bluuebunny/crossref_metadata_2025 huggingface dataset:
European Corn Borer Resistance in Half‐Sib Families from a Sorghum Random‐Mating Population1
Authors: Ross W. M. , Kindler S. D. , Kofoid K. D. , Hookstra G. H. , Guthrie W. D. , Atkins R. E.
Published: July 2010

One hundred half‐sib families from a sorghum [Sorghum bicolor (L.) Moench] random‐mating population were artificially infested with European corn borer [Ostrinia nubilalis (Hubner)] egg masses, and the same families were treated with an insecticide to reduce natural infestation. A two‐replicate split‐plot design with treatments as whole plots and families as subplots was used for 2 years. Agronomic effects of insect damage were assessed, and a quantitative genetic analysis provided information for use in recurrent selection.

Total grain yield (including that from lodged stalks and heads) was reduced 13.0% by infestation and subsequent damage, combine grain yield (excluding lodged stalks and heads) was reduced 18.4 %, and potential yield loss (excluding all unlodged stalks and unfallen heads with borer cavities plus lodged stalks and heads) was 48.7%. Weight of 100 seeds determined from total grain yield samples was reduced 7.9 % by infestation. Borer damage (breakage) traits generally had strong negative correlations with grain yield in the infested families.

Total grain yield, combine grain yield, seed weight, and stalk breakage had heritabilities of 0.60, 0.64, 0.80, and 0.56, respectively, in the infested families. Selection for these traits, in the presence of borers, should initially improve a population for resistance to the European corn borer. Head damage was determined easily by hand breakage but had a heritability of only 0.32 because of a high family ✕ year interaction and a seemingly nonrandom distribution.
Interrelationships among Wheat Genes H3, H6, H9, and H10 for Hessian Fly Resistance1
Authors: Stebbins Nancy B. , Patterson F. L. , Gallun R. L.
Published: July 2010

The resistance of ‘Elva’ wheat, CI 17714, (Triticum turgidum L. durum group) to biotype D of Hessian fly [Mayetiola destructor (Say)] was studied at the tetraploid and hexaploid chromosome levels at 20C. In testcross analysis at the tetraplold level, Elva wheat has two independent dominant genes that confer resistance to biotype D of Hessian fly. A backcross breeding scheme to common wheat (Purdue 5517 sel./2/‘Monon’/Elva) generated three resistant F4 common wheat selections, 812‐24 (named ‘Stella’), 817‐2, and 822‐34 (named ‘Ella’). Prior research showed Stella and sel. 817‐2 have two linked partially dominant genes 36 map units apart (designated H9 and H10). Ella has the H9H9 gene pair. The linked genes were separated using a BC1 test‐cross of Stella. Ella (H9H9) was used in crosses to distinguish lines derived from Stella that have the H9H9 or H10H10 gene pair. Ella was used in a similar manner with 817‐1 selections (817‐1 is a F4 sister line of 817‐2 but 817‐1 was heterozygous for reaction) to identify lines of 817‐1 that have the H9H9 or HIOHIO gene pair. Repulsion phase F3 line analysis revealed that H9 and HIO were independent.

The H6 gene (in ‘Caldwell’) was found linked 2.02 ± 2.01 map units from H9 (in Ella). Thus the gene order on chromosome 5A wheat most likely is H3, H6, H9.
Leaf Water Relations and Gas Exchange in Relation to Forage Production in Four Asiatic Bluestems1
Authors: Coyne P. I. , Bradford J. A. , Dewald C. L.
Published: July 2010

The Old World bluestems (OWB, Bothriochloa spp.) comprise broad germplasm reservoir showing extreme variability in phenology, morphology, seed production, cold hardiness, and water‐use efficiency (WUE). Previous research has demonstrated their potential for use in forage‐based beef production systems of the Southern Great Plains. Four accessions representing a range in water stress tolerance as measured by forage production were grown under optimum soil water conditions in the glasshouse for purposes of comparing their gas exchange characteristics and leaf water relations. At a leaf temperature of 25 C, leaf CO2 exchange rate (CER) ranged from 40 to 56 mg dm−2hour−1 (highest/WW‐477, WW‐765, WW‐ 573, WW‐604/lowest). However, the ratio of stomatal CO2 resistance (r′1) to total CO2 resistance (r′1), an index of WUE based solely on plant parameters, ranked the accessions: WW‐573, WW‐765, WW‐477, WW‐604. The higher r′2r′1 of WW‐573 indicates that it was realizing a greater proportion of its potential maximum CER (the CER which would occur if limited only by r′2) than the other accessions and therefore had better coupling between CO2 uptake and stomatal opening. At 35 C (near optimum for CER) mean values of CER and r′2r′1 increased 41 and 33%, respectively, while r′2 decreased only 10%. Stomatal control over CER increased relatively more in the less water‐use efficient accessions so that there were no differences in r′2r′1 at 35 C. While differences in osmotic potential among accessions were minimal, the relatlve water content at which turgor potential = 0 (RWC0) ranged from 0.84 (WW‐477) to 0.78 (WW‐573). Differences in field drought performance and measurable variation in CER, WUE, and turgot maintenance among these OWB's for selected conditions encourages the pursuit of screening techniques based on these physiological parameters.
Oil and Protein in Field Crops Treated with Morphactins and other Growth Regulators for Senescence Delay1
Authors: Dybing C. Dean , Lay Charles
Published: July 2010

