bluuebunny/crossref_metadata_2025 huggingface dataset:
Partial Suppression of Boll Weevil Oviposition by a Primitive Cotton1
Authors: McCarty Jack C. , Jenkins J. N. , Parrot W. L.
Published: July 2010

Four photoperiodic, primitive race stocks of cotton, Gossypium hirsutum L., which had previously exhibited resistance to oviposition by the boll weevil, Anthonomus grandis Boheman, were each crossed to ‘Deltapine 16’ and subsequently selected for the dayneutral flowering habit. These progeny were then backcrossed twice to their respective original primitive stocks and selected for day neutrality after each backcross. The resulting progenies were evaluated using a laboratory technique which measures boll weevil oviposition. Weevils oviposited significantly (α = 0.10) less often on a BC2F3 progeny of T‐78 than on the controls, Deltapine 61 and ‘Stoneville 213’. The level of resistance in the day‐neutral T‐78 progeny approached that of the original photoperiodic stock. No differences in amount of oviposition among the controls and the other three BC2F3 progenies (i.e., T‐80, T‐759, and T‐1149) were detected.
Tissue Culture Variability in Wheat: Callus Induction and Plant Regeneration1
Authors: Sears R. G. , Deckard E. L.
Published: July 2010

Thirty‐nine genotypes of winter wheat (Triticum aestivum L.) were examined for potential use in tissue culture studies. Tissue cultures were initiated from immature embryos approximately 12 days old on a modified Murashige and Skoog medium containing 1.0 mg 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. Cultures were maintained on the same medium with 0.5 mg 2,4‐D/liter. Shoots were initiated by reducing the 2,4‐D to 0.1 mg/liter and complete plants were regenerated by transferring to 2,4,‐D‐free medium. Variability was observed among the wheat genotypes tested for callus induction, regenerable callus formation, response to subculture, and plant regeneration potential. Eighteen genotypes were capable of regenerating plants after four subcultures (90 to 125 days). Cultures from five genotypes remained totipotent after 240 days. Tissue cultures derived from ND 7532 and Roughrider remained totipotent for 420 days. Selection ND7532 demonstrated higher percentage of calli induction and regenerable calli formation, faster in vitro growth rates, and higher frequency of totipotent calli than other genotypes. Plant regeneration from tissue cultures derived from immature embryos is predictable and stable when the appropriate genotype is used. Five hundred thirty‐two plants were regenerated from callus tissue in this study and 510 of these produced seed. It appears that the response in tissue culture of cultivated wheat varies with genotype and that lines with good potential can be identified.
Optimal Population Density and Random vs. Selective Elimination of Genotypes Under a Modified Single‐Seed Descent Method with Spring Oats1
Authors: Cisar G. , Howey A. E. , Brown C. M.
Published: July 2010

A modified single‐seed descent (SSD) method of generation advance is used in the Univ. of Illinois spring oat (Avena Saliva L.) breeding program. The method couples high plant density with limited soil fertility and moisture levels to produce a population with a high proportion of single or few seeded plants, along with some barren plants. Questions regarding the technique are twofold: 1) what population density will yield a high proportion of plants with one or very few seeds and a minimum of barren plants, and 2) are the genotypes which are lost due to barrenness randomly or selectively eliminated?

In a series of population densities, ranging from 10 to 150 seeds per 15‐cm clay pot in 10 seed increments, 30 to 40% of the plants grown at densities of 100 to 150 seedlings per pot produced single seeds. Populations of 120 to 150 seedlings per pot allows adaptation of the technique to the SSD principle with a considerable savings in harvest time and greenhouse space.

To determine whether barren plants were randomly or selectively eliminated, progenies of two segregating crosses were grown at high (60 seedlings per pot) and low (10 seedlings per pot) population densities. After two generations of modified SSD, 34.5% of the original population was lost due to barrenness at the high density in one cross and 26.5% in the other. Seed of surviving genotypes was increased for a replicated field trial where maturity (days after 1 June), plant height (cm), oil content (nuclear magnetic resonancevalue), and grain yield (g/hill plot) were measured. Means and variances between progenies advanced under high or low densities generally did not differ for any of the traits, leading to the conclusion that the genotypes eliminated due to barren plants were randomly and not selectively eliminated due to selection pressures of the technique.
Hydrogen Uptake (HUP) Activity of Rhizobium japonicum from Major U.S. Soybean Production Areas
Authors: Uratsu S. L. , Keyser H. H. , Weber D. F. , Lim S. T.
Published: July 2010

The purpose of these experiments was to determine the distribution of the hydrogen uptake (Hup) system among Rhizobium japonicum isolated from major soybean production areas of the USA. Soybean nodules were collected from approximately 100 different locations during the 1979 and 1980 growing seasons. The major conclusion is that a majority (> 75 %) of the Rhizobium japonicum strains isolated from major soybean producing areas are missing H2 uptake activity. The role of the H2 uptake system in energy efficiency of nitrogen fixation is discussed.
Fungal Penetration of Soybean Seed through Pores1
Authors: Hill H. J. , West S. H.
Published: July 2010

