bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and Physiological Response of Alfalfa to Diazinon and Methoxychlor Insecticides1
Authors: Wolf D. D. , Buss G. R. , Pienkowski R. L.
Published: July 2010

An effective insecticide must control insects with minimum adverse influence on the plant. During a cultivar performance study, a commercial insecticide containing diazinon [0,0‐diethyl 0‐(2 isopropyl‐6‐methyl‐4‐pynimidinyl) phosphorothiorate] and methoxychlor [l,l,l‐trichloro‐ 2,2‐bis= (p‐methoxyphenyl)] was applied to alfalfa (Medicago sativa L.) as a control for alfalfa weevil (Hypera postica Gyllenhal). A phytotoxic response was noted and several experiments were conducted to elucidate the nature of the toxicity. Weevil control by the insecticide was satisfactory, but total nonstrnctural carbohydrate concentration (TNC) in tap roots decreased and growth rate of shoots was not increased when compared with check treatments during 2 weeks following insecticide application. Greenhouse studies indicated that the diazinon component was phytotoxic and caused a reduced growth rate for at least 5 days. Carbon dioxide exchange rate and TNC concentration in leaves were reduced by nearly 50% for several days following application of the insecticide. Hay yields were increased by control of the insects but yield increase might have been greater if a nonphytotoxic insecticide had been used. Diazinon should not be recommended for use on actively growing plants until it has been shown that the beneficial effects out weigh the risks of phytotoxicity.
Breeding Potentials of Noncultivated Cottons. II. Inheritance of Peduncle Length1
Authors: Wilson F. D. , Wilson R. L.
Published: July 2010

Long peduncles, characteristic of some primitive race stocks of cotton, Gossypium hirsutum L., could be disadvantageous agronomically because they may possibly grow at the expense of early maturity and of fiber production. However, they may have value as a deterrent to larvae of pink bollworm, Pectinophora gossypiella (Saunders), if incorporated into a pubescent strain. We determined that Texas 711, a primitive race stock with long peduncles, differed from ‘Stoneville 7A’ by two major factor pairs that act additively. Another cultivated parent, ‘Deltapine 16,’ apparently differs from Stoneville 7A in a recessive epistatic modifier. Two other race stocks, Texas 40Y and Texas 203, apparently carry a partially dominant epistatic modifier rather than a recessive one. The latter race stock may also be monomeric for the major factor pairs. Results suggest that transfer of long peduncles into improved agronomic types of cotton should be relatively easy.
Variability for Components of Yield Induced in Soybeans by Seed Treatment with Gamma Radiation, Fission Neutrons, and Ethylmethane Sulfonate1
Authors: Conger B. V. , Skinner L. W. , Skold L. N.
Published: July 2010

The purpose of this study was to determine the variability for individual components of yield in soybean [Glycine max (L.) Merr.] induced by seed treatment with fission neutrons, gamma radiation, and ethylmethane sulfonate. Nine M3 populations, including three doses of each mutagen, were compared with a control for pods/plant, wt/100 seeds, and total seed wt/plant. The means for individual yield components were not significantly altered by the mutagenic treatments. A comparison of frequency distributions of populations from mutagen‐treated seed vs. the control revealed differences for certain treatments. The most effective mutagen for increasing variability of the yield components was ethylmethane sulfonate.
Gene Loss in Pearl Millet Germplasm Pools1
Authors: Burton Glenn W.
Published: July 2010

Six different germplasm pools of pear millet, Pennisetum americanum (L.) K. Schum. (formerly P. typhoides (Burm.) Stapf and Hubb) were advanced in isolation three to five generations. A comparison of the last generation with the first showed that advancing germplasm pools of this cross‐pollinated (up to 85%) species narrowed phenotypic variability, lost genes, and obscured hard to recover characters such as very long seed heads. A significant shift in maturity resulted from an attack of European corn borer. I believe, therefore, that longtime storage is the only practical way to preserve pearl millet germplasm without loss. At Tifton, pearl millet seeds dried to less than 12% moisture, enclosed in airtight containers, and stored at 5 C germinated well (70%) after 26 years. Growing germplasm pools in an environment with short days and temperatures approaching 40 C will make most genotypes flower at about the same time, facilitate intennating, and reduce gene loss. Pooling fewer lines, selecting plants to advance the population as if they were self‐pollinated, and preparing pools from equal numbers of live seeds from each selected plant will also help to reduce gene loss
Aflatoxins in Cottonseed: Effects of Pink Bollworm Control
Authors: McMeans J. L. , Brown C. M. , Parker L. L. , McDonald R. L.
Published: July 2010

In 1971 and 1973 field tests were conducted to determine if control of the pink bollworm [Pectinophora gossypiella (Saunders)] at or below 5% infestation would reduce the incidence of bright greenish yellow (BGY) fluorescence of cottonseed (Gossypium hirsutum) that is associated with the fungus Aspergillus flavus and the accumulation of aflatoxins. Control of the pink bollworm by application of insecticides on a 5 or 7‐day schedule resulted in a decrease in the BGY fluorescence of cottonseed and in the accumulation of aflatoxins. The reduced pink bollworm infestation did not insure that the present FDA guideline of 20 ppb for aflatoxins in cottonseed would be attained.
Observed Gain from Visual Selection for Yield in Diverse Oat Populations1
Authors: Stuthman D. D. , Steidl R. P.
Published: July 2010

