bluuebunny/crossref_metadata_2025 huggingface dataset:
Inheritance of Three Groups of Indole Alkaloids in Reed Canarygrass1
Authors: Marum P. , Hovin A. W. , Marten G. C.
Published: July 2010

Certain tryptamine alkaloids and their derivatives appear to cause the severe diarrhea seen in sheep and sometimes in cattle that graze reed canarygrass, Phalaris arundinacea L. This malady is either absent or less prevalent in animals that graze trytamine‐carboline‐free, gramine‐containing clones. Our objectives were to study the mode of inheritance and genetic relationships among indole alkaloid phenotypes in this species.

We characterized three groups based on chemical structure and occurrence in breeding materials of seven of the nine known indole alkaloids. Group G consisted of gramine; group T included N‐methyltryptamine (NMT), N,N‐dimethyltryptamine (DMT), and 2‐methyl‐l,2,3,4‐tetrahydro‐β‐ carboline (MTHC); and group MeO included 5‐methoxy‐N‐methyltryptamine (5‐MeO‐NMT), 5‐methoxy‐ N,N‐dimethyltryptamine (5‐MeO‐DMT) and 2‐methyl‐ 6‐methoxy‐l,2,3,4‐tetrahydro β‐carboline (6‐MeO.THC).

A genetic model was proposed on the basis of data obtained from progeny analysis following self‐pollination and hybridization within and between alkaloid groups. The model was tested by analyzing F1 and F2 families from separate crosses between groups G and T, within group G, and testcrosses to group G of selected F1 plants. The results verified a two‐gene model in which a single dominant allele T at one locus controls synthesis of alkaloids for phenotypes in group T and a single dominant allele M at a second locus controls synthesis of alkaloids for phenotypes in group MeO. Phenotypes in group G are produced only when both recessive alleles m and t are homozygous.

The M allele is epistatic to T and the two loci appear to be closely linked. Unidentified modifying factors appear to affect this interpretation in certain genetic backgrounds, and require further studies to ascertain their mode of inheritance. Alleles M and T had frequencies of 0.21 and 0.01, respectively, in the diverse reed canarygrass source, NCRCI.

The fact that gramine is synthesized only in the presence of the double recessive will enable plant breeders to select directly for this type without progeny testing to verify the genotype.
Drought Resistance and Dryland Adaption in Winter Wheat1
Authors: Keim D. L. , Kronstad W. E.
Published: July 2010

Nine winter wheat cultivars (Triticum aestivum L.) were evaluated for drought resistance and adaptation to a wide range of moisture‐limited environments (23 year‐location combinations). Drought resistance is described in terms of relative grain yield under severe soil moisture stress. Regression of the cultivar mean yield on the year‐location site mean yield was used to measure the environmental response of a particular cultivar. Low deviation mean square estimates indicated that cultivar response was highly predictable when based on site mean yield. The ideal cultivar, described as having both the high yield under the most severe moisture stress and a strong yield response (b ≥ 1.0) to more favorable environments, was not found. ‘Nugaines’ gave the largest b value, primarily due to its poor performance under severe stress; it could neither be considered drought resistant nor widely adapted. ‘Hyslop’ and McDermid' were the most widely adapted having better than average yields under the severe moisture stress and high yields under more favorable environments. The club wheats, ‘Paha’ and ‘Omar’, were not drought resistant; they yielded poorly under stress conditions. Paha responded well (large b) to better moisture conditions. ‘Yamhill’ and ‘Wanser’ were classified as drought resistant because of their high yields under severe stress. However, their small b values were not indicative of wide adaptation. The dissimilarity of morphological characteristics of ‘Yamhill’ and ‘Wanser’ suggest that different morpho‐physiological traits may condition their drought resistance. The degree of association of drought resistance and wide adaptation have implications in breeding to combine both traits in a single cultivar.
Stability of Sorghum Midge Resistance1
Authors: Faris M. A. , de A. Lira M. , de S. Leao Veiga A. F.
Published: July 2010

Eight sorghum (Sorghum bicolor (L.) Moench) entries which are claimed to be resistant to sorghum midge (Contarinia sorghicola Coq.), were studied at different levels of midge populations on 16 planting dates. The midge population was maintained all year on sorghum and wild sorghum (verticilliflorum) (Stendel) stapf.) at Serra Talhada Research Station, Pernumbuco, Brazil. Adult emergence data were analyzed using the stability technique that will be described in Materials and Methods. Stability was described by the average number of insects from a random sample of exposed heads and by the regression of the average number of adults on an environmental index (in this case environments being different seasons). A stable line should have: a low average adult emergence; a regression coefficient equal to or near zero; the deviations from regression as small as possible. Sorghum line ‘AF‐28’ was shown to be most stable source of resistance tested. Two selections (IS 2757C and IS 2508C) from the Cooperative Texas Sorghum conversion program showed moderate stability. Other sources of midge resistance were less stable over planting dates. The linear regression technique adequately describes the stability of entries over a range of midge populations and environments. This technique facilitates the breeder in his search for adequate sources of resistance to different pests.
Plant Water Stress Effects on Irrigated Grain Sorghum. I. Effects on Yield1
Authors: Eck H. V. , Musick J. T.
Published: July 2010