Mycelium of seed‐borne fungi have been postulated to enter the seed coat of soybeans [Glycine max (L.) Merr.] through seed coat defects and the hilum region. The objective of this study was to determine if fungal mycelia could also enter the seed via the naturally‐occurring pores on the seed coat surface. Using scanning electron microscopy, naturally occurring pores on the surface of the seed coat were observed as providing a means of entry into the seed. These pores were found to penetrate deeply into the palisade layer providing passage into the hourglass layer. Fungal hyphae were observed to extend into these pores. These pores, therefore, can provide a means of fungal entry without the presence of visible seed coat defects.
Some Statistical Analyses for a Maize and Beans Intercropping Experiment
Authors: Wijesinha Anila , Federer Walter T. , Carvalho Josȳ Ruy , De Aquino Portes Tomas
Published: July 2010

Several univariate and multivariate analyses were applied to observations from a single experiment involving sole crop and intercropped combinations of two maize (Zea mays L.) and four bean (Phaseolus vulgaris L.) cultivars. Some of the strengths and weaknesses of the analyses are indicated. For joint analyses on maize and bean yields, analyses for crop value or income, land equivalent ratios, and a multivariate analysis with maize yields as one variable and bean yields as a second variable, were performed on the data. The last analysis necessarily ignores sole crop yields. These different types of analyses provided insight into different aspects of an intercropping experiment. It was found that an intercropping system which maximized the yield of any one crop did not necessarily maximize total crop value or income or land equivalent ratio. This indicated that the type of analysis required clearly depended on the goals of the experiment, and that all these analyses may usefully be performed on an intercropping experiment. The conclusions from the multivariate analyses for this experiment were found to agree with those from the univariate analyses. All eight mixtures had a land equivalent ratio greater than one. Combined crop values computed for bean prices three times that of maize were larger for three of the eight mixtures than for the highest sole crop value for a tall maize cultivar. Considering total yield of maize plus beans, none of the mixtures yielded as high as the higher yielding maize cultivar. In considering combined yields in a multivariate analysis, yields of beans were relatively twice as important as maize yields in determining differences in total yield.
Hilum Color Variation in Soybean Seed with Imperfect Black Genotype1
Authors: Taylor B. H. , Caviness C. E.
Published: July 2010

Hilum color of soybean [Glycine max (L.) Merr.] seed is one of the traits commonly used to differentiate offtypes for seed certification. Variation in hilum color in imperfect black genotypes has resulted in difficulty in classification. The objective of this research was to determine the accuracy of visual classification of hilum color in genotypes with imperfect black hila.

Seeds with buff hila were selected from the cv. ‘Pickett 71’ which normally produces seed with imperfect black hila. Forty‐two percent of the plants grown from these seeds produced plants that had seeds with typical imperfect black hila which were the Pickett 71 genotype. Progeny tests showed that the remaining 58% were offtypes. These data clearly showed that visual selection of buff offtypes from the Pickett 71 cultivar was not an accurate method of identifying hilum genotypes. Plants must have gray pubescence, purple flowers, and the R gene to produce seeds with imperfect black hila; therefore, certain offtypes can be quickly identified by growing seedlings and observing hypocotyl color. Seedlings with green hypocotyls will produce white flowers. Seeds that produce seedlings with green hypocotyls definitely are not imperfect black genotypes, but seeds with buff hila that produce seedling with purple hypocotyls may not be offtypes.
Variation among Inbred Lines of Crimson Clover for N2 Fixation (C2H2) Efficiency1
Authors: Smith G. R. , Knight W. E. , Peterson H. H.
Published: July 2010

Inbred lines of crimson clover (Trifolium incarnatum L.) were assayed for N2 fixation using the acetylene reduction assay. The seedlings were inoculated with a single pure strain (162K13) of Rhizobium trifolii and cultured in a nil‐nitrogen nutrient solution contained in individual plastic growth pouches. The acetylene reduction assay was carried out on live plants using the plastic pouches to contain the gas mixture. In the first experiment, significant differences were noted among 14 crimson clover lines for acetylene reduction. Top dry matter, leaf number, and visual scores of nodulation, root growth and top growth were significantly correlated with the acetylene reduction assay. A relatively large coefficient of variation (27.1%) was noted for this experiment. In the second experiment refinement of culture and assay techniques resulted in a lower coefficient of variation (15.2%) and significant differences among six crimson clover lines for acetylene reduction were found.
Dry Matter Production, Leaf Area Development, and Light Interception of Cowpea Lines with Broad and Narrow Leaflet Shape1
Authors: Wien H.C.
Published: July 2010

