bluuebunny/crossref_metadata_2025 huggingface dataset:
Triacylglycerol Metabolism in Soybean Seed with Genetically Altered Unsaturated Fatty Acid Composition1
Authors: Carver Brett F. , Wilson Richard F.
Published: July 2010

Recurrent selection methodology has been utilized in the development of a soybean [Glycine max (L.) Merr.] genotype, designated as N78‐2245, that contains a high concentration of oleic acid (18:1) and lower concentrations of linoleic (18:2) and linolenic (18:3) acids compared to seed from typical soybean cultivars. Triacylglycerol (TG) is the predominant glycerolipid soybean oil. The nature of triacylglycerol deposition during the ontogeny of soybean seed with the high‐l8:l trait has not been shown previously. The objective of this study was to determine how expression of the high‐18:1 trait was affected through TG molecular species composition during seed development. To achieve that objective TG composition was evaluated in seed of N78‐2245 and ‘Dare’, a typical soybean cultivar, at four stages of reproductive growth. For both genotypes developmental changes in TG fatty acid composition primarily were reflected by the levels of nine TG species enriched in 18:1 (SM2, M3, and M2D), 18:2 (SD2, MD2, and D3) or 18:3 (MT2, D2T, and DT2); where S = palmitic (16:0) or stearic (18:0) acid, M = 18:1, D = 18:2, and T = 18.3. In N78‐2245 seed all designated species enriched in 18:1, 18:2 or 18:3 respectively accounted for 80.8 mol%, 12.8 mol%, and 6.4 mol% of the TG deposited between 30 and 45 days after flowering (DAF); but accounted for 17.0 mol%, 76.8 mol%, and 6.2 mol% of the TG deposited between 45 and 75 DAF. These data have indicated that factors associated with increased seed age have significantly influenced the expression of the high‐18:l trait in N78‐2245 by restricting the deposition of TG species enriched in 18:1.
Variation in Lemma Thickness in Indian Ricegrass: Implications for Dormancy, Scarification, and Breeding1
Authors: Zemetra Robert S. , Cuany Robin L.
Published: July 2010

Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] has been of interest for revegetation of western mine lands, however, high seed dormancy restricts stand establishment. Breeding to improve Indian ricegrass is hampered by this inherent dormancy, often as high as 98%. Scarification to break dormancy using sulfuric acid has been successful but reduction of viability has occurred. This study examined whether the number of seeds damaged by scarification was related to the thickness of the indurate lemma possessed by Indian ricegrass. Twelve strains and cultivars of Indian ricegrass were examined with a range in lemma thickness of 42 to 76 μm. They differed significantly for this trait, which was not affected by environment. Acid scarification treatments of 20, 30, and 40 rain were followed by water rinses. Viability before and after scarification was determined by tetrazolium tests. Lemma thickness had a significant protectiveffect on seed viability after scarification for all three scarification durations. Coefficients of determination (R2) values were 0.56, 0.75, and 0.79 for 20, 30, and 40 min time, respectively. These results indicate that lemma thickness can be utilized to determine proper scarification duration to minimize seed damage while maximizing germination, resulting in uniform stand establishment and evaluation of Indian ricegrass germplasm.
Variability in Salt Tolerance of Four Triticale Lines at Germination and Emergence1
Authors: Norlyn J. D. , Epstein Emanuel
Published: July 2010

Improving crop tolerance of salinity is one way to help maximize production on irrigated lands in arid and semiarid areas where the salinity of soils and irrigation water is a problem. Four lines of triticale (✕ Triticosecale Wittmack) were compared for salt tolerance at germination and emergence. At 200 mM NaCl from planting to the 7th day, line 6TB371 emerged at a rate of 884%, ‘Siskiyou’ at 46.2%, 6TB278 at 18.0%, and 6TA208 at 13.7%. The emergence of Siskiyou was improved to 60.0% by adding 5.0 mM CaSO4 to the treatment solution. The variation in emergence observed may be useful in programs to improve salt tolerance in this crop, and for comparative studies on mechanisms of salt tolerance.
Yield Stability of Sorghum Hybrids and Random‐Mating Populations in Early and Late Planting Dates1
Authors: Francis C. A. , Saeed Mohammad , Nelson L. A. , Moomaw R.
Published: July 2010

Yield stability is an important characteristic for commercial hybrids with a wide range of adaptation. Measurement of stability may be confounded by the diversity of genotypes included or the planting conditions in which the tests are conducted. The effect of early and late planting time on yield stability was studied for 16 grain sorghum [Sorghum bicolor (L.) Moench] hybrids and four random mating populations in eight diverse environments in Nebraska. One stability analysis was performed for all genotypes in each planting time and another over planting times. Genotype yields showed less interaction with environments when planted late than when planted early, perhaps due to more rapid development and less exposure to stress conditions. When genotype means were regressed on environment means, the magnitudes of genotype × environment interactions were found largely due to nonlinear responses of genotypes to environments. Stability of individual genotypes varied between planting times. There were few hybrids that seemed equally stable and desirable in early and late planting. Some hybrids that were not stable in early planting were identified as stable in late planting and vice versa. Hybrids and populations were relatively more stable in late planting than in early planting. The stable populations in late planting did not produce yields higher than the average yield of all genotypes. Hybrids were more stable than populations in early planting, but the reverse was true in late planting. The influence of planting date cannot be ignored in evaluating yield stability in grain sorghum, and a useful guideline would be to plant all nurseries at the same time as commercial plantings in each area.
Chromosomal Location of Genes Controlling Oleic and Linoleic Acid Composition in the Germ Oil of Two Maize Inbreds1
Authors: Widstrom N. W. , Jellum M. D.
Published: July 2010

