairs transmission of this Particular translocation chromosome. Crossing to the line extracted from Cornell Wheat Selection 82al‐2‐4‐7 resulted in an increased transmission rate.
Inheritance of an Auxin Inducible Peroxidase in Oats (Avena sativa L.)1
Authors: Levings C. S. , Stuber C. W. , Murphy C. F.
Published: July 2010

Inheritance of an auxin inducible peroxidase was investigated in a cross of two cultivars of oats (Arena sativa L.). Appearance of the IAA inducible peroxidase was characteristic of coleoptile sections in one cultivar but not in the other. F2 segregations produced a 3:1 (monohybrid) ratio with presence of the enzyme dominant to the null condition. A synthetic hormone (2,4‐D) produced results analogous to those found with IAA.
Isolines in Cotton: Effects of Nine Dominant Genes1
Authors: Kohel R. J. , Richmond T. R.
Published: July 2010

Nine isolines of cotton, Gossypium hirsutum L., were developed by backcrossing lines carrying dominant marker alleles at a total of nine loci to Texas Marker‐1. The marker alleles were isolated into separate lines and backcrossed for eight generations to provide a common genetic background in which the effects of the individual marker loci could be evaluated and characterized. The effects of the qualitative characters on quantitative agronomic traits were determined for each line in a replicated performance test and compared to the performance of the recurrent parent. Certain quantitative traits of the isolines remained variable, and this variability was interpreted to be caused by linkage associations.
Microenvironment and Plant Characteristics of Corn (Zea mays L.) Planted at Two Row Spacings
Authors: Rumawas F. R. , Blair B. O. , Bula R. J.
Published: July 2010

Development and yield of hybrid corn planted at 50‐ and 75‐cm row spacings and thinned to final stands of 44,000 plants/ha were studied. Micrometeorological parameters were recorded during the 3 weeks before and 3 weeks after anthesis. Carbohydrate levels of ear leaves were determined during the same period.

Temperature, precipitation and solar radiation levels during the 1967 growing season were below recorded norreals. Air and soil temperatures, dew point temperatures, wind speeds, and carbon dioxide concentrations were similar at all canopy heights for the 50‐ and 75‐cm row spacings. Likewise, the daily maximums and minimums for the above listed parameters occurred at approximately the same time in the two row spacings.

Carbohydrate percentages of plants grown in 50‐ or 75‐cm row spacings were similar. For both row spacings, diurnal changes in carbohydrate concentration were highly significant. Concentration of water‐soluble carbohydrates increased considerably during anthesis and early ear formation. Acid‐soluble carbohydrate concentration decreased during this same period. Under the climatic conditions of the 1967 growing season a wider row spacing resulted in better yield performance although these differences were not statistically significant.
Effect of Initial Seed Moisture Content on Emergence and Yield of Grain Sorghum1
Authors: Phillips J. C. , Youngman V. E.
Published: July 2010

Emergence and yield of grain sorghum (Sorghum bicolor (L.) Moench) were studied as affected by the moisture content of seeds at sowing time. Sorghum seed sown with 8% moisture content emerged less than seed sown with either 11 or 14% moisture. Low initial seed moisture content and low substrate temperatures resulted in delayed radicle protrusion from the pericarp as well as a decrease in seed respiration rate during imbibition. Effects on emergence were great enough to be reflected in grain yields, especially under dryland conditions.
F1 Hybrids Versus Random F5 Line Performance and Estimates of Genetic Effects in Spring Wheat1
Authors: Busch R. H. , Lucken K. A. , Frohberg R. C.
Published: July 2010

Three hard red spring wheat (Triticum aestivum L.) crosses which had exhibited significant heterosis in a previous study were analyzed genetically by Hayman's generation mean analysis. Approximately 90 random F3‐ derived F5 lines were used as an agronomic comparison with the F1 hybrid generation and to determine if the genetic analysis based on parental, F1, F2, F3, F4, and backcross selfed generation means were of use in determining the possible results of selection.

Results of the genetic analysis indicated that selection of individual plants should be effective for plant height and heading date. Less value was realized from the analysis of the three crosses for yield.

F5 lines which performed significantly better than the F1 hybrid were found in each cross. One F1 hybrid failed to exceed the yield of its high parent, but both of the other hybrids were heterotic. F0 lines, derived from the best‐yielding F5 lines, and their respective parental F5 lines performed similarly when grown in the same experiments.
Influence of Drought Stress on Female Gametophyte Development in Corn (Zea mays L.) and Subsequent Grain Yield1
Authors: Moss G. I. , Downey L. A.
Published: July 2010

Many abnormal embryosacs (43% of the total observed) were recorded in ears from corn plants that had been drought stressed twice over a period of 10 days during embryosac formation (treatment T3). Also, hermaphrodite spikelets were commonly observed. Yery few grains were produced by these plants. In ears of plants drought stressed once over a period of five days during embryosac formation (treatment T2), 15% of the observed embryosacs were abnorraal compared with only 2.5% in ears of the unstressed control plants. The grain yield of T2 plants was not significantly reduced. Both T2 and T3 treatments greatly delayed silking; in the former there was a lag of 13 days between anthesis and silk emergence, and 16 days in T3 as compared to 3 days in the controls. Plants were hand‐pollinated to prevent sterility caused by the lack of pollen during silking, so that the large reduction in grain yield by treatment T3 was due mostly to embryosac abortion.