The effectiveness of visual selection for yield in four diverse oat (Avena sativa L.) populations was examined. Progenies from high and low visual selections from among random F3 lines were compared with progenies of a group of random lines in four trials over 2 years. Maturity, seed weight and number, and plant height were measured in addition to grain yield. High selections from three of the populations yielded more than their random group; however, high selections from a fourth population yielded less than random. Low selections from three of the populations yielded less than their random group but equaled the random group yield in a fourth population. Yield increases were accompanied by later maturity and yield decreases were generally associated with earlier maturity. Changes in other characters followed a pattern of favoring adapted parents for high selections and unadapted parents for low selections. Based on results from one of the populations we believe elimination of large portions of progeny of diverse crosses based only on visual observation of yield potential should be approached with caution.
Evidence for Two Independent High Lysine Genes in Barley1
Authors: Muench S. R. , Lejeune A. J. , Nilan R. A. , Kleinhofs A.
Published: July 2010

Progeny of crosses between two high lysine barley (Hordeum vulgare L.) lines were studied to determine if the genes for increased lysine content were allelic or non‐allelic. Lysine data from amino acid analysis of F1, F2, and F3 seeds from the cross Bomi mutant 1508/‘Hiproly’ (CI 3947) showed that the two high lysine genes involved are independent.
Action of Temperature and Light on the Control of Seed Germination in Alta Tall Fescue (Festuca arundinacea Schreb.)1
Authors: Danielson H. Rodger , Toole Vivian K.
Published: July 2010

Temperature, light, and their interactions were studied for their effects of germination of ‘Alta’ tall fescue (Festuca arundinaeea Schreb.) seeds. A thermogradient plate was used to study effects of 30 constant temperatures on germination in darkness. Germination was maximum at 12 through 18 C, although seeds germinated in varying number from 8 to 31 C during the 9‐day test period. Rates of germination increased with temperature and were highest between 16 and 19 C. Seeds exhibited a high temperature sensitivity and became more dormant with increased temperature above 18 C and with increased periods at high temperatures. Studies of alternating temperature cycles revealed that germination was significantly reduced when seeds were held longer than 16 hours at 25, 8 hours at 30, and 4 hours at 35 C in daily cycles with 15 C.

The lowered germination at temperatures above 18 C was probably due to Pfr reversion and decay of total phytochrome (P). Seeds were more dormant at 30 than at 25 C. At 25 and 30 C a single saturating red light (R) treatment caused a germination increase of 25% above the dark controls. Repeated R irradiances caused significantly higher germination than one brief exposure at 25, but not at 30 C. However at 30 C, where reversion and decay of P would be greater, continuous R caused a significant increase in germination.

Seeds held for 7 days at 35 C and then germinated at 15 and 25 C showed the typical reversible P reaction. Single, brief R again increased germination about 25 to 30% above the dark controls. Recovery from the 35 C treatment was greater at 15 C than at 25 C as shown by germination in darkness of 63 and 3%, respectively. Apparent P synthesis, which is also temperature sensitive, probably occurs at 15 but not at 25 C.

The period required for Pfr action was 20 to 24 hours at 15 C. Germination of seeds following P conversion and Pfr action depended on temperature and was lower at 30 than at 25 C. Thus high temperature imposes a block to germination processes beyond that of Pfr action.
Effects of a Nonnodulating Gene (rj1) on Seed Protein and Oil Percentages in Soybeans with Different Genetic Backgrounds1
Authors: Liu Ming‐Chin , Hadley Henry H.
Published: July 2010

Seventeen nodulating (nod) plant introduction (PI) soybean lines [Glycine max (L.) Merr.] were crossed ‘Clark’ and ‘Harosoy’ cultivars to give nod ✕ nod crosses and to corresponding nonnodulating (nonnod) near isogenic derivatives of Clark and Harosoy to give nonnod ✕ nod crosses. The protein proportions in seeds from nonnod (rj1rj1) F2 plants were 2 to 5% lower and the oil proportions 1 to 3% higher than those in seeds from nod (Rj1—) sibs. The proportions of protein and oil in Rj1Rj1 F2 plants from nod ✕ nod crosses were similar to those of Rj1— plants from corresponding nonnod ✕ nod crosses. Correlation coefficients between percent prorein and oil, protein and residual (0.95 × total seed wt less protein and oil), and oil and residual averaged −0.65, −0.43, and −0.41, respectively, over all F2 genotypes. Apparently the absence of nodules did not affect the relationships between seed components. Frequency distributions for seed protein percentages in nod and nonnod F2 plants overlapped with some rj1rj1 individuals being higher in protein than some of their Rj1— sibs. Phenotypic variances for percent protein among rj1rj1 F2 plants averaged 1.6 times as much as those among Rj1— sibs. However estimated genetic variances averaged only 1.2 times as much. Broad sense heritability estimates were higher or lower for difference in protein percent in Rj1— than in rj1rj1 F2 classes depending upon how estimates of environmental variance were made. However heritability estimates based on regression of F3 progeny means on F2 plant phenotypes were 0.09 and 0.31 for the Rj1— and rj1rj1 classes, respectively. It is suggested that in some crosses nitrogen fixation (in nod plants) may act as a “buffer” obscuring the segregation of genes for utilization of combined nitrogen.
Analysis of Nuclear Genetic Resistance in Maize to Race T of Southern Corn Leaf Blight
Authors: Johnson G. R.
Published: July 2010

Two maize (Zea mays L.) inbred lines, in Texas malesterile cytoplasm (Tcms), with high levels of nuclear genetic resistance to race T southern corn leaf blight (Helminthosporium maydis Nisikado and Miyake) were derived by selfing and selection from two open‐pollinatedcomposite sources. The lines were confirmed to be in Tcms and were utilized in crosses with an extremely susceptible Tcms line in two generation‐mean analysis experiments.