Studies were conducted to determine whether growth regulators which delay senescence also affect oll and protein in flax (Linum usitatissimum L.), soybean [Glycine max (L.) Merr.], wheat [Triticum aestivum (L.) em. Thell.], and oats (Avena sativa L.). Treatment with a morphactin, chlorflurenol (methyl 2‐chloro‐9‐hydroxytiuorene‐9‐carboxylate), significantly increased percent oil in all four crops. Levels of increase were 0.1 to 0.3 percentage units for the cereals, 0.3 to 1.6 units for soybean, and 0.8 to 4.8 units for flax. Dichlorflurenol (methyl 2,7‐dichloro‐9‐hydroxyfluorene‐9‐carboxylate) also increased percent oil but to a lesser degree than chlorflurenol. Optimum treatments were 25 g/ha (chlorflurenol) and 100 g/ha (dichlorflurenol) applied postbloom for flax or at R6 stage for soybean, and 1000 g/ha (either chemical) applied 4 to 5 days postanthesis for the cereals. The increase in percent oil was consistent over several years of testing for flax and soybean. Percent protein declined as percent oil increased in flax and soybean but not in the cereals. Yield of oil per hectare was more closely associated with seed yield than with percent oil for all crops. As a result, oil yield of flax was significantly increased by chlorflurenol treatment in two of seven trials and significantly decreased in one trial.

Seed size of flax declined as percent oil increased, except when treatment was late in the life cycle, when rate was reduced, or when dichlorflurenol was used instead of chlorflurenol. No relations between seed size and change in oil percent were observed for the other crops. Treatments which raised percent oil also delayed canopy yellowing for flax and soybean but not for the cereals. Iodine value of flax usually was not affected by morphactin treatment. Further research is needed to determine causes of the changes in chemical composition and to adapt the technique to commercial practice.
Genetic Control of Modified Endosperm Texture in Opaque‐2 Maize1
Authors: Wessel‐Beaver L. , Lambert R. J.
Published: July 2010

High lysine (opaque‐2) maize (Zea mays L.) has not gained wide acceptance because of problems associated with this seed character. One solution may be to use modifier genes that change the endosperm phenotype of the opaque‐2 (o2) homozygotes to a more normal endosperm appearance. Modifier loci change the soft chalky appearance of the endosperm to varying degrees of hard vitreous texture. The inheritance of modifier genes for endosperm texture in o2 maize was studied in crosses of seven modified endosperm texture and five nonmodified endosperm texture o2 lines. The inheritance of o2 modifier genes for endosperm texture was complex. Both dominant and recessive gene action for o2 endosperm modification were found in genotypes tested. Cytoplasms did not appear to be important in endosperm modification as differences between reciprocal crosses in the F2 generation were found for four of 12 reciprocal crosses. This indicates a small contribution of the cytoplasm to o2 endosperm modification. Significant xenia effects were observed for percent endosperm modification, kernel volume, 100‐kernel weight, and kernel density when open‐pollinated and self‐pollinated S1 families were compared. The differences observed for percent endosperm modification necessitate controlled pollinations in a breeding program designed to improve endosperm modification in o2 maize.
Sequential Experiments and Isoprobs: A Method for Determination of Optimal Nutrient Levels1
Authors: Geng S. , DaVia D. J. , Williams W. A.
Published: July 2010

Effects of calcium and phosphate on the yield of Geraldton subclover (Trifolium subterraneum L.) were studied. Optimum combinations of the nutrients were determined from isoprobs derived from a response surface function. The maximum yield can be attained at 2,318 ppm and 206 ppm of Ca and P, respectively. In searching for optimum combinations, standard errors and variance inflation factors were suggested to be useful criteria for designing follow‐up experiments if the initial experiment fails to produce all needed information. Isoprobs were useful visual diagnostic tools for determining the reliability of the prediction.
Root‐Pulling Resistance and its Relationship to Grain Yield in F1 Hybrids of Maize1
Authors: Peters D. W. , Shank D. B. , Nyquist W. E.
Published: July 2010

In 1977 and 1978, all possible single‐cross hybrids between 12 maize (Zea mays L.) inbreds were evaluated for root‐pulling resistance and yield at plant densities of 38,500 and 55,300 plants per ha. Griffing's diallel analysis was used to determine the nature of genetic effects responsible for production of a large root system as estimated by root‐pulling resistance. Both additive and nonadditive genetic effects contributed significantly (P < 0.01) to the expression of root‐pulling resistance. General combining ability effects interacted significantly (P < 0.01) with environmental changes caused by plant densities and by years, in particular. These interactions may reduce effectiveness of selection for root size based on root‐pulling resistance. The correlation of root‐pulling resistance to grain yield was not significant in either year at either plant density, suggesting that selection for increased root size to gain increased corn rootworm tolerance would not result in decreased grain yield.
Effects of Generation and Method of Synthesis on Performance of Orchardgrass Cultivars1
Authors: McClain E. F.
Published: July 2010

Commercial Syn‐1 seed produced by pollination among S1 or S1F1 (first‐generation increase of an S1 family in isolation) families of the parental clones of a conventional synthetic to produce generations designated here as 1‐Syn‐1 and 2‐Syn‐1, respectively, might more fully utilize heterosis. Effects of increased inbreeding in the parental populations, however, theoretically are not completely eliminated in the autotetraploid F1. Applicability of these considerations to orchardgrass (Dactylis glomerata L.) for forage yield, panicle production, and rust (Puccinia spp.) reaction was assessed by comparing Syn‐1, Syn‐2, Syn‐3, 1‐Syn‐1, and 2‐Syn‐1 generations of 29 experimental synthetics (clonal combinations) in three tests. Tests I, II, and III contained primarily two, four, and two parents per clonal combination, respectively.

