bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Soil Water Holding Capacity on the Cold Test for Soybean1
Authors: Tao Kar‐Ling J.
Published: July 2010

Two types of soil varying in water holding capacity (WHC) were used for the cold test. The same seed lot of ‘Wells’ soybean (Glycine max (L.) Merr.) showed 71% emergence in a muck soil (WHC 78% w/w) in contrast to 2% in a silt loam (WHC 25% w/w). Soil sterilization slightly increased the emergence percentage in both soils. Modifying the WHC of the muck soil with the addition of sand showed a significant decrease in the emergence percentage at a level of 42% but not at 52%. Seedling length also varied among soils of different WHC. Similar emergence percentages were obtained in the silt loam soil and the muck soil after the WHC of both soils had been adjusted to approximately 50% w/w by the addition of sand. However, other additives tested caused a decrease in germination. Results of the cold test using a soil with WHC of 52% showed high correlation with the field emergence of five seed lots of three cultivars in two different plantings under stress conditions (r ‐ 0.91 and 0.96). Evidence, however, indicated that cold tests failed to predict seed vigor in ‘Evans’ soybeans.
Cytoplasmic Male‐Sterility in Flax: Restorer Gene Frequency and Degree of Corolla Opening1
Authors: Thompson T. E. , Miller J. F.
Published: July 2010

A cytoplasmic male‐sterile flax (Linum usitatissimum L.) line was crossed with 1,455 entries from the USDA World Flax Collection. We determined the frequency of restorer genes in the collection and the possibility of using this type of sterility to develop a random mating breeding population to mix germplasm. Because 1,155 of the lines (79%) are sterility maintainers and because some natural field crossing occurs in flax, this sterility system should allow random mating flax populations to be developed for the first time. A second objective was to identify sources of genes that condition the production of open‐corolla, male‐sterile flowers in plants containing the sterile cytoplasm. This factor has prevented the use of this male‐sterility system to produce commercial flax hybrids. Thirty accessions were identified as possible sources of genes for this trait. It appears that breeding systems can be used to develop male‐sterile lines that produce normal open flowers accessible to insect pollination. Plant age affected degree of corolla opening and male‐fertility of the F1 plants. Average corolla opening decreased from 13.97 to 8.8 mm in I0 weeks for plants expressing this trait, while the number of F1 plants producing F2 seed increased from 155 to 302. Stability of both traits varied from line to line and should be of concern to breeders who use this form of sterility in flax improvement.
Inheritance of Seed Weight, Pappus, and Striped Hull in Safflower Species1
Authors: Kotecha Ashok , Zimmerman L.H.
Published: July 2010

Wild parents of safflower (Carthamus palaestinus L.) had abundant pappus and small seed, whereas domestic parents had little or no pappus and large seed. Low variances of nonsegregating populations suggested that environmental effects on pappus and seed weight were not strong and that variability was largely genetic. Nonadditive gene action for seed weight and pappus was indicated by the Mather and Jinks model. Heritability estimates in the broad sense for pappus were high (above 93%); however, they ranged from 66 to 85% for seed weight. Heritability estimate in the narrow sense for pappus was 88%. Maternal effects were not observed for seed weight. At least two loci are involved in the inheritance of seed weight and pappus. Anthocyanin pigmentation and striped hull assorted independently. Correlation coefficients for seed weight with pappus were low.
Seasonal Competition in Spring and Winter Wheat Mixtures1
Authors: Jensen Neal F.
Published: July 2010

