bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency of Single‐Seed‐Descent vs. Anther‐Derived Dihaploid Breeding Methods in Tobacco1
Authors: Schnell R. J. , Wernsman E. A. , Burk L. G.
Published: July 2010

The productivity and leaf chemical composition of random dihaploid (DH) and single‐seed‐descent (SSD) lines of Nicotiana tabacum L. from the same F1 hybrid plant, were compared. ‘Hicks Broadleaf’ was crossed with ‘Coker 139,’ anthers from a single F1 plant were cultured, and 50 DH lines were produced for testing. The same F1 was selfed, and 50 random F8 lines were developed by the SSD procedure. Experimental lines and check cultivars were compared in three environments.

The DH population yielded 10.6% less cured leaf, possessed inferior leaf quality, was later flowering, produced reduced leaf numbers, and its cured leaf was lower in total alkaloids than the SSD population. The antherculture procedure produced a DH population with greater genetic variability for leaf yields than the conventionally‐inbred population, but the suppressed DH mean overwhelmed the benefit of increased variation. Results indicate that selection in SSD populations would be preferable to selection in DH population for the identification of superior genotypes.
Effect of Recurrent Selection for Crushing Strength on Several Stalk Components in Maize1
Authors: Zuber M. S. , Colbert T. R. , Darrah L. L.
Published: July 2010

The objective of this 2‐year study was to determine the relative contributions of the rind and pith components to total stalk crushing strength in Zea mays L. Experimental material consisted of the original population and the first, third, and fifth cycles of recurrent selection for high and low crushing strength in two maize synthetics (MoSQA and MoSQB). Six replications in randomized complete block design experiment were used where one row of each two‐row plot provided intact stalk‐sections, and the second row provided rind‐only (pith removed) crushing samples. Crushing strength the intact section and rind‐only followed a linear response to selection in both the high and low directions. Selection for high crushing strength resulted in average increases of 51.8 load‐kg per cycle for intact sections and 33.3 load‐kg for rind only sections. Low crushing strength selection decreased crushing strength by 35.3 load‐kg per cycle for intact sections and 26.6 load‐kg for rind‐only sections. Intact section and rind‐only weights had similar responses. Rind thickness was altered due to recurrent selection for crushing strength, but the magnitude of change was small and inconsistent. The pith component contributed proportionally more to stalk crushing strength in the high selections than in the low selections. Pith contribution to total stalk strength was from 20 to 50% and is greater than previously realized. The magnitude of change in rind thickness did not account for the increase in rind strength in the high selections, suggesting that rind composition may be as important as rind thickness in improving total stalk strength.
Production Traits of Oats Selected under Low, Medium, and High Productivity1
Authors: Shabana R. , Bailey T. , Frey K. J.
Published: July 2010

Selection for yield (10% intensity) was carried out in two groups of random oat (Avena saliva L.) lines (group T and group G contained 200 and 480 lines, respectively) under low‐, medium‐, and high‐productivity conditions. Selected lines from each selection condition were tested for mean, response, and stability of yield, in evaluation experiments that encompassed production environments from low to high.

Actual gains in mean yield from selection averaged across the three selection environments were 16 and 7% in the T and G groups, respectively. Actual advances were 16, 13, and 18% of the population mean under low, medium, and high productivity, respectively, for group T, and 7, 5, and 8%, respectively, for group G. In each group, advances from selection under high and low productivities were superior to that from medium productivity. There was no superiority for one selection condition over another for either response or stability of yield.

Lines selected only under low or medium productivity gave mean yields not significantly greater than the respective group means, whereas those selected only under high productivity gave significantly greater ones. The number of lines common to the samples selected under low, medium, and high productivity were three for group T and six for group G. These lines averaged 20% greater than the group means for yield, and were significantly superior under low, medium, and high productivity.

Low‐ and high‐productivity conditions were nearly equal for selecting high‐yielding lines of oats, and both were somewhat superior to medium productivity. However, a detailed analysis showed that high productivity tended to differentiate high‐yielding lines best. The most superior lines for all conditions of production were those chosen in all three selection environments and those chosen in both low and high productivity.
Tertiary Seed Set in Oat Cultivar1
Authors: Takeda K. , Frey K. J.
Published: July 2010

Tertiary seed development may be a way for increasing the “sink size” for spring oats (Avena sativa L). Most cultivars set only prunary and/or secondary seeds in a spikelet, but occasionally, one will set a high proportion of tertiary seeds. Genotypic and environmental causes of variation of the tertiary seed set in oat spikelets were examined. The environmental variable was sowing date. Cultivars varied significantly for the tertiary seed set, and those with remarkably high values were ‘C.I. 8044’ and isolines of it. Heritability for the tertiary seed set was 68.3% on a per‐plot basis. Tertiary seed set was slightly negatively genotypically correlated with primary seed set, but independent of secondary seed set. It was environmentally independent of both primary and secondary seed set. It was significantly lower in the late than in the early sown plots, which suggests that this trait is susceptible to high‐temperature stress.
Nectariless Cotton: Effect on Growth, Survival, and Fecundity of Lygus Bugs1
Authors: Benedict John H. , Leigh Thomas F. , Hyer Angus H. , Wynholds Paul F.
Published: July 2010