The surmise that femaleness of corn plants was reduced by drought stress because of a reduction in auxin levels was discussed.
Response of Different Rice Varieties to Gibberellin1
Authors: Harada J. , Vergara B. S.
Published: July 2010

The response to gibberellin of 119 rice (Oryza sativa L.) varieties, including some dwarf mutants, was studied. The japonica, indica and dwarf mutants showed a negative correlation between the lengths of their second leaf sheaths and their responses to gibberellin. No such correlation was obtained with the javanica varieties.

There was a negative relationship between gibberellin response and culm length. Some short varieties, however, showed a low response to gibberellin, indicating that lack of endogenous gibberellin is not the only factor responsible for dwarfness.
Combining Ability, Heritability, and Cytoplasmic Effects in Oats1
Authors: Muehlbauer F. J. , Marshall H. G. , Hill R. R.
Published: July 2010

Combining abilities, heritabilities, and cytoplasmic influences in oats (Avena saliva L.) were investigated in the F1, F2, and F3 generations of reciprocal crosses involving winter and spring oat cultivars. Reciprocal differences between F1 hybrids in the greenhouse were frequent for days to first head, growth habit, number of tillers, and plant height; maternal effects were a major component of variation. The need for vernalization appeared to be under cytoplasmic control, and this requirement may have influenced the expression of the other characteristics measured in the F1 generation. Only a few significant differences between reciprocal populations were found in the F2 and F2 generations under field conditions, and maternal effects were of no general importance. Reciprocal effects were important in some cases for maturityand seed weight differences.

Specific combining ability was significant for plant height and tiller number in the F1, but generally was not important in the F2 and F3, for maturity, plant height, straw strength, and yield. General combining ability was a consistent source of significant variation in the F2 and F3. Heritability estimates were highest for maturity and plant height and lowest for straw strength and yield. Combining ability and heritability estimates were influenced by the environment.
Genetic Relationship Between Tobacco Budworm Feeding Response and Gland Number in Cotton Seedlings1
Authors: Wilson F. D. , Lee J. A.
Published: July 2010

Tobacco budworms, Heliothis virescens (F.), discriminated among seedlings of Upland cotton (Gossypium hirsutum L.) possessing the nine possible genotypes involving the gland‐determining alleles Gl2, gl2, Gl3ral, and gl3. The insect larvae preferred glandless seedlings (gl2gl2gl3 gl3), then showed a decreasing amount of preference as the number of Gl2 and Gl3ral alleles increased. Seedling damage, number of larvae left on the seedlings, number of pigment glands on the cotyledonary petiole, and percent seed‐gossypol were correlated inter se. A diallel analysis showed that additive effects accounted for 84 to 97% of the total genetic variances for seedling damage, number of larvae per seedling, and gland number. Dominance and epistatic effects were generally small, but sometimes statistically significant. The analysis showed also that Gl2 usually contributed more to the total additive genetic variance than did Gl3ral, an expected result because the former allele has a more profound effect on gland density and thus on gossypol content.
Discovery of Sexuality in Eragrostis curvula (Schrad.) Nees1
Authors: Voigt P. W.
Published: July 2010

A search for sexual reproduction in Eragrostic curvula has revealed four introductions with pollen of diploid size. One of these, a known diploid, was extensively studied. Self‐pollinated seed set and all progeny performance data support the hypothesis that this introdduction is a highly cross‐pollinated, sexual strain.
Effect of Leaf Pubescence on Transpiration, Photosynthetic Rate and Seed Yield of Three Near‐Isogenic Lines of Soybeans1
Authors: Ghorashy S. R. , Pendleton J. W. , Bernard R. L. , Bauer M. E.
Published: July 2010

Apparent photosynthesis (AP), transpiration (TR) and seed yield were determined under field conditions for three near‐isogenic lines (isolines) of ‘Clark’ soybeans (Glycine max (L.) Merr.) differing in pubescence. AP of fully expanded leaves near the top of the plant and TR of individual plants were measured during the flowering stage.

Seed yields artd AP rates were not affected by pubescence but the dense pubescent isoline had lower transpiration rates than the normal or glabrous isoline.
Sensitivity of Lima Bean (Phaseolus limensis Macf.) Yield to 60Co Gamma Radiation Given at Three Reproductive Stages1
Authors: Bottino P. J. , Sparrow A. H.
Published: July 2010

Potted plants of lima beans (Phaseolus limensis Macf. ‘Fordhook 242’) were given a series of 16‐hour constant rate exposures to 60Co gamma radiation. The plants were at one of three stages of reproductive development: 1) buds in early pollen development; 2) flowers in anthesis or young pods after fertilization; and 3) large pods containing small partially developed seeds. The decreasing order of sensitivity measured as seed yield was buds, floweis or young pods, large pods. The 50% yield reduction exposures were 0.42 ± 0.43 kR for buds, 1.47 ± 0.47 kR for flowers and young pods, and 6.34 ± 0.02 kR for large pods, indicating about a 15‐fold difference between the most sensitive and most resistant stage.
Influence of Photoperiod and Thermoperiod on the IVDMD and Cell Wall Components of Tall Fescue1
Authors: Allinson D. W.
Published: July 2010