Generation means expressed as percent of the Syn‐1 and based on 2‐year forage yields were 91.3 (Syn‐2), 87.3 (Syn‐3), and 88.2 (1‐Syn‐1) in Test I and 100.2 (1‐Syn‐1) in Test II. Mean yields of the 1‐Syn‐1 and 2‐Syn‐1 as percent of the Syn‐3 were 113.3 and 107.1, respectively, in Test III. No consistent change occurred in panicle production or rust scores. Significant interactions for clonal combinations with generations occurred in Tests I and III for yield and rust and in Tests I and II for panicle production. Correlation coefficients between generations generally were significant only for panicle production and rust score. Although yield depression generally increased as inbreeding increased, selection of clonal combinations with attenuated inbreeding depression appears possible. However, selection of such combinations would tend to exclude the more productive Syn‐1's
Effects of Plant Density on the Performance of 10 Barley Cultivars
Authors: Baker R.J. , Briggs K.G.
Published: July 2010

The effects of plant density on yield and related traits were studied in ten cultivars of spring barley, Hordeum vulgare L., to determine if selection in low density stands is effective in improving expression in dense stands. Five plant densities (1.6, 6.2, 25, 100, and 400 plants/m2) were evaluated in each of 3 years.

Spikes/plant, shoot weight and grain yield were the only characteristics that had significant cultivar × density interactions. All three characteristics increased asymptotically as density decreased and did not show significant changes in cultivar rank.

Interplant variability, although minimum at a density of 100 plants/m2 for spikes/plant, shoot weight and grain yield, showed a significant decrease at a density of 6.2 plants/m2 (40 × 40 cm) for all traits. Our results show that single plant selection may be most effective at plant spacings near 40 × 40 cm and that selection under low densities should be effective in improving dense seeding expression of yield and several related traits.
Late Senescence Oil Losses in Soybeans1
Authors: Sale P.W.G. , Campbell L.C.
Published: July 2010

The objectives of this study were to determine 1. whether oil was lost during late senescence from the whole of the seed fraction of the soybean cultivars ‘Lee’ and ‘Bragg’ and 2. whether late senescence oil losses occurred in six commercial cultivars at different sites spanning almost 5° of latitude. In the first year, plants of Lee were grown in pots beneath a rainshelter at Camden, New South Wales. Significant reductions (p < 0.05) in oil percentage, oil content per seed (averaged over the whole seed fracton) and oil yield per plant occurred during the final stages of podfilling (50 to 60 days after flowering). In the following year, the average oil content of Bragg seed, grown in the field at Camden, was measured regularly during crop senescence. Oil content per seed declined significantly (p < 0.05) as the majority of the pods changed color from yellow to brown, which corresponded to a fruit maturity index change from 4 to 5. In another experiment, where pods were removed at mid senescence (R7) and at plant maturity (R8) from a range of cultivars (Maturity Groups V to VII) grown at five sites in NSW. Oil losses occurred at four of the five sites in New South Wales and in all cultivars except the partially indeterminate, earliest maturing Ruse. Oil losses were not correlated with late senescence increases in seed protein content from different cultivars. The economic consequences of these late senescence oil losses can be quite significant. The cv. Forrest lost more than one‐eighth of the total oil produced by the crop, without any concomitant increase in protein or seed yield.
Breeding for Rust Resistance in Orchardgrass by Phenotypic and Phenotypic‐Genotypic Selection1
Authors: Miller Terry L. , Carlson Irving T.
Published: July 2010

Effectiveness of alternative selection methods is an important consideration in any plant breeding program. The purpose of this research was to evaluate recurrent phenotypic selection and selection based on both phenotypic performance and a polycross progeny test (phenotypic‐genotypic method) for resistance to rust (Puccinia graminis Pers.) in ‘Sterling’ orchardgrass (Dactylis glomerata L.). Rust resistance was improved by each of three cycles of phenotypic selection. One cycle of phenotypic‐genotypic selection (Cl‐PG) achieved the same level of rust resistance and required the same length of time as did two cycles of phenotypic selection (C2‐P). The mean rust rating of C1‐PG and C2‐P did not change with advancement from the first to the second generation; however, plant to plant phenotypic variation increased. Smaller phenotypic variances in both generations of C1‐PG and C2‐P than in Sterling suggested a decrease in genetic variance with selection; however, significant genetic variation was found in all derived populations. High parent clone‐topcross progeny correlations indicated that progeny testing for rust resistance is unnecessary. The recurrent phenotypic selection method would favor maintenance of greater genetic diversity for resistance than the phenotypic‐genotypic method because more plants could be selected in each cycle.
Comparative Growth Analysis of Two Spring Wheats and One Spring Barley1
Authors: Baker R. J. , Gebeyehou Getinet
Published: July 2010

Two cultivars of spring wheat, Triticum aestivum L., cvs. ‘Neepawa’ and ‘Pitic 62’, and one cultivar of spring barley, Hordeum vulgare L., cv. ‘Bonanza’, were compared for grain yield and its relationship to patterns of leaf area development and dry matter accumulation. Each cultivar was planted at an early and a late seeding date at Saskatoon in 1980 and in 1981. Leaf area (cm2/plant) and biological yield (g/m2) were determined at weekly intervals commencing five weeks after seeding. Grain yield, components of grain yield, and final biological yield were measured at maturity. Grain yield was found to be a curvilinear function of final biological yield in Pitic 62 and Bonanza but the relationship appeared to be linear for Neepawa. Within a cultivar, higher biological yield gave higher grain yield.