Experiments were conducted in the laboratory, greenhouse, and field to evaluate the effect of the nectariless character in cotton, Gossypium hirsutum L., on growth, survival, oviposition rate, and population increase of lygus hugs, Lygus hesperus Knight. Survival of L. hesperus nymphs on Stoneville 7A nectariless was 16% lower than on ‘Stoneville 7A’ during a 7‐day growth period. Reduction on other nectariless lines was not as great. Survival of female L. hesperus, confined for 14 days on a nectariless cotton, was 6% less and the number of nymphs emerging was 12% less than on the nectaried commercial standard, ‘Acala SJ‐I.’ Growth rates of lygus populations, during two generations in field cages, were reduced 34% by the nectariless character in Acala H4016 nectariless and 40% on Stoneville 7A nectariless when compared to their nearisogenic nectaried commercial standards. Populations of lygus bugs on Deltapine 16 nectariless were not lower, however, than on its nectaried near‐isoline. Thus, the response of the insect was affected not only by the nectariless character but also by the genetic backgrounds of the cultivars and lines tested.
Cell Membrane Stability as a Measure of Drought and Heat Tolerance in Wheat1
Authors: Blum A. , Ebercon Adelina
Published: July 2010

Drought and heat tolerance tests that were developed for sorghum (Sorghum bicolor L. Moench) were adapted to and evaluated in field grown wheat (Triticum aestivum L. and T. durum Desf.) during 1977/1978 and 1978/1979.

The drought tolerance test is based on the measurement of the electroconductivity of aqueous media containing leaf discs that were previously water stressed in vitro by exposure to a solution of polyethylene glycol‐6,000 (PEG). The heat tolerance test is similarly based on exposure of leaf discs to heating, in vitro, to 44 C.

Drought tolerance of wheat leaves decreased with plant age. For a given plant growth stage, some variation was revealed in drought tolerance, according to leaf position. Maximal separation of wheat cultivars in drought tolerance was obtained with 40% (w/v) solution of PEG, when plants were grown under conditions of favorable moisture regime and sampled during the late jointing growth stage.

Wheat was more drought tolerant than maize, sorghum or millet, based on published data.

When plants were sampled during a period of water stress, they were more drought tolerant than well‐watered plants, indicating adjustment of cell membrane stability to drought stress. Wheat cultivars varied in their ability to adjust, in this respect.

Unlike in sorghum, drought and heat tolerance were not correlated in wheat.

The inclusion of a limited number of barley (Hordeum vulgare) and triticale (X Triticosecale Wittmark) genotypes in this study indicated that the methods discussed work equally well with these crop plants.
New Genes for Resistance to Whitebacked Planthopper in Rice1
Authors: Angeles Enrique R. , Khush G. S. , Heinrichs E. A.
Published: July 2010

The inheritance of resistance to whitebacked planthopper, Sogatella furcifera (Horvath), in 12 resistant rice Oryza sativa L. cultivars was studied. This study was undertaken to identify additional genes for resistance and to determine the allelic relationships of newly identified genes and Wbph. The bulk seedling test was utilized for testing the hybrid materials for resistance to the insect. The reactions of F1, F2, and F3 populations from the crosses of resistant cultivars with ‘TN1’ revealed that resistance in ‘P580,’ ‘Sathra 267,’ ‘Sonpattar 45,’ ‘Sufaida 172,’ ‘ARC 10239,’ ‘Jhinuwa,’ ‘N32,’ and ‘Latighawar’ is controlled by a single dominant gene. Resistance of ‘IR2035‐117‐3’ is governed by two independent dominant genes. Similarly, resistance of ‘Colombo,’ ‘368,’ and ‘WC 1240’ is conferred by one dominant and one recessive gene that segregate independently of each other.

P580, Sathra 267, Sonpattar 45, Sufaida 172, Jhinuwa, N32, and Latighawar have the Wbph gene for resistance. This gene was redesignated as Wbph 1. ARC 10239 has a single dominant gene which segregates independently of Wbph 1. It is designated as Wbph 2. IR2035‐117‐3 is homozygous for Wbph 1 and Wbph 2 whereas Colombo has Wbph 2 and another recessive gene. Wbph 1 and a recessive gene confer resistance in WC 1240 and 368.
Preflowering Levels of Phytohormones in Sorghum. I. Analytical Procedure1
Authors: Dunlap J. R. , Hanks A. H. , Morgan P. W.
Published: July 2010

Procedures are described for the analysis of indole‐3‐acetic acid (IAA), abscisic acid (ABA), and gibberellin (GA)‐like compounds in sorghum, Sorghum bicolor (L.) Moench. Shoots of seedlings were harvested, frozen in liquid N, lyophilized, ground in a Wiley mill, and replicate samples extracted with methanol/water. After vacuum removal of methanol the residual was fractionated by partitioning against petroleum ether and ethyl acetate. Free, acidic forms of the phytohormones were recovered in the final ethyl acetate fraction, and a portion of the conjugated forms were obtained by mild acid hydrolysis of the aqueous residue followed by partitioning into ethyl acetate. Fractions containing IAA‐, ABA‐, or GA‐like compounds were further purified by ascending paper chromatography. Chromatograms of purified extracts were cut into various Rf intervals, eluted with methanol, and analyzed with high performance liquid chromatography (HPLC) operating in the reverse‐phase mode (µ Bondapak C18) for IAA or ABA and with the lettuce hypocotyl bioassay for GA‐like activity. Substantial quantities of IAA and ABA were obtained from sorghum tissue samples; recovery averaged 40 ± 10%. The identity of IAA and ABA was tentatively confirmed by: (a) identical retention times as authentic standards on gas‐liquid chromatography, (b) co‐chromatography with their respective standards on HPLC operated at different flow rates or solvent compositions. Gibberellin‐like compounds were tentatively identified as GA3, GA4, and/or GA7, by comparison to standards chromatographed on paper and bioassay ed. The putative GA3, was the most abundant GA‐like compound present. Additional quantities of putative IAA, ABA, and GA3, were obtained by mild acid hydrolysis of the final aqueous residue.
Method of Reproduction in Napiergrass and in the 3X and 6X Alloploid Hybrids with Pearl Millet1
Authors: Hanna Wayne W.
Published: July 2010