A field study was conducted to evaluate effects of plant water stress at different stages of growth on grain and forage yields and yield components of grain sorghum [Sorghum bicolor (L.) Moench]. Irrigated grain sorghum was subjected to various periods of plant water stress beginning at (i) early boot, (ii) heading, and (iii) early grain filling. Unstressed sorghum yielded 7,410 kg grain/ ha. Stress periods of 13 to 15 days [average afternoon leaf water potentials (LWP) −15.8 to −20.3 bars] did not reduce grain yields but, 27− to 28‐day stress periods (average afternoon LWP, −21.7 bars) beginning at early boot or heading stages reduced yields 27%. However, a 27‐day stress period (average afternoon LWP, −22.7 bars) beginning at early grain filling reduced yields only 12%. Thirty.five and 42‐day stress periods (average afternoon LWP, −22.9 and −24.0 bars), beginning at boot stage reduced yields 43 and 54%, respectively. Yield reductions from stress initiated at early boot stage resulted from both reduced seed size and seed numbers. When stress was imposed at heading or later, only seed size was reduced. Forage yields were not affected by 27‐ to 28‐day stress periods but were reduced by stress periods imposed at early boot stage and extended for 35 or 42 days.
Plant Water Stress Effects on Irrigated Grain Sorghum. II. Effects on Nutrients in Plant Tissues1
Authors: Eck H. V. , Musick J. T.
Published: July 2010

A field study was conducted to determine nutrient concentration and dry matter and nutrient accumulation patterns in grain sorghum [Sorghum bicolor (L.) Moench] plants and to determine the effects of plant water stress on these parameters. Grain sorghum hybrid ‘Pioneer 8311’ was grown under five irrigation treatments to givestress periods varying in timing and duration.

Samples were collected at weekly intervals from plants grown with and without stress from (i) early boot until early grain filling, (ii) heading until late grain filling, (iii) early grain filling until near physiological maturiy, and (iv) from early boot until mid‐grain filling. Plants were partitioned into component parts for dry matter estimation and analysis for N, P, K, Ca, Mg, and NO3. Plant water stress reduced N and P concentrations in leaves and increased N concentration in stalks and heads, but did not affect NO3−N, K, Ca, and Mg concentrations.

In unstressed plants, dry matter accumulation proceeded at a near constant rate from about 40 days after planting until physiological maturity. Nutrient accumulation rates tended to be near‐constant from 40 days after planting until flowering and then slowed somewhat. At flowering, plants had accumulated 59, 77, 72, 90, 88, and 65% of their total dry matter N, P, K, Ca, and Mg, respectively. Plant water stress reduced dry matter and nutrient accumulation. Nitrogen and P were affected more than K, Ca, and Mg.
Elongation Force of Seedlings of Leguminous Crops1
Authors: Inouye J. , Tanakamaru S. , Hibi K.
Published: July 2010

Using an unbonded strain gauge transducer and a null balancing recorder, the vertical elongation or lifting forces of 3‐ and 5‐cm tall seedlings of 12 leguminous species grown in darkness at about 23 C were measured. The elongation force (El) gradually increased after initially setting the cotyledons of hypogeous seedlings or plumular hooks of epigeous seedlings against the receptor of the transducer. The maximum force was reached 20 to 50 hours after the initial setting, with a gradual decrease thereafter.

The maximum Ef differed significantly among species and among cultivars within species. The mean value for the maximum Ef of a species was positively correlated with seed weight (0.787** in 3 cm, and 0.816** in 5 cm tall seedlings). Furthermore, in seedlings 3 cm tall, highly positive relationships were found between stem area at the center portion‐of the seedling and seed weight (0.787**) or the mean value for the maximum Ef of a species (0.971**). The results indicate that the large seeded species produce large stems and therefore a large Ef.

The maximum Ef per unit mass of seed was smaller in species which produced an epicotyl such as broad bean (Vicia faba L.), pea (Pisum sativum L.), and azuki bean (Phaseolus radiatus L. vat. aurea Prain.) compared to species which produced a hypocotyl such as peanut (Arachis hypogaea L.) and soybean (Glycine max (L.) Merrill). Among species which produce a hypocotyl, the elongation force was less in soybean and sword bean (Canavalia gradiata DC.) than in other species tested.
Convergent‐Divergent Selection for Area Improvement in Maize1
Authors: Lonnquist J. H. , Compton W. A. , Geadelmann J. L. , Loeffel F. A. , Shank Boyd , Troyer A. F.
Published: July 2010

The development of basic breeding populations that are adapted to a wide area and have at least some resistance to crop hazards in a region is important to breeders. A program designed to develop such a population of maize (Zea mays L.) for the northern Cornbelt is described. Six breeders in the area contributed germplasm samples (convergence) which were intercrossed. Samples of the resulting population were sent to each collaborator (divergence) who practiced mass selection for healthy, productive plants. In subsequent years, harvested samples (balanced composites) sent to Wisconsin (the convergent phase) were subdivided and redistributed (divergence) in such a way that seed for each location did not include seed harvested from that location the previous year.

Results from the first four cycles of selection were evaluated in performance trials at all locations over a 2‐year period. Significant increases in productivity (gram yield) and reduction in grain moisture at harvest were obtained. Evidence of increased stability was noted over the four cycles of selection.
Implications of Genotype ✕ Planting Date and Row Spacing Interactions in Double‐cropped Soybean Cultivar Development1
Authors: Carter T. E. , Boerma H. R.
Published: July 2010

Soybeans (Glycine max (L.) Merr.) are grown in the southeastern U.S. as both a full‐season crop and a double crop. The cultivars currently grown in the doublecropped environment were developed and released based on performance in full‐season environments. To determine the need of a breeding program for double‐cropped cultivars, 10 genotypes were evaluated at two row spacings (48 and 96 cm) in an early (21 May and 3 June) and late (28 June and 30 June) planting date in 1975 and 1976.