The effects of competition on yield of grain was studied in mixed populations of a winter and a spring wheat (Triticum aestivum L.) cultivar sown in their respective planting seasons. Viable and nonviable seeds of the two cultivars, winter ‘Genesee’ and spring ‘Justin’, were mixed in 26 planting ratios. Separate nurseries were sown for the fall and spring planting seasons, respectively. The nature of the cultivars was such that only Genesee was harvested in the fall‐sown experiment and only Justin in the spring‐sown experiment, that is, fall‐sown Justin winterkilled and spring‐sown Genesee remained in the vegetative stage. In the fall‐sown nurseries there was root or underground competition and a low level of aerial competition throughout the season. The results showed that winter wheat yields depended largely upon the density and vigor of the post‐winter population stand. The Genesee plants showed excellent ability through tillering and vigor to compensate for stand differences. The yields of spring wheat were depressed by the presence of winter plants in their midst and this effect was approximately in proportion to the planting ratios. Conclusions from the study point towards the importance of breeding winter wheats with superior post‐winter plant establishment.
Inheritance of Resistance to Cucumber Mosaic Virus Infection in Mungbean1
Authors: Sittiyos Prathes , Poehlman J. M. , Sehgal Om P.
Published: July 2010

The resistant reaction to cucumber mosaic virus, CMV‐M, infection in mungbean (Vigna radiata (L.) Wilczek) strain PI 271401, in crosses with susceptible strains PI 201868 and PI 368307, was conditioned by a single dominant gene designated Cmm. The Cmm locus was not linked with loci controlling color of seed texture layer or color of seed coat. Seed yields of CMV‐M susceptible F2 plants in the field were reduced by more than 50% compared to resistant plants.
Studies of Inbreeding Depression, Breeding Behavior, and Heterosis with Inbred Lines of Buckwheat1
Authors: Marshall H. G.
Published: July 2010

Homomorphic, self‐fertile inbred lines of buckwheat (Fagopyrum esculentum Moench) are a recent development, and little is known about their potential for improvement of the crop. My objectives were to determine the breeding behavior of several inbred lines and to measure the effects of inbreeding depression and heterosis on several characteristics of buckwheat.

In polycross blocks during 2 years, all inbreds had reduced gross size, plant height, seed yield, and seed weight relative to an open‐pollinated parent. The percentage of hybrid plants in the polycross populations ranged from 0 to 93. All polycross hybrids exhibited heterosis for plant height and dry weight at the early blossoming stage compared to their seed parent and to all the possible inbred pollen parents. During 2 years, populations with the highest percentages of hybrids were the highest yielding, but none exceeded the yield of an open‐pollinated check strain.

The four inbred lines with the least selfing in the polycross trials were paired in enclosed areas to produce single‐cross populations. ‘Kasho’, a cultivar with both compatible and incompatible pollen, also was paired with each of the inbreds. The percentage of hybrid plants in the inbred line combinations ranged from 5 to 72. Differences were found between reciprocal crosses for some combinations. When Kasho was the pollen parent, the percentage of hybrid plants ranged from 28 to 97. Regardless of the pollen parent, an inbred with the shortest style (0.58 vs. up to 1.16 mm) provided the fewest hybrids. The higher percentages of hybrids from Kasho pollinations apparently resulted from a differential rate of pollen tube growth that favored compatible pollen from thrum flowers. Differential pollen tube growth could provide pollen control to produce hybrid cultivars if thrum‐flowered inbred lines can be developed.

Heterosis was studied in 10 of the single‐cross populations. Relative to the high inbred parent, all single‐crosses showed heterosis for plant height and total dry matter yield, eight showed heterosis for seed yield, and five showed heterosis for seed weight.
Flower Induction in Glycine Tomentella Hayata following Grafting onto G. Max (L.) Merr.1
Authors: Newell C. A. , Hymowitz T.
Published: July 2010

An accession of Glycine tomentella Hayata, subgenus Glycine Willd. (P.I. 393567) from Northern Territory, Australia was induced to flower by grafting it onto a stem of the cultivated soybean G. max (L.) Merr., subgenus Soja (Moench) F. J. Herm. All previous attempts to obtain seed from P.I. 393567 by short photoperiods and ageing had failed. The G. tomentella scion grew vigorously and produced a large number of seed pods under a photoperiod regime conducive to flowering in the soybean. The parent plant from which the scion was obtained did not flower under the same conditions. These results indicated that flowering in the scion probably was induced by a floral stimulus from the soybean stock. Cytological examination showed P.I. 393567 to be tetraploid with 2n=80.