Resistance was polygenic, and additive genetic effects accounted for most of the variation among generations. Dominance effects accounted for a small but significant portion of the genetic variance in both experiments.

The results suggest that gene frequencies for resistance could be enhanced by recurrent mass selection. In a program for development of commercial hybrids, selection should be practiced in male‐sterile cytoplasm in two unrelated source populations. Lines would be extracted by inbreeding and crossed. Resulting hybrids would be evaluated for disease resistance, agronomic suitability, and yield.
Daily Fluctuations of Some Metabolic Characters of Durum Wheat under Field Conditions
Authors: Di Marco G. , Giovannozzi‐Sermanni G. , Grego S. , Veri G. , Pietrosanti T. , Tricoli D. , Catarcione M. , Di Pietro A.
Published: July 2010

Physiological and biochemical parameters have been studied simultaneously with micrometeorological characters of a crop of durum wheat (Triticum durum). Micrometeorological measurements and plant analysis on flag leaves before spike appearance were done during 2 days in May 1973 to ascertain the fluctuation of chosen leaf parameters in comparison with the micrometeorological ones. The results indicate that biochemical and physiological changes occur during the day and night and that stomatal opening is the main factor dependent on climatic conditions. Specific leaf weight (SLW) seems to vary with the level of free amino acids. Ribulose diphosphate carboxylase (RuDPcase) showed daily fluctuations insensitive to climatic conditions, whereas phosphoenolpyruvate carboxylase (PEPcase) exhibited little day change.
Awned vs. Awnless Isogenic Winter Barley Grown at Three Environments1
Authors: Shannon J. G. , Reid D. A.
Published: July 2010

Four pairs of homozygous winter barley (Hordeum vulgare L.) lines, isogenic for full‐awned and near‐awnless, and their respective recurrent parents were grown at Quantico, Md.; Hagerstown, Md.; and Tucson, Ariz. in 1973.

The awned isogenic line showed a more consistent and significant yield advantage over the awnless isoline in each of the four genetic backgrounds under the irrigated, Arizona conditions than under Maryland conditions. At Hagerstown, where lodging was severe, and at Quantico where scald [Rhynochosporium secalis (Oud.) J. J. Davis] was present, the awned isogenic lines yielded more than their awnless counterparts in six of eight instances suggesting the importance of awns where photosynthesis is reduced due to lodging or disease.

The advantage of the awned vs. awnless isogenic pairs was more consistently expressed in test wt/hl and kernel wt than in yield. The greatest advantage of awns for test wt and kernel wt was shown under the irrigated (Arizona) environment. In general the isogenic pairs did not differ in heads/unit area or kernels/spike.
Linkage and the Synthesis of Better Genotypes in Self‐fertilizing Species1
Authors: Bailey Theodore B. , Comstock R. E.
Published: July 2010

The basic task of the breeder of self‐fertilized species is the aggregation of superior alleles in a single pure line or cultivar. This study focused on the model problem of collecting into one line all the favorable alleles present in one or the other of any pair of pure lines. Background theory and simulation data are presented. The breeding procedure investigated involved intra‐line selection during the formation of single seed descent lines from an F2, followed by selection among the derived lines. We also considered recurrent use of the procedure; two selected lines from one cycle being crossed to provide the F2 base for the next cycle. Simulation was used to investigate the effect of genetic linkage on response to selection as reflected by probabilities of fixation of favorable alleles. As was to be expected, our data show that those probabilities are decreased by repulsion but increased by coupling linkages among the superior alleles. It follows that the impact of linkage depends on the way in which the superior alleles present in one parent line but not in the other are distributed among and within linkage groups. Assuming this to be random, our results indicate that, when parent lines are about equal in genetic value, the balance between repulsion and coupling will be such that linkage will have little effect on the average probability of fixation. However when one parent line is substantially better than the other, there will be more coupling linkage and the average probability of fixation will be increased. Nevertheless the average genetic value of selected lines will be less than or, at best, little above the level of the superior parent line

We conclude that the full genetic potential of a two line gene pool is not likely to be achieved by the selection system described. Two systems believed superior to the one on which this study was focused are discussed. Both require increases in the proportion of seed produced by cross‐pollination but this may be justified by the associated potential for genetic improvement.
Effect of Temperature and Osmotic Concentration on Cotyledon Cracking During Imbibition of Soybean1
Authors: Sorrells M. E. , Pappelis A. J.
Published: July 2010