The genotype ✕ planting date interaction was significant for seed yield, lodging, flowering date, and height at flowering and maturity over years. For seed yield, this interaction resulted hi changes in rankings of genotypes and differences in the results of the L.S.D. means test. The genotype ✕ row spacing interaction was significant for seed yield, seed size, and number of pods/ms over years. The interaction for seed yield was large enough to cause changes in rankings of genotypes and differences in the results of L.S.D. means test. The genotype ✕ planting date ✕ row spacings interaction was significant for seed yield. Comparison of the yield of the 10 genotypes in the early‐wide and late‐narrow environments, the common planting date‐row spacing combination for full season and double‐cropped soybeans, respectively, indicated that the two highest yielding genotypes hi the early‐wide environment ranked ninth and 10th in the late‐narrow environment. The correlation for yield or rank order based on yield of the genotypes between the two environments were negative, but nonsignificant.

The relationships between yield and various plant traits were different in the various planting date‐row spacing environments. A later flowering date, more seeds/pod, longer internodes, and shorter reproductive period were associated with increased yield in the late‐narrow but not the early‐wide environments. Since double‐cropped soybeans are usually planted in late June in narrow rows, the magnitude of the interactions among genotypes, planting date, and row spacing for yield and the different relationships between plant traits and yield in the fullseason and double‐cropped environments would indicate that development and testing of double‐cropped cultivars should be practiced in a late‐planted, narrow‐row environment for maximum progress.
Genetic Variability Among Glandless Cottons for Resistance to Two Insects1
Authors: Meredith W. R. , Hanny B. W. , Bailey J. C.
Published: July 2010

The objective of this study was to determine if genetic resistance to tarnished plant bug (Lygus lineolaris Palisot de Beauvois) and tobacco budworm (Heliothis virescens F.) could be detected among glandless strains of cotton (Gossypium hirsutum L.). We grew 97 glandless strains in the field in two environments. In the first environment, tarnished plant bugs were controlled by five weekly sprayings of an insecticide. In the other environment, tarnished plant bugs were attracted and increased by growing mustard (Brassica juncea (L.) Czern. & Coss), nearby rows. A significant strain ✕ environment interaction for lint yield indicated that there was genetic variability among the glandless strains for resistance to tarnished plant bug. Inspection of the least sensitive strains indicated that many possessed some combination of nectarilessness, hirsuteness, or rapid fruiting ability. These traits and characteristics had been previously found to result in less susceptibility to tarnished plant bugs.

First instar tobacco budworm larvae were established on young plants of 99 glandless strains when the third true leaf was expanding. Significant variability was detected for 7‐day average larval weight. Inspection of the 14 strains supporting these smallest larva revealed no readily observable morphological trait that might confer resistance. A second test with the 14 selected strains indicated that the ability of the larvae to develop on these strains was generally lower than on glandless ‘Stoneville 7A’. While four strains did not differ significantly from glanded Stoneville 7A, none of the resistant glandless strains equalled glanded Stoneville 7A in suppressing larval weight. Most of the resistant glandless strains came from one cross of the Louisiana breeding program at Bossier City.

These results indicate that significant useful variability for decreased susceptibility to both tarnished plant bug and tobacco budworm is present in glandless cottons.
A Second Gene for Resistance to Peanut Mottle Virus in Soybeans1
Authors: Shipe E. R. , Buss G. R. , Tolin S. A.
Published: July 2010

Peanut mottle virus (PMV) occurs naturally in peanuts (Arachis hypogaea L.), soybeans [Glycine max (L.) Merrill], and a few leguminous weed species. This disease is widespread on soybeans in areas of the southeastern U. S. where both peanuts and soybeans are grown. In an effort to identify additional genes for resistance to PMV in soybeans, the allelic relationships between genes for resistance from various germplasm sources were studied. Crosses were made between resistant and susceptible lines and among resistant lines. The F1, F2, and F3, generation seedlings derived from selected crosses were tested in the greenhouse for reaction to a PMV isolate (PMV‐S/V74S). It was shown that resistance in the cultivar ‘Peking’ is conditioned by a single recessive gene, designated rpv2, that has not been previously reported.
Handling Cross‐pollinated Germplasm Efficiently1
Authors: Burton Glenn W.
Published: July 2010

Germplasm is one of man's most valuable natural resources. It has been and will continue to be the source of genes to modify and protect his crops. It must be collected and preserved. It must also be used now and in the future. Supplying specific genes (many of them recessives) to protect or modify man's crops has been the principle use made of germplasm collections in the past. Today they are improving populations as well as supplying useful specific genes. Germplasm samples reaching plant breeders must be increased before they can be evaluated, used, and preserved. Vegetative increase and maintenance may be the most efficient method of handling germplasm of some perennials such as bermudagrass (Cynodon spp.). Producing both selfed and intercrossed seed in the increase will insure seed production should an introduction prove to be partially self‐incompitable and will facilitate its evaluation. Selfed seed is the most efficient source of specific genes and appears to be the most efficient storage form for future use. Drying selfed seeds to 5 to 7% moisture content, sealing them in glass containers with labels on the inside, and storing them at −20 C appears to be the most efficient method of preserving germplasm in a readily usable form. Mixing S1 seed from a number of introductions into logical groups may facilitate the distribution and use of cross‐pollinated germplasm.
Heterosis in Maize as Measured by K Uptake Properties of Seedling Roots: Pedigree Analyses of Inbreds with High or Low Augmentation Potential1
Authors: Frick Hugh , Bauman Loyal F.
Published: July 2010