Six field experiments were conducted with cowpea Vigna unguiculata L. Walp.) to determine if production could be increased by changing leaflet shape. In two trials, leaf area and light interception were measured for successive 10 cm canopy layers of two narrowleaf (NL) and two broad‐leaf (BL) lines grown at equidistant spacing. All lines reached full light interception at a leaf area index of 3, and showed similar leaf area‐light interception relationships. Dry matter production and leaf area development rates were compared for F3 populations of a cross between a BL and NL line grown at 25 cm and also 75 cm row spacings. Both populations had similar dry matter production rates and yields in two seasons, although early leaf area development was less and branching more profuse for the NL population. Light supplementation after flowering was provided to the lower canopy by placing white metal reflectors at 45° angle below widely spaced rows of 2 NL and 2 BL lines. This increased yields by 32 and 12% in April and August plantings, respectively, and increased root and nodule production, but consistent differences between NL and BL lines were not observed. All these experiments indicated that narrow leaflet shape per se would not increase the productivity of cowpeas at Ibadan.
Genetics of Host Plant Resistance of Wheat to Septoria nodorum1
Authors: Nelson L. R. , Gates C. E.
Published: July 2010

F1 progeny from diallel crosses (reciprocals included) among five wheat (Triticum aestivum L.) cultivars were tested in the greenhouse for reaction to infection by Leptosphaeria nodorum Muller [imperfect stage = Septoria nodorum (Berk.) Berk.], the cause of glume blotch. In a separate experiment, four wheat parents and all F1, F2, and backcrosses were likewise tested for reaction to the pathogen. Significant effects were found for additive, dominance, and additive ✕ additive genetic effects as well as heterosis. Cultivars with the additive type resistance were ‘Oasis’ and ‘Blueboy II’ in Exp. I and Oasis in Exp. II. Crosses involving ‘McNair 1813’, a susceptible parent, demonstrated heterosis for a more resistant reaction. These results indicate that resistance to S. nodorum is inherited in a very complex manner and that several genes may be involved.
Respiration, Carbohydrate Content, and Leaf Growth of Tall Fescue1
Authors: Moser L. E. , Volenec J. J. , Nelson C. J.
Published: July 2010

Tall fescue (Festuca arundinacea Schreb.) was grown in controlled environment chambers with a 14‐hour photoperiod, and then kept in darkness for 8 days in one experiment and 20 days in another. The objectives were to determine concentrations of total nonstructural carbohydrates (TNC) and relate them to leaf elongation rates (LER) and to rates of dark respiration (RD). After various times in darkness, leaf terminal meristems in vegetative tillers, root tips, and center‐sections of collared leaf blades were excised, and oxygen consumption was measured.

Oxygen consumption was generally highest in terminal meristems, intermediate in root tips, and lowest in mature leaf blades. For the first 6 days the daily LER was greater in plants growing in darkness compared with those in 14‐hour photoperiods. From 6 to 12 days of darkness, LER was similar on both sets of plants. After 12 days the dark‐grown plants had lower LER. By extrapolation of the LER/RD, relationship to zero LER, maintenance respiration of leaf terminal meristems was estimated to be about 0.95 μ1 02‐mg structural dry weight (SDW)‐1.hour‐1, which represented 24% of the oxygen consumed. Collared leaf segments approached maintenance levels of RD after 2 days of darkness and root tips after 8 days. However, terminal meristems had a high TNC concentration and continued to support leaf growth actively for up to 16 days of darkness. The RD, TNC, and LER were all directly associated. Maximum RD in terminal meristems occurred at 35% TNC while LER remained similar when TNC levels were higher than 28%. In mature leaf tissue about 60% of the oxygen consumption was associated with maintenance respiration.
The Influence of Environment on the Expression of Trichomes in Wheat1
Authors: Wellso Stanley G. , Hoxie Robert P.
Published: July 2010

Cereal leaf beetles (CLB), Oulema melanopus (L.), oviposited more eggs on ‘Downy’ winter wheat, Triticum aestivum L., than expected based on its previous classification as very resistant to the CLB. Within a field of Downy, beetles oviposited on those leaves with fewer and shorter trichomes. The trichome profile (length and density) of all leaves were determined for Downy grown in southwestern Michigan. Trichome profiles differed significantly between years for the same leaf number and between different leaves the same year. The flag leaf was not as resistant as the three leaves below it. The overall trichome profile was best estimated by samples from the mid‐region of the leaf. Trichome density of the seedling first leaf was positively correlated with leaf length and negatively correlated with soil moisture in laboratory studies. Trichome profiles of the first seedling leaf were positively correlated with temperature. Downy grown in the field in 1979 was rated between susceptible and moderately resistant (depending upon which leaf was rated).
Cultivar Differences in Canopy Apparent Photosynthesis and Their Relationship to Seed Yield in Soybeans1
Authors: Wells R. , Schulze L. L. , Ashley D. A. , Boerma H. R. , Brown R. H.
Published: July 2010

Differences in leaf photosynthesis among soybean [Glycine max (L.) Merr.] genotypes have not been shown to be correlated with seed yield, probably because leaves selected for measurement have not been representative of the soybean canopy. In order to obtain a measure more representative of photosynthesis by plant communities and to explore the relationship of canopy apparent photosynthesis (CAP) to seed yield, field experiments were conducted during 2 years. Four soybean cultivars in each of four Maturity Groups (V through VIII) were grown in field plots in 1975 and two of each Maturity Group were grown in 1976. Measurements of CAP were made throughout the reproductive period by placing a large plastic covered chamber over a square meter segment of the canopy and measuring CO2 depletion during a 1 to 2 min period. Measurements were made near noon when solar radiation was above 0.9 Ly/min.