One to three genes controlling changes in oleic and linoleic acid of maize, Zea mays L., germ oil by 10% or more have been reported. Two dent inbreds (GE82, 54% oleic and 30% linoleic, and X‐187, 23% oleic and 62% linoleic) were tested using the waxy gene marked reciprocal translocation technique to identify chromosome arms with gene(s) having major effect on the two 18 carbon fatty acids. The inbreds were each crossed with 16 translocation lines and one inversion, all of medium fatty acid composition. The interchanges were evaluated as testcrosses to a waxy tester stock with similar fatty acid composition. Testcrosses demonstrating significant chi square deviations indicating an association of the waxy gene marker and fatty acid composition were also tested as F2 segregates for reinforcement of testcross results. The data did not consistently support a close inverse relationship between oleic and linoleic acid composition in germ oil, but did indicate the existence of a gene(s) on the long arm of Chromosome 5 that influenced germ oil composition for o|eic and linoleic acids of inbred GE82. Both testcross and F2 data suggest the presence in inbred X‐187 of a recessive gene on the long arm of Chromosome 4 controlling high linoleic acid. It could be the same one reported previously. The short arm of Chromosome 1 of both test inbreds was involved in controlling linoleic acid, but the absence of F2 data prevented corroboration. Further testing is needed to identify specific locations of the genes on chromosome arms.
Mechanical Properties of Maize Stalks from the Plant Introduction Collection1
Authors: Foley D. C. , Clark R. L.
Published: July 2010

The Plant Introduction (PI) Collection of maize (Zea mays L.) contains accessions with stronger stalk rinds than the check hybrid ‘AES704’. Stalk rind “thickness” was based on strength of the sclerified hypodermal area measured in tension. Many accessions selected as being superior were based on means from at least 2 years of tests. There was a significant year effect in measuring stalk rind “thickness.” Accessions having high mean stalk rind “thickness” were found in accessions from diverse regions. The largest group of accessions having superior stalk rind “thickness” came from Ethiopia. Flint, dent, floury, and popcorn types were represented among the varieties with a high mean stalk rind “thickness.” The PI 414178 ‘Breve Padilla White‘ from Texas had the highest value for stalk rind “thickness” relative to AES704. Stalk rind “thickness” was highly correlated with stalk diameter among genotypes. The simple correlation coefficients were r = 0.53, 0.85, 0.85, 0.82, and 0.72, for the years 1973, 1975, 1976, 1977, and 1978, respectively. The theoretical stress at which localized buckling of the rind occurs or critical compressive stress (Nx) was calculated from the ratio of stalk rind “thickness” to stalk diameter. Nx ranged from 71 to 382 MPand was always highly correlated with stalk rind “thickness” but not necessarily with stalk diameter.
Evaluation of Two Procedures to Select for Resistance to the European Corn Borer in a Synthetic Cultivar of Maize1
Authors: Tseng C. T. , Guthrie W. D. , Russell W. A. , Robbins J. C. , Coats J. R. , Tollefson J. J.
Published: July 2010

A recurrent selection breeding procedure was used to reduce leaf‐feeding damage by lst‐generatlon European corn borer (ECB), Ostrinia nubilalis Hübner, and to increase 2,4‐dihydroxy‐ 7‐methoxy‐(2H)‐l,4‐benzoxazin‐3(4H)‐one (D1MBOA) content in a synthetic maize, Zea mays L., cultivar (BS1); chemical analysis was for 6‐methoxybenzoxazolinone (MBOA). Thin‐layer chromatography (TLC) plate ratings (intensity of MBOA on TLC plates) also were determined. Cycle populations, population crosses, and check crosses were evaluated. Plants from the ClI, C2I, and C3I populations were selected on the basis of insect damage, whereas the CID, C2D, and C3D populations were selected by chemical analysis for DIMBOA. Leaf‐feeding damage caused by the insect, MBOA concentration in whorl leaf tissue, and TLC plate ratings of MBOA intensity on TLC plates were all improved with recurrent selection procedures when selection was made on the basis of insect damage and also when selection was made by chemical analysis for MBOA in leaf tissue. Each method of selection accumulated about the same level of resistance. Gene actioin for these traits was found to be primarily additive. One hundred S1 lines from each of the CO, C31, and C3D populations were evaluated for leaf‐feeding resistance by first‐generation ECBs. Mean leaf‐feeding ratings of the S1 lines from CO, C3I, and C3D populations were 4.3, 2.8, and 2.5, respectively. Means of CO S1's were significantly greater (higher susceptibility) than were the means of the C3I and C3D S1's. The mean of the C3I S1's was greater than the mean of the C3D S1's. These results were consistent with the results of the C3 population per se. Plants from cycle populations and population crosses were susceptible to sheath‐collar feeding and stalk feeding by second‐generation ECBs.
Influence of Sample Treatment on Apparent Hydrocyanic Acid Potential of Sorghum Leaf Tissue1
Authors: Haskins F. A. , Gorz H. J. , Hill R. M. , Youngquist J. Brakke
Published: July 2010