Grafting was demonstrated to be a successful method of promoting seed production in a wild Glycine accession which did not otherwise flower under experimental conditions, thereby enabling conservation of germplasm which could not readily be replaced.
Identifićation of a Combine‐Height Grain Sorghum Dominant for Dw1
Authors: Ross W. M. , Kofoid K. D.
Published: July 2010

A combine‐height sorghum (Sorghum bicolor (L.) Moench) selection from SC 102‐9 gave tall F1'S when crossed to lines dominant for the height genes Dw2 Dw3 or Dw4. Appropriate test crosses indicated that the line was the first recorded instance of the height genotype Dw1 Dw1 dw2 dw2 dw3 dw3 dw4 dw4. It can be used for genetic studies and for classification of parents for proper use in either grain or forage sorghum hybrids.
Spikelet Abscission in Guineagrass as Influenced by Auxin and Gibberellin1
Authors: Weiser Glen C. , Smith Rex L. , Varnell Ray J.
Published: July 2010

Seed production of guineagrass (Panicum maximum Jacq.), an important pasture and forage crop in the tropics, is hindered by its heavy loss of seeds through spikelet abscission. A method whereby abscission could be delayed or arrested would be a great aid in seed harvest of this and other Panicum species.

Auxin and gibberellin at three concentrations (10‐3, 5✕10‐3 and 10‐2M) were applied to the inflorescences of two experimental genotypes (PM285 and 68s‐5‐2) when the panicle was three‐fourths emerged from the flag leaf to inhibit spikelet abscission. Growth chamber and field experiments were conducted.

Response was dependent on plant genotype and growth regulator concentration. In the growth chamber, panicle branch explants were inserted into semisolid agar solutions of growth regulators. The most responsive auxin treatment inhibited abscission by 32%. In the field, aqueous sprays of growth regulators were app.lied to entire inflorescences. The most responsive auxin treatment inhibited abscission by 40%, The two genotypes responded differently to IAA treatment with 68s‐5‐2 exhibiting significantly less abscission than PM285. Gibberellin treatments either stimulated abscission or had no influence under the conditions tested.

Histological sections of pedicels of the genotype 68s‐5‐2 were made to follow the development of the abscission zone with and without applied auxin. The abscission zone exhibited no readily observable morphologlc or histologic response to auxin.
Recurrent Selection in Soybeans. II. Selection for Increased Percent Protein in Seeds1
Authors: Brim C. A. , Burton J. W.
Published: July 2010

Recurrent selection for increased percent protein in seeds was conducted in two soybean (Glycine max (L.) Merrill) populations to test the utility of the selection procedure. Population I was derived from a cross of two highly adapted experimental lines. Population II was generated from backcrosses of nine unadapted plant introductions with high percent seed protein to a highly adapted experimental line. Each population was subdivided into an A and a B population. The effective population size of populations IA and IIA was about three times larger than that of IB and IIB. A cycle of selection involved intermating selected lines, testing S1 lines from the matings, and selecting those with highest percent seed protein as parents for the next cycle. Selection progress was evaluated in replicated field trials using composite popula. tions of the parents chosen from the testing generation in each cycle as entries.

Percent seed protein increased significantly and linearly in all populations. Seed protein increased from 46.3 to 48.4% with six cycles of selection in population IA and from 46.4 to 47.6% with four cycles in population IB. In population IIA, protein increased from 42.8 to 46.1% with five cycles and from 43.2 to 45.9% with four cycles of selection in population IIB.

Yield of the last cyde in both populations IIA and IIB. was significantly lower than that for C0, yet the change in total protein produced per unit area was nonsignificant. In population IA, however, both yield and total protein produced increased significantly from C0 to C8. There was no significant change from C0 to C4 for yield or total protein in population IB. Despite the significant linear decrease in percent seed oil, the total oil produced per unit area decreased significantly in populations IIA and IIB only.