‘Kenwell’ and ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) were grown in chambers under the following conditions: (a) 27/16 C day/night temperature, 16‐hour photoperiod, (b) 27/16 C day/night temperature, 10‐hour photoperiod, (c) 16/4 C day/night temperature, 16‐hour photoperiod, and (d) 16/4 C day/night temperature, 10‐hour photoperiod. Two harvests were taken. Both long days and high temperatures significantly (P<0.01) lowered the percent in vitro dry matter digestibility (IVDMD) and also lowered the percent in vitro cellulose digestibility of tall fescue. These changes in digestibility were associated with increased levels of structural cell wall components. In the second harvest Kenwell was significantly greater in percent IVDMD (P<0.01) and hemicellulose (P<0.05) than Kentucky 31.
Relationships of Nitrate Reductase Activity to Protein Content in Related Nodulating and Nonnodulating Soybeans1
Authors: Liu Ming C. , Hadley Henry H.
Published: July 2010

Every 2 weeks over a 2‐month period we measured nitrate reductase (NR) activity and nitrate nitrogen content in leaves of soybean plants (Glycine max L. Merrill) from eight pairs of lines differing in ability to nodulate. Six of the pairs were F3 lines derived by crossing six nodulating P.I. lines to either the ‘Clark’ or the ‘Harosoy’ variety and to corresponding nonnodulating backcrossderived versions of these varieties. Two of the pairs were Clark and Harosoy and their respective (near isogenic) nonnodulating versions. NR activity of nodulating F3 and parental lines was significantly higher than that of corresponding nonnodulating lines, especially in the late stage of the growing season. A greater difference in NR activity was found between members of late‐maturing pairs than between members of early‐maturing lines. Nitrate content was higher in nodulating than in nonnodulating lines, and higher in late maturing than in early maturing lines. A significant positive correlation was observed between NR level and nitrate content and between stem protein and seed protein. NR activity was strongly associated with vegetative growth and plant maturity.
Effects of Seed Size on Seedling Performance in Soybeans. I. Seedling Growth and Respiration in the Dark1
Authors: Burris J. S. , Wahab A. H. , Edje O. T.
Published: July 2010

Growth and respiratory rates were compared in four cultivars and in four seed sizes of soybeans. The larger seed produced larger embryos, although the relative rate of dry matter accumulation did not vary appreciably. The percentage of cotyledonary dry weight loss was inversely related to seed size. However, the ratio of embryo growth to cotyledonary loss was not significantly different between sizes. The large seed exhibited a higher respiratory rate both in the cotyledons and in the root‐shoot axis, although these differences were not obvious until after 3 days of growth. Total embryo length at 7 days was optimum at an intermediate size, while the shoot growth increased with decreasing size at the expense of radical growth.
Randomness of Mating in a Polycross of Orchardgrass, Dactylis glomerata L.1
Authors: Carlson Irving T.
Published: July 2010

Randomness of mating was studied by using a genetic marker. The polycross contained 10 plants from each of five selections including four recessive alboviridis clones and one normal green clone homozygous dominant at the marker locus. Three‐year average percentages of crossing with the normal clone ranged from 30 to 39 among the four alboviridis clones. There was considerable yearly variation in the average percentage for each clone. Data on panicle number and seed yield indicated that the normal clone porduced the most pollen, which may account for average percentages greater than the 25% expected on the basis of random mating and no selling. Amount of crossing with the normal clone was not affected consistently by degree of self‐fertility of the maternal parent except in a year of sparse heading when average percentages of normal seedlings in progenies of two relatively self‐fertile clones were lower than those for two relatively self‐sterile clones. Percentages of normal seedlings in progenies of individual albovirldis plants ranged from 2 to 72, and in 2 of 3 years the percentages were associated with wind conditions and distance downwind from a normal plant.
Nyctoperiod Modification During Late Summer and Autumn Affects Winter Survival and Heading of Grasses1
Authors: Klebesadel L. J.
Published: July 2010

Subarctic‐adapted and midtemperate‐adapted cultivars of bromegrass (Bromus spp.), red fescue (Festuca rubra L.), and Kentucky bluegrass (Poa pratensis L.), springseeded in rows, were subjected to normally lengthening (9 to 15 hr.), artificially shortened (9 hr), lengthened (15 hr), and normal but interrupted (90 min light near midpoint) nyctoperiods3 from late August to killing frost in mid‐October in subarctic, south‐central Alaska. Nyctoperiod treatments influenced seedling stature, winter survival, and subsequent amount of heading. Shortened and interrupted nyctoperiods generally increased the height of seedlings and predisposed grasses to greatest winter injury. Subarctic‐adapted native Alaskan bromegrass (B. pumpellianus Scribn.), ‘Polar’ bromegrass, ‘Nugget’ Kentucky bluegrass, and ‘Arctared’ red fescue headed most following normal subarctic nyctoperiods the previous autumn. Midtemperate‐adapted ‘Southland’ bromegrass (B. inermis) was least winter injured and headed most after exposure to artificially lengthened nyctoperiods that more closely approximated diurnal conditions during autumn at its latitude of adaptation. The same treatment virtually prevented heading in subarctic‐adapted B. pumpellianus. Temperate‐adapted ‘Merion’ Kentucky bluegrass and ‘Illahee’ red fescue sustained severe winter injury and headed little under all treatments.
Plant Compositional Changes Resulting from Two Cycles of Directional Selection for Nutritive Value in Alfalfa1
Authors: Shenk John S. , Elliott Fred C.
Published: July 2010