Seeds of soybean [Glycine max (L.) Merr.] cultivars ‘Williams’ and ‘Clark 63’ were imbibed at 10, 30, and 50 C and examined at 15 min intervals for transverse and crescent cotyledon cracks. Both cultivars exhibited extensive injury first at 50 C (within 45 min) and last at 10 C (after 5 hours). After 12 hours, up to 83% of the cotyledons had cracked regardless of temperature. Seeds from the same two cultivars were imbibed in mannitol solutions (0.1 to 1.0 M in 0.1 M steps) and were injured most in the 0.1 M solution (Williams, 53%; Clark 63, 20%) and less as molarity increased. In Williams, less than 3% cracking was observed in treatments above 0.5 M. In Clark 63, less than 1% cracking was observed in treatments above 0.2 M. Twenty‐eight cultivars, three of which were obtained from two different seed sources, were imbibed in water at 22 C and examined for cotyledon cracks after 12 hours. More than 85% of the seeds of 22 cultivars exhibited cotyledon cracks. Four cultivars were injured significantly less than the others, the least damage being 29%. Response varied with seed source. The percentages of cotyledons with cracks for the two sources of Williams (88.8 and 63.8%) and Clark 63 (87.5 and 28.7%) were significantly different at the 5% level, but the two sources of ‘Wayne’ (78.8 and 77.5%) resulted in nonsignificant differences.
Acid Invertase Activity in Kernels of Normal and Opaque‐2 Corn at Different Growth Stages through Maturity1
Authors: Fullerton S. G. , Svec L. V.
Published: July 2010

Acid invertase activity in the placento‐chalazal tissue of developing corn (Zea mays L.) kernels was measured from 23 to 49 days after pollination. Because sucrose, the transported saccharide in corn, is thought to be converted by acid invertase to glucose and fructose before passing into the developing endosperm, acid invertase activity of the placento‐chalazal tissue during kernel‐fill period may be a useful index of maturity and potential productivity, as well as an indicator of yield difference among genotypes.

Ten single cross corn hybrids were grown in the field near Middletown, Del., in 1973, including five normal endosperm hybrids of varying relative maturity and their sister hybrids with opaque‐2 (o‐2) genotype. Daily high and low temperatures and rainfall were recorded for the growing period. At 23 to 49 days post‐pollination, kernel samples were harvested, lyophilized, and acid invertase activity of the placento‐chalazal tissue determined.

Pioneer Brand hybrids 3570, 3516, and 3387 had significantly higher levels of acid invertase activity than did Pioneer Brand hybrids 3369 A and 3306, but no differences in acid invertase activity were found between normal and o‐2 hybrids. During the period from 23 to 37 days post‐pollination, acid invertase activity decreased, then the activity increased sharply from 37 to 39 days and decreased but more slowly during the 39 to 49 day period. The o‐2 hybrids had lower yields than did the normal genotype hybrids, even though the acid invertase activity was very similar in the paired comparisons. Acid invertase activity in the placental‐chalazal tissues did not appear to be limiting yield of these hybrids.
Chromosome Homology of Avena magna Murphy and Terrell and the Hexaploid Species A. sativa L. and A. byzantina C. Koch1
Authors: Sadanaga K.
Published: July 2010

Homology of Avena magna M. and T. and the hexaploid species A. sativa L. and A. byzantina C. Koch. chromosomes was determined by the use of telosomes of the hexaploid species. F1 hybrids with 34 chromosomes + 1 telosome were produced from crosses between A. magna used as the male parent and nine telosomic lines of A. sativa and one of A. byzantina. Microsporocytes of each F1 hybrid were analyzed for the presence of a heteromorphic bivalent involving the telosome. Heteromorphic bivalents observed in four hybrids from the telosomic lines indicated that four chromosomes of A. magna are homologous with those four telosomes of the hexaploid species. Two of the telosomes involved in the hetermorphic bivalents are included in the As genome of the standard karyotype of hexaploid oats.
Genetics of Time of Internode Elongation and Duration of Rosette Habit in Carthamus tinctorius L. and C. flavescens Spreng1
Authors: Zimmerman L. H.
Published: July 2010

Rosette habit is an important component in the length of the life cycle of safflower (Carthamus spp.). Rosette habit results from nonelongation of internodes. Segregating populations indicated that time of internode elongation, a measure of duration of rosette habit, was influenced by a major gene and modifier genes in C. tinctorius L. (cultivated safflower) and C. flavescens Spreng (an annual herbaceous weed, indigenous to the Middle East). All crosses showed that earliness of internode elongation had dominance, ranging from partial to over dominance. At threshold levels of expression, the frequency of rosette habit in some C. tinctorius genotypes changed with environments; however, the mean length of the first internode of these nonrosette plants was from 1/5 to 1/2 that of ‘Gila,’ which is noted for its nonrosette habit in a wide range of environments.
Comparison of Pollination Methods in Maize1
Authors: Genter C. F.
Published: July 2010

Paired‐row plantings of maize (Zea mays L.) with different endosperm colors were made to compare pollinations made from tassels bagged overnight with pollinations made by shaking a tassel into a bag just prior to pollination. Outcrosses were determined by xenia effects on kernel color. The superiority of bagged over open (unbagged) tassels was clearly evident among hybrids but the two methods were not so distinctly different for inbreds. Tearing tops from shoot bags at pollination significantly reduced contamination. If plants are short or are inbred sufficiently that outcrosses can be accurately identified, pollinations can be made more efficiently without tassel bagging and an acceptable level of outcrosses can be maintained. However if plants are tall, or if freedom from outcrosses is of major importance, bagging tassels overnight and tearing tops from shoot bags at pollination appears to be the most reliable technique.
Selection for Resistance to Stemphylium botryosum in Alfalfa1
Authors: Borges O. L. , Stanford E. H. , Webster R. K.
Published: July 2010