Bonanza barley produced more dry matter and greater leaf area than either wheat cultivar early in the season. This advantage disappeared as the crop approached maturity. Pitic 62, although having greater maximum leaf area index and greater leaf area duration than Neepawa, tended to have a similar pattern of dry matter accumulation early in the season. Pitic 62 had greater final biological yield and grain yield by virtue of its later maturity. Yield of wheat might be increased without delaying maturity by searching for types which grow quickly under cool spring conditions.
Heritability of Sugarcane Smut Resistance and Correlation Between Smut Grade and Yield Components1
Authors: Wu K. K. , Heinz D. J. , Meyer H. K.
Published: July 2010

This study was conducted to estimate the heritability of sugarcane (Saccharum sp.) smut (Ustilago scitaminea Syd.) resistance and to evaluate the association between smut grades and sugarcane agronomic traits. The progenies of diallel crosses involving four highly smut‐susceptible and four highly smut‐resistant Hawaiian commercial sugarcane clones were used. Heritability in the narrow sense was estimated at 0.56 on the basis of individual smut grades. The heritability of this breeding population might have been overestimated because the eight parents used in this study represented two extreme smut infection groups. Nevertheless, a fairly rapid response to selection for smut resistance can be expected. There were no correlations between smut grade and stalk diameter, stalk number, or plant volume. Correlation coefficients between smut grade and stalk length and refractometer solids were about 0.1. Since all correlations were low, there should be no difficulty in selecting smut‐resistant, highyielding clones.
Meiotic and Reproductive Behavior of Facultative Apomictic BC1 Offspring Derived from Pennisetum americanum‐P. orientale Interspecific Hybrids1
Authors: Dujardin Michel , Hanna Wayne W.
Published: July 2010

This study reports on the chromosome numbers, meiotic behavior, method of reproduction and fertility of BC1 progenies from Penniserum americanum L. Leeke, pearl millet ✕ P. orientale L.C. Rich. interspecific hybrids backcrossed to P. americanum. This information would be useful for future studies on transfer of genes controlling apomixis from the tertiary gene pool to P. americanum. Two facultatively apomictic interspecific hybrids between Pennisetum americanum, (A. chromosomes) and P. orientale (O chromosomes), 2n = 25, were pollinated with P. americanum. Sixteen backcross progenies were obtainewhich were of three cytotypes: 32‐(14 A + 18 O), 23‐ (14 A + 9 O)and 27‐(7 A + 20 O) chromosomes. They resulted from fertilization of unreduced gametes or partially reduced gametes by a 7 A chromosome gamete, or by development or unreduced aposporic embryo sacs, respectively. In 23 chromosome plants, the 14 A chromosomes paired mainly as blvalents or remained as univalents while the 9 O chromosomes appeared as univalents, Intergenomal pairing between P. americanum and P. orientale also were observed and could make segmental exchange possible. In the 27 chromosome progeny, the 20 O chromosomes paired, while the 7 A chromosomes remained as univalents. Meiotic behavior in 32‐chromosome plants was regular with 7 A bivalents plus 9 O bivalents. The backcross progenies were male sterile but partially female fertile and produced a few seeds when pollinated with P. americanum pollen. The 23‐chromosome, BC1 progeny were reconstituted in BC2 progenies of 32‐ chromosome plants ✕ pearl millet. All BC1 progenies had some degree of apomictic embryo sac development and the 23‐chromosome plants showed apomictic development even though the O chromosomes on which the genes controlling apomixis are located were in the simplex condition. Both the 23‐and 32‐chromosome plants showed facultative apomictic development whereas the 27‐chromosome plants showed only obligate apomictic development, Intergenome pairing, chromosome instability, female fertility in 32‐chromosome plants, and the expression of apomixis genes in both the simplex and duplex condition indicates that genes controlling apomixis may be transferred from the tertiary gene pool to pearl millet using various gene transfer and recombination techniques.
Seed Density Classification Influences Germination and Seedling Growth of Cotton1
Authors: Leffler H. R. , Williams R. D.
Published: July 2010

Among cotton (Gossypium hirsutum L.) seeds with densities less than 1.00 g cm−3, germination performance has been shown to be proportional to the seed density. Since cotton seeds produced in the mid‐South usually attain densities higher than 1.00 g cm−3, we evaluated the germination performance of seeds with densities ranging from ≤ 1.00 to 1.10 g cm−3 to determine if the proportionality between seed density and germination performance might extend beyond 1.00 g cm−3. In laboratory, greenhouse, and growth chamber studies, maximum germination and sustained seedling growth were produced by seeds with initial densities of 1.04 and 1.06 g cm−3. The quantity of oll in the seeds was increased with seed density, but both seed weight and seed volume were decreased in the higher density seed classes. The ratio between seed oil and seed protein contents increased through a seed density of 1.06 g cm−3, then decreased slightly. Germination and seedling growth exhibited the same response to density classification as did the oil:proteln ratio. The principal deficiency of the high density cotton seeds appeared to be the low weights of cotyledonary reserves available for mobilization during germination. Selection of cotton seeds on the basis of density should therefore be done so that the small volume, light weight, but high density seeds are eliminated with the low density seeds.
Determination of Protein Percentage of Wheat Vegetation at Two Growth Stages by near Infrared Reflectance1
Authors: LÖffler C. M. , Busch R. H.
Published: July 2010