Maximum values of CAP were 4 to 6 g CO2m‐2hr‐1 during the early reproductive stages and decreased with age throughout pod filling. The decrease was most rapid for Maturity Group V and slowest for Group VIII. Dates when CAP dropped to zero were mid‐September for the Group V cultivars and mid‐October for Group VIII. Differences in CAP among cultivars occurred during seed development for all Maturity Groups. These differences could not be attributed to leaf area index or light interception since differences in CAP occurred while light interception was above 97%. Seed yield also differed among cultivars within Maturity Groups, the range in yield being from about 2,000 to 3,600 kg/ha in both years. Correlation coefficients for the association between yield and CAP measured during seed development were significant and ranged from 0.43 to 0.62. An integral of the CAP measurements from the full‐pod stage of development (R‐4) to maturity was correlated with yield with a coefficient of 0.66 in 1975 and 0.59 in 1976. Data from these experiments indicate that yield differences among cultivars are partially accounted for by differences in photosynthetic capacity of the plant canopy during seed development.
Flowering in the Garden Pea: Expression of Gene Sn in the Field and Use of Multiple Characters to Detect Segregation1
Authors: Murfet Ian C.
Published: July 2010

The major flowering locus, sn, was previously identified in the garden pea with the aid of special environmental conditions. The present study examines the effect of segregation for the Sn/sn pair of alleles in an F2 grown under field conditions. The dominant allele, Sn, caused a substantial increase in the time to first open flower, number of reproductive nodes and seed yield. Gene Sn generally increases the nodeo f first flower but this effect was minimized in the present F2 by choosing a particular genetic backgrounwd hich would allow emphasis on other important characters influenced by Sn. The increased time to open flower arose largely from the fact that Sn slowed the rate at which the flower buds developed relative to the rate of leaf expansion. A new variable, flower/leaf relativity (FLR), was devised to describe this effect in quantitative terms. Flower/leaf relativity proved to be the most effective of all the variables measured at discriminating Sn and sn segregates. However, none of the individual variables gave a clear‐cut separation between the Sn and sn segregates, which were positively identified by growing F3 progeny in controlled‐environment conditions. Certain two‐way data plots, e.g. seed yield/FLR, improved the chance of correctly distinguishing the two genotypes. Complete separation of the two genotypes, with the exception of one aberrant plant, was obtained by using six variables and either of two multivariate statistical techniques; a Principal Components analysis or a single Canonical Variate designed to maximally discriminate between the two genotypes. The results show that multivariate statistics can help to identify segregates where a major gene influences several characters in a quantitative manner.
Evaluation of Yield Components as Selection Criteia in Barley Breeding1
Authors: Puri Y. P. , Qualset C. O. , Williams W. A.
Published: July 2010

A combination of statistical procedures was used to determine which yield components were most likely to be effective selection criteria for yield improvement in barley (Hordeum vulgare L.). The procedures included: 1) simple phenotypic correlations between grain yield and its endpoint components, 2) ridge regression to determine which characters were strongly interrelated, and 3) multivariate models and path analysis. Each procedure was applied in a 2‐year study of 25 near‐homozygous spring barley selections from ‘Coast’/‘Lion’//‘Winter Club’ and two check cultivars. Yield/plant (Y) was the primary measure of grain yield. Components measured were X1, spikes/plant; X2, kernels/spike; X3, kernel weight; and X4, kernel weight/spike. Two models were studied using original data and log transformed data: YA, involving X1, X2, and X3, and YB, involving X1 and X4. These relate to grain yleld/plant as YA = X1‐X2‐X3 and YB = X1‐X4 because X4 = X2X‐3. Phenotypic correlations gave unstable inter‐year and intercharacter relationships. X3 and X4 were strongly correlated with Y. Path analysis of model YA identified X3 and model YB identified X4 as having stronger direct effects on yield than other characters. X4, weight/spike, was judged as the primary character worthy of further investigation as a simply applied selection criterion. Results of the analyses with the log transformed data were completely consistent and practically identical with the analyses of untransformed data.
Techniques of Screening Peas for Resistance to Phoma medicaginis var. pinodella1
Authors: Sakar D. , Muehlbauer F. J. , Kraft J. M.
Published: July 2010

Footrot and foliar phases of the disease caused by Phoma medicaginis var. pinodella in peas (Pisum sativum L.) were studied. Major objectives were to develop repeatable inoculation procedures and to identify pea lines resistant to footrot and foliar infection. All tests were conducted under controlled environmental conditions. Fungal spore concentrations and plant age at inoculation were important for identifying differences in disease reactions among lines. Significant differences in reactions to footrot were obtained among lines when pea seeds were immersed for 5 min. in inoculum adjusted to 1 ✕ 104 spores/ml, planted in a sterile soil mixture, and scored 10 days later. Significant differences in resistance among pea lines to the foliar phase of the disease were obtained when 15‐day‐old pea seedlings were sprayed with inoculum containing 1 ✕ 105 spores/ml and scored 10 days later. Footrot scores ranged from 1.2 to 4.8, and foliar disease scores ranged from 2.1 to 4.9 when 96 pea genotypes were rated on a 1 to 5 scale (1 = symptomless and 5 = very severe disease). There was no significant correlation between footrot and foliar disease scores, indicating that different genetic factors may control reactions to the two phases of the disease.
Regeneration of Proso Millet from Embryogenic Calli Derived from Various Plant Parts1
Authors: Heyser J. W. , Nabors M. W.
Published: July 2010

Totipotency in cereal tissue cultures is often lost soon after callus initiation. Work by others with embryogenic cultures derived from various plant parts suggests that long term totipotent cultures can be obtained for some cereals and grasses. Long term totipotent tissue cultures of proso millet (Panicum miliaceum L.) which readily regenerated normal fertile plants were sought.