The results show that significant progress can be obtained from recurrent selection for protein in soybeans. Reduced effective population size and numbers of lines tested per cycle had little effect on progress.
Progress from Adaptive Mass Selection in Incompletely Adapted Maize Populations1
Authors: Compton W. A. , Mumm R. F. , Mathema B.
Published: July 2010

Increasing genetic variation by the use of exotic germlasm is commonly recognized as desirable. Methodology or large scale application of this principle to maize (Zea mays L.) has not been very well developed. This study shows that mass selection for adaptation and prolificacy can result in yield increases without necessarily changing other traits which usually show correlated responses to selecton for yield alone. Mass selection for adaptation and prolificacy resulted in increases in yield, plant height, and ear height, slight increases in days‐to‐flower and ears‐per plant, and no change in grain moisture at harvest.
Stormproof Boll in Upland Cotton. I. Development of Instrumentation and an Inheritance Study1
Authors: Dilbeck R. E. , Quisenberry J. E.
Published: July 2010

The stormproof boll is a desirable trait for cultivars of cotton (Gossypium hirsutum L.) grown for once‐over stripper‐type harvest. The purpose of this study was to develop instrumentation to measure stormproofness (lock tenacity) and to determine the inheritance of the stormproof boll in a particular cross using this instrumentation. Parental, F1, F2, and backcross populations from a cross between ‘Acala 1517 Br‐2’ (non‐stormproof) and Z‐2557 (stormproof) were scored for visual appearance and measurement of lock tenacity to study qualitative inheritance patterns. Analysis of variance and joint scaling tests were conducted on the lock tenacity data for quantitative determinations of inheritance.

The instrumentation developed was capable of detecting differences between stormproof and non‐stormproof boll types. Differences between combinations (pulls per boll ✕ number of bolls per entry) were not significant, while differences between entries were significant. Visual classification of segregating populations indicated that a single dominant gene controlled the stormproof character. However, data from lock tenacity determinations made on these same populations indicated a more complex mode of inheritance. Estimates from the joint scaling test suggested that additive, dominant, and epistatic genetic effects controlled the expression of lock tenacity.
Improved Rate of Callus and Green Plant Production from Rice Anther Culture Following Cold Shock1
Authors: Genovesi A. Dennis , Magill Clint W.
Published: July 2010

Rice (Oryza sativa L. subsp. japonica) panicles containing pollen at the G1 G2, early binucleate, and late binucleate stages of development were subjected to 5, 10, and 13 C temperatures for 3, 7, 10, 14, and 21 days before placing the anthers on callus‐inducing medium. The uninucleate stages gave much higher frequencies of callus induction in both control and treated samples. In general, the more moderate temperature over a 10‐ to 14‐day treatment gave maximum frequency of callus induction. While most of the plants derived from G1 and G2 stage anthers stored in the cold for 2 weeks or less were green, plants from later pollen stages or 21 days of cold storage were predominately albino.
Haploid Plant Development from Anthers and In Vitro Embryo Culture of Wheat1
Authors: Schaeffer G. W. , Baenziger P. S. , Worley J.
Published: July 2010

Experiments were designed to identify cultivars of wheat (Triticum aestivum L., aestivum group) and culture media most suitable for successful in vitro anther culture and development of haploids. Anthers containing uninucleate pollen from 17 cultivars grown in the greenhouse and five lines grown in the field were excised and cultured on a potato (Solanum tuberosum L.) medium. ‘Kitt’, ‘Downy’, ‘Centurk’, and ‘GWO‐1809’ produced the highest number of embryoids from microspores.

Calli removed from anthers cultured in vitro were differentiated into plantlets. Over 50 plants have been recovered. Preliminary cytological determinations proved that the plants were haploid. The results demonstrate the feasibility of the anther culture techniques for the development of haploids in agronomically important wheats.