The potential usefulness of near infrared reflectance analysis to study genetic variability for plant protein percentage in spring wheat (Triticum aestivum L.) was evaluated using a Technicon Near Infrared Analyzer (Infra Alyzer 300). Kjeldahl protein values were used calibrate the instrument for plant samples taken at anthesis and maturity. Reflectance readings, obtained using five filter positions, were fitted to Kjeldahl values using multiple linear regression, and regression constants were obtained. Coefficients of determination (R2) were 0.75 and 0.89 for samples at anthesis and maturity, respectively. Correlation coefficients between Kjeldahl and near infrared reflectance analyses were calculated from four sets of independent samples. The correlation coefficients for samples at anthesis and maturity were 0.88 and 0.93 (p≤0.01), respectively. These relationships indicated that near infrared reflectance analysis had sufficient accuracy to study genotypic variation for total aerial plant protein and changes in protein concentration during ontogeny of spring wheat.
Use of Callus Cultures to Screen Tall Fescue Seed Samples for Acremonium Coenophialum1
Authors: Conger B. V. , McDaniel Judith K.
Published: July 2010

Calli derived from embryos were used to detect the presence of the endophyte Acremonium coenophialum Morgan‐Jones and W. Gams in tall rescue (Festuca arundinacea Schreb.) seed. Mature embryos from several seed samples, including from field established plants previously regenerated from tissue cultures, were plated on a modified Schenk and Hildebrandt medium containing 4.4 mg/liter of 3,6‐ dichloro‐o‐anisic acid. (dicamba). Resulting calli were scored for presence or absence of the fungus after 28 days of culture in the dark at 25 C. None of the more than 2300 embryos of 56 individual plants regenerated from tissue cultures exhibited the fungus. Other fungus‐free seed included two samples of ‘Kenhy’ and three samples of ‘Kentucky 31’ (Ky 31). Infected seed were found in four samples of Ky 31. Seed harvested from plants grown from infected seed were infected while seed harvested from plants grown from fungus‐free seed were not. The slow growth of the endophyte under our culture conditions make its identification highly reliable and hundreds of seeds from several samples may be screened with ease.
A Numerical Index to Assess Early Inflorescence Development in Wheat1
Authors: Klepper B. , Tucker T. W. , Dunbar B. D.
Published: July 2010

Understanding of environmental effects on floral initiation and spikelet differentiation in winter wheat requires a quantitative method of assessing inflorescence development. This note presents a numerical staging scheme for measuring progression of inflorescence development for material which has been preserved in formalin‐acetic acidalcohol. The assessment is based primarily on the production of successive floral appendages; but, since these are difficult to observe in preserved material, additional criteria involving spike shape and size are included. The system works for club and for common wheats, and permits clear delineation of the timing of occurrence of floral initiation and of termination of spikelet differentiation.
Performance of Near‐Isogenic Genotypes of Rice Differing in Growth Duration. II. Carbohydrate Partitioning During Grain Filling1
Authors: Van Dat Tran , Peterson Maurice L.
Published: July 2010

The distribution of non‐structural carbohydrates during grain filling was compared for a near‐isogenic pair of rice (Oryza sativa L.) genotypes that differed by 18 days in their vegetative growth duration. The objective was to determine the effect of the longer vegetative growth period on the production of assimilates that would later be remobillzed and used in grain filling. The percentage of total sugars in all measured vegetative plant parts declined after 17 days of grain filling of EDT, the earlier genotype. Sugar percentages did not decline from heading to full maturity for ‘Calrose 76,’ the later genotype. Starch percentage at the start of grain filling was greater for Calrose 76 than for EDT. At maturity, Calrose 76 had 33.6, 12.5, and 2.3% starch, respectively, in the third internode, second internode and sheath, and first internode and sheath. At maturity, ED7 was essentially devoid of starch in these same plant parts. Calrose 76 also used some of the vegetatively stored starch during grain filling. The apparent contribution of preheading stored nonstructural carbohydrates to grain filling of the two genotypes was about the same for the early sown (11 May) comparison. The same comparison for the later sown (21 May) trial showed ED7 with 15.6% and Calrose 76 only 6% apparent contribution to grain filling. Increased rates of N fertilizer enhanced the apparent contribution to grain filling of both genotypes sown early but not for the later sown trial. Daily rates of starch accumulation in the panicles averaged for the two genotypes began to decline by the 17th day after heading. The daily rates of sugar accumulation were nearly the reciprocal of daily rates of starch accumulation in the panicle. In an environment of full sun and warm days during grain filling, cultivars with longer growth periods probably can support larger panicles than those with shorter growth periods.
Survival of Phoenix Pollen Grains under Cryogenic Conditions1
Authors: Tisserat B. , Ulrich J. M. , Finkle B. J.
Published: July 2010

Date palm (Phoenix dactylifera L.) pollen may retain viability for a single growing season. Pollen self‐life may be extended through low temperature storage but viability progressively declines. As an alternative, Phoenix pollen was subjected to various cryogenic treatments in order to develop a new method to preserve palm pollen for prolonged periods. A simple means to store date palm pollen in liquid nitrogen (LN) is presented. Phoenix pollen grains may be cryogenically stored by immersion of aluminum foil packages into LN. Grains are rapidly thawed by removal from LN and then plunging into germination medium until bubbling subsides. Germination tests conducted on a commercial date palm pollen blend revealed no difference in survival of unfrozen (79.9%)and frozen grains (78.9%). Pollen germinated at 28 C for 24 hours on a modified Brewbaker and Kwack medium containing 15% sucrose. Multistage freezing of Phoenix grains, either dry or in the presence of various concentrations of a cryoprotective mixture consisting of polyethylene glycol, glucose, and dimethylsulfoxide (PGD) in a temperature controlled freezer, was less effective than the direct freezing technique for retaining pollen viability. Only 44.2% pollen germinated following multistage freezing and germination was further reduced by addition of 20%/16%/20%, 10%/8%/10% or 5%/4%/5%, w/v PGD to 17.6, 15.3, and 16.8% germination, respectively. Pollen derived from the Crane cultivar frozen in LN for 7 and 435 days germinated at 58.7 and 59.2%, respectively, compared to the unfrozen control of 56.2%. A commercial pollen blend was found to germinate originally at 68.5%. Pollen stored in LN germinated at 66.4 and 73.5% after 7 and 435 days, respectively. The germination rate was compared for eleven sources of Phoenix pollen before and after exposure to LN. In all cases no significant difference in germination rates were observed.
Oat Anther Culture: Genotype Effects on Callus Initiation and the Production of a Haploid Plant1
Authors: Rines H. W.
Published: July 2010