When dhurrin [p‐hydroxy‐(S)‐mandelonitrile‐β‐D‐glucoside], the cyanogenlc glucoside of sorghum [Sorghum bicolor (L.) Moench], is hydrolyzed by autoclaving, p‐hydroxybenzaldehyde (p‐HB) is released. The spectrophotometric determination of p HB concentration in autoclaved sorghum leaf extracts provides a measure of the hydrocyanic acid potential (HCN‐p) of leaf tissue. Extracts of field‐grown sorghumle aves contained substances that interfered with this procedure, but ether extraction effectively separated p‐HB from these interfering materials. We observed that when flag leaf tissue from field‐grown sorghum was dried at 75°C and then autoclaved, HCN‐pva lues were about three times as high as those based on tissue that was autoclaved without drying. Investigations of this apparent enhancement supported the conclusion that when fresh field‐grown sorghum leaf tissue was autoclaved, dhurrin was extensively altered or lost, but neither p‐HB nor HCN was produced. Drying the tissue at 75°C prior to autoclaving effectively reduced this loss. Inclusion of tissue drying and ether extraction steps in the spectrophotometric assay made this procedure, which was designed for use with sorghumse edlings, satisfactory for use with field‐grown sorghum leaves.
Review of Data Analysis Methods for Seed Germination1
Authors: Scott S. J. , Jones R. A. , Williams W. A.
Published: July 2010

Numerous procedures for data analysis of seed germination responses are scattered throughout the literature. Here an attempt has been made to summarize the existing methods, to compare the information they provide and to examine their strengths and weaknesses. The methods reviewed include the percent germination, germination index, coefficient of velocity, median response time, probit analysis, curve‐fitting of cumulative germination, heat sums, survival analysis with life tables, logistic regression, proportional hazards regression and accelerated failure time analysis. Comparisons among these method are discussed and illustrated with data from germination responses in tomato (Lycopersicon eseulentum Mill.). Seed germination involves not only qualitative responses of individuals, but also population responses which are distributed over time. Standard analysis of variance or regression methods are appropriate for a data analysis where germination of all viable seed is observed, but they are inappropriate when some viable seeds fail to germinate. Such missing (censored) data complicates statistical analysis and subsequent interpretation. Germinations tests should be designed to determine the nature of censored responses, which can be subsequently accommodated by several statistical procedures referred to as survival analysis.
Hybrid Alfalfa Seed Production Using a Female‐Sterile Pollenizer1
Authors: Brown D. E. , Bingham E. T.
Published: July 2010

A recently discovered female‐sterile trait in alfalfa (Medicago sativa L.) was used as a male pollenizer along with three cytoplasmic male‐sterile clones to study the feasibility of mixed plantings for hybrid alfalfa seed production. Rows with mixed stands of male‐sterile (seed parent) and female‐sterile (pollenzier) clones produced significantly more seed than alternate rows of seed parent and pollenizer clones. Leafcutter bees [Megachile rotundata (Fabricius)] served as pollinators. Significant differences were noted among cytoplasmic male‐sterile clones for seed set. Their average yield was only 76% of the first‐year seed yield in an adjacent experiment. Commercial lines with the femalesterile trait and more attractive cytoplasmic male‐steriles are needed before hybrid seed yields will equal those of conventional synthetics.
Genes for Low Reaction to Puccinia recondita in Newton Hard Red Winter Wheat1
Authors: Modawi R. S. , Browder L. E. , Heyne E. G.
Published: July 2010

A hypothesis from a previous study, based on analysis of infection‐type data, that the hard red winter wheat Triticum aestivum L.) cv. Newton has Lrl as well as other Lr genes was tested by crossing Newton with a line having Lrl. No segregation occurred in progeny of this cross when inoculated with an Lp1 culture of Puccinia recondita Rob. ex Desm. Thus, we accept that Newton does have Lrl. Segregation did occur in progeny of crosses between Newton and lines having Lr3a and Lr10, showing that Newton does not have Lr3a and Lr10. Analyses of seedling test and field reaction data of 200 head‐row progenies of Newton breeder's seed indicated that Newton is heterogeneous for reaction to P. recondita and that some plants of Newton have Lr genes detectable only when tests are made at low (5°C) temperature with certain cultures.
Performance of Semideterminate and Indeterminate Soybean Genotypes Subjected to Defoliation1
Authors: Fehr W. R. , Lynk B. D. , Carlson G. E.
Published: July 2010

The percentage reduction in seed yield from defoliation has been shown to differ between indeterminate and determinate soybean [Glycine max (L.) Merr.] cultivars, but no information is available on the response of semideterminate cultivars to loss of leaf tissue. The objective of our study was to compare the performance of semideterminate and indeterminate genotypes when subjected to defoliation. Ten pairs of near‐isogenic lines were used, one line of each pair being semideterminate and the other indeterminate. The lines were completely defoliated at R2 (full bloom) or R5 (beginning seed) during 2 years. Seed yield, 100‐seed weight, time of maturity, plant height, and lodging of treated plots were compared with untreated controls. The average yield reduction from the R2 treatment was significantly greater for the semideterminate than for the indeterminate genotypes by 10.9 percentage units in 1981 and 10.2 in 1982. Yield loss from the R5 treatment was significantly greater for the semideterminate genotypes by 7.9 percentage units in 1981 and 10.4 in 1982. The average reduction in 100‐seed weight was only 1.6 percentage units greater for the semideterminates than for the indeterminates, which indicated that reduction in seed number was primarily responsible for the difference in yield loss between the stem‐termination types. The maximum difference between stem‐termination types for the change in other agronomic characters was 1 day in time of maturity, 5 cm in height, and 0.7 score for lodging. A distinction between semideterminate and indeterminate cultivars may be useful in assessing the yield loss from defoliation that occurs during reproductive development.
A Genetic Study of Number of Involucral Bract Teeth in Cotton1
Authors: Wilson F. Douglas
Published: July 2010