The ability of the primary root of maize (Zea mays L.) seedlings to increase its rate of K+(86Rb) uptake when submerged and aerated, its augmentation potential, is heritable and selectable in early backcross generations. A pedigree analysis was performed using 10 inbreds with either a high or low augmentation potential. The basal K+ uptake rate was strongly conserved in S1 progeny of crosses between inbreds with high or low augmentation potential, whereas the augmentation potentials of the S1 progeny tended to be non‐conserved or open. The augmentation potential of backcross progeny tended in the direction of the parental inbred augmentation potential, whether high or low. There was some indication that augmentation potential was open in hybrids agronomically selected for yield heterosis.
A Non‐Nodulating Peanut1
Authors: Gorbet D. W. , Burton J. C.
Published: July 2010

Nodules that form on the roots of peanut (Arachis hypogaea L.) when infected with Rhizobium are the site of N‐fixation. F3 plants were identified in a breeding nursery at Marianna, Fla., which showed N starvation symptoms toward maturity and apparently had no nodules on their roots. These plants were derived from a cross between two normal nodulating parents, 487A‐4‐1‐2 ✕ PI 262090. Subsequent evaluations in the F4 to F6 generations confirmed that numerous selections from this cross failed to nodulate in the field at Marianna. Growth chamber inoculation studies with various strains of rhizobia confirmed the field evaluations. Seed of selected plants from field plots classified as non‐nodulated were utilized in these studies. Only five of 400 progeny from non‐nodulating plant selections bore nodules in these tests.
Effects of Mineral Elements on Hydrocyanic Acid Potential in Sorghum Seedlings1
Authors: Clark R. B. , Gorz H. J. , Haskins F. A.
Published: July 2010

Sorghum [Sorghum bicolor (L.) Moench ‘Early Hegari’] seedlings were grown in nutrient solutions with various combinations of chlorides, nitrates, sulfates, and phosphates (dihydrogen) of ammonium, potassium, calcium, and magnesium to determine the effects of the mineral elements on hydrocyanic acid potential (HCN‐p) in leaves.

Growth was maximum or near maximum for the shoots of sorghum seedlings at 1 to 30 meq salt in solution and for the roots at 0.3 to 3 meq. The duration of exposure of seedlings to the treatment solution required for significant changes in HCN‐p was at least 2 days. The effects of various concentrations of individual salts on HCN‐p were: KCl, a slight decrease; K2SO4, KH2PO4, NH4Cl, NH4NO3, (NH4)2SO4, NH4H2PO4, and Ca(H2PO4)2, an increase; and KNO3, CaCl2, Ca(NO3)2, CaSO4, MgCl2, Mg(NO3)2, and MgSO4, no significant effect.

When potassium and ammonium salts of a common anion were added in 3 × 3 factorial experiments, increasing levels of ammonium salts at the 1X potassium level generally increased HCN‐p, but varied effects of higher levels of potassium salts were observed. In factorial experiments, different levels of pairs of potassium salts of the various anion had no significant effect on HCN‐p. In experiments with pairs of ammonium salts, increases in salt concentration generally increased HCN‐p.

It was concluded that large changes in salt concentration affected alterations in HCN‐p were associated with changes in ammonium salt levels.
Cyanogenesis in Indiangrass Seedlings1
Authors: Haskins F. A. , Gorz H. J. , Vogel K. P.
Published: July 2010

In a study of seedlings of 72 entries representing 39 species, 14 genera, and 2 tribes of grasses, only entries of the genus Sorghastrum were found to contain the cyanogenic glucoside, dhurrin [(S)‐p‐hydroxymandelonitrile β‐D‐glucopyranoside], Dhurrin was found in seedlings of each of the 10 entries of indiangrass [Sorghastrum nutans (L.) Nash] and the three entries of S. pellitum.

Seedlings of five indiangrass cultivars were assayed for dhurrin concentration. Levels expressed as HCN potential (HCN‐p) ranged from about 900 ppm for ‘Holt’ to about 1,200 ppm for ‘Llano’ and ‘Oto’.

Further studies with Oto seedlings indicated that first leaves were higher and more uniform in HCN‐p than were other portions of the shoot, but all shoot portions contained dhurrin. Seedling roots also contained dhurrin, but the HCN‐p of roots was appreciably lower than that of shoots.

Spectral evidence indicated that dhurrin was present in extracts of leaves of tillers harvested from field‐grown plants. Dhurrin was not detected in all such tillers, however. Indiangrass tiller extracts contained more interfering substances than seedling extracts, in agreement with previous observations on Sorghum seedlings.
Selection for Cold Germination in Two Corn Populations1
Authors: McConnell R. L. , Gardner C. O.
Published: July 2010

Tolerance of corn (Zea mays L.) to low temperature conditions after planting requires rapid germination, vigorous seedling growth, and resistance to disease and insect pests. A selection scheme designed to improve cold tolerance in breeding material was initiated in two breeding populations, Iowa Stiff Stalk Synthetic (SSCG) and Pioneer Cold Tolerant Synthetic (CTCG). Laboratory and field selection were employed in the procedure. Seedlings developed from the first seeds to germinate at 7.2 C in the laboratory (20% selected) were transplanted to the field, selected for agronomic traits, and self‐pollinated. The selfed progenies were recombined in winter nurseries to initiate the next cycle of selection in the laboratory.