Calli were initiated from 2,627 of approximately 65,000 anthers of oats (Avena sativa L.) placed on various culture media. One haploid (n = 3x = 21) and two diploid (2n = 6x = 42) plants were recovered from an anther of the cultivar ‘Stout’. These were the first plants known to be producebdy anther culture in oats. Ther elated cultivars Stout and ‘Clintford’ were the source of most of the anthers which formed callus. These lines responded with more than 30% anthers callusing under defined culture conditions, while no other genotypes among over 100 initially tested had more than 6% anthers callusing and most had none. When Clintford was crossed with five nonresponding genotypes, the F1 plants from three of the crosses produced relatively high frequency anther‐callusing responses while F1 plants of the other two crosses gave low responses indicating a complex inheritance of the trait. The highest frequency of callusing anthers was achieved with a Stout ✕ Clintford F2 plant where 12 of 15 cultured anthers responded. Murashige and Skoog basal medium with 10% sucrose and no hormonegs ave the highest anther callus initiation frequencies among media tested, but the only anther to produce plants had been initially plated on a modified potato extract medium containing 2 mg/ liter 2,4‐dichlorophenoxy acetic acid and 0.5 mg/liter kinetin. This anther had also been heat‐shocked at 35 C for 24 hours immediately after plating and prior to standard incubation at 22 C. Cold shocks reduced sucrose levels, and the addition of various growth substances had either no or detrimental effects on callus initiation frequencies and did not promote plant differentiation. Means to regenerate plants from initiated calli on a consistent basis are needed to make oat anther culture a useful technique.
Sugar Metabolism in Developing Kernels of Wheat and Barley1
Authors: Chevalier Peggy , Lingle Sarah E.
Published: July 2010

The tissue distribution of two enzymes of sucrose cleavage, invertase (E.C.3.2.1.26) and sucrose synthase (E.C.2.4.1.13), was studied during the development of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) kernels. Kernels from the center of the ear were sampled every three or four days from anthesis to maturity and dissected into outer pericarp, inner pericarp, and endosperm. Each tissue was assayed for insoluble invertase, sucrose synthase, and starch. The amounts of sucrose, glucose, and fructose leached from the tissues into cold osmoticum in 60 min and remaining in the tissue after leaching were also determined. Insoluble invertase activity was predominantly associated with the outer pericarp tissue in wheat. The tissue location and activity of invertase was less clear in barley. Sucrose synthase activity was associated largely with the endosperm in both wheat and barley. Substantial amounts of sucrose were found in the teachable and non‐leachable fractions of all tissues of both wheat and barley. Very little free glucose or fructose was found in any tissue at any stage of development. Starch was present in the outer pericarp immediately after anthesis, but disappeared as starch accumulation in the endosperm began. Sucrose in the leachable endosperm fraction of wheat increased as the activity of sucrose synthase declined. From the data, we suggest that sucrose is not cleaved as it moves from the phloem to the endosperm in wheat or barley. The duration of sucrose synthase activity in the endosperm may be important in determining the duration of grain filling.
Source‐Sink Ratio Alteration and Its Effect on Physiological Parameters in Maize1
Authors: Barnett K. H. , Pearce R. B.
Published: July 2010

Improving grain yield in maize(Zea mays L.) can be facilitated by determining whether the source (leaf photosynthesis) or the economic sink (grain development)is more limiting. The long‐term effects defoliation and/or ear removal were measured on five maize genotypes (three inbreds and two hybrids) differing in relative source‐sink ratios. Plants were sown in the field on Clarion (fine‐loamy, mixed, mesic Typic Hapludoll) soils during the 1978 and 1979 growing seasons. Leaf carbon dioxide exchange rates (CER), stalk total nonstructural carbohydrates (TNC) and the dry weights of the leaves, sheaths, stalk, and ears were measuread at 10‐day intervals after source and/or sink manipulation (defoliation and/or ear removal).Grain yield, 100‐kernel weight, and the days to physiological maturity also were measured. The relative source‐sink ratio of the genotypes was the most important factor measured in determining how the imposed treatments affected leaf CER. Leaf CER increased after defoliation only in genotypes with large source‐slnk ratios in untreated plants and decreased following ear removal only in genotypes with small source‐sinkr atios in untreated plants. None of the treatments delayed leaf senescence. Defoliation caused a decrease in the weights of stalks, leaves, sheaths, ears, and stalk TNC of most genotypes. Ear removal increased these parameters, with the exception of leaf weight. The cob and grain weights, 100‐kernel weight, and the days to physiological maturity were decreased by defoliation. Both stalk TNC and stalk dry weight were reduced when plants were defoliated indicating increased mobilization of stored assimilates to other plant parts (i.e., the ear). These experiments showed that manipulation of source‐sink ratios affected leaf CER and utilization of stored assimilates according to the source‐sink ratio in untreated plants of that genotype.
Genetic Analysis of Amylose Content, Alkali Spreading Score, and Grain Dimensions in Rice1
Authors: McKenzie K. S. , Rutger J. N.
Published: July 2010