Texas 207 is a photoperiodic accession of cotton, Gossypium hirsutum L., that has many toothed involucral bracteoles (bracts) that enclose the flower bud more completely than do the few‐toothed bracts of modern cultivars. This character could possibly be of value in deterring small insects, such as thrips, Frankliniella spp., from damaging very small flower buds. The inheritance of number of bract teeth was studied in a series of crosses with Texas 207 as one founder parent (✕ = 17.3 teeth/ bract) and a cultivar, Stoneville 7A (St 7A) as the other (g 8.7). From a cross of a day neutral selection of (T‐207 ✕ St 7A) with St 7A, quantitative and qualitative genetic analyses taken together suggested that those two parents differed by at least three pairs of genes which acted additively in concert. Narrowsense heritability, estimated in F2 on a plant basis, was 46%. I failed to transfer a high number of bract teeth into the 7A background apparently because certain advanced‐generation populations from backcrosses to St 7A were too small to recover the many bract‐teeth phenotype. However, the genetic analyses suggest that it should be possible to recover that phenotype by growing larger populations of BCnF2.
Development of the Vascular Tissue of the Wheat and Barley Caryopsis as Related to the Rate and Duration of Grain Filling1
Authors: Lingle Sarah E. , Chevalier Peggy
Published: July 2010

An anatomical study of developing wheat (Triticum aestivumL.) and barley (Hordeum vulgare L.) caryopses was conducted in order to relate the development of the vascular and associated tissues to the rate and duration of grain filling. Caryopsis development of the two species was similar, differing mainly in the timing of events, including the date of flowering and the duration of the grain‐filling period. The main vascular bundle began to differentiate after anthesis and differentiation was completed at about the same time elongation of the kernel ended. The sieve tubes of the main bundle remained open and visually functional until the end of grain filling. The cell walls of the chalaza began to lignify midway through the grain‐filling period, but lignification was not a barrier to grain filling. Yellow or brown‐colored compounds (possibly phenolics) accumulated within the vacuoles of the chalazal cells of barley, but these did not adversely affect the rate of grain filling. In both wheat and barley, the marked decline in the rate of dry matter accumulation occurred prior to the collapse of the phloem and chalaza. Thus, the collapse of these tissues did not trigger events leading to the termination of grain filling. Barley had more sieve tubes than wheat, yet the rate of grain filling was similar for the two species. Thus the number of sieve tubes was not related to the rate of grain filling.
Genetic Variability, Heterosis, and Combining Ability Estimates for Root Weights of Maryland Tobacco1
Authors: Aycock M. K. , McKee C. G.
Published: July 2010

Based on the hypothesis that a larger root system will increase lodging resistance in Maryland tobacco (Nicotiana tabacum L.), the present study was initiated with two objectives: (i) to obtain root and top data on several Maryland tobacco cultivars and hybrids, and (ii) to determine the importance of heterosis, general combining ability, and specific combining ability for root and top weights. Greenhouse studies conducted in 1977 and 1978 included seven parents and 21 hybrids. Fresh weights of roots and tops plus the top/root ratio were obtained at 20, 35, and 52 days after transplanting (DAT) for plants grown in 15 cm plastic pots. Significant genetic variability was found among the parents and hybrids within each year. Due to a large entry ✕ year interaction in the combined analysis, no significant variation was found among the parents and hybrids over the 2 years. Estimates of heterosis ranged from 0.3% at 35 DAT for top/root ratio to 31.9% for top weight at 20 DAT. General combining ability (GCA) and specific combining ability (SCA) estimates were significant for most traits at the three sampling dates within each year. For the combined analysis over the 2 years, GCA ✕ Y and SCA ✕ Y interactions were significant in most cases. The results from this study suggest that selection for increased lodging resistance in tobacco is possible based on the amount of genetic variability and additive genetic variance present in the population. However, the presence of a large genotype ✕ environment interaction may delay progress. Possible breeding techniques, problems, and procedures for reducing the G ✕E interaction are considered.
Effect of Sample Grinding Size on Forage Quality Estimates of Smooth Bromegrass Clones1
Authors: Casler M. D. , Shenk J. S.
Published: July 2010

Particle size of ground forage influences in vitro digestibility and the concentration of cell wall constituents. Little information is available on the effect of ground forage particle size on the relative rankings of genotypic or phenotypic values for quality of ground forage. Our objective was to determine the effect of two grinder screen sizes on the relative rankings and repeatability of forage nutritive value estimates of smooth bromegrass (Bromus inermis Leyss.) clones. Dried forage of 75 smooth bromegrass clones was ground through a 2‐mm screen, from which a sample was reground through a 1‐mm screen. Neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), hemicellulose, cellulose, and ash were determined on duplicate samples of fine‐ and coarse‐ground forage. All traits except ADF and hemicellulose had average absolute values of duplicate differences reduced significantly by fine grinding. The correlation between duplicate samples was increased by fine grinding for each trait, except hemicellulose and ash. Fineness of grind severly affected the relative rankings of ADL and hemicellulose; NDF, ADF, and cellulose were also more highly correlated with one another when forage was ground finely. The interactions between particle size groups and clones raises the question of which size provides a better predictor of animal performance potential. We concluded that forage breeders should grind forage samples fine enough to obtain adequate repeatability unless it can be shown that coarser grinds give results more highly correlated with animal performance.
Temperature Effects on Germination of Perennial Warm‐Season Forage Grasses1
Authors: Hsu F. H. , Nelson C. J. , Matches A. G.
Published: July 2010