Regression analyses of the four cycles of selection indicated that cold germination under laboratory conditions (7.2 C) improved 8.8 and 9.9% per cycle in CTCG and SSCG, respectively. In the field, however, little improvement was observed in emergence or seedling vigor. The lack of correlation between laboratory and field results for these cold‐tolerant traits was attributed to mild spring weather during the 2 years of evaluation. Selection for germination at cold temperatures did not have any detrimental effects on other agronomic traits measured in the populations.
Imbibitional Chilling Sensitivity Among Soybean Cultivars1
Authors: Bramlage W. J. , Leopold A. C. , Specht J. E.
Published: July 2010

Fifteen soybean (Glycine max (L.) Merr.) cultivars were screened for sensitivity of embryos to imbitional chilling injury. All were susceptible to injury, but sensitivity varied greatly. Some showed no injury at 7 C while others were injured at 17 C. Embryos of earlier maturing cultivars tended to be more susceptible to imbibitional chilling injury than those of later maturing cultivars. This relationship of time of maturation to chilling sensitivity was confirmed using near‐isogenlc lines of ‘Clark’ soybean, a cultivar possessing various genes that advanced or delayed maturity. Earlier maturing lines were more sensitive to chilling than later maturing lines. Leakage of solutes during imbibition, measured as OD280, was negatively correlated with germination when near.isogenic strains were compared, but was not closely correlated when different cultivars were compared.

It is proposed that seed maturation occurring later in the growing season, during periods of relatively low temperature, hardens seeds against chilling injury.
Environmental and Genetic Influences on Alfalfa Nectar1
Authors: Teuber L. R. , Barnes D. K.
Published: July 2010

Alfalfa (Medicago sativa L.) is a major source of nectar for honey production in the USA, but no attempts have been made to improve its nectar production potential. The objectives of this research were to provide basic information on several environmental and genetic factors to establish recommended sampling and selection procedures for a nectar breeding program.

Two high, two intermediate, and two low nectar‐producing clones from each of two unrelated sources (‘Vernal’ and ‘Team’) were used to study the effect of soil moisture, raceme age, and raceme position on nectar volume and percentage solids. Twenty‐eight clones from Vernal were used to compare measurements of nectar volume and percentage solids on plants grown in the field and greenhouse. Inheritance studies of nectar volume were conducted on diallel crosses made among six parents in each of two populations. Design II crosses were made between populations. Pxogenies from all crosses were grown in the greenhouse.

Soil moisture did not significantly affect either nectar volume or percentage solids in the nectar. Raceme age significantly affected nectar volume but not percentage solids in the nectar. Racemes with newly opened terminal florets had less nectar than either intermediate age racemes or older racemes on which some basal florets were beginning to wilt. Raceme position on the stem did not affect either nectar volume or percentage solids in the nectar. The correlation between field and the average of three greenhouse measurements of nectar volume was significant (r = 0.49, 26 dr). Nectar volume plants selected based on two greenhouse sampling dates (May‐October) was 125% of the nectar volume of the population grown in the field. Results of the inheritance study indicated there were no reciprocal differences for nectar volume and that inheritance of nectar volume was predominantly additive. A recommended list of sampling procedures was developed for nectar breeding.
Temperature and Drought Effects on Blast and Other Characteristics in Developing Oats1
Authors: Chinnici Madeline F. , Peterson David M.
Published: July 2010

Increased blast and reduced kernel yield have been observed in oat (Arena sativa L.) when periods of environmental stress occur during the growing season. The objective of this experiment was to determine the differential effects of controlled temperature and drought stress at specific times during panicle development on percent blast (blasted spikelets/total spikelets ✕ 100), total spikdets/panicle, plant height, and several kernel characteristics.

‘Froker,’ a late season cultivar, and ‘Clintland 64’ and ‘Wright,’ midseason cultivars, were grown in pots in a mixture containing equal parts of peat and vermiculite. The pots were irrigated with half‐strength Hoagland's solution, and placed in an environmental room programmed for the natural photoperiod and daily normal temperatures and relative humidity for 23 April to 15 August at Madison, Wis. Plants were subjected to heat, cold, and drought treatments at four times during panicle development: 26, 40, 53 and 63 days after planting, stages 1 to 4 respetively.

Typical environmental stresses that occur during the growing season of oats were found to increase blast and decrease yield and kernels/panicle. Blasting in Froker was increased by temperature and/or drought at all stages, in Wright by drought at stage 1 and temperature at stages 2 and 3, but in Clintland 64 only by drought at stage 4. Total spikelets/panicle were reduced by drought and heat at stages 2 and 3 (mean of all cultivats). These effects resulted in fewer kernels/panicle and reduced yield. The most severe yield reductions occurred as a result of drought at stage 2 and 4, and heat at stage 3. Compensation for increased blasting by formation of heavier kernels did not occur. Drought at stage 4 reduced kernels/fertile spikelet to near 1.0. In general, plant height was reduced by the same treatments causing yield reductions. Kernel protein concentration was mostly unaffected, except for an increase in kernels from plants that were drought stressed at stage 4.