Research on napiergrass, Pennisetum purpureum Schumach. (2n = 28), has been emphasized in the United States and in India, Africa, South America and other tropical and subtropical countries. Napiergrass has high yield potential and produces interspecific hybrids with pearl millet, P. americanum (L.) Leeke (2n = 14) that have both high yield potential and high forage quality. There are numerous reports on chromosomal behavior and number in napiergrass and in the pearl millet · napiergrass hybrids but there is only one limited report on embryo sac development in napiergrass and it appears to be inaccurate. The objective of this research was to establish the method of reproduction in napiergrass and in the triploid (3x = 21) and hexaploid (6x = 42) alloploids of crosses of napiergrass with pearl millet. Cytological observations showed that megasporogenesis and embryo sac development were typically sexual in 12 napiergrass accessions and four hexaploid interspecific hybrids. A large number (736) of interspecific hybrids were produced using six different napiergrass accessions as the female parent, which confirmed that napiergrass is a sexually reproducing species. The triploid interspecific hybrids also were sexual, but in over 99% of the ovules, all of the megaspores in the linear tetrad aborted resulting in an ovule without an embryo sac. Since the hexaploids were highly male and female fertile, they should be easy to use in a backcrossing program for the transfer of germplasm between species. The triploids have excellent forage potential but cannot be used in backcrossing because of their high male and female sterility.
Genetic Control for Percentage Grain Protein and Grain Yield in Grain Sorghum1
Authors: Finkner R. E. , Finkner M. D. , Glaze R. M. , Maese Gloria
Published: July 2010

Inheritance of grain protein and yield was investigated in grain sorghum [Sorghum bicolor (L.) Moench]. Divergent selection was applied to a series of individual plants from the breeding nursery for high and low protein content. Protein percentage was determined from a random sample of finely ground grain by the Udy dye‐binding method. The selected lines were crossed onto A‐lines ‘Martin’ (high protein) and ‘Wheatland’ (low protein). Test crosses, parents, and checks were planted in replicated lattice‐designed tests at Clovis, N.M., for 3 years.

Highly significant differences were detected between the lines selected for high and low protein content for both percentage of grain protein and grain yield. Significant differences also were found between the two female lines. Genetic analyses of the test crosses and their parents indicated that low protein content was partially conditioned by dominant genes. Of 155 test crosses, 3% produced grain protein content significantly below the lower parent, indicating negative heterosis; 35% of the test crosses were signifidcantly below their mid‐parent mean, indicating dominant genes for low protein. Grain yield was determined by dominant or overdominant gene action as 43% of the test crosses yielded significantly above their midparent mean, and 35% of the crosses yielded significantly more than the highest yielding parent. Protein percentage had a highly significant negative correlation with yield (r = ‐0.53, significant at the 0.01 level).

Partitioning of the genetic variance indicated that additive gene action was more important than nonadditive gene action for both attributes studied. The genetic variances for males were greater than for females for both attributes; however, many more males were tested than females. Narrow‐sense heritability values of 35 and 44% were computed for grain protein percentage and yield, respectively.
F3 Yield Response to F2 Selection for Gibberellic Acid Insensitivity in Eight Wheat Crosses1
Authors: O'Brien L. , Pugsley A. T.
Published: July 2010

The hypothesis that the Gai/Rht alleles have a positive pleiotropic effect on grain yield was investigated by examining the F3 yield responses to F2 seedling selection for GA3 insensitivity within eight wheat(Triticum aestivum L.) crosses. Seedlings were liberally sprayed with a 100 ppm solution of GA3 (Berelex) at the three‐leaf stage. Seven days after spraying they were visually sorted into two groups, those that were insensitive and those responsive to applied GA3 as expressed by elongated internodes and a general etiolated appearance. Significant F3 yield increases were obtained in response to F2 seedling selection for GA3 insensitivity in two out of four crosses with the Gai/Rht 1 genotype and three out of four crosses with the Gai/Rht 2 genotype. In seven out of the eight crosses, the highest yielding F3 lines came from the GA3 insensitive populations, but the large Least Significant Differences that resulted from the use of two replicate randomized complete block yield experiments meant the differences among lines were generally not significant. Selection for GA3 insensitivity was simple and rapid, however, the visual classification into only two groups in this study meant that the so‐called GA3 sensitive group contained plants heterozygous for GA3 insensitivity. Actual measurement of the height to the second leaf node was the most reliable means of selection for GA3 response among seedlings. Selection for reduced plant height at the F2 seedling stage resulted in subsequent F3 yield increase because of the positive pleiotropic effect of the Gai/Rht genotype on yield. The technique can be integrated with any breeding methodology.
Hybridization of Melampsora lini to Identify Rust Resistance in Flax1
Authors: Statler G. D. , Hammond J. J. , Zimmer D. E.
Published: July 2010