Calli were initiated from immature embryos, mature seeds, mesocotyls, and leaf and stem segments cultured on Linsmaier and Skoog medium (L and S), 4% sucrose, 1% agar, and variable levels of 2,4‐D or 2,4,5‐T. For seeds, most callus was initiated on 1 mg/1 2,4,5‐T. Less callus was initiated by dark‐cultured seeds than by light grown seeds on 2,4‐D. Only dark‐grown seeds and immature embryos produced embryogenic callus on the first (initiation) passage. In light grown secondary callus, embryogenic and nonembryogenic calli had similar growth during a 6 week culture period. After 24 weeks in culture, 32% of embryogenic calli formed shoots as compared with 2% of non‐embryogenic calli cultured on no auxin.
Inhibition of Germination and Seedling Growth of Eight Forage Species by Leachates from Seeds1
Authors: Cope Will A.
Published: July 2010

Seeds of many plant species contain phytotoxic compounds which inhibit seed germination or seedling growth of other seeds in their immediate vicinity. Seeds of tall fescue (Festuca arundinacea Schreb.), annual ryegrass (Lolium multiflorum Lam.), orchardgrass (Dactylis glomerata L.), Kentucky bluegrass (Poa pratensis L.), alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), sericea lespedeza [Lespedeza cuneata (Dum. de Cours.) G. Don], and crownvetch (Coronilla varia L.) were leached in water for 24 hours and the leachates were used to moisten filter paper in petri dishes for germination. Seeds of each species were germinated in leachate from all eight species. Seeds of the four legumes were also germinated in leachates from nine other ryegrass cultivars and six other orchardgrass cultivars. Germination and seedling growth of a species was not inhibited by leachate from its own seeds. There was no phytotoxicity to any of the grasses by leachate from other grass species. The only phytotoxicity to any of the grasses was a slight inhibition of bluegrass germination and shoot growth by crownvetch seed leachate. Leachate from one commercial lot of annual ryegrass seed almost completely inhibited germination and root growth of each of the legumes. Other cultivars of ryegrass varied from moderate to no phytotoxicity of their leachates. Leachate of ‘Potomac’ orchardgrass seeds caused moderate germination inhibition of white clover and sericea. Six other orchardgrass cultivars showed little variation in phytotoxicity, while uniformly inhibiting root growth of sericea and crownvetch. Inhibition of germination was not a good measure of phytotoxicity since seedling growth was often inhibited when germination was not.
Morphology and Yield in Winter Wheat Grown in High Yielding Conditions
Authors: Ledent J.F.
Published: July 2010

To reassess the relations of morphological characters and yield components in high yielding field conditions measurements were taken on a series of modern cultivars of winter wheat (Triticum aestivum L. em. Thell.) over 4 years. Morphological traits measured were leaf area, leaf dry weight, leaf area duration, specific weight of each of the three uppermost laminae, maximum width of the two upper laminae, dry weight and length of the flag sheath and peduncle, and of ear weight at anthesis. The relationships of these characters with yield/m2, yield/shoot, and yield components (no. spikes/m2, kernels/spikelet, spikelets/spike, kernel weight) were investigated across cultlvars using simple correlation, canonical correlation, multiple regression, factor, and principal components analyses.

Yield/shoot but not yield/m2 was related to plant morphology. Dry weight of the flag sheath and of the second or third uppermost laminae were associated with the components of yield per shoot. Leaf area, leaf area duration and specific leaf weight were poorly associated with yield/shoot or yield/m2. There was a consistent negative relationship between yield/shoot and number shoots/m2. No yield component ranked consistently above the others in its relation to yield/shoot. The relationships with yield/shoot were not simply due to the association among vegetative areas producing assimilates and plant parts using them to grow in a predominantly source limited situation. The results could be explained by developmental correlations arising during the period of rapid stem elongation preceding anthesis.
Callus Induction, Maintenance and Plantlet Regeneration in Creeping Bentgrass1
Authors: Krans J. V. , Henning V. T. , Torres K. C.
Published: July 2010