The inheritance and interrelationships in rice (Oryza sativa L.) of amylose content, alkali spreading score, and grain dimensions were studied in six crosses each involving a low amylose medium‐grain parental line. High amylose appeared to be controlled by a single dominant gene in four crosses and by two dominant complementary genes in a fifth cross. Evidence that amylose content was also influenced by modifying genes of minor effect was noted in these crosses. In the sixth cross, between two low amylose lines, control of amylose content was attributed to a few genes of small effect. Segregation patterns for alkali spreading scores in five crosses did not conform to any identifiable genetic model. In one cross alkali spreading score was probably controlled by a single gene. In the other crosses one or a few additive genes of major effect, along with modifier genes, were probably controlling alkali spreading score. Heritability estimates for alkali spreading score were very high. Kernel length and width appeared to be governed by quantitative genes. Transgressive segregation for kernel width was indicated in one cross. Heritability estimates suggested that selection for kernel length and width would be effective. Amylose content and mean alkali spreading score were not strongly correlated in these crosses. However, contingency tables showed a highly significant association between amylose content classes and alkali reaction types in three crosses. The linkage test between amylose class and alkali reaction type was highly significant in cross one, with an estimated recombination value of 0.34. Kernel length and width were negatively correlated in all crosses, with r values ranging from −0.36 to −0.58.
Traditional Combining‐Ability and Gardner‐Eberhart Analyses of a Diallel for Cold Resistance in Winter Wheat1
Authors: Parodi P. C. , Nyquist W. E. , Patterson F. L. , Hodges H. F.
Published: July 2010

Six soft red winter wheat (Triticum aestivum L. era. Thell.) genotypes were crossed in a diallel system to estimate gene action and heterosis as expressed for cold resistance. Following cold hardening in the seedling stage, parental and F1 genotypes were exposed to 2, −7, and −10 C for 4 hours and allowed to recover for 10 days. Both the traditional partitioning of genotypes and that by Gardner and Eberhart were performed. The F1 hybrids exceeded the better parents by 26% for regrowth tissue weight and by 30% for crown weight after freezing, averaged over all temperatures. These two characters were significantly correlated. The major portion of the genetic variability was associated with specific combining ability or specific heterosis effects due to dominance or addltive‐by‐additive gene action.
Effect of Senescene and Nonsenescence on Carbohydrates in Sorghum During Late Kernel Maturity States1
Authors: McBee G. G. , Waskom R. M. , Miller F. R. , Creelman R. A.
Published: July 2010

Nonsenescence and sweet culms are being incorporated into cultivars of grain sorghum [Sorghum blcolor (L.) Moench.] for potential improvement in yield. Clarification of carbohydrate production and accumulation patterns within the culm during grain filling is needed for guidance in breeding. Data on culm carbohydrate levels are also needed to evaluate blomass for possible energy uses. A senescent, hybrid, cultivar designated 37 and three non senescent, hybrid, cultlvars designated PS, 65, and 6R were harvested at three stages of maturity: (i) 15 days post anthesls (PA), (il) black layer (BL), and 15 days post black layer (PBL). Panicles on some plants within each replicate were also removed at BL Glucose, fructose, sucrose, and starch concentrations were determined on the culms. Culm and total plant weight, kernel weight, and grain per panicle were also measured. Culm glucose levels at PA were 90.5, 48.1, 39.5, and 12.6 mg/g oven dry weight (ODW), respectively, for PS, 6R, 65, and 37. Glucose levels declined at each successive harvest except in cultivar 65. A similar pattern was obtained for fructose at PA with values of 78.8, 44.2, 43.7, and 21.1 mg/g ODW for the same cultivar sequence. Levels of sucrose decreased from PA to BL by 66.8 and 21.9 mg/g ODW, respectively, for P5 and 65, and then increased to 124.6 and 173.3 mg/g. Sucrose increased in 6R at each maturity stage and a significant increase to 303 mg/g ODW was obtained in PBL. Slight increases of sucrose occurred in 37 during the successive maturing stages. Starch levels increased at all stages in 6R, but declined from PA to BL in PS, 65, and 37, then increased by PBL. Weight/100 kernels was 2.86, 2.80, 2.17, and 1.91g at PBL, and grain weight/panicle was 66.7, 66.5, 55.3, and 48.2g, respectively for PS, 65, 6R, and 37. These results suggest that sweet culms do not reduce grain weights. Culm sugar accumulation patterns differed among cultivars. Patterns exhibited by P5 and 65 appeared to be desirable for grain production and possibly as biomass for energy use since the culms continued to fill with sugar after BL. The nonsenescing cultlvars contained significantly more carbohydrates at all maturity stages than the senescing one. Plants with panicles removed at BL had accumulated more culm carbohydrates at PBL than reported above in most cases.
Irrigation of Soybean Genotypes During Reproductive Ontogeny II. Yield Component Responses1
Authors: Korte L. L. , Specht J. E. , Williams J. H. , Sorensen R. C.
Published: July 2010