These results emphasize the value of early planting to avoid the potential damage of heat and drought. Cold treatments had the least effect on yield. The data suggest cultivar variability in stress tolerance. Stress‐tolerant cultivars could possibly be developed by selection and breeding, if suitable screening procedures could be established.
Isozyme Patterns in Tobacco Plant Parts and Their Derived Calli1
Authors: Bassiri A. , Carlson P. S.
Published: July 2010

This study was initiated to determine if different tissues of the same plant maintain persistent tissue specific patterns of gene expression during in vitro culture or if in vitro cultures are characterized by identical patterns of gene expression no matter what their tissue of origin. Two‐millimeter sections were excised from the root, lower leaf, upper leaf, pith, sepal, ovary, and anthers of a mature ‘Wisconsin 38’ tobacco (Nicotiana tobacum L.) plant and were grown on a common medium for callus formation. Transfer to fresh medium was made when the calli reached about 8 mm in diameter. One to five such transfers were made depending upon the growth rate of different explants. Extracts from the original explants and each callus transfer were assayed for several isozyme systems using horizontal starch‐gel electrophoresis. Malate dehydrogenase and peroxidase isozymes were found to have good xesointion and to be suitable for the study. The patterns of the isozymes displayed tissue specific differences at the explant level; however, substantial differences between the isozyme patterns of the calii and that of the original explant were displayed. Initially there were differences in isozyme patterns among the calli from different origins and within the different transfers of the same explant callus. However, after the second or third callus transfer, isozyme patterns became more uniform for calli of the same explant.
Effect of Planting Dates and Soybean Cultivars on Pod Damage by Corn Earworm1
Authors: Joshi J. M.
Published: July 2010

Eight soybean [Glycine max (L.) Merr.] cultivars during 1974 and 16 cultivars during 1975 and 1976 were planted on five different planting dates with 14‐day intervals between each planting to determine which soybean cultivars may escape corn earworm (Heliothis zea Boddie) damage. Soybeans planted by or after mid‐June generally were more susceptible to corn earworm than the earlier plantings. Each successive delay in planting resulted in more pod damage.

The cultivar ‘Delmar’ was highly susceptible, whereas ‘Wye’ exhibited minimum pod damage. The corn earworm showed a high level of non‐preference towards Wye. Corn earworm infestations increased with each successive delay in planting. Maximum infestation was observed on soybeans planted in July. Strain ED 73.371 had the highest amount of active infestation, yet pod damage was very low. This indicates some other mechanism of resistance, such as antibiosis. Proper choice of soybean cultivar according to the desired planting date can help in minimizing pod damage from corn earworm.
Occurrence of Pinitol in Foliage of Several Forage Legume Species1
Authors: Smith A. E. , Phillips D. V.
Published: July 2010

Although it has been reported that (D) pinitol (1D‐3‐0‐ methyl‐chiro‐inositol) occurs naturally in leguminous species, there is a lack of information concerning its concentration in foliage of forage legumes. The purpose of this research was to determine the pinitol concentration in the foliage of several forage legume species and the relative concentration of pinitol in leaf, stem and root tissue. Pinitol concentration was determined in foliage of five cultivate of alfalfa (Medicago sativa L.), 11 cultivars of red clover (Trifolium pratense L.), 13 cultivars of white clover (Trifolium repens L.), and 9 cultivars of birdsfoot trefoil (Lotus corniculatus L.) grown in small field plots. Pinitol distribution in leaf, stem, and petiole tissue was determined for three cultivars of arrowleaf clover (Trifolium vesiculosum Savi.) and Ladino white clover grown in the greenhouse There were minor but significant differences in pinitol concentration among cultivars within each species Pinitol concentration was nearly equal to sucrose concentration in red clover and birdsfoot trefoil foliage and nearly half as high in alfalfa and white clover cultivars The range of pinitol concentrations among species was only 6.7 mg/g of dry tissue, being lowest for red clover (20.4 mg/g) and highest for white clover foliage (27.1 mg/g). In general, concentrations of pinitol and sucrose were similar in leaf and stem tissue of greenhouse grown plants. Pinitol concentration was 4 to 8 times higher in the foliage than in root tissue. The data indicate a relatively high concentration of pinitol in the foliage from forage legumes and imply the need for research on pinitol metabolism, physiological function, and influence on forage quality.
Gibberellin Studies with Sugarcane. III. Effects of Rate and Frequency of Gibberellic Acid Applications on Stalk Length and Fresh Weight1
Authors: Moore Paul H. , Ginoza Harold
Published: July 2010

Sugarcane (Saccharum spp. hybrids) stalk length, fresh weight, dry weight, and sucrose content, normally reduced when plants are grown under reduced sunlight (250 Langleys/day) and cool temperatures (mean daily temperature 23 C), can be increased with foliar applications of gibberellic acid (GA3). Maximum increases in lengths and fresh weights of seven Hawaiian commercial cultivars were a function of cultivar treated, the amount of GA3 applied, the number of applications, and the interval between applications.