Progeny from three‐clone combinations of alfalfa (Medicago sativa L.) selected for high or low 6‐hour in vitro matter disappearance (6H‐DMD) had significantly different neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) concentrations. The only significant change in cell wall composition was lower‐calculated hemicellulose (NDF‐ADF) of the cell walls of progeny from clones with high 6H‐DMD. Leaves of two‐clone combinations with high or low 6H‐DMD had similar NDF concentrations, but stems differed significantly in NDF. Histological studies of the stems revealed greater number of xylem cells in progeny with high NDF and low 6H‐DMD.
Inheritance of a Male‐Sterile Character in Soybeans
Authors: Brim C. A. , Young M. F.
Published: July 2010

The inheritam:e of a male‐sterile character in soybeans, Glycine max (L.) Merrill, was investigated in the F1, F2, and F3 generations. Sterility was a result of nonfunctioning pollen. Male‐sterile plants, although indistinguishable from fertile plants until the onset of maturity, remain green past usual maturity, have thick, leathery leaves, and have only a few, fleshy, one‐seeded pods. The proportion of fertile to male‐sterile plants in segregating populations indicated that the character is inherited as a single recessive gene pair. Plants were classified as male‐sterile on the basis of pollen viability or plant morpho.logy. The genetic symbols ms1ms1 were proposed for the male‐sterile character. In a natural crossing block, 99% of the seed obtained from malesterile plants were the result of cross‐pollination. Low seed set and the lack of genetic markers for distinguishing male‐sterile iplants before flowering restrict the use of this character in exploiting heterosis in the species.
Effect of Growth Regulator and Antitranspirant Chemicals on Water Requirement and Growth Components of Alfalfa (Medicago sativa L.)1
Authors: Cole D. F. , Dobrenz A. K. , Massengale M. A.
Published: July 2010

Plants of Medicago sativa L. cult. ‘Mesa‐Sirsa’ were grown in both the greenhouse and controlled environmental growth chambers and used to evaluate the effect ot various antitranspirant and growth regulator chemicals on water requirement and growth components. Gibberellic acid (GA) significantly lowered the water requirement of alfalfa in all environments. Indoleacetic acid (IAA), (2‐chloroethyl) trimethylammonium chloride (CCC), phenylmercuric acetate (PMA), and dodecenylsuccinic acid (DSA) did not alter the water requirement of alfalfa. The antitranspirant chemicals did not reduce the amount of water transpired, and further DSA caused plant damage when used as a foliar spray.

Gibberellic acid significantly increased the amount of stem tissue produced in all environments, which resulted in more total dry‐forage yield. Gibberellic acid had no effect on the amount of leaflet tissue produced except in experiments where GA stimulated secondary branching.
Age vs. Net CO2 Exchange Rate of Leaves of Coastal Bermudagrass1
Authors: Hart Richard H. , Lee David R.
Published: July 2010

Net CO2 exchange (NCE) of ‘Coastal’ bermudagrass (Cynodon dactylon (L.) Pers) leaves was highest at collar emergence and decreased with age. It decreased more rapidly at high light intensities, although initial NCE was higher. Leaves died in about 18 (natural sunlight) to 35 days (22 klux artificial light) after collar emergence. The much higher photosynthetic rate of younger leaves may explain the high production of frequently cut Coastal stands.
Germination and Seedling Growth of 48 Plant Species as Affected by a Leachate from Seeds of Coronilla varia L.1
Authors: McKee G. W. , Langille A. R. , Ditmer W. P. , Joo Pilju Kim
Published: July 2010

The germination of seeds of 48 plant species was not inhibited by exposure to aqueous leachate solutions from viable seeds of crownvetch (Coronilla varia L.). However, for most species tested freeze‐dried ‘Penngift‘ crownvetch leachate at dilutions up to 1:2,000 (wt./v.) induced drastic shortening of the shoot and root and resulted in almost complete elimination of root hair growth. Root tips were necrotic and roots thickened. Roots of some test species germinated on blotters moistened with crownvetch leachate were negatively geotropic. Seedlings of some species were adversely affected at leachate dilutions of 1:10,000. The osmotic pressure of a 1:200 solution of leachate was approximately 0.4 bar. This is too low to account for the effects noted on shoots and roots. Leachate from viable crownvetch seeds was more phytotoxic than that from viable sweetclover (Melilotus alba) seeds; this, in turn, was more phytotoxic than leachate from aged (weathered) red clover (Trifolium pratense L.) seeds of low germination and vigor. The phytotoxic compounds in crownvetch leachate appear to be low molecular weight phenols and polyphenols but differ from those in leachates from red clover and sweetclover.
Behavior of Long‐chain Fructosan in the Basal Top of Timothy as Influenced by N, P, and K, and Defoliation1
Authors: Suzuki Michio
Published: July 2010

An automatic gel‐filtration technique was used to isolate and examine long‐chain fructosan, the main watersoluble carbohydrate in the basal top tissue of timothy (Phleum pratense, L.), before and after defoliation. Timothy plants were grown on either the P‐ or K‐deficient soil that received different rates of N, P, and K. Watersoluble carbohydrates extracted from K‐deficient plants, unlike those deficient in N and P, showed an effluent pattern with an extremely low peak of long‐chain fructosan and a relatively high peak of sugars. This indicated that K played an important role in the accumulation of long‐chain fructosan. Defoliation sthnulated the decolnposition of long‐chain fructosan to sugars without noticeable accumulation of shorter‐chain fructosans. Total water‐soluble carbohydrates reached a minimum level 7 days after the cutting and were restored at 16 days mainly front the accumulation of sugars. No change in the average molecular size of the long‐chain fructosan was observed during accumulation and decomposition of the water‐soluble carbohydrates.
Sunflower Phenology—Year, Variety, and Date of Planting Effects on Day and Growing Degree‐day Summations1
Authors: Robinson R. G.
Published: July 2010

Six sunflower (Helianthus annus L,.) varieties were planted at seven dates ranging from April 24 to June 28, 1967 through 1969. Day and growing degree‐day (GDD) summations were calculated for consecutive growth periods.