Slow germination and low seedling vigor limit establishment of perennial warm‐season forage grasses, and temperature is a major environmental factor influencing both processes. Therefore, three experiments were conducted to determine temperature effects on germination of big bluestem (BB) (Andropogon gerardi Vitman), caucasian bluestem (CB) [Bothriochloa caucasica (Trin.) C.E. Hubb.], indiangrass (IG) [Sorghastrum nutans (L.) Nash.], and switchgrass (SG) (Panicum virgatum L.), as well as an annual species, crabgrass (CG) [Digitaria sanguinalis (L.) Scop.]. In Exp. I and II seeds were chilled at 4°C for 2 weeks before the germination test. In Exp. I, germination temperatures were 15, 20, 25, 30, 35, and 30/20°C with one entry of each species, except for two of SG. In Exp. II, two to four entries of BB, IG, and SG were tested at 20, 25, and 30° C. In Exp. III, unchilled seeds of two strains of BB, IG and SG, and one of CB were germinated at 9, 12, 15, 20, 25, and 30°C. A logistic function was used to describe cumulative germination. Germination was maximum between 20 and 30°C for chilled seeds compared with 12 to 20°C for unchilled seeds because lower temperatures probably met partially the chilling requirement. Chilling also enhanced speed and percentage of germination of perennial species over unchilled seeds. Calculated minimum temperatures for germination of IG, BB, SG, and CB were 8.6, 8.9, 10.3, and 10.9°C, respectively. Time to reach 50% of final germination (Gt50) decreased with increasing temperature. Further, Arrhenius plots of Gt50 indicated a change in temperature response between 20 and 25°C for perennial species. True germinationrate (% day‐1) was maximum at Gt50 for each treatment. Corrected germination rate index and GR30 (reciprocal of Gt50) were highly correlated and might be good indices to estimate speed of germination. The lower minimum temperatures for germination of IG and BB may allow these species to be planted earlier in spring than SG and CB.
Resistance of Triticum dicoccoides Collected in Israel to Infection with Puccinia recondita tritici1
Authors: Moseman J. G. , Nevo E. , Gerechter‐Amitai Z. K. , El‐Morshidy M. A. , Zohary D.
Published: July 2010

Triticum dicoccoides (Koern. ex Aschers. and Graebn.) Aaronsohn, a progenitor of hexaploid wheat (Triticum aestivum L.) and tetraploid wheat (Triticum turgidum L. var. durum), grows wild in many sites in Israel. Reactions were determined of 687 accessions of T. dicoccoides from that country to infection with culture PRTUS6 of Puccinia recondita Rob. ex Desm. f. sp. tritici, which incites the disease wheat leaf rust. Fourteen percent (or 98 accessions) were at least moderately resistant in the first‐leaf stage to infection with culture PRTUS6. Nineteen of 34 accessions collected at site 12 were moderately resistant as were 10 of 35 from Site 2 and four of nine from Site 8. Resistant accessions were obtained in low frequencies from Sites 6 and 7. Resistant and moderately resistant accessions were obtained among 353 accessions collected at approximately 180 sites throughout the region from Upper and Lower Galilee, Mt. Gilboa and the Judean Mountains, and Mt. Hermon and the Golan Heights. Additional resistant and moderately resistant accessions of T. dicoccoides could probably be obtained by collecting from additional sites. The resistant accessions identified in this study are being used to develop enhanced hexaploid and tetraploid wheat germplasm resistant to P. recondita tritici, Erysiphe graminis DC. ex Merat. f. sp. tritici (Em. Marchal), and P. stri‐iformis West.
Freeze‐Induced Changes in Soluble Carbohydrates of Rye1
Authors: Olien C. R. , Lester G. E.
Published: July 2010

Changes in the composition of sugars that are extractable from ‘Rosen’ rye (Secale cereale L.) crowns occurred while the plants were frozen at −3°C for 24h. Fructosan decreased while fructose and sucrose increased. The fructose content of liquid readily extracted from plant crowns increased 5.2 times over nonfrozen controls. Freeze incubation at −3°C apparently caused conversion of fructosan to the cryoprotective sugars, fructose and sucrose, and deposition of these sugars in the intercellular liquid.
Southwestern Corn Borer Larval Growth on Corn Callus and its Relationship with Leaf Feeding Resistance1
Authors: Williams W. Paul. , Davis Frank M.
Published: July 2010