Cultures with selective pathogenicity were developed through hybridization or selfing to identify genes for resistance in flax (Linum usitatissimum L.) to flax rust [Melampsora lini (Ehrenb.) Lev). Selected races of M. lint were crossed and selfed to produce virulent patterns to identify combinations of resistance alleles L11, M3, M6, and P3 relatively simple.
Quantifying Morphological Development of Alfalfa for Studies of Herbage Quality1
Authors: Kalu Bernard A. , Fick Gary W.
Published: July 2010

A more precise and quantitative method of specifying the morphological development of alfalfa (Medicago sativa L.) is needed for communication among scientists working with the crop and for associating alfalfa phenology and forage quality. A 10‐stage numerical system for individual stems (Stages to 9) was defined, and two procedures for calculating the mean stage of a herbage sample were compared on alfalfa samples grown in the spring, summer, or autumn and representing weekly age increments up to 10 weeks from all seasons. Samples were collected during one growing season from a 3‐year‐old stand of ‘Iroquois’ alfalfa grown in Tompkins County, N.Y. Mean stage by count (MSC) was the average of the individual stages present in the herbage sample, weighted for number of stems in each stage. Mean stage by weight (MSW) was the average of individual stages present, weighted for dry weight of herbage in each stage. Both methods quantified morphological development of alfalfa canopies with the anticipated effects of seasonal temperature, but the MSW procedure was superior in showing greater numerical differentiation and in distinguishing samples of diverse age and stage structure.

Linear regression in vitro true digestibility (IVTD) on MSW across seasons and ages of herbage samples was highly significant:

IVTD = 92.93−3.98·(MSW), r2 = 0.984, n = 11. Crude protein (CP) was characterized by a highly significant quadratic regression: CP = 40.89−7.38·(MSW) + 0.57 (MSW)2, R2 = 0.995, n = 11. The association of alfalfa quality and MSW has not been sufficiently tested to represent a general prediction model. However, the observed relationship indicates the potential usefulness of MSW in developing such a model.
Nitrogen Fixation by Corn‐Azospirillum Associations in a Temperate Climate1
Authors: Albrecht S. L. , Okon Y. , Lonnquist J. , Burris R. H.
Published: July 2010

The association of maize with the N2‐fixing bacteria Azospirillum brasilense was examined under controlled environment and field conditions to evaluate possible benefits for agriculture in temperate regions. Koch's postulates were established by inoculating, reisolating, and reinoculating sterile Zea mays L. plants. Under such artificial conditions, although nitrogenase activity was observed, there was no benefit for the plant. In greenhouse experiments inoculation o| Z. mays with Azospirillum showed slight increases in plant N and dry weight. Four field experiments were carried out with numerous Z. mays lines, and other grass species. In two experiments inoculation with A. brasilense showed increases in plant weight and percent N and the mean difference due to inoculation corresponded to 14 and 15 kg N/ha. Inoculation with Azospirillum produced no consistant beneficial effect, in either yield or increased plant N content. Our data suggest that an increased understanding of plant root‐rhizosphere N2‐fixing bacterial interactions is required before any consistant, significant beneficial N2‐fixing association can be developed.
Improvement of Sugarbeet Seed Emergence with Dilute Acid and Growth Regulator Treatments
Authors: Akeson W.R. , Freytag A.H. , Henson M.A.
Published: July 2010

Poor emergence of sugarbeet seedling under moisture, temperature, and impedance stress conditions can limit satisfactory stand establishment. The objective of this study was to permeate seeds with dilute acid, growth regulators, and other chemicals, alone and in combinations, and to determine the effect of these treatments on emergence under favorable and unfavorable conditions. Commercially processed seed was treated with 1.0 N hydrochloric acid, propylene, ethylene, 10 and 100 ppm gibberillic acid (GA3), 10 and 100 ppm kinetin, 10 and 100 ppm 6‐benzyl‐aminopurine (6‐BA), 1% sodium hypochlorite, 0.01 M pH 6.7 and 11.4 phosphate buffers, and fermentation, alone and in combination.

Effects of treatments on emergence of ‘GWH 58’ were evaluated in laboratory tests with combinations of moisture, temperature, and impedance stress and in field trials in 1977, 1978, and 1979. Laboratory tests showed that the acid treatment stimulates emergence under moisture and temperature, but not impedance stress conditions. The growth regulators ‐ GA3, kinetin, ethylene, and propylene stimulated emergence under combined moisture, temperature, and impedance stress. Under these conditions, acid and growth regulator treatment effects were additive.

In field tests, the growth regulator seed treatments stimulated emergence only in combination with acid pretreatment. The acid + 100 ppm GA3 treatment gave the most consistent positive results (significant at 0.05 in 69% of trials) and greatest average improvement in emergence (9.3% of seeds planted) over the control. Significant improvements in field emergence were also obtained with acid + 10 ppm GA3, acid + 10 and 100 ppm kinetin, acid + 10 and 100 ppm 6‐BA, and acid + 100% propylene. Combinations of growth regulators gave no improvement in emergence over that of the individual growth regulators. The acid seed treatment improved emergence only under moisture stress conditions. Cultivars differed in their response to acid + 100 ppm GA, and acid + I00 ppm kinetin treatments in laboratory and field emergence trials conducted in 1980.
Seedling Growth of Cicer Milkvetch as Affected by Seed Weight and Temperature Regime1
Authors: Townsend C. E. , Wilson A. M.
Published: July 2010