Varietal differences in relative maturity were apparent at head‐visible stage. Differences among varieties in length of growth periods after first‐anther stage were small. Day summations in the prebloom periods declined from early to late planting in contrast with relatively small and random variation in GDD summations. The decrease in day summations from early to late planting in the emergence to head‐visible and emergence to first‐anther periods was not attributed to photoperiod but to increase in GDD per day.

GDD summation to either head‐visible or first‐anther stage was an effective rating of varietal maturity and did not vary greatly under differing environments. Both day and GDD summations declined from early to late planting in both last anther to maturity and planting to maturity periods. Both day and GDD summations varied among years for all growth periods, but the magnitude of variation in some periods was not great.
Reaction in Diallel Crosses of Corn Inbreds (Zea mays L.) to Maize Dwarf Mosaic Virus1
Authors: Josephson L. M. , Naidu B.
Published: July 2010

Two six‐parent sets of crosses, each consisting of three resistant inbreds and three susceptible inbreds, were grown under heavy natural infections of maize dwarf mosaic virus (MDMV) in two locations in Tennessee in 1968. Highly significant differences among genotypes were obtained in all experiments for reaction to the virus. White inbred Ga209 and yellow inbred T232 were the most resistant both as inbreds and in F1 crosses. Mean MDMV ratings for R ✕ R, R ― S, and S ✕ S crosses were 1.09, 1.78, and 3.41, respectively. The data showed that resistance to MDMV was largely dominant and was controlled by only a few major genes. Indications were that minor genes also were necessary for a high degree of resistance. General combining ability effects for reaction to MDMV were highly significant and were more important than specific effects. Significant specific effects were associated with crosses involving highly susceptible inbreds. Hybrids having high tolerance are obtainable from crosses involving these resistant inbreds. The data indicate that a backcrossing procedure can be used to transfer the resistance factors into elite lines. Alternating generations of backcrossing with selfing or sib‐pollination of resistant plants will facilitate incorporation of any minor genes necessary for a high degree of resistance. Some form of recurrent selection in populations having a degree of resistance also is suggested.
Genetic Variance in Autotetraploid Maize1
Authors: Levings C. S. , Dudley J. W. , Alexander D. E.
Published: July 2010

This study represents the first attempt to characterize genetic variability in an autotetraploid maize population. Estimates of additive and digenic genetic variance were obtained from a sib analysis in autotetraploid maize (Zea mays L.), Synthetic B. Estimates of additive genetic variance larger than one standard error were obtained for yield, ear length, ears per plant, plant height, and percent oil. Positive estimates of digenic variance larger than one standard error were found only for plant height. The estimate of additive genetic variance for yield is smaller in the autotetraploid, Synthetic B, than is norreally encountered in diploid populations.
Effectiveness of Frego Bract as a Boll Weevil Resistance Character in Cotton1
Authors: Jenkins Johnie N. , Parrott W. L.
Published: July 2010

In 1970 four farms located in different parts of Mississippi each were planted to 4 to 8 ha of cotton (Gossypium hirsutum L.), homozygous for frego bract ( fg fg ), and to an approximately equivalent acreage of a nonfrego commercial variety. Cottons with frego bract have shown resistance to boll weevils (Anthonomus grandis Boh.) when grown in small plots. Our 1970 tests were designed to measure the cumulative effects of a fregobract cotton, designated M‐64, on boll weevil populations when this cotton was grown in large acreages and when the resistance was measured over three or four insect generations. Results from these tests will be used to assess the role of cottons resistant to boll weevil in an integrated approach designed to eradicate this insect. A pilot scale boll weevil eradication program is now underway in Mississippi.

In the frego‐bract cotton boll weevil oviposition, an indirect measure of population, was suppressed 66, 71, 75, and 94% below that in the nonfrego varieties. The variation in suppression was due to different numbers of overwintering weevils and to various control measures used during the season. On two farms no insecticides were required for boll weevil control in the frego‐bract strain. The frego‐bract strain suppressed the population 94% on the farm with the smallest number of overwintering weevils. Thus, oviposition suppression was greatest where it can be of the most use in an eradication program.