Callus induction, from mature caryopses, and callus maintenance and plantlet regeneration, using 14‐month‐old stock callus (SC), were investigated in Penncross creeping bentgrass (Agrostis palustris Huds.). Greatest callus induction occurred on Murashige and Skoog (MS) medium with 1.0 mg 2,4‐dichlorophenoxyacetic acid (2,4‐D) under light incubation and 1.0 or 10.0 mg 2,4‐D/1 under dark incubation. Kinetin supplements were not required for callus induction, however, caryopses incubated in the dark with 0.01 mg kinetin had greater callus formation than caryopses incubated without kinetin when combined with 1.0 mg 2,4‐D/1. Under dark incubation, caryopses produced the greatest callus yields (47 and 57 mg) and callus removal from caryopses required less time and effort. Callus induced from caryopses originated from the scutellum, root cortex and along the coleoptile up to and adjacent the first node. Callus growth using SC was greatest at 1.0 mg 2,4‐D/1. Callus previously cultured on 1.0 mg 2,4‐D maintained good plantlet regeneration capacity; whereas, callus previously cultured at 10 and 100.0 mg 2,4‐D/1 had poor and no plantlet formation, respectively. The best combination for shoot and root development in SC occurred at 0.10 mg and 1.0 mg kinetin/1 without 2,4‐D. All plantlets were potted in a sand:peat (1:1) mix and maintained in a glasshouse. Callus induced plants were similar to seeded plants. Less than 1% of the plantlets formed were albino.
Relationships among Seedling and Mature Root System Traits of Maize1
Authors: Arihara J. , Crosbie T. M.
Published: July 2010

Maize (Zea mays L.) breeders often have resorted to various techniques, which measure root strength or type, in an effort to select for decreased root lodging. Seedling root traits of S1 lines selected for high and low mature root‐pulling resistance in the field from C0 and C8 cycles of Iowa Stiff Stalk Synthetic [BSSS(R)] and Iowa Corn Borer Synthetic #1 [BSCB1(R)] were studied in a preliminary experiment. Also, we used 90 S1 lines from each of the C0 and C8 cycles of BSCB1(R) to estimate genetic parameters for seedling root‐pulling resistance.

Estimates of heritability for seedling pulling resistance were 0.56 ± 0.15 and 0.42 ± 0.16 for 90 random S1 lines from each of the C0 and C8 cycles of BSCB1(R). Predicted genetic advance was 0.7 kg/plant for BSCB1(R)C0 and 0.6 kg/plant for BSCB1(R)C8. Estimates of S1 line × environment interactions for seedling pulling resistance of selected, low and high lines from C0 and C8 cycles of BSCB1(R) were not significant when measured in two greenhouse environments. Rank and genotypic correlation coefficients, however, between seedling root‐pulling resistance and mature rootpulling resistance measured at two dates and between seedling pull and lodging were small (all r‐values were lower than 0.33). Selection differentials for root pulling resistance at any stage suggested that selection would be more effective in discarding lodging‐susceptible lines than in identifying those with superior lodging resistance. We have concluded that selection for high seedling root pulling resistance has limited utility in improving mature root strength of these populations.
Assimilate Distribution in Soybeans as Affected by Photoperiod During Seed Development1
Authors: Cure J. D. , Patterson R. P. , Raper C. D. , Jackson W. A.
Published: July 2010

The duration of the seed filling period for soybean [Glycine max (L.) Merr.] may be limited by rapid nutrient diversion from leaves to seeds resulting in reduced leaf assimilation capacity. In this study, the effect of short‐day and long‐day photoperiods on the duration and rate of seed filling and on nutrient remobilization were examined in two determinate genotypes, ‘Ransom’ and ‘D72‐8126’. The photoperiod treatments were imposed during the seed development phase in controlled‐environment chambers. Dry matter and N distributions throughout reproductive development were measured.

Under long days, both genotypes maintained far greater leaf area and attained greater total and vegetative growth relative to short days. Reproductive growth was decreased 11% for Ransom but was increased 16% for D72‐8126 under long day conditions. The rates of growth and N accumulation per seed also were reduced by long days for Ransom but were unaffected for D72‐8126. The duration of the seed filling period was not extended for either genotype. Seed number was increased 5 and 18% by long days for Ransom and D72‐8126, respectively.

Ransom plants grown under long days had higher N concentrations in vegetative parts and lower seed N concentrations than short day plants as the reproductive phase progressed. Long‐day photoperiods caused a similar increase in vegetative N concentrations for D72‐8126, but by final harvest reproductive N concentration under long days was equal to that under short days. Nitrogen remobilization from leaves to seeds under short days did not appear to limit the dry matter or N assimilation efficiency of either genotype.
Genetic Control of Seed Longevity in Soybeans1
Authors: Kueneman E. A.
Published: July 2010

Soybean [Glycine max (L.) Merr.] seeds have a short storage life, especially in humid, tropical environments. However, a few varieties have been identified recently that have superior seed longevity. The purpose of this study was to determine if seed longevity is under maternal plant influence as is the case with many seed characteristics.

Four reciprocal crosses were made between genotypes with good and poor seed longevity. A modified accelerated ageing test, followed by evaluations of seedling emergence from soil, was used to predict seed longevity of F1 seeds for three of the four crosses; for one cross the test was repeated. Differences between reciprocal crosses were significant for all four tests. A hot water stress test was also used to predict seed longevity of reciprocal F1 seeds for two crosses; two tests were run for each cross. The difference between reciprocal F1's was significant in one of the four tests. These results suggest that the maternal plant genome can influence the longevity of soybean seed.