Selection for resistance to Stemphylium botryosum Wallr. was practiced in the alfalfa (Medicago sativa L.) cultivars, ‘SW44’ and ‘Caliverde.’ The parental clones were evaluated by clonal and selfed progeny testing. The observations from clonal replicated experiments permitted an estimation of broadsense heritability of 49 and 75% for SW44 and Caliverde, respectively. Significant positive correlations between parental clones and their selfed progenies were obtained for both cultivars. From these results we concluded that selection for resistance to S. botryosum would be effective in both cultivars. This expectation was tested experimentally, determining the response after one cycle of selection. For this purpose, four synthetic populations were obtained by intercrossing the selected clones and two populations were developed by intercrossing the best plants within the best selfed families. All synthetics were compared with their respective unselected populations. The results showed that selection for resistance was effective in all synthetic populations. Selfed progeny tests and selfed selection were more efficient than clonal evaluation in increasing the level of resistance.
Combined Half‐sib and S1 Family Selection in a Maize Composite Population1
Authors: Goulas Christos K. , Lonnquist J. H.
Published: July 2010

Recurrent selection for intrapopulation improvement in maize (Zea mays L.) using combined HS‐S1 progeny evaluation was studied. The source population (3‐L Composite) originated from three inbred lines (W64A, W182E, A635). The F2 generations of the three possible single crosses were planted in an isolated plot. At flowering time, ear shoots were covered on prolific plants. The lower ear was self‐pollinated to provide Si seed and the upper ear exposed to open‐pollination to provide half‐sib (HS) seed. Half‐sib and S1 progenies were evaluated in separate trials using incomplete blocks of 10 entries each with two replications. Selection was carried out on a per block basis. Plants with superior HS and S1 progeny performance, i.e., above average yield and equal or below average moisture in the grain at harvest in both trials, were selected. Selection intensity was 22 and 20% in CO and Cl, respectively. Each new cycle was initiated from remnant HS seed. Two selection cycles have been completed. The estimated degree of inbreeding was 34% in CO, 43% in Cl, and 44% in C2. Relative to CO, selection resulted in 5% yield improvement in Cl (based on 3‐year testing) and 20% improvement for C2 (2‐year tests). Also, Cl was 1 day earlier to flower, taller with slightly higher (103%) ear placement, and had less moisture in the grain at harvest (97%). C2 exhibited no further change for moisture in grain at harvest but was taller, ear height being 111% relative to CO. Thus far, selection has reduced inbreeding depression in the population without decreasing heterosis for yield in HS families.
Combining Ability for Seedling Dry Weight and Forage Yield in Cicer Milkvetch1
Authors: Townsend C. E.
Published: July 2010

Polycross progenies of plants from three selected populations of cicer milkvetch, Astragalus cicer L., were evaluate for combining ability for seedling dry weight in the greenhouse and for forage yield in the field. Parental plants were selected for high vigor, low vigor, or large seed. The large‐seeded group was average or above average for vigor. About 80 progenies were evaluated in the greenhouse and at two field locations. In another study 45 progenies were evaluated at one field location.

Seedling dry weight of the progenies in the greenhouse ranged from 19 to 118% of the reference progeny which had been selected for high seedling emergence in the field. Only one progeny was significantly better than the reference and it was from the large‐seeded group. Of the 19 progenies that did not differ significantly from the reference, one was from the low‐vigor, five from the large‐seeded, and 13 from the high‐vigor population.

In field studies the frequency of high‐yielding progenies was higher in the high‐vigor and large‐seeded populations than in the low‐vigor population through the second year. However, in one study that was conducted for 3 years, the performance of the low‐vigor population was much better in the third year while that of the large‐seeded population was relatively poorer. In general, genetic variation within cicer milkvetch for seedling dry weight and forage yield appeared sufficient to permit improvement of these characters.
Aflatoxin Production in Several Corn Hybrids Grown in South Carolina and Florida
Authors: Lillehoj E. B. , Kwolek W. F. , Manwiller A. , DuRant J. A. , LaPrade J. C. , Horner E. S. , Reid J. , Zuber M. S.
Published: July 2010

Susceptibility of developing ears of several corn hybrids (Zea mays L.) to infection by Aspergillus flavus Link ex Fr. determined by aflatoxin production was studied. Five experimental single‐cross hybrids (SC) adapted for growth in the South and a single‐cross hybrid (A) adapted to the Corn Belt were grown in South Carolina and Florida. Treatments consisted of: (a) periodic spraying with an insecticide to control ear damage by insects; (b) inoculation of ears with A. flavus spores; (c) mechanical damage of ears to simulate insect damage; and (d) nontreated controls. Cracked kernels from individual ears were examined for bright greenish‐yellow fluorescence (BGY). Shelled corn from each treatment replication was combined, blended, sampled, and assayed for aflatoxin. The five SC hybrids exhibited a lower level of BGY occurrence and aflatoxin than hybrid A. Inoculating silks with A. flavus spores increased the incidence of BGY fluorescence and concentrations of aflatoxin. Corn from nontreated control ears was extensively contaminated with aflatoxin. Insecticide reduced but did not eliminate insect damage and toxin development in field corn except for one hybrid (SC76 ✕ SC413). The results suggested relationship between insect damage and presence of the toxin.
Peanuts: Germplasm Resources1
Authors: Banks D. J.
Published: July 2010