Lowland cultivars produced the largest gains in response to the largest quantities of GA3; highland cultivars produced smaller gains. The effects of two applications of 1.0 mg GA3 per stalk depended on the interval between applications. Least growth gains occurred when the intervals were 0 and 45 days; greatest growth gains occurred when the interval between applications was 15 days. The effect of a 30‐day interval was nearly equal to the 15‐day interval, but the 30‐day interval did not result in as great a loss of stalks as occurred at the 15‐day interval. Three and four applications of 0.5 mg GA3 per stalk at 15‐day intervals were less effective in increasing stalk length and fresh weight than were three and four applications of 0.5 mg GA3 per stalk at 30‐day intervals. Greatest gains in fresh weight in response to 2.0 mg GA3 per stalk were in response to the greatest number of applications, four, if they were at 30‐day intervals.
Male‐Fertility Restoration in Crosses of R5 with Soft Red Winter Wheats1
Authors: Wickersham Dale S. , Patterson F. L.
Published: July 2010

The inheritance of male‐fertility restoration was studied in crosses of the spring wheat restorer germplasm line R5 with cms ‘Monon’ and cms ‘Redcoat’ soft red winter wheat (Triticum aestivum L.) cultivars with T. timopheevii Zhuk. cytoplasm. Two greenhouse cycles of Fl's, F2's, BC1's, along with the restored parent, and malesterile parents, were grown to provide two sets of data. Genetic hypotheses were postulated as expected ratios of fertile: semi‐sterile: sterile plants and data were tested for goodness of fit by chi‐square analyses. The BC1F2 populations and F3 populations were grown in the field to determine the proportion of families segregating for sterility. Results from the cms Monon/R5 crosses indicated the presence of two partially dominant complimentary restorer factors in the greenhouse and field environments. Complete fertility restoration was expressed only when both dominant factors were present to either the homozygous or heterozygous condition. Results from the cms Redcoat/R5 crosses suggested the presence of three dominant factors in the greenhouse environment, but segregation in the field environment suggested that only two factors were involved.

The complete restoration of fertility of F1 plants in the environments tested suggests that R5 is a valuable source of restorer factors for developing R‐lines for hybrid soft red winter wheats.
Computations for Estimating the Genetic Parameters in Joint‐Scaling Tests1
Authors: Rowe K. E. , Alexander W. L.
Published: July 2010

Weighted least squares has been used to estimate the genetic parameters in Three Parameter Joint Scaling Tests. The principles are presented to generalize the method to any combination of generation means and genetic models including epistasis. The method is adaptable to computers with matrix algebra programming and certain programmable calculators.
Seasonal Variation in the Performance of Soybeans in Hawaii1
Authors: Beard Benjamin H. , Gilbert James C. , Sekioka Terry
Published: July 2010

Our objectives were to determine the variation in yield and other characteristics of soybeans (Glycine max (L.) Merr.) grown in Hawaii. We were especially interested in finding the best adapted cultlvars for planting during the winter months to use as parental germplasm for cultivar improvement.

Soybean cultivars were grown at three locations in Hawaii in each month of the year, except July and December. Higher than average yields were obtained when soybeans were planted in March, April, May, or June, while lower than average yields were obtained if planted in other months.

Significant differences in soybean yields were associated with years, locations, dates of planting, and cultivars. Cultivar ✕ date, and cultivar ✕ location interactions were significant in some analyses, but nonsignificant in others. ‘Davis’ had the highest mean yield at each location.
Interrelationships among Wheat Genes for Resistance to Hessian Fly1
Authors: Stebbins Nancy B. , Patterson F. L. , Gallun R. L.
Published: July 2010

The interrelationships among genes for resistance in six cultlvars and one llne of hexaplold wheat (Triticum aestivum L. aestivum group) of three biotypes of Hessian fly (Mayetiola destructor Say) were analyzed using reactions of F, lines or backcrosses plant progenies at 20 C. Chi‐square goodness‐of‐fit tests were used to test genetic hypotheses. Recombination frequencies and standard errots were determined using the maximum fikelihood method.

Three hexaploid wheats, Purdue 4835A4‐6, ‘Knox 62’, and ‘Lathrop’ have resistances to biotypes A and B of Hessian fly derived from PI 94587 tetraploid durum wheat (T. durum L. durum group). The single dominant gene pair H6‐H6, which also confers resistance in Knox 62 and Purdue 4835A4‐6, governs Lathrop's resistance. Pur

Purdue selection 822‐34 has a single dominant gene pair derived from ‘Elva’ (T. turgidum L. durum group) for resistance to biotype D of Hessian fly. The resistance was found to be inherited independently of the H5H5 gene pair in ‘Abe’. The new gene for resistance was assigned the symbol H9 H9 was linked to H3 (on chromosome 5A) with a recombination frequency of 0.155±0.048. This places H3, H6, and H9 on chromosome 5A but the gene order was not established. The genotypes of ‘Arthur 71’ and Abe were found to be H3H3 H5H5. We established that H5 is independent of the linkage block containing H3, H6, and H9.
Gene Effects on Water Soluble Polysaccharides and Starch of Near‐Isogenic Lines of Sweet Corn1
Authors: Soberalske R. M. , Andrew R. H.
Published: July 2010

Effects of 10 gene combinations in near‐isogenic backgrounds on endosperm water soluble polysaccharides (WSP) and starch in corn (Zea mays L.) are reported. The genes, dull (du), sugary‐2 (su2), and waxy (wx) and one double combination (du wx) were incorporated into seven lines of corn in association with the sugary alleles (Su and su) Additionally, for each line the shrunken‐2 (sh2) gene was incorporated with Su, and the su sh2 genotype (standard sweet corn) included for comparison. For the near‐isogenic lines or series studied here, genotypes su du, su su2, and su du wx had high levels of WSP, low levels of starch, and slow rates of starch increase as compared with standard sweet corn. There were marked differences among the near‐isogenic series within genotypes. For the su genotypes, range was greater among series than among genotypes for WSP, but greater among genotypes for starch. For su genotypes, all except su du had a wide range among series for WSP, while su wx and su Sh2 had the widest range among series for starch. Modifying genes of the seven series had greater differential effects on WSP and starch later as compared to early in kernel development. In view of the range of expression in a limited number of lines for the genes studied here, they should be incorporated into a broad range of germplasm in a search for other modifers which may further enhance their potential for improved sweet corn quality as compared to standard sweet corn.
Hydrocyanic Acid Potential in Several Sorghum Breeding Lines as Affected by Nitrogen Fertilization and Variable Harvests1
Authors: McBee George G. , Miller F. R.
Published: July 2010

Many sorghum (Sorghum bicolor (L.) Moench) breeding lines have not been evaluated for inherent potential hydrocyanic acid (HCN‐p) levels under field conditions. Additionally, levels of HCN‐p remaining in sorghum stover used for animal grazing after grain harvest needs elucidation as well as N effects on lines shown to be inherently low in HCN‐p.