Seedling vigor of cicer milkvetch (Astragalus cicer L.) has been improved by breeding for high seed weight, but it is not known how growth characteristics differ among seedlings derived from seed of different weight classes. Therefore, the objective of this study was to determine the effect of seed weight (3.2, 3.6, 4.0, 4.4, 4.8, 5.2, and 5.6 g/1,000 seeds) and temperature regime (20 C day/15 C night and 25 C day/20 C night) various seedling growth traits. When averaged over all sampling dates, temperature regime significantly affected area of upper leaves; dry weight of cotyledons, primary leaf, upper leaves, stems, and roots; height of seedlings; total dry weight of shoots; and total dry weight of seedlings. Values for all traits except weight of cotyledons and primary leaf were higher at 25/20 C than at 20/15 C. Cotyledon area and primary leaf area were not influenced by temperature. Within a temperature regime, seed weight also significantly affected all characters. For most seedling traits an increase in dry weight or area was associated with increased seed weight.

In a growth analysis study, temperature treatments significantly affected initial seedling weight, initial leaf area, relative growth rate, relative leaf area expansion rate, relative leaf weight expansion rate, leaf area partitioning coefficient, leaf weight partitioning coefficient, and final seedling weight. Temperature regime did not affect initial leaf weight and net assimilation rate. Seed weight was positively and linearly associated with initial seedling weight, initial leaf area, and initial leaf weight at both temperatures and with final seedling weight at 20/15 C. The lack of association of seed weight with some important growth analysis traits suggests that certain seedling vigor characters are entirely independent of seed weight. The initial advantage of high seed weight progenies, however, tended to be maintained in the early phases of seedling development, as indicated by final seedling weight. Thus, with populations selected for high seed weight, additional progress in improving seedling vigor might be achieved through selection for relative leaf area expansion rate, net assimilation rate, or other traits.
Non‐Genetic Factors Affecting Primary Root Absence in Lovegrass and Kleingrass1
Authors: Tischler C. R. , Voigt P. W.
Published: July 2010

Small percentages of seedlings of ‘Selection 75’ kleingrass (Panicum coloratum L.) and ‘Ermelo’ lovegrass [Eragrostis curvula (Schrad.) Nees] have no primary root at emergence. An investigation was undertaken to determine whether light, temperature, mechanical damage, or butyric acid treatment increases the frequency of seedlings having no primary root (no‐root seedlings). In both grasses, frequency of the no‐root characteristic was significantly higher in seedlings grown at 35 C than in seedlings grown at 20 C. Lighter (less mature) seed produced higher percentages of noroot seedlings than heavier (more mature) seed. Frequency of no‐root seedlings was significantly increased in Selection 75 by a butyric acid treatment of 7.5 × 10‐3 M. Vigorous mechanical threshing (hammermilling) did not increase the frequency of no‐root seedlings in Ermelo. Results of a depth‐of‐planting experiment demonstrated that in seedlings of Selection 75, exposure of the coleoptile to light led to normal root growth in no‐root seedlings. In Ermelo, however, coleoptile exposure to light had no effect on percentages of no‐root seedlings. These data suggest that the cause of no‐root plants differs between the two species.
Mechanical Disruption of Leaf Tissues and Cells in Some Bloat‐Causing and Bloat‐Safe Forage Legumes1
Authors: Lees G. L. , Howarth R. E. , Goplen B. P. , Fesser A. C.
Published: July 2010

Whole leaves and isolated mesophyll cells from three bloat‐causing and three bloat‐safe legumes were mechanically damaged to identify characteristics which might contribute in resisting cell and tissue rupture during chewing and hence reduce bloat potential. Whole leaves were subjected to sonication, homogenizing with a ground glass tissue grinder, and shaking with glass beads. Isolated cells were exposed only to rupture by sonication. In the bloat‐safe legumes, birdsfoot trefoil (Lotus corniculatus L.) had strong cell walls alone, while sainfoin (Onobrychis viciifolia Scop.) and cicer milkvetch (Astragalus cicer L.) revealed moderately strong cell walls combined with a high degree of tissue strength. The bloat‐causing legumes, alfalfa (Medicago sativa L.) and white clover (Trifolium repens L.) showed weak cell walls with low tissue strength while red clover (T. pratense L.) had moderately strong cell walls and low tissue strength. Cell wall strength alone or combined with tissue strength appears to be a factor in determining cell rupture.
Inheritance of Photoperiod Response in Barley1
Authors: Barham R. W. , Rasmusson D. C.
Published: July 2010