Peanut germplasm resources in the USA are considerable and contain a great amount of genetic diversity. However, some are rather poorly organized and few have been adequately evaluated, mainly because of limited funding and support personnel. Progress is underway to organize these genetic stocks systematically and to strengthen germplasm resources and evaluation. Further explorations in South America for additional genetic resources are needed to preserve the present germplasm while these sources are still available. Unfortunately, the cultivars of Arachis hypogaea L. are susceptible to several important diseases and pests. Some of the wild species of Arachis possess resistance to certain of these pests but they have not been utilized because of poorly understood species cross‐incompatibility factors. Proper utilization of the genomes of the 30 to 50 species from seven clearly differentiated taxonomic sections should revolutionize peanut breeding not only in pest resistance but in plant structure as well. Efforts are underway at several locations to develop methods of hybridizing species of this genetically difficult group. As the barriers to crossing are broken by bridging schemes and other methods, a great amount of additional genetic material will become available for future variety development.
Hypocotyl Diameter as a Predictive Selectin Criterion in Sugarbeet1
Authors: Doney D. L. , Theurer J. C.
Published: July 2010

Investigations concerning sugarbeet (Beta vulgaris L.) seedling characters and field root yield suggested a relationship between seedling hypocotyl diameter and root yield. This report deals with the hypocotyl diameter character and its relation to root yield, its genetic characteristics and its use as a selection criterion.

The hypocotyl diameter of 3‐week‐old seedlings was measured with a micrometer caliper (graduations of 0.01 mm). Seedlings were grown in vermiculite in growth chambers and watered daily with equal amounts of nutrient solution. Hypocotyl diameter measurements were significantly correlated with root yield (0.70, 0.73, and 0.76) in three separate field trials. Significant heterosis for this character was observed in 14 of 18 crosses. In a six‐female ✕ three‐male sib analysis, general and specific combining ability and estimates of the proportion of additive to non‐additive genetic variance were similar for root yield and hypocotyl diameter. Selection of individual plants in heterozygous populations significantly increased the hypocotyl diameter of 3‐week‐old seedlings. The expected rate of increasing root yield (relative selection efficiency) when selecting for this character was 1.46 relative to selecting for root weight of space‐planted beets. These data suggest that this character could be an effective selection criterion for increasing root yield in sugarbeet.
Inheritance of Resistance to Peanut Mottle Virus in Soybeans1
Authors: Boerma H. R. , Kuhn C. W.
Published: July 2010

Four soybean, Glycine max (L.) Merr., crosses between resistant and susceptible cultivars were used to study the inheritance of resistance to peanut mottle virus (PMV). From greenhouse inoculation tests performed on the F1, F2, and F3 generations, resistance was shown to be conditioned by an allele at a single locus, designated as Rpv which exhibited complete dominance under the conditions of this study. These results indicated that cultivars resistant to PMV can be obtained either by screening the early segregating generations of crosses between resistant and susceptible parents or by transferring the gene for resistance through a backcrossing program into existing susceptible cultivars.
Genetic Variation in Stomatal Length and Frequency and other Characteristics in Bromus inermis Leyss.1
Authors: Tan Geok‐Yong , Dunn G. M.
Published: July 2010

Genetic variation in stomatal length and frequency was investigated in 10 single crosses of a half‐diallel cross involving five bromegrass (Bromus inermis Leyss.) genotypes.

The diallel analyses revealed much higher general combining ability (GCA) than specific combining ability (SCA) for all characters. The SCA was not significant for any character. Relatively high narrow‐sense heritability estimates were obtained for stomatal length (0.69) and frequency (0.85) and for other leaf characters. General combining ability effects of the parental clones were also estimated for all characters. Negative genotypic correlations were obtained between stomatal length and stomatal frequency of the same leaf. The phenotypic and genotypic correlations obtained between stomatal characters and other traits showed that stomatal length was positively while stomatal frequency was negatively correlated with leaf length, width, area, and tiller dry weight. These data indicated that selection for larger and fewer stomata should tend to result in longer and wider leaves of larger areas and greater tiller dry weight. None of the characters under study was associated with the spaced plant yield.
Mass Selection in a Composite of Intercrosses of Mexican Races of Maize1
Authors: Genter C. F.
Published: July 2010

Mass selection was used to incorporate desirable traits from 25 Mexican races of maize (Zea mays L.) into a single population with maturity and plant type that would be useful to temperate zone maize breeders. Ten generations (cycles) of selection have been completed. The original population ranged from early to very late at Blacksburg, Va, where it was grown in isolation with 600 or more ears selected each cycle. Selection was practiced primarily for erect, disease‐resistant plants with mature grain, without particular regard to plant and ear type. Earlier maturity was gradually achieved by a combination of natural selection against very late plants and artificial selection of ears from several of the earliest maturing plants each cycle. Seed increases were made in 1972 from C1, C4, and C7 remnants. These, together with C10 produced in 1972, were grown in performance trials in 1973 and 1974. Over the 10 cycles, yield increased 171%, days to mid‐silk decreased 11 days, and moisture at harvest decreased 7.7 percentage points. The ratio of plant‐to‐ear height decreased; in C10, ear height averaged 115 cm — 50% of plant height. Average spread between pollen shed and silk emergence decreased from 9.1 to 7.0 days. Incidence of corn smut [Ustilago maydis (DC.) Cda.] decreased from 43.6 to 19.3 smut galls/100 plants. Selection had little effect on root lodging, but stalk lodging increased. C10 is highly variable but has a sufficient frequency of plants with satisfactory maturity and morphology to provide a readily usable source of tropical germplasm in major temperate zone maize production areas.
Soft Wheat Quality of Preripe Harvested Wheat1
Authors: Yamazaki W. T.
Published: July 2010