Embryos from presoaked and surface‐sterilized seed of 26 wheat lines were excised and planted on defined agar media to measure in vitro growth rates. Embryonic cells from mature wheat seeds divided and produced partially differentiated tissues on standard tissue culture media containing supplements of 2,4‐dichlorophenoxyacetic acid (2,4‐D), 2‐isopentenyladenosine, and naphthaleneacetic acid. Transfer of the calli to a medium with less 2,4‐D or to a medium with 1 mg/liter of indole‐3‐acetic acid and kinetin enhanced differentiation and the differentiated tissues ultimately produced whole plants. There were statistically significant differences in the growth rates, measured as fresh weight, among different lines. Among the promising lines for in vitro cultures were Kitt, GWO‐1809, ‘Baart’, ‘Coker 75‐6’, and others. Isolated embryos from some cultivars did not form calli in vitro. Kitt and GWO‐1809 grew well as partially differentiated calli.
Seedling Growth Responses of Oat Genotypes1
Authors: Murphy C. F. , Long R. C.
Published: July 2010

The objectives of these investigations was to utilize a seedling growth technique to (i) verify previous reports on growth responses of germinating seedlings to nutrient additives; (ii) determine how soon seedling growth sponses occur; (iii) measure differences in genotypic respouses.

A preliminary test with two F2 oat populations (Arena sativa L.) and their respective parents (‘Firecracker’ and ‘Goodand’; Goodland and N.C. 55) verified earlier observations of increased shoot growth and reduced root growth by 10‐lay‐old seedlings grown with a modified halfstrength Hoagland's solution, as compared to a growth medium of distilled water. Parental means were different and within‐parent variability was exhibited.

Shoot and root lengths and dry weights, plus root volume, were measured on 4‐ to 10‐lay‐old seedlings of four oat genotypes (‘Carolee’, ‘Salem’, N.C. 2469‐3, and Firecracker) grown in distilled water and in modified half‐strength Hoagland's solution. Responses to the nutrient solution were apparent for shoot length and weight, and generally occurred after 6 to 8 days, depending upon the genotype. Hoagland's solution resulted in increased shoot length and shoot weight but reduced root length. Root weight and volume did not respond to the nutrient solution.

Genotypic differences were evident for all five characters. The dwarf llne, N.C. 2469‐3, developed both shoots and roots more slowly than any of the other genotypes. Firecracker developed shoots and roots most rapidly while Carolee and Salem developed them at intermediate rates. Genotype ✕ growth medium interactions were evident for shoot length and weight and for root volume. A method for determination of root volume using the displacement technique is presented.
Linkage Studies in Sorghum1
Authors: Kullaiswamy B. Y. , Goud J. V.
Published: July 2010

Linkage relationships of six characters were studied in the sorghum (Sorghum bicolor (L.) Moench) cross SB1066 Χ M35‐1. The involvement of one to three genes was observed in different characters. Ratios for four of six characters are reported for the first time. Analysis of the joint segregation data revealed the existence of both pleiotropy and linkage. The gene q, controlling pigmentation in leaf sheath, was found to be linked with Ym1 (midrib color). Al2, (phyllotaxy), Lt2, (leaf sheath covering), and I‐Er (position of panicle). These genes were assigned to linkage group II.
Fusarium Wilt Resistance in Day‐Neutral Selections from Primitive Races of Cotton and Crosses of Race Selections with a Commercial Cultivar1
Authors: Kappelman A. J. , Jenkins Johnie N. , Parrott W. L.
Published: July 2010