Inheritance of photoperiod response was studied in barley (Hordeum vulgare L.). ‘Manker,’ which is relatively insensitive to daylength was crossed to four sensitive genotypes: CI 8044, ‘Steptoe,’ CI 5064, and CI 7452. The F1, F2, F3, and backcross generations were evaluated for photoperiod response in a short‐day environment (10 hours light and 14 hours dark). Photoperiod response was measured by the number of days from emergence to the beginning of internode elongation (identified as node at ground level, NGL). Manker required 23 days, on the average, to reach NGL, while CI 8044, Steptoe, CI 5064, and CI 7452 required 44, 57, 60, and 66 days, respectively. In a long‐day environment Manker reached NGL in 21 days, which was within the range of 19 to 25 days required for the sensitive genotypes to reach NGL. Thus the large differences observed in short days appear to be due to photoperiod sensitive genes rather than maturity genes. The progeny distributions were continuous in all generations and serve to indicate that quantitative inheritance is important in determining photoperiod response in barley. Additive effects predominated, although dominance appeared important in one cross and epistatic effects were detected in three of the four crosses. Parent‐offspring regression of F3 family means on F2 plants gave estimates of heritability of 0.96 ± 0.04, 0.77 ± 0.10, 0.74 ± 0.06, and 0.77 ± 0.06 in the four populations. These estimates are in good agreement with realized heritability estimates, obtained in a selection experiment, of 0.94, 0.70, 0.75, and 0.95. Although major genes were not detected, the high heritability values and the selection results indicated that breeders should have little difficulty when selecting for photoperiod response in these and similar barley populations.
Natural Cross‐Pollination in Diploid and Autotetraploid Soybeans1
Authors: Sadanaga K. , Grindeland R.
Published: July 2010

Natural cross‐pollination in diploid and autotetraploid soybeans [Glycine max (L.) Merr.] was determined by use of recessive genes d1d2, which conditioned green seed color, in the female parents and the dominant alleles D1D2 in the pollen parents. In three‐row plots, the center row was planted to the female parents, and the outer rows to the pollen parents. The frequency of cross‐pollination in the autotetraploids flanked by diploids was 0.04%, in the control (normal diploids flanked by normal diploids), 0.17%; in the normal diploids flanked by autotetraploids, 0.07%; and in diploid male‐sterile (ms2) strain flanked by autotetraploids, 62%. Natural cross‐pollination between diploid and autotetraploid soybeans tailed to produce triploids. Seedlings from hybrid seeds from autotetraploid plants were autotetraploids; seedlings from hybrid seeds from diploid plants were diploids. The hybrids were the result of cross‐pollination from nonflanking rows of 4n male parents in the former and 2n male parents in the latter.

Five trisomics, one monotelotrisomic, one tetraploid, and one mixoploid were found among 175 hybrid progeny in the ms2 strain.
Variability in Primitive and Wild Wheats for Useful Genetic Characters1
Authors: Sharma H. C. , Waines J. G. , Foster K. W.
Published: July 2010

Ninety‐three accessions of primitive domesticated diploid wheat (Triticum monococcum L.), five each of two wild tetraploid wheats (T. turgidum L. var. dicoccoides Körn and T. timopheevii Zhuk. var. araraticum Jakubz.), one cultivated durum wheat (T. turgidum L. var. durum Desf. ‘Modoc’) and one cultivated bread wheat (T. aestivum L. var. aestivum ‘Anza’) were compared for plant height, seed weight, flour protein content, flour lysine content, lysine content in protein, spike weight, days to head, and days to flower under irrigated and dryland conditions in 1977. Superior lines were retested in 1979. Variation among lines for each trait in different species was significant except plant height in dicoccoides and araraticum. Over all species, plant height and seed weight were significantly higher, and protein and lysine contents were significantly lower in irrigated than in dryland conditions, although differences within dicoccoides for seed weight and protein and lysine contents were nonsignificant. Two accessions of monococcum were short and headed and flowered as early as Modoc and Anza. Primitive and wild wheats were higher in protein content and lysine content but lower in spike weight and seed weight than the two modern cultivars. Wild tetraploids were higher in flour protein content and in flour lysine content but lower in lysine content in protein than monococcum. Accessions of dicoccoides and araraticum having 30.9 and 30.5% protein, respectively, were identified. Correlations between traits were influenced by species and by moisture conditions. Best lines of monococcum, dicoccoides, and araraticum were identified as sources of genes for different traits.
Pollination of Male‐sterile Soybeans in Caged Plots1
Authors: Koelling P. D. , Kenworthy W. J. , Caron D. M.
Published: July 2010

Seed production on male‐sterile soybeans [Glycine max (L.) Merr.] in cages with honeybees (Apis mellifera L.) and alfalfa leafcutting bees [Megachile rotundata (F.)] was compared with plants exposed to native insect populations in open‐caged plots and with plants grown in closed cages. All plots consisted of alternate rows of ߢWilliamsߣ male‐sterile plants (ms2, ms2) and ‘Calland’ which were covered by cages after flowering commenced. Significant differences were found between treatments for the number of seeds/plant, pods/plant, and seeds/pod. A significant increase in seed production of over 477% was observed on plants in cages containing the bees compared with plants in open or closed cages. No significant differences in seed production were observed between open or closed cages or between the use of honey or alfalfa leafcutting bees as the pollen vector. Honeybees were efficient pollen vectors, but were inconvenient to handle. Leafcutting bees seem to be preferable for mass pollination of male‐sterile soybeans in caged studies because of their temperament and ease of handling.
Nitrogen Volatilization from Rice Leaves. I. Effects of Genotype and Air Temperature1
Authors: Stutte C. A. , da Silva P. R. F.
Published: July 2010