Leaf feeding damage by the southwestern corn borer [Diatraea grandiosella (Dyar)] can significantly reduce corn (Zea mays L.) yields. Inbred lines with reistance to such damage have been developed; however, little information is available on the inheritance or basis of this resistance. Earlier investigations indicated a relationship between level of leaf feeding resistance of corn genotypes and growth of larvae on plants or on callus initiated from these genotypes. To gain additional information on the relationship between level of leaf feeding resistance and larval growth rate on corn callus, the F1 hybrid progeny of a six‐parent (three leaf feeding resistant and three susceptible inbred lines) diallel cross were evaluated for leaf feeding damage in field tests in 1982 and 1983 as well as larval growth on corn callus initiated from each of the 15 hybrids. Leaf feeding damage sustained by a hybrid and larval growth on callus of the hybrid were highly correlated (r = 0.81). Mean squares for general combining ability were highly significant for leaf feeding damage and larval growth rate on callus. The specific combining ability mean square was significant for larval growth rate on callus but not for leaf feeding damage. Larvae reared for 7 days on hybrids of two susceptible inbreds had a mean weight of 17.8 mg compared to 10.8 mg for larvae reared on hybrids of two resistant inbreds. The differences among hybrids in larval weights on callus and their high correlation with leaf feeding ratings indicate that weights might be used as an additional technique in selecting corn genotypes with resistance and investigating the basis of resistance.
Recurrent Selection for Improved Seed Germination, Seedling Elongation, and Seedling Emergence in Cicer Milkvetch1
Authors: Townsend C. E.
Published: July 2010

Relatively poor seedling vigor restricts the use of citer milkvetch(Astragalus cicer L.), a nonbloating forage legume. To capitalize on the genetic variability for early seedling vigor, one cycle of simple recurrent selection and one cycle of modified simple recurrent selection were conducted within the cv. Monarch for improved seed germination and seedling elongation at 5/20 °Ca nd1 2/20 °C temperature regims in the laboratory and for seedling emergence in the field. Seedling emergence was the primarcyr iterionf or selecting parentsf or the next cycle. Following one cycle of selection at 5/20 °C, 32, 37, and 26% of the progenies were significantly (5%)b etter than Monarch for seed germination, seedling length, and seedling emergence, respectively. Following one cycle of selection at 12/20° C, 12, 19, and 21% of the progenies were significantly better than Monarch for seed germination, seedling length, and seedling emergence,respectively. Selection for early ~eedling vigor under relatively cool eonditions in a controlled environment improved seedling emergence under field conditions. Although percentage seed germination and seedling length were significantly (5%) correlated in all populations, the correlation coefficients were of low predictive value (r = 0.25 to 0.63). Seedling emergence was not consistently correlated with percentage seed germination, seedling length, or seed weight. Consequentlys,e lected progenies must be evaluated under field environments to determine early seedling vigor.
Nitrogen Partitioning and Dry Matter Allocation in Soybeans with Different Seed Protein Concentration1
Authors: Salado‐Navarro Luis R. , Hinson Kuell , Sinclair Thomas R.
Published: July 2010

Physiological studies of soybean (Glycine max L. Merr.) genotypes with wide differences in seed protein concentration may permit detection of important yield‐related processes. Crop growth analyses were performed in 1977 and 1980, at Gainesville, FL, on seven and eight near homozygouds eterminates oybean genotypes, respectively. In 1977, the relationships between yield, seed protein concentration, and the visual length of seed filling were also studied in 23 genotypes. The purpose of this work was to characterize N partitioning and dry matter allocation to seed, and their association with yield and other characteristics. Soybean genotypes with a range in seed protein concentration of approximately 0.38 to 0.50 kg/kg were used. Nitrogen partitioning to seeds was estimated as the change in Harvest Nitrogen Index (HNI), the ratio of seed N weight shoot N weight (disregarding fallen leaves) with time, from beginning linear seed growth until maturity. Nitrogen partitioning in high seed protein genotypes was positively associated with their higher seed N demanda nd faster or earlier vegetative N depletion. In both years, Harvest Index (HI) estimated as the ratio of seed dry weight to shoot dry weight (disregarding fallen leaves) increased linearly with lime in all genotypes from the beginning of linear seed growth until maturity (R8). The Dry Matter Allocation Coefficient (DMAC), an estimate of the rate of dry matter allocation to seed, is defined as the derivative of HI with respect to time, during the linear phase of HI increase. Thus, DMAC is a constant for each genotype‐environment combination. Dry Matter Allocation Coefficient exhibited less variability than Seed GrowthR ate estimated on a land area basis (CV = 6.8 vs. 21.8%). In both years, DMAwCa s positively associated with seed protein conten~ and faster vegetative dry weight decline during seed filling, and negatively associated with seedfilling duration, and yield. Yield was positively associated with seed‐filling duration (RS‐R7), and negatively associated with seed protein concentration. Thus, in general, high seed protein genotypes exhibited faster N partitioning and dry matter allocation into seeds, shorter seed‐filling duration, and lower yield.
Anatomical Characteristics of Smooth Bromegrass Clones Selected for In Vitro Dry Matter Digestibility1
Authors: Ehlke N. J. , Casler M. D.
Published: July 2010