Fifteen entries, including 13 sorghum lines, one sweet sorghum, and one sudangrass (Sorghum sudanense (Piper) Stapf), were evaluated for differences in HCN‐p, influence of N fertilization, and date of harvest. The entry Tx7000 was consistently low in HCN‐p at all harvest dates and only exceeded the “threshold of danger” (200 ppm) at the preboot stage. This level is considered to be an approximate value at which HCN may become toxic to ruminant animals. The highest ranking entry was SC0599‐6, a Rio selection, which exceeded the 200 ppm level at all stages of harvest employed. Even in entries inherently low, added N increased HCN‐p, which supports the theory that caution must be exercised when growing cultivars reportedly low in HCN‐p, especially when N fertilizer is applied.

As expected, HCN‐p tended to decrease with plant maturity. After physiological maturity of the grain, panicles were removed and leaf blades sampled 8 days later. Two of the entries still retained HCN‐p in excess of 200 ppm, indicating a need to exercise caution with some cultivars when allowing cattle to graze stover after grain harvest.
Influence of Water Deficits and Osmotic Adjustment on Leaf Elongation in Rice1
Authors: Cutler J. M. , Shahan K. W. , Steponkus P. L.
Published: July 2010

The influence of water deficits on leaf elongation of several cultivars of upland rice (Oryza sativa L.) was studied. Mild water deficits resulted in marked reductions in leaf elongation rates. Previous conditioning, by exposing plants to one or more moderate water stresses, decreased the sensitivity to subsequent stress allowing elongation to continue to more negative water potential. This reduced sensitivity in conditioned plants was accompanied by an enhanced capacity for tugor maintenance resulting from osmotic adjustment but was not entirely explained by this adjustment. The relation between leaf elongation rate and turgor potential was also altered in conditioned plants, indicating that growthinfluencing characters in addition to tugor maintenance capacity were altered. Control and conditioned plants appeared to have similar turgor thresholds for leaf elongation but, above this threshold, control plants required less turgor for similar rates of elongation. Under slower drying conditions, despite reductions of water potential, bulk leaf turgor was unchanged as a result of osmotic adjustment. However, despite this turgor maintenance, leaf expansion rates were markedly reduced. Although the sensitivity of leaf expansion to water deficits was similar among the varieties studied, this response provides a sensitive basis for scoring for the incidence of stress and provides a means for rapid screening for drought resistance in larger varietal comparisons.
Somatic Embryogenesis from Cell Suspension Cultures of Red Clover1
Authors: Phillips Gregory C. , Collins G. B.
Published: July 2010

In the present study, plants were regenerated from cell suspension cultures of ‘Arlington’ red clover (Trifolium pratense L.). Evidence was obtained which demonstrated that these plants regenerated via somatic embryogenesis. The source and concentration of auxin used in culture media had significant effects on the initiation of somatic embryogenesis. Somatic embryos were formed on up to 40% of the culture plates which contained 0.01 mg/liter 2,4‐dichlorophenoxyacetic acid (2,4‐D) (0.045 µM) and 2.0 rag/liter adenine (14.8 µM) in a basal dium. Shoots and plants were obtained on the same medium or after subculture onto medium containing 0.001 mg/llter 4‐amino.3,5,6‐trichloropicolinic acid (pi. cloram) (0.004 µM), and 0.2 mg/llter 6‐benzyladenine (0.88 µM). Regenerated plants were characterized cyto. logically, morphologically, and reproductively. In vitro regeneration of plants is a prerequisite for the application of selection techniques at the cellular level. Genetic selection at the cellular level in red clover breeding should now be possible with the present identification of a reliable system for cell to plant totipotency.
Predicting Heterosis in Wheat1
Authors: Bailey T. B. , Qualset C. O. , Cox D. F.
Published: July 2010

Quantitative gene action and heterosis effects were estimated using populations derived from matings of four wheat (Triticum aestivum L. aestivum) cultivars. The cultivars included in the study were ‘Ramona 50,’ ‘Pitic 62,’ ‘INIA 66’ and D6301. DiaIlel and triallel crosses among these cultivars, and F2 populations were grown in repficated trials in 2 years at Davis, California. Additive and heterosis effects were the major genetic effects in this study, whereas epistasis was not an important component of genetic variability in either year. Significant mid and high‐parent heterosis values were observed in certain single‐crosses. One of 12 three.way crosses showed significant high‐parent heterosis. Single‐cross means were closely predicted by using estimates of genetic effects obtained from parent, F2, and three‐way F1 means. Thus, heterosis in wheat can be predicted for specific hybrid combinations without field testing the F1 hybrid. The expected sampling variances of mid and hlgh‐parent heterosis values were developed and used to illustrate the number of replicates needed in field experiments to detect heterosis.