Rice (Oryza sativa L.) plants lose significant amounts of volatile N in conjunction with the transpirational water vapors. This experiment was designed to examine the patterns of volatile N loss and transpiration in a number of cultivars and to determine the influence of air temperature on this loss. Water‐soluble, nonelemental N in the transpirational condensate was analyzed by pyro‐chemiluminescence. The results indicated that marked differences in the rates of volatile N loss occurred among rice cultivars. On most sampling dates, ‘Lebonnet’ showed the lowest rate of N loss among the very short‐season cultivars, and ‘Nortai’ generally lost less N/dm2 leaf area than the other two midseason cultivars. The increase in temperature from 30 to 35 C greatly increased the rate of volatile N loss in all cultivars tested. Within a maturity group, differences in rates of N loss among cultivars were relative to their sensitivity to temperature variations. The process of volatile N loss may constitute a defense mechanism of plants against ammonium toxicity under stress temperature.
Brown Midrib Mutants in Sudangrass and Grain Sorghum1
Authors: Fritz J. O. , Cantrell R. P. , Lechtenberg V. L. , Axtell J. D. , Hertel J. M.
Published: July 2010

Three low lignin, brown midrib (bmr) sorghum (Sorghum bicolor L. Moench) mutants, designated bmr‐6, bmr‐12, and bmr‐18, were each backcrossed to normal grain‐ and grassy‐type sorghums. The objective was to determine if the effect of the brown midrib mutants on fiber composition would be expressed equally in both grain‐ and grassy‐type genetic backgrounds.

Analysis for fiber composition and in vitro dry matter disappearance (IVDMD) was conducted on mature stem tissue of mutant and normal plants from the F2 generation Of the first and second backcross. The bmr‐6 mutant reduced lignin percentage from 10.3 to 8.5 (P < 0.01) and increased IVDMD percentage from 39.6 to 48.7 (P < 0.01). Mutant ✕ background and mutant backcross interactions were not significant (P > 0.10), indicating that the effect of the bmr‐6 mutant was expressed as well in grassy‐type as in grain‐type backgrounds. Similar results were obtained with the bmr‐12 and bmr‐18 mutants. These mutants, evaluated after only one backcross, reduced stem lignin from 8.3 to 6.1% (P < 0.01) and increased IVDMD from 44.0 to 55.5% (P < 0.01). The effects were expressed as well in grassy‐type as in grain‐type backgrounds.

Results indicate that sudangrass sorghums containing brown midrib mutant genes are lower in lignin percentage and higher in digestibility than normal genotypes. Mutant sudangrasses of this nature should be higher in digestible energy percentage and should result in greater animal production than normal sudangrasses [Sorghum sudanense (Piper) Stapf] when fed to ruminant animals.
Gramine in Barley Forage ‐ Effects of Genotype and Environment1
Authors: Hanson A. D. , Traynor P. L. , Ditz K. M. , Reicosky D. A.
Published: July 2010

Consumption of reed canarygrass (Phalaris arundinacea L.) containing about 2,000 μg dry wt or more of the indole alkaloid gramine can adversely affect ruminant performance. Because gramine occurs in barley (Hordeum vulgare L.) leaves, 20 cultivars of barley and four races of Hordeum spontaneum Koch were analyzed for gramine and related alkaloids after growth in controlled environments (21/16 C, day/night) to the fourleaf stage. Shoot gramine levels ranged from <30 to >10,000 μg/dry wt; 10 ‘high‐gramme’ genotypes (six H. vulgare, four H. spontaneum) contained at least 2,000 μg/g. Other indole alkaloids were absent or present only in trace amounts.

Beginning at the two‐leaf stage, the high‐gramine barley cultivars ‘Arimar’ and ‘Maraini’ were grown for 2 weeks at 21/16 C and 30/25 C, with either adequate or limited water supply. Growth of both cultivars at the higher temperatures approximately doubled their gramine concentrations (to about 4,000 μg/g). Cyclic wilting, which resulted from limiting irrigation, did not greatly affect gramine concentrations. In a cool, spring, field planting at a loamy, non‐irrigated site, the gramine concentration in Arimar shoots was 1,700 μg/g at the three‐to‐four‐leaf stage, but fell to 200 μg/g at the six leaf stage. In a warm, summer, field planting at a sandy irrigated site, the gramine concentrations at both three‐to‐four and six‐leaf stages were ≥2,700 μg/g in Arimar and ≥4,500 μg/g in Maraini.

Gramine merits attention as a potential anti‐quality factor in breeding programs for barley suited to grazing or other forage uses.
Selection to Modify Sugar Content of Soybean Seeds1
Authors: Openshaw S. J. , Hadley H. H.
Published: July 2010

The objectives of this study were to investigate the inheritance of sugar concentration in soybean [Glycine max (L.) Merr.] seeds and the effect of selection for that trait on protein and oil concentration, weight, and yield of seeds. We studied the F2, F3, and F4 generations of one cross and the F2 and F3 of another. Heritability estimates of sugar concentration based on parent‐progeny regressions were 0.38 and 0.14 when selection was based on individual F2 plants and 0.69 when selection was based on F3 progeny means. The values agreed well with estimates based on variance components and with realized heritabilities. In one cross, realized heritabilities were greater for increased than for decreased sugar. There was no indication of genotype × year interaction for sugar content. Sugar was positively associated with oil and negatively associated with protein and the sum of oil + protein. In some generations, low sugar was associated with decreased yield.
Inheritance of Dwarf and Semidwarf Plant Height in Barley1
Authors: Sears R. G. , Kronstad W. E. , Metzger R. J.
Published: July 2010