Digestibility plays an important role in forage nutritive value. Anatomical components have repeatedly been demonstrated to influence digestibility of forage crops. Eighteen clones of smooth bromegrass (Bromus inermis Leyss.) selected for either high or low in vitro dry matter digestibility (IVDMD) were evaluated determine if adequate genotypic variation existed for anatomical and chemical components and their relationship with IVDMD. Clones were planted in five randomized complete blocks at Arlington, WI (Piano silt loam—fine‐silty, mixed, mesic Typic Argiudoil) in August 1981. In June 1982, when the clones were just 100% headed, whole‐plant, leaf and stem material were collected for evaluation of IVDMD, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent linguine, insoluble ash, and anatomical components of stems and leaves. A cryostat was used to cut 12 μm sections of leaf and stem material for estimation of percentage tissue types. High IVDMD clones had significantly greater percentages of the most readily digestible tissue types (stem chlorenchyma and leaf mesophyll), a significantly lower percentage of lignified leaf vascular tissue, and thicker stems than the low IVDMD clones. Reduced genotypic variation within the high IVDMD group of clones was observed for IVDMD and most anatomical components compared to variation among the low IVDMD clones. Significant variation for NDF, ADF and cellulose was detected among the high IVDMD clones. Continued gains from selection for improve digestibility within the population derived from the nine high IVDMD clones may be difficult due to the narrowed genetic base for IVDMD and stem and leaf anatomy, but selection for improved dry matter intake potential appears to have some merit.
Effects of the Density of Pubescence on Some Traits of Extra‐long‐stapled Cotton1
Authors: Lee Joshua A.
Published: July 2010

Most modern cultivars of extra‐long‐stapled cotton (Gossypium barbadense L.) display glabrous stems and variable densities of pubescence on leaves. These cottons produce long, strong, and fine fibers. The Tanguis cultivars, and the American Pima Stock, E‐2, produce coarse, although lengthy and strong, fibers. Because Tanguis and E‐2 have dense tomentum on leaves and stems, there arose the question of whether grade of plant vestiture affected fiber fineness and perhaps other fiber and agronomic traits. Three phenotypes, normally pubescent, hirsute, and glabrous, were fixed in ‘Pima S‐5’, Coastland Sea Island, and ‘Seabrook Sea Island’, selection AS‐2. The nine resulting entries were grown in replicated experiments at two locations in North Carolina in 1983. Compared with normal, the hirsute phenotype of AS‐2 showed significantly increased lint percentage, and glabrousness reduced lint percentage significantly in AS‐2 and Pima S‐5. Hirsuteness significantly reduced g seed cotton boll‐1 and lint index in Coastland. Glabrousness significantly reduced 2.5% span fiber length in AS‐2 and length uniformity index was reduced in both hirsute and glabrous Coastland. Fiber tenacity was significantly reduced in glabrous Coastland, and hirsute Coastland showed a significant reduction in fiber elongation. None of the phenotypes affected micronaire values in any of the families. Increased pubescence was associated with fewer deficits in agronomic and fiber traits than glabrousness, and each of the Sea Island cottons showed more significant changes in the traits sampled than Pima S‐5.
Association of Seed Yield with Partitioned Lengths of the Reproductive Period in Soybean Genotypes1
Authors: Hanson W. D.
Published: July 2010

The total reproductive period (TRP) of the soybean [Glycine max (L.) Merr.] was partitioned into a period for pod initiation and establishment (PEP) and a period for pod‐filling and maturation (PFP). The objective was to determine the effects increasing PEP vs. PFP upon seed yield. The study utilized a broad‐base population of 140 soybean genotypes selected for determinant growth habit and for full‐season maturity within a 2‐week period. The selected lines were field tested for 3 years at one location. The lengths for the three reproductive periods and the PFP/PEP ratio had heritabilities between 62 and 86% and would therefore respond to selection. The genotypic correlation between PEP and TRP was +0.77 while the genotypic correlations involving PEP and TRP with PFP were −0.21 and +0.45, respectively. No association was found between PEP and seed yield. Non significant increase in seed yield was associated with genotypes having larger PFP/PEP ratios or longer TRP. Genotypes with larger node numbers or with longer PFP had significantly greater seed yields. Selecting genotypes with both longer TRP and larger proportion of TRP devoted to pod filling relative to pod establishment led to the identification of a unique set of genotypes with high seed yields. The length of PEP in this study was apparently sufficient to establish sink load (number of seeds), but longer PFP was needed to insure photosynthetic availability to the sinks over an extended period of time.
Relationship Between Coefficient of Parentage and Genetic Similarity Indices in the Soybean1
Authors: Cox T. S. , Kiang Y. T. , Gorman M. B. , Rodgers D. M.
Published: July 2010

Estimates of genetic similarity or distance between populations or strains of plants are useful in planning crosses for hybrid or pureline cultivar development. We compared coefficients of parentage (r) and similarity indices (s, sz, and sM, based on 20, 13, and 7 genetic loci, respectively) for combinations of 115 soybean [Glycine max (L.) Merr.] cultivars and ancestral introductions. Correlations between r and s were higher than those between r and sz or sM, primarily because s includes information from more loci. The correlation between r and s was higher for the group of soybean cultivars released in the 1970s than for earlier cultivar groups, primarily because of the greater importance of identity by descent relative to identity in phenotype in determining s. The most useful estimate of genetic relationship is a composite index that includes both r and s.
Sample Size and Experimental Design for Detecting Differential Anatomical Composition of Smooth Bromegrass Stems and Leaves1
Authors: Casler M. D. , Ehlke N. J.
Published: July 2010