Wheats (Triticum aestivum L. em Thell) of five cultivars were harvested periodically from about 24 days preripe to ripe and evaluated for suitability of the dried grain for soft wheat products. In grain harvested as early as 13 days preripe, quality attributes were comparable to those that are characteristic of test cultivars present when harvested at full maturity. At that early stage of grain development, wheat moisture content was about 40 to 45%.
Timing of Glyphosate for Conversion of Bermudagrass Turf to Tall Fescue1
Authors: Johnson B. J.
Published: July 2010

Renovation of bermudagrass [Cynodon dactylon (L.) Pers.] turf to tall rescue [Festuca arundinacea Schreb. ‘Kentucky 31’] is a major problem since soil fumigation is usually necessary to completely kill the existing turf. This study was conducted to determine if bermudagrass could be controlled with a fall application of glyphosate [N‐(phosphonomethyl) glycine] and the turf successfully reestablished by over‐seeding with tall rescue without disturbing the soil surface. Herbicidal treatments were applied 0, 1, 5, or 10 days before overseeding, and 1, 5, or 7 days after overseeding.

Bermudagrass ground cover was reduced most after 1 year where glyphosate was applied any time before overseeding in fall 1973 (1 to 4% ground cover), and l0 days before overseeding in fall 1974 (6% ground cover). After the second growing season, bermudagrass ground cover ranged from 9 to 18% cover. Glyphosate treatments did not injure tall rescue either year when applied 1, 5, or 10 days before overseeding. Glyphosate applied as a single treatment significantly reduced bermudagrass ground cover, but did not give complete control.
Particle Size Index — Breeding Behavior and Association with Protein Percentage in Wheat1
Authors: Trupp C. R.
Published: July 2010

A small‐sample particle size indexing procedure was altered to require only 2.0 g of wheat (Triticum aestivum L. em Thell.) meal per determination. Particle size index (PSI) values were determined on a wide range of materials over a series of experiments and years. High repeatability in duplicate determinations, high correlations between locations, ability to differentiate lines of proven quality acceptance, and relatively low environmental influence indicated its reliance as a measure of kernel texture. A correlation of 0.83 between 56 selected F2 plants and their F3 bulk progenies grown in the subsequent season indicated a high heritability. The divergence of F3 population means resulting from selection of F2 extremes indicated a high degree of response to selection for PSI in early segregating generations. Application of the particle size indexing procedure to breeding materials in the MSU (Michigan State Univ.) hybrid wheat breeding program indicated a large genetic potential for selection. Genotypic and environmental correlations between PSI and protein percentage were small. The possibility of breeding higher protein pastry‐quality soft winter wheat cultivars is discussed.
Effects of Recurrent Selection for Crushing Strength on Morphological and Anatomical Stalk Traits in Corn1
Authors: Chang H. S. , Loesch P. J. , Zuber M. S.
Published: July 2010

Twelve morphological and anatomical traits were evaluated in two synthetics of corn, Zea mays Lo, which had undergone selection for high and low crushing strength. The two synthetics were represented by third cycle selections designated ‘MoSQ A‐High,’ ‘MoSQ A‐Low,’ and ‘MoSQ B‐Low.’ The study was conducted to determine whether selection for stalk strength resulted in corresponding changes in one or more anatomical traits. Most of the traits evaluated were affected by selection. Significant differences, however, were not detected among the four sub‐populations for rind density. Multiple regression coefficients indicated that stalk density and rind density were relatively less important than rind weight and area of rind in predicting rind crushing strength. The area of vascular bundles, the area of lignification, and the we;.ght of rind and stalk section were correlated with rind crushing strength responses to selection.

MoSQ A and MoSQ B were similar in stalk strength, but derived their essentially equal strength in different ways. MoSQ A had greater number of vascular bundles than MoSQ B, and vascular bundle number was greater for the high than for low selections. MoSQ B had more lignification per vascular bundle than MoSQ A, and the lignified area in the rind was correlated with crushing strength. We concluded that populations may differ in the particular array of anatomical traits that contribute to stalk strength. Nevertheless, strength in this study appeared to reside principally in the rind tissue.
Inheritance and Interrelationships of Grain Yield and Selected Yield‐Related Traits in a Hard Red Winter Wheat Cross1
Authors: Sidwell R. J. , Smith E. L. , McNew R. W.
Published: July 2010

The parents, F1, F2, and backcrosses derived from two hard red winter wheat (Triticum aestivum L. em Thell.) cultivars were studied in a field experiment grown on the Agronomy Research Station at Stillwater, Okla., during the 1971‐1972 crop season. Data were taken on individual plants to estimate gene action, heritability, and interrelationships of grain yield and selected yield‐related traits. Characters studied were 1) grain yield, 2) tiller number, 3) kernel weight, 4) kernels/spike, 5) spikelets/spike, and 6) kernels/spikelet. The direct and indirect effects of characters 2, 3, and 4 on grain yield were also studied.