The fact that emergence of F1 families was often different from their respective maternal parent and that pooled F2 variances (seed from individual F1 plants) were larger than pooled parental variances, suggests that the genotype of the seed also may influence it's longevity. F2 seeds were examined for differences between reciprocals for one cross. The difference, though relatively small compared to reciprocal F1 differences, was statistically significant suggesting that cytoplasmic gene action may also be involved in expression of seed longevity. Because of the large noncytoplasmimc aternal plant influence, it is suggested that selection for seed longevity be delayed at least until the F3 generation.
Trichomes in Segregating Generations of Sorghum Matings. I. Inheritance of Presence and Density1
Authors: Gibson P. T. , Maiti R. K.
Published: July 2010

The presence of trichomes on the leaves of sorghum [Sorghum bicolor (L.) Moench] is associated with reduced susceptibility to shootfly (Atherigona soccata Rond.) attack. Segregation ratios in successive generations of five single‐cross matings between trichomed and trichomeless parents indicated that the presence of leaf‐blade trichomes is recessive and controlled by a single locus. Inheritance of the trichome trait in three matings among four trichomed parents involved the same locus. The symbol tr is proposed for the gene controlling trichome presence.

Trichome density on the abaxial leaf lamina varied among trichomed lines derived from single‐cross matings. Standard unit heritability for F4 on F3. estimated only in the cross IS 1054 x B CK60, was 0.75 on a plot basis.
Screening Peas for Winterhardiness Under Field and Laboratory Conditions1
Authors: Auld D. L. , Ditterline R. L. , Murray G. A. , Swensen J. B.
Published: July 2010

Winter injury of the winter pea (Pisum sativum subsp. arvense (L.) Poir) crop of northern Idaho causes severe losses. The development of cultivars with higher levels of winterhardiness would increase both the seed yield and area of adaptation of this crop. To evaluate techniques for determining winterhardiness in peas, 14 genotypes of winter‐hardy peas, and six genotypes of spring peas (P. sativum L.), were screened in the field and laboratory. Trials were planted on three dates at Moscow, Idaho, and a single date at Bozeman, Mont., during the fall of 1976 and 1977. Seedlings were counted in both the fall and spring to determine the percent survival. At all planting dates and locations, the spring pea cultivars failed to survive the winter, indicating that spring types can be eliminated from segregating populations by fall planting. Three lines, ‘Romack’, ID 89‐1, and C8‐M‐23, appeared to be intermediate in winterhardiness and could be used as controls in future trials. Screening at −9 C in a programmable freezer eliminated all spring cultivars and produced differential survival among the winter‐hardy lines. Correlation coefficients between percent survival of the 13 winter‐hardy lines in the eight field environments and three test temperatures indicated that screening in the laboratory at −9 C successfully identified those lines with intermediate levels of winterhardiness. Fourteen lines of the P. sativum and four lines of the P. arvense USDA plant introduction collection had usable levels of winterhardiness in field trials at Moscow.
Quality Prediction of Small Grain Forages by Near Infrared Reflectance Spectroscopy1
Authors: Marten G. C. , Halgerson J. L. , Cherney J. H.
Published: July 2010

A paucity of information exists concerning the utility of near infrared reflectance spectroscopy (NIRS) for prediction of forage quality of annual forage crops and concerning the influence of environmental and plant factors on NIRS prediction equation development and use. Our objective was to ascertain whether NIRS can be relied upon to predict the quality of small grain crop forages at diverse maturation stages. We assayed five forage quality traits in a total of 700 forages comprised of up to four field replicates of two cultivars each of oats (Arena sativa L.), barley (Hordeum vulgate L.), spring wheat (Triticum aestivum L.), and triticale (Triticum durum Desf. ✕ Secale cereale L.) each harvested at six growth stages in two locations in years. Empirical quality prediction equations were obtained by multiple linear regression of known quality values on NIR values from 48 samples obtained from one replicate from one location in 1 year. A scanning monochromator NIR spectro‐computer system was used to develop the prediction equations and to validate them via tests of their applicability to the remaining 652 samples that were grown in other replicates or in other environments. From two to six wavelengths were needed to develop the best prediction equations for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) or in vitro digestible dry matter (IVDDM). The squared coefficients of multiple determination (R2) of the prediction equations ranged from 0.92 for IVDDM to 0.99 for CP. These calibration equations predicted the quality values for samples from other replicates, locations, and years within standard errors of ± 0.7 to 1.1% for CP, ± 1.8 to 2.3% for NDF, ± 1.0 to 1.6% for ADF, ± 0.3 to 0.4% for ADL, and ± 3.1 to 4.1% for IVDDM. We concluded that NIRS can evaluate forage quality of small grain crops to a degree of accuracy equivalent to or greater than that reported for perennial forage species, and that relative forage quality of small grain crops was adequately determined for several growth environments when prediction equations were developed from forages grown in a single environment.
Genetic Variability in Maize for Maysin Content1
Authors: Widstrom N. W. , Wiseman B. R. , Mcmillian W. W. , Elliger C. A. , Waiss A. C.
Published: July 2010