Precise quantitative assessment of anatomical composition in smooth bromegrass (Bromus inermis Leyss.) is difficult due to (i) small differences among many genotypes or types of treatments, (ii) an extreme amount of random variation, and (ill) an associated requirement for large sample sizes. The objectives of this study were to determine the importance of sources of error and to develop a strategy for more precise estimation of genetic differences in anatomical composition of smooth bromegrass stems and leaf blades. Eighteen clones were grown at Arlington, WI in 1982 in two randomized complete blocks of spaced plants. Two leaf blades of each of two tillers were sampled from each plant at early heading for estimation of percentage cross‐sectional area of stem and leaf blade anatomical components. for stem characters, the variance component due to tillers within plants was always the largest. Repeatability of clone means was generally low and resulted in poor power (<45%) for pairwise tests of clone means with true differences of 20 or 40% of the range among clone means (R−c). Power was adequate for vascular bundle number (VBN), diameter, and percentage phloem at 60% of R−c but never exceeded 55% for percentage chlorenchyma, vascular bundle schlerenchyma, and vascular bundle tissue. Sample sizes required for 80% power varied considerably among characters but should be larger than the four total tillers per clone sampled in this study. Replication should be kept to a minimum (two) for all characters except VBN and xylem. The optimum number of tillers per plant was one for VBN and two for xylem. For all leaf blade characters, except VBN, the leaf age ✕ tiller variance component was the largest. Repeatability was slightly higher than for most stem characters, but power for small differences (20 or 40% of R−c) was similarly low, except for VBN. Power was nearly 60% or greater for all characters at 80% of R−c and nearly 80% or greater for all characters at 100% of R−c. Small total sample sizes (e.g., eight total leaf blades per clone) would be adequate for VBN and percentage vascular bundle tissue, but not other characters. Future studies of these leaf blade characters should emphasize (i) a minimum number leaf blades per plant, (ii) sampling leaves of equal ages, (iii) tiller per plant, and (iv) adequate experimental replication.
Effects of Location and Plant Density on Yield and Architectural Traits in Dry Beans1
Authors: Nienhuis James , Singh Shree P.
Published: July 2010

Plant architectural traits associated with yield have been suggested as indirect selection criteria for improving seed yield of dry beans (Phaseolus vulgaris L.) but critical data from selection experiments are lacking. Six dry bean experimental lines of growth habits I, II and III, bred for one or more plant architectural traits, were therefore compared at three locations in Colombia with six other cultivars which were conventionally developed experimental lines of similar growth habits. At each location plant densities of 5, 13, 22, and 30 plants/m2 were established. The objectives were to examine: a) whether lines bred for architectural traits outyielded cultivars and experimental lines bred conventionally, b) the effects of environment and plant density on architectural traits and seed yield, and c) the associations between architectural traits and yield. We did not find a genotype of any growth habit bred for specific architectural traits outyielding the commercial check cultivar. Indeterminate, prostrate type llI, and type II cultivars, in that order, were among the highest yielding regardless of environment and plant density. These also offer the best opportunity for the development of broadly adapted, high yielding cultivars of dry beans for monoculture. Locations, seasons within locations, and plant densities each affected yield and architectural traits. Significant interactions were observed between environment, growth habit, and plant density; and these factors affected yield and all architectural traits. Differences were greatest between determinate and indeterminate growth habits (type I vs. types II and III). For plant density the shape of the response curves for yield was parabolic whereas the shape for type I beans was asymptotic. Curvilinear (types I and II) and linear (type III) increases nodes/m2 were observed as plant density increased. Branch and node number/plant decreased linearly with increasing plant density for genotypes of all three growth habits. Linear reductions in node number on the main stem were observed in indeterminate types II and III with increasing plant density, but internode length did not change. In contrast, the number of nodes on the main stem of determinate type I remained unchanged but internode length increased linearly as plant density increased. Nodes/m2 and branches/plant were positively correlated with yield regardless of environment or plant density. In contrast, nodes/branch and internode length on the main stem were positively correlated with yield over the range of plant densities used, but showed variable correlation over environments. Therefore, development of bean plant ideotypes with enhanced expression of certain architectural traits can result in limited adaptation and reduced yield potential in some environments.
Inheritance of Density of Erect Glandular Trichomes in the Genus Medicago1
Authors: Kitch L. W. , Shade R. E. , Nyquist W. E. , Axtell J. D.
Published: July 2010

The successful development of an interspecific, erect glandular‐haired, tetraploid population of alfalfa, involving Medicago sativa L.; M. prostrata Jacquin; and M. falcata glandulosa David, with an adequate density of hairs for resistance to several insect pests is described. The objective of this study was to determine magnitudes of genetic and nongenetic variance components, repeatability, and heritability of glandular‐hair density in this population. A random sample of 40 genotypes from this population was randomly intermated. Twenty‐two genotypes and their progeny were measured for density of glandular hairs in a randomized complete‐block design with two blocks. Parental plots consisted of eight vegetatively propagated plants of each parental clone, and the progeny plots included 16 random‐intercross individuals from each parent as a female. The third fully elongated internode from the apex on two stems per plant was measured for number of glandular hairs per square millimeter (g.h. mm−2). The design variance components of parental clones were estimated. The phenotypic variance was partitioned into additive (29%), nonadditive (16%), general environmental (29%), and special environmental (26%) variances. A repeatability of 0.74 was obtained and used to compute the gain in accuracy to be expected from repeated measurements. The gain was substantial with two measurements per plant, but the extra time and effort required to obtain more than two measurements would be generally unwarranted. Parent‐offspring regression analysis gave an estimate of 0.55 for the narrow‐sense heritability. The predicted gain in number of g.h. mm−2, obtained by selecting the upper 10% of the parent plants and recombining them, was 1.76 g.h. mm−2. This gain represented 45% of the parental population mean.