Day‐neutral plants of selections from the primitive cotton (Gossypium hirsutum L.) race collection and from crosses of these with ‘Deltapine 16’ (DPL‐16) were evaluated for resistance to Fusarium wilt [Fusarium oxysporum Sehlect. f. vasinfectum (Atk.) Snyd. & Hans.]. Yield and fiber properties of advanced material from these crosses were also determined. When evaluated as race stock selections per se, or as advanced generation materials from crosses with DPL‐16, Fusarium wilt resistance of materials with either an accession 69 or 88 background was high. Selections of advanced materials from crosses of DPL‐16 with six other race accessions (78, 80, 87, 113, 116, and 495) were also highly resistant. Based on a I‐year evaluation at one location lint yields and fiber properties of all advanced materials (BC2F4) from crosses with DPL‐16 were not statistically significant from those of the two check cultivars (DPL‐16 and ‘Stoneville 213’).
Application of a Modified Diallel Analysis to Evaluate Recurrent Selection for Grain Yield in Maize1
Authors: Smith O. S.
Published: July 2010

The modified diallel analysis proposed by J. J. Hammond and C. O. Gardner in 1974 and the model proposed by O. S. Smith in 1979 to evaluate progress from recurrent selection were used ta evaluate half‐sib and S1 recurrent selection programs in the maize (Zea mays L.) cultivar, ‘BSK.’ Changes in the mean of selected populations and their crosses were found to be a function of inbreeding depression and changes in the frequencies of alkies with additive effects. Estimates of changes due to alleles with dominance effects were not significant. Terms involving changes due to alleles with dominance effects would be expected to be very small based on quantitative genetic theory and based on the way the terms were defined. Use of the modified diallel analysis for evaluating progress from recurrent selection may be limited to populations that have large effective population sizes and have undergone a large number of cycles of selection.

Use of the analysis proposed by Smith showed that half‐sib and S1 selection increased the frequencies of alleles with additive effects and S1 selection was more affective than half‐sib selection. The analysis also provided an estimate of the rate of inbreeding depression and indicated that this rate was the same for both selection methods.
A Self‐Leveling Cone Seedier for Experimental Plots1
Authors: Dewey W. G. , Albrechetsen R. S. , Merrill Jed
Published: July 2010

A four‐row cone seeder was constructed with the objective of retaining the speed and efficiency of the cone distribution system while overcoming its deficiencies on uneven terrain. A self‐leveling mechanism was developed which utilizes mercury switches to activate small electric motors and screw‐jacks. A single‐cone unit with a spinnerdistributor for multiple‐row plots is interchangeable with a four‐cone unit for planting individual rows. Disc, deep furrow, and shallow openers are easily interchangeable, as are three types of press wheels. Row lengths ranging continuously from 1.5 to 30 m are possible. The drill performed very satisfactorily in planting small grain yield trials over a wide range of terrain types during the 1978 season.
Inbred Lines vs. the Populations as Testers in Reciprocal Recurrent Selection1
Authors: Comstock R. E.
Published: July 2010

In reciprocal recurrent selection (RRS) the change in the average value of genotypes in the cross between the selection populations is a function of allele frequency changes in the two selection populations; the change is not a function of the details of the selection process by which those changes are promoted. Thus, the proper criterion to employ in comparisons of variations of RRS is the expectation of change per unit tune in the frequency of an allele. Using this criterion and theory flowing from the genetic model that assumes linkage equilibrium and no epistasis but allows any number of alleles per gene, I found that the RRS populations are slightly superior, as testers for each other, to inbred lines extracted from those populations. This finding contrasts to the suggestion by Russell and Eberhart (1975) that such inbred testers should be superior. Their suggestion was based on evidence of greater genetic variance among test progenies when inbred line testers were used. The theory reported herein shows this is to be expected (unless gene action is completely additive) but that a corresponding increase in allele frequency changes is not to be expected.