Additive and dominance variances were much smaller than the environmental variance for each character except kernel weight. Kernel weight, tiller number, and spikelets/spike displayed rather high broadsense herRabilities while kernel weight was the only character to display a high narrow‐sense estimate. Other heritability estimates ranged from intermediate to low. On the basis of gene action and heritability estimates, direct selection to improve a trait, should be more effective for kernel weight than for any of the other traits.

Tiller number had a high positive phenotypic correlation and an intermediate genetic correlation with grain yield. Phenotypic correlations of kernel weight and kernels/spike with grain yield were intermediate and low, while their genetic correlations were low and intermediate, respectively. Negative associations observed between kernel weight and tiller number and between kernel weight and kernels/spike suggests that simultaneous improvement of these characters will be difficult. Large positive phenotypic and genetic correlations were observed between kernels/spike and spikelets/spike and between seeds/spike and kernels/spikelet.

Path coefficient analyses at the phenotypic level indicated that the direct effect of tiller number on grain yield was large while the direct effects of kernel weight and kernels/spike were intermediate and low, respectively. At the genetic level, the direct effect of each component was intermediate and about equal in magnitude. This implies that the large direct effect of tiller number at the phenotypic level was due largely to nonadditive genetic or environmental effects or both.

The results of this study indicated that selection for kernel weight in early generations is the most important factor in a breeding program for increasing grain yield. Tiller number makes a greater contribution toward grain yield but is much more difficult to improve by selection in early generations.
Resistance in Digitaria species to Pyricularia grisea (Cke.) Sacc.1
Authors: Oakes A. J. , Graham J. H.
Published: July 2010

Twenty species and two subspecies comprising 369 accessions of the USDA Digitaria collection were screened in greenhouse trials for resistance to gray leaf spot, Pyricularia grisea (Cke.) Sacc. Techniques were developed whereby living plants could be evaluated for comparative resistance following inoculation. Tests were conducted to ascertain differential resistance to gray leaf spot among and within species. Three species were immune, various degrees of resistance were present in 13 species and two subspecies, and four species were susceptible. Immune or highly resistant germplasm constitutes approximately two‐thirds of the collection, thus enhancing its value as a source of disease resistance. Paramount consideration should be given to individual clonal behavior in the continued search for and utilization of disease‐resistant germplasm.
Association of Genotype ✕ Environment Interactions with Performance Level of Soybean Lines in Preliminary Yield Tests1
Authors: Baihaki Achmad , Stucker R. E. , Lambert J. W.
Published: July 2010

This study was conducted to determine the relationship of genotype ✕ environment interaction to yield level (high, medium, or low) of preliminary yield test materials. Forty‐four soybean (Glycine max L. Merr.) breeding lines and four cultivars were tested at three locations in each of 2 years and were categorized into high, medium, and low‐yielding groups. Genotype ✕ environment interactions were estimated within each group and over all lines. Stability parameter estimates were computed for the lines as an assessment of stability of each group.

About 50% of the total genotype ✕ environment interaction for yield was contributed by the low yielding group, 25% by the medium yielding group and 25 by the high yielding group.

The regression of stability parameter estimates (b values) on mean yield of the lines was positive and highly significant (r2 = 0.26). In general, the medium‐yielding group of lines was the most stable and the low‐yielding group was the least stable.

Selecting the best one‐third of the lines in any of the single‐environment tests identified 11 of the top 16 lines based on means from all tests. Further, in each environment four or five of the five highest yielding lines (over all environments) were identified. We conclude that single environment preliminary yield tests can be used without serious risk of discarding outstanding lines.
Ethidium Bromide Induced Cytoplasmic Male Sterility in Pearl Millet1
Authors: Burton Glenn W. , Hanna Wayne W.
Published: July 2010

Seeds of homozygous ‘Tift 23DB1’ pearl millet [Pennisetum americanum (L.) K. Schum], maintainer for cytoplasmic male sterile (cms) ‘Tift 23DA1,’ were soaked in deionized water solutions of 250 and 1,000 ppm of ethidium bromide (EB) at 5 C for 40 hours. Treated seeds were rinsed in tap water for 30 min, surface‐dried, and planted in replicated two‐row plots in the field with two‐row plots of untreated Tift 23DB1. Male‐sterile mutants (whole heads, sectored heads, or heads with intermingled male‐sterile and male‐fertile florets) occurred at frequencies of 1 in 30,100, I in 515, and 1 in 274 in total head populations of 30,100, 22,700, and 19,200 treated with 0, 250, and 1,000 ppm EB, respectively. Occurrence of M1 sterile mutants that set seed when pollinated and gave rise to some cms progenies in the greenhouse proved that the mutants were cytoplasmic male sterile.
Precise Back‐Saving Transplanter for Small Potted Plants1
Authors: Burton Glenn W.
Published: July 2010

A transplanter that permits the operators to stand erect as they precisely set small potted plants in the field is described. Some 6,500 potted seedlings of bahiagrass, Paspalum notatum Flugge., set in the field with this homemade tool in mid‐April 1975 were transplanted with little shock and grew off so uniformly and rapidly that it was possible to complete a cycle of recurrent reciprocal phenotypic selection in 1 year instead of 2 years generally required.