Fiber properties and yields of the frego strain were adequate for a nonbiased test of the boll weevil resistance attributed to frego bract.
Inheritance of Seed Size in Chickpeas (Cicer Arietinum L.)1
Authors: Niknejad M. , Khosh‐khui M. , Ghorashy S. R.
Published: July 2010

Two chickpea (Cicer arietinum L.) pure lines, one having small seeds and another with large seeds, were crossed reciprocally. Parents, F1, and F2 generations were grown in a field study to determine the inheritance of seed size. The results showed that large seeds were partially dominant to small seeds with at least eight pairs of genes controlling seed size. Broad sense heritability was estimated to be 81%. No maternal effects were observed in this study.
Disease Reaction of Thirty Sources of Cytoplasmiic Male‐Sterile Corn to Helminthosporium Maydis Race T1
Authors: Smith D. R. , Hooker A. L. , Lim S. M. , Beckett J. B.
Published: July 2010

Thirty source of cytoplasmic male sterile (cms) corn (Zea mays L.) were evaluated for their disease reaction to H. maydis race T. Plants with cms‐B, ‐C, ‐CA, ‐D, ‐EK, ‐F, ‐G,. H, ‐I, ‐IA, J, ‐K, ‐L, ‐M, ‐ME, ‐ML, ‐MY, ‐PS, ‐R, ‐RB, ‐S, ‐SD, ‐TA, ‐VG, and ‐W designations were resistant. Four sources, cms‐HA, ‐P, ‐Q, and ‐T, were susceptible. Differences in disease reaction were observed on seedlings in the form of lesion type and on field‐grown adult plants in the form of lesion type and lesion number.
Protease Levels in “High” Versus “Low” Grain Protein Wheats and Their Association with the Production of Amino Acids, Tryptophan, and IAA During Early Growth1
Authors: Rao S. C. , Croy L. I.
Published: July 2010

Protease levels in the juvenile wheat (Triticum aestivum L.) plant were greater for a “high” grain protein variety (NB #65317, a selection from a cross between ‘Atlas 66’ and ‘Comanche’) than for a “low” protein variety (‘Triumph 64’, C. I. 12132) during early seedling growth. Also, higher amounts of AA, tryptophan, and IAA were found in NB #65317. The data suggest that “high” grain protein varieties will exhibit higher protease, AA, tryptophan, and IAA concentrations in the vegetative parts of the plant than will a “low” protein variety.
Amino Acids in Different Plant Parts of Normal and Male‐sterile Maize (Zea mays L.)1
Authors: Sarvella Patricia , Grogan C. O. , Stojanovic B. J.
Published: July 2010

Amino acids were studied in the fertile and malesterile (Tcms) versions of the single‐cross maize (Zea mays L.) hybrid F44 ✕ F6 and the inbred parents. Samples were taken from leaves, stalks, tassels, ears, husks, and silks at various stages of plant development. Generally, leaves in the fertile versions were higher in amino‐acid concentrations, while other vegetative organs showed no differences. However, in hybrid tassels after anthesis and in ears at all sampling dates, the male‐sterile version had more amino acids than the normal version. Ears generally contained more total amino acids per unit weight than the other plant parts. The influence of both inbred parents was observed in the amino‐acid content of the hybrid.
Height Modification Within Three‐dwarf and Four‐Dwarf Progenies of Grain Sorghum1
Authors: Thompson T. E. , Schertz K. F. , Rosenow D. T. , Miller F. R.
Published: July 2010

Three and four‐dwarf varieties and hybrids of grain sorghum [Sorghum bicolor (L.) Moench] were used to determine the effectiveness of selection for height within these major height genotypes. Selection was begun for short and tall plants, as measured by height to the flag leaf in the F2 and S2 and was continued in the F3 and S3 generations. Tests were conducted with the F4 and S4 generations to evaluate the effects of selection on height of flag leaf, total plant height, and days to first bloom.

Selection for height of flag leaf was successful in four of the 30 progenies tested. As a result, total plant height was altered in three of these progenies. Number of days to first bloom was reduced for one progeny effectively selected for shortness.
Hybrid Performance Among Six‐Rowed Winter Barleys (Hordeum vulgare L.) Varying in Kernel Size1
Authors: Crook Wayne J. , Poehlman J. M.
Published: July 2010

A large‐kerneled, 6‐rowed, winter barley (Hordeum vulgare L.) cultivar (P1) was crossed as the maternal parent with seven 6‐rowed, winter barley cultivars varying in seed size (P2 through P8) as pollen parents. The seven F1 hybrids were compared with the eight parents at Columbia, Mo., in 1968‐69. Heterosis for kernel size was indicated in specific crosses with five of the seven F1's exceeding their respective midparents and four of the F1's exceeding their respective highparent for both percentage of plump kernels and kernel weight. As an average over all crosses, the F1's exceeded the midparent for survival, early maturity, height, lodging, grain yield, tillers per plant, and kernels per spike in addition to kernel plumpness and kernel weight. Correlation data confirm the close association of kernel plumpness and kernel weight as measures of kernel size and the independence of these kernel size measurements from the other agronomic characters studied. The genetic potential for improvement of kernel size and kernel plumpness is demonstrated by heritability estimates of 0.886 and 0.710, respectively, for these two characters.
Phenotypic Stability of Cotton1
Authors: Quisenberry J. E. , Kohel R. J.
Published: July 2010

We studied the effects of level of ploidy and of heterozygosity on the phenotypic stability of certain inbred lines of cotton (Gossypium sp.) and their F1 hybrids. The experimental material consisted of four inbred lines from each of three cultivated species of cotton. These species were an Old World diploid (G. arboreum L.), and two New World allotetraploids (G. hirsutum L. and G. barbadense L.). Eight phenotypic characters or traits were measured in five environments. In each environment the material was grown in two randomized blocks, divided into split‐plots. Inbreds and their F1 hybrids were used to minimize genetic variance, and estimated environmental variances were analyzed.