The relative maysin [a flavone glycoside that is antibiotic to the corn earworm, Heliothis zea (Boddie)] content of maize (Zea mays L.) silks, measured as UV absorbance at 352 nm, was determined for several inbreds, crosses, and their derived populations. The objectives of the study were to a) examine the repeatability of maysin determinations, and b) determine the potential for selection to increase silk maysin content, based on inheritance patterns. Significant differences occurred among silks of inbreds and crosses, but not between reciprocal crosses. The interaction between crosses and years was nonsignificant, demonstrating that the relative maysin content of hybrids tended to remain constant and that the relative ranking of genotypes in the various tests were repeatable. Single‐factor inheritance was not probable based on generation means or the distribution of individual plant values in the P1, P2, F1, F2, BC1, and BC2 generations of six crosses. The analysis of variance of generation means indicated that nonadditive genetic effects (dominance plus epistatis) were about equal to additive effects. Approximately 20% transgressive segregates existed in the F2 and backcrosses of the cross, ‘Zapalote Chico’ 2451# ✕ ‘Antigua’ 2D‐118, which may provide an opportunity to select for increased levels of maysin in those segregating populations.
Effect of Altered Source‐Sink Ratio on Growth of Maize Kernels1
Authors: Jones R. J. , Simmons S. R.
Published: July 2010

Grain yield in maize (Zea mays L.) is a function of the relationship between assimilate supply to the grain and inherent potential of the grain to accommodate this assimilate. In this study we sought to ascertain the effects of altering assimilate supply per kernel during early and late kernel development on kernel growth rate and final weight. We also sought to elucidate the effect of such alterations on the plant's compensatory responses, specifically kernel abortion and carbohydrate/ N redistribution. The single‐cross hybrid M14 ✕ W64A, selected because of intermediate weight per kernel was grown in field plots in 1979, 1980, and 1981. Assimilate enhancement per kernel was achieved by ear tip removal, which resulted in a 20 to 40% reduction in kernels per ear. Total defoliation was the assimilate reduction treatment. Both treatments were applied 12 days (early) and 24 days (late) after mid‐silking. Early defoliation greatly reduced both kernel growth rate and filling period duration, resulting in lower weight per kernel. These defoliation effects occurred despite large compensatory reductions in number of kernels per ear on treated plants. Soluble carbohydrate content of the internode above the ear of defoliated plants declined following defoliation, probably in conjunction with remobilization of stem reserves. This decline was more rapid for the later defoliated plants. In contrast, N concentration of this stem internode of defoliated plants was higher than in control plants and did not decline after treatment. Soluble carbohydrate and N concentration in the internode above the ear of plants in which ear size was reduced was higher than in control plants. Nitrogen concentration of the grain was also increased. However kernel growth rate, final kernel weight, and soluble carbohydrate concentration at maturity were not affected by this treatment. These results show that the remobilization patterns for stems in response to changes in assimilate supply, differs for N as compared to soluble carbohydrates. In addition, the data suggest that kernel growth rates and final seed size may be already approaching the upper limits of their potential in this hybrid. Undetermined factors other than assimilate supply appear to be restraining higher kernel growth rates and final weights.
False Positive Results in the Vanillin‐HCl Assay of Tannins in Sorghum Forage1
Authors: Walton M. F. , Haskins F. A. , Gorz H. J.
Published: July 2010

Vanillin‐HC1 procedures are widely used for the assay of tannins in plants. In attempts to adapt such procedures for use with sorghum [Sorghum bicolor (L.) Moench.] forage it was found that false positive reactions resulted, that is, red color developed in the presence of HC1 with or without vanillin. Leucoanthocyanldins (monomeric proanthocyanldins) may be the constituents responsible for this red color. A “chloroform‐HCl” procedure was developed for measuring leucoanthocyanldins in sorghum forage. The procedure avoids interference by chlorophyll or other chloroform‐soluble constituents. With vanillin added to the solution, this procedure should also be useful for the assay of condensed proanthocyanidins (tannins).
Field Assessment and Inheritance of Cassava Resistance to Superelongation Disease1
Authors: Kawano Kazuo , Umemura Yoshiki , Kano Yoshiaki
Published: July 2010

Effects of superelongation disease, caused by the fungus Elsinoe Brasiliensis Zeigler and Lozano, on cassava (Manihot esculenta Crantz) clones (different genotypes) were studied in fields under high natural disease infection to assess value of genetic resistance and efficiency of field selection. The disease caused 20 to 70% yield reduction on susceptible clones relative to resistant clones depending on planting time and presence of cassava bacterial blight. Susceptible clones could not produce good planting stakes for next plantings. On resistant clones, the disease spread slowly while on susceptible ones it spread rapidly causing abnormal stem elongation and leaf death. Resistance was a quantitative trait controlled largely by additive genetic factors and not negatively correlated with yielding ability per se. Cultivar order of resistance was stable over 8 years of observation. Use of resistant parents in hybridizations combined with simple phenotypic field selection under high natural disease pressure should effectively improve resistance of cassava cultivars.