The magnitude of a seed yield increase that occurs when soybeans [Glycine max (L.) Merr.] are irrigated depends upon the phenologic timing of the irrigation in relation to the temporal sequence with which the components of seed yield are established and fixed. Eight soybean cultivars, varying in stem growth habit and maturity, were irrigated according to a factorial treatment design in which either no irrigation or one irrigation was applied at three reproductive stages: R1 to R2 flowering (F), R3 to R4 pod elongation (P), or R5 to R6 enlargement (S). An F irrigation increased the numbers of pods/plant (+ 2.8) and seeds/plant (+ 5.8), but an offsetting decrease occurred 100‐seed weight (−0.9 g), resulting in little change in seed yield. P irrigation had no effect on 100‐seed weight, but increased the numbers of pods/plant (+3.4) and seeds/plant (+7.9) resulting in a large increase in seed yield. An S irrigation resulted in only slight increases in the numbers of pods/plant (+1.0) and seeds/plant (+3.3), but greatly increased 100‐seed weight (+1.4 g), again leading to a large seed yield increase. These observations suggested that irrigation early in reproductive ontogeny greatly reduced flower and pod abortion, whereas irrigation later in ontogeny reduced ovule abortion within developing pods. The cultivar ‘Harcor’ possessed unusually high numbers of oneand two‐seed pods, while ‘Elf’ had substantially fewer numbers of three‐seed pods, and ‘Woodworth’ possessed larger numbers of fourseed pods. Irrigation timing differentially influenced the frequencies of the various pod classes relative to their contribution to the increase in total pods/plant, primarily because of effects on ovule abortion within developing pods. The effects of irrigation timing on number of seeds/plant and 100‐seed weight were thus consistent with the effects on seed yield reported earlier.
Effect of Environmental and Management Factors on the Accumulation of N‐acetyl and N‐formyl Loline Alkaloids in Tall Fescue1
Authors: Kennedy C. W. , Bush L. P.
Published: July 2010

The alkaloid fraction in tall rescue is associated with poor animal performance during summer grazing. In an effort to relate alkaloid response to field situations, the effects of water stress, temperature, N application, and harvest interval on accumulation of N‐acetyl and N‐formyl loline in G1‐307, a Lolium‐Festuca hybrid derivative (2n = 42) experimental strain of tall rescue, were studied in greenhouse and controlled environment chamber experiments. The N‐acetyl loline increased five‐times above control levels by the ninth week of severe water stress. The N‐formyl loline increased two‐times above control levels by the 12th week. Protein loss, decreased dry weight, and low plant water potentials were among possible causes for increased alkaloid concentrations. The N‐acetyl loline increased five‐fold and N‐formyl loline increased three‐fold from initial levels by the 10th week of 21/15 C temperature regime. The high (32/27 C) and low (16/10, 10/7 C) temperature regimes depressed alkaloid accumulation. Accumulation of N‐acetyl and N‐formyl lolines was not positively associated with N application. The largest N application tended to result in the least accumulation of alkaloids. Forage regrowth obtained after harvesting 6 to 8 weeks accumulated forage contained significantly higher concentrations of N‐acetyl and N‐formyl loline.
Environmental Physiology of Sorghum. I. Environmental and Genetic Control of Epicuticular Wax Load1
Authors: Jordan W. R. , Monk R. L. , Miller F. R. , Rosenow D. T. , Clark L. E. , Shouse P. J.
Published: July 2010

The effects of genotype and environment on the epicuticular wax (EW) load on sorghum [Sorghum bicolor (L.) Moench.] leaves were studied in a series of field experiments between 1976 and 1981. Entries in the tests were normal, bloom‐type sorghums and represented a range of lines and hybrids. Leaf samples were collected near anthesis, EW was extracted with chloroform, and quantities of EW were estimated by a colorimetric method. In a 4‐year test at Temple, Tex., significant variability in average EW loads occurred among genotypes (0.97 to 1.63 mg dm−2) and among years (0.91 to 1.51 mg dm−2). EW loads increased under hot, dry conditions, but wax loads were not closely related to seasonal rainfall. General and specific combining abilities were determined in a study of 30 F1 hybrids from crosses between six male and five female parents in five environments. General combining abilities of both males and females were significant (P < 0.001), but specific combining ability effects were not significant. Both the broad and narrow‐sense heritabilities were estimated at 36.0%. Because the parents were not chosen in a random manner, these estimates only pertain to our specific germplasm and cannot be considered general. The portion of the genetic variance contributed by females was 73% while the males contributed 27%. The best parental lines for increasing EW loads in hybrids were RTx430 among the males and ATx623 among the females. RTx7078, RTx7000, and A4R generally decreased the EW load of their hybrids. Genetic stability for EW load across environments also varied. The value of low genetic stability of adaptive responses such as EW loads for crops grown in drought‐prone environments is discussed.
Meiotic behavior of a Male‐Fertile Triploid Arachis L. Hybrid1
Authors: Simpson C. E. , Davis K. S.
Published: July 2010

A triploid hybrid (2n = 30) from a cross between Arachis hypogaea L. (2n = 40) and F1 hybrid (2n = 20) from A. cardenasii Krap. et Greg. nom. nud. and A. chacoensis Krap. et Greg. nom. nud. was male fertile, and produced up to 92% stained, uniform pollen grains. Meiotic analyses of the fertile triploid revealed that meiosis I was irregular, with the univalents lagging at anaphase and all 30 chromosomes were incorporated into one cell after anaphase I. Telophase I was not observed in these cells. Meiosis II resulted in dyad formation instead of tetrads. Normal appearing pollen grains were formed which transmitted 30 chromosomes to progeny produced from artificial cross pollinations with A. hypogaea