The level of ploidy did not significantly affect the phenotypic stability of the eight characters. The diploid G. arboreum was as well buffered against environmental variation as the two allotetraploids, G. hirsutum and G. barbadense. Thus, the intergenomic heterozygosity associated with amphidiploidy conferred no advantage to plants by enhancing their ability to adjust to fluctuations in the environment. Significant differences in phenotypic stability usually were not found in comparisons of inbred lines (F0) and hybrid progenies (F1). The expression of phenotypic stability appeared to be random with respect to five specific environments in which the plants were grown. Apparently the cultivated species of cotton we studied do not possess homeostatic systems associated with either homozygosity or heterozygosity.
Combining Ability of Coumestrol Content and its Association with Uterotropic Activity, Yield, and Plant Height in Medicago sativa L.1
Authors: Stuthman D. D. , Chorush I. S. , Nyquist W. E. , Davis R. L. , Stob Martin
Published: July 2010

Six alfalfa (Medicago sativa L.) clones, selected for varying amounts of uterotropic activity (UA, increase in uterine weight of castrated female mice fed the plant material), were crossed in all combinations, keeping reciprocals separate. F2’s were produced by selling and intercrossing F1 sibs. Backcrosses of F1’s to both parents were produced reciprocally. UA, coumestrol concentration, forage yield, and plant height were measured.

General combining ability variation among F1 family means was hnportant for all characters. Specific combining ability variation was not important.

Uterotropic activity and coumestrol content were positively correlated, indicating that coumestrol concentration accurately reflects this biological activity of alfalfa in castrated female mice. Both UA and coumestrol were generally negatively correlated with yield and height.

Inbreeding significantly affected all characters except coumestrol content. Yield, in particular, decreased more rapidly than the coefficient of inbreeding increased. This inbreeding depression could not he adequately explained by present concepts of inbreeding.
Breeding Beans, Phaseolus vulgaris L., for Improved Germination Under Unfavorable Low Temperature Conditions1
Authors: Dickson M. H.
Published: July 2010

Bean lines (Phaseolus vulgaris L.) with good pod and plant type have been bred with the ability to germinate at 8 to 10 C. At temperatures of 10 C day and 8 C night these lines grew faster than the cultivars with which they were compared. Seed color and resistance to seed decay by soil organisms were strongly associated with good germination at low temperatures. However, a low percentage of white‐seeded lines also had good germination and decay resistance. Heritability for germination at low temperatures was about 35%. No specific segregation pattern was detectable.
Association Between Root‐Knot Resistance and Economic Characters of Flue‐cured Tobacco After Seven Backcrosses1
Authors: Chaplin James F. , Ford Z. T. , Graham T. W.
Published: July 2010

The effect of the root‐knot nematode resistance factor on agronomic characteristics and chemical constituents of flue‐cured tobacco (Nicotiana tabacum L.) was studied. Within each of four cultivars efforts were made to isolate lines that were genetically identical with their respective parental cultivars in all attributes except root‐knot resistance. ‘PD 611’ was used as the source of root‐knot resistance and the following four cultivars were used as recurrent parents: ‘Coker 316,’ ‘Coker 187,’ ‘402,’ and ‘Hicks Broadleaf.’ Each cultivar, a root‐knot susceptible selection, and two resistant selections were compared for days to flower, number of harvestable leaves per plant, plant height, yield, value per 45.4 kg, leaf senescence, percent total alkaloids, and sugars. Estimates were made of the degree to which the genotypes of the recurrent parents were recovered. The recovery of the recurrent parent genotype was sufficient in at least one family to study each of the traits. The root‐knot resistance factor was associated with slower leaf senescence in every family, and in the Hicks Broadleaf family with a lower value per 45.4 kg. There was no other significant effect attributed to the root‐knot resistance factor for any of the other traits studied.
Response of Cotton Mitochondria to Chilling Temperatures1
Authors: Stewart James McD. , Guinn Gene
Published: July 2010

Chilling cotton (Gossypium hirsutum L.) seedlings at 5 C for 2 and 4 days reduced the specific activity of succinate oxidation by the isolated root mitochondria. Chillhardening at 15 C for 2 days prior to the chilling treatment only partially protected against the decrease. When mitochondria were isolated from unchilled plants and activity measured from 5 to 30 C, a break in the activity curve was noted at 15 C. Mitochondrial enzyme inactivations may help explain the nature of chilling injury in cotton.
Differential Phytotoxic Reaction of Sorghum Cultivars to Insecticides. I. Genetic Resistance to Trichlorfon1
Authors: Riccelli‐Mattei Mauricio
Published: July 2010

The application of trichlorfon (dimethyl trichlorohydroxyethyl phosphonate) to susceptible genotypes of sorghum (Sorghum bicolor L. Moench) caused marked phytotoxic reaction and even death under field conditions at Maracay, Venezuela. In the plants that survived new growth appeared normal, but panicles were sometimes injured. Backcross F2, and F3 populations from crosses among susceptible and resistant cultivars evidenced the genetic control of a single locus, with resistance recessive to susceptibility. Data from reciprocal crosses ruled out the existence of maternal effects. The presence of modifying genes that can accumulate and reduce the expression of phytotoxicity was suggested in certain crosses. Gene symbols Dtp for susceptibility and dtp for resistance were used for the trait. These alleles appeared randomly distributed among sorghum cultivars. The two characters, awned florets and reaction to trichlorfon, are inherited independently.
Combining Ability for Yield, Protein, and Lysine in an Incomplete Diallel of Sorghum bicolor (L.) Moench1
Authors: Collins F. C. , Pickett R. C.
Published: July 2010

Estimates of general and specific combining ability for grain yield and protein and lysine levels in the grain were obtained by evaluating the performance of 48 Fl sorghum hybrids which were derived from crossing 12 restorer lines unto 4 male sterile testers. Significant differences among restorer lines were found in general combining ability for yield, protein, and lysine while significant differences among the male sterile testers existed for yield and protein. The variation due to specific combining ability was not significant for any of the characters.