Inheritance of dwarfism in barley (Hordeum vulgare L.) was studied in a six parent diallel involving the standard height cv. ‘Larker’ and five short statured lines: OR‐SS‐2, Minn. 66‐102, ‘Indian Dwarf,’ ‘Apam Dwarf’ and Xv 2334‐6R. Data from F2 populations and selected F3 progenies indicated that four recessive gene pairs segregating independently account for the differences observed in plant height. Apam Dwarf, Indian Dwarf and Xv 2334‐6R appear to have the same two major recessive gene pairs for dwarfness which act in an additive manner. Minn. 66‐102 and OR‐SS‐2 each carry a different single recessive gene pair for semidwarf plant height. Segregation observed in crosses among Minn. 66‐102, OR‐SS‐2, and Apam Dwarf indicated all three parents have different genes for dwarfness. Four genes were identified. They are recessive, additive and are transmitted independently.
Release of Soluble Protein and Nitrogen in Alfalfa. II. Infleunce of Potassium and Nitrogen Fertilizer on Three Cultivars1
Authors: Walgenbach R. P. , Marten G. C.
Published: July 2010

Reduced incidence of ruminant bloat was reported on legume pastures fertilized with high levels of potassium (K) or K plus nitrogen (N). Amount of soluble protein released from alfalfa (Medicago sativa L.) into sodium maleate buffer (pH 6.9) was proposed as possible estimate of ruminant bloat potential in comparative studies. Our objective was to determine whether K and N fertilization would influence concentration of several N fractions released from alfalfa.

‘Ramsey,’ ‘Saranac,’ and ‘520’ alfalfa cultivars were fertillzed in the fall with 0 (control), 350, and 700 kg as K2SO4/ha and in the following spring with these same levels of N as NH4NO(34 3 × 3 factorial). The upper 10 to 15 cm of told‐bud stage alfalfa in first and second crops was analyzed for several N fractions.

As N applied increased, mean concentrations of total N (TN), total soluble N (TSN), soluble nonprotein (SNPN), and soluble protein N (SPN) increasedm first‐harvest herbage. Mean concentrations of SPN increased 10.8% at 300 kg N/ha and 13.3% at 700 kg over that in alfalfa not fertilized with N. As the K level increased, mean concentrations of TN, TSN, and SNPN decreased in first‐harvest herbage. Fertilization with K did not affect concentration of SPN. Mean concentrations of TN, TSN, and SNPN in Saranac and TN, TSN, and SPN in 520 first‐harvest herbage were slightly but significantly greater than those in Ramsey. Cultivars did not affect concentrations of N fractions in secondharvest herbage.

We found no evidence that fertilization of alfalfa with K or N reduced its apparent bloat potential, as estimated by SPN release. Instead, we showed that alfalfa fertilized with high levels of N had a slightly increased apparent bloat potential.
Cytoplasmic Male Sterility in Helianthus giganteus L. × H. annuus L. Interspecific Hybrids1
Authors: Whelan Ernest D. P.
Published: July 2010

A potential new source of male‐sterile cytoplasm was successfully produced using interspecific hybridization of Helianthus spp. A partial substitution of the nucleus of cultivated sunflower [H. annuus L. (2n 5 34; x = 17)] into the cytoplasm of the perennial H. giganteus L. (2n = 34) was obtained by hybridizing H. giganteus with wild H. annuus, and then backcrossing four times, using the open‐pollinated sunflower ‘Saturn’ as the recurrent pollen parent. Plants with indehiscent anthers and white, rather than normal yellow, pollen were found after two crosses by Saturn. Progeny from these plants were male sterile for two further backcrosses. In vivo germination tests of pollen from 20 such male‐sterile plants indicated complete pollen sterility for 15, but normal seed set when cross‐pollinated, suggesting that female fertility was not affected. Crosses between an inbred tester line without genes for pollen fertility restoration as the pollen parent and an existing source of male‐sterile cytoplasm or four putative malesterile backcross lines as the female parents, failed to restore pollen shed in the 15 F1 families evaluated. In similar crosses using three pollen fertility restorer sources as the pollen parents, pollen shed was restored in some or all plants of nine F1 families involving an existing source of male‐sterile cytoplasm. However, pollen shed was restored in male‐sterile backcross lines by only one of the three pollen restorer sources, suggesting that the backcross substitution lines from H. giganteus are a potential new source of male‐sterile cytoplasm, which has been designated as cms3.
Phenotypic Recurrent Selection for Increased Leaf Weight and Decreased Alkaloid Content of Burley Tobacco1
Authors: Gupton C. L.
Published: July 2010

Nine populations were derived in the selection phase of experiments designed to evaluate a recurrent selection scheme in hurley tobacco (Nicotiana tabacum L.). We produced an unselected population of heterozygotes (Co), three populations by recurrent selection for increased weight of green leaves, and five populations by recurrent selection for decreased percent total alkaloids (% TA) of green leaves. Evaluations of the experimental material were made at three locations. The objectives wre to determine the effects of phenotypic recurrent selection on green tobacco and to ascertain the correlated effects of such selection on the yield and alkaloid content of cured tobacco.

In response to selection, green leaf weight increased somewhat consistently from C0 to C3 and % TA declined linearly from Co, to C3 The correlated response of cured leaf weight to selection on a green weight basis was a linear increase, averaging 8.1 g per plant per cycle. Percent total alkaloids of cured leaf also declined linearly with successive cycles of selection on a green leaf basis. Five cycles of selection resulted in nearly 23% reduction in percent TA.

The genetic correlation coefficient between green leaf weight and percent TA was −0.50 and −0.62 at two locations. This negative relationship may be a limiting factor in practical usage of phenotypic recurrent selection to increase yields without the aid of a selection index.