Hetercsis for yield was exhibited by most of the hybrids while only four hybrids demonstrated heterosis for percentage protein and no hybrids were superior to either parent for percentage lysine.

Percentage protein was negatively correlated with yield and percentage lysine and levels of lysine was not significantly related to yield. However, the degree of these associations was not strong enough to prevent incorporating high levels of protein and lysine into high yielding lines if simultaneous selection was performed for all three characters.
Growth Rate and Physiology of Alfalfa as Influenced by Canopy and Light1
Authors: Wolf D. D. , Blaser R. E.
Published: July 2010

Specific leaf weight (SLW) and net C exchange (NCE) of alfalfa (Medicago sativa L.) leaves were measured in very sparse canopies that allowed about the same light intensity to all plant heights. With 100% normal daylight SLW and NCE values remained high throughout a growth cycle; however, these values declined sharply with light intensities of 27 and 45% of normal daylight. Concurrently, for natural dense alfalfa canopies under field environments with normal daylight, the SLW and NCE values of upper young leaves increased until they were fully expanded; thereafter, these values declined sharply because of diminishing and low light intensities in the lower layers of accumulating canopies. The data suggest that the decline of photosynthetic efficiency and SLW of the basal leaves was caused by low light intensities in the lower layers of normal dense canopies.
Differential Response to Two Bean Varieties to Zinc as Revealed by Electrophoretic Protein Pattern1
Authors: Jyung W. H. , Camp M. E. , Polson D. E. , Adams M. W. , Wittwer S. H.
Published: July 2010

The Saginaw and Sanilac varieties of navy beans (Phaseolus vulgaris L.), were utilized. The former is tolerant and the latter is extremely sensitive to both zinc deficiency and excessive levels of zinc. Electrophoretic patterns of the water‐soluble leaf proteins revealed a slowmoving, major band, the change in intensity of which clearly reflected a differential zinc response of the two varieties. There was a moderate decrease in band intensity under low zinc for the tolerant Saginaw, with a striking depression for the sensitive Sanilac. This protein band, with a relative electrophoretic mobility of 0.11 in 7% polyacrylamide gel at pH 8.9, was tentatively identified as Fraction I protein which is reported to contain ribulose diphosphate carboxylase, the enzyme primarily responsible for photosynthetic carbon dioxide fixation in many plants. Fraction I protein, zinc nutrition, and the differential response of Saginaw and Sanilac plants to zinc were correlated.
Distribution of the Post‐illumination CO2 Burst Among Grasses1
Authors: Brown R. H. , Gracen V. E.
Published: July 2010

Evolution of CO2 upon transition of leaves from light to darkness was studied in 44 species of grasses, mostly from genera possessing the 4‐carbon dicarboxylic acid cycle of CO2 fixation. Attached leaves were placed in small acrylic plastic chambers and illuminated at 6,500‐7,000 ft‐c. Ten to 15 min after steady rates of photosynthesis had heen attained, the lights were turned off and CO2 evolution was measured for at least 5 min thereafter. Species that exhibited a post‐illumination CO2 burst (PIB) had a peak CO2 output at slightly less than 0.5 min after the lights were extinguished. Species lacking the PIB required about 1 min to reach the maximum respiration rate. The PIB was lacking in all species tested in the tribe Andropogoneae. Of 22 species in the tribe Paniceae, none possessed the PIB except those in the Panicum genus. All 10 Panieum species exhibited a burst. Five species in the tribe Chlorideae exhibited a PIB, as did Eragrostis curvula (Schrad.) Nees of the Eragrosteae tribe and Uniola paniculata L. of the Unioleae tribe.

Well‐developed grana were observed in parenchyma sheath chloroplasts of the species that possessed the PIB. Species lacking the PIB also lacked well‐developed grana in parenchyma sheath chloroplasts. There was a fairly close association between the existence of a PIB and location of the parenchyma sheath chloroplasts against the centripetal walls of the sheath cells.
Stable Foam Volume and Pectin Methyl Esterase Activity of Forage Mixtures1
Authors: Rumbaugh M. D.
Published: July 2010

Alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), crownvetch (Cornilla varia L.), sainfoin (Onobrychis viciaefolia Scop.), and Kentucky bluegrass (Poa pratensis L.) forage samples were tested individually and in two species component mixtures for stable foamproducing capacity and for pectin methyl esterase activity. Oven drying at 100 C reduced average foam volume by 18% of the wet sample mean. Species interacted in a nonadditive manner during all foam viscosity tests. The magnitude of the deviations from the averages of the component species responses was not as great as observed in an earlier investigation. Liquid viscosities of forage mixtures as expressed by their pectin methyl esterase activities were dependent solely upon the mean values of the component species tested alone. Results of the two types of empirical in vitro procedures were positively and significantly correlated, r̄ = .86.