The results summarized above are discussed in relation to situations in which epistasis and linkage disequilibrium may be present. It is concluded that they are qualitatively correct in more general situations.
Germination and Stand with Cottonseed Treatment Fungicides: Formulations and Rates1
Authors: Minton Earl B. , Green Janet A.
Published: July 2010

Obtaining a stand of vigorous seedlings is a major problem in cotton (Gossypium hirsutum L.) production. The purpose of this study was to determine the effects of fungicide formulations and concentrations applied to cottonseed on germination in the laboratory and on emergence and survival of seedlings in greenhouse and field tests. Germination percentages with standard procedures at two temperature regimes were similar for cottonseed treatment with different rates and formulations of captan, N‐[(trichloromethyl)thio]‐4‐cyclohexene‐1, 2‐dicarboximide, and carboxin, 5,6‐dihydro‐2‐methyl‐l, 4‐oxathiin‐3‐carboxanilide, alone and in combination. No fungicide seed treatment gave significantly higher germination percentage than captan 0.94 g ai/kg, the rate used commercially. Germination was higher for some fungicide seed treatments than for the control (untreated), but most responses were not significant. Initial seedling stands for the control and the captan seed treatments were higher in field than in greenhouse evaluations, but coating the seed with either carboxin or captan + carboxin gave higher initial stands in the greenhouse. Final stands for all treatments were higher in field because of lower disease pressure from Rhizoctonia solani and Fusarium spp. than in greenhouse tests. Both pre‐ and post‐emergence damping‐off were more severe in green. house than in field tests. Slightly higher stands were obtained with the high rate of the fungicide seed treatments. All formulations of each fungicide gave similar results when used at comparable rates of active ingredient. Carboxin was superior to captan in increasing plant populations under severe disease infestations. Stands were higher for captan + carboxin than for either fungicide used alone but were lower than the sum of the effects of each fungicide alone.
Enzymatic Changes During the Senescence of Field‐grown Wheat1
Authors: Patterson T. G. , Moss D. N. , Brun W. A.
Published: July 2010

Senescence in the canopy of two field‐grown hard red spring wheats (Triticum aestivum L. em Thell ‘Era’ and ‘Kitt’) was evaluated during the post‐anthesis period. The upper three leaf blades and flag leaf sheath were measured for total and specific dry weights, RuBP‐carboxylase (RuBPCase) activity, and glucose‐6‐phosphate dehydrogenase (G‐6‐PDH) activity. Leaf dry weights and specific leaf weights were relatively constant during most of the grain‐filling period and declined slightly as maturity approached. RuBPCase activity was highest after anthesis, then declined for the rest of the post‐anthesis period. G‐6‐PDH activity increased after anthesis, then remained constant during the remainder of the grain‐filling period. Activities of both enzymes were not detectable at the end of the grain‐filling period, thus providing an indication of leaf senescence. By evaluating senescence on the basis of functional leaf metabolic activity, it should be possible to screen wheat genotypes or chemical treatments for altered senescence patterns.
Inheritance of Resistance to Bacterial Wilt in Two Alfalfa Gene Pools: Qualitative Analysis1
Authors: Viands D. R. , Barnes D. K.
Published: July 2010

Bacterial wilt caused by Corynebacterium insidiosum (McCull.) H. L. Jens. is a serious disease of alfalfa (Medicago sativa L.). Inheritance studies were conducted with germplasm from two diverse gene pools, MSA and MSB. Two sets of six‐parent diallels with reciprocals and selfs were produced within each gene pool. Two sets of parents from one gene pool were crossed with two sets of parents from the other. Eleven‐week‐old seedlings of progenies were inoculated with C. insidiosum and transplanted to the field. Fifteen weeks later the taproot of each plant was cross‐sectioned and scored for the amount of yellow‐brown discoloration.

MSA contained one dominant gene, BW1, for resistance. In the absence of other genes for resistance, plants with the genotype BW1… were classified as resistant and bw1bw1bw1bw1 plants were classified as susceptible. In addition to the BW1 gene, we believe that MSA contained two other genes, BW2 and BW3 with additive and smaller gene effects than those from BW1. The BW3 gene had a larger effect than the BW2 gene. The MSB gene pool did not contain resistant alleles at the BW1 locus, but it did contain resistant alleles at the BW2 and BW3 loci. Based on the genetic origins of the two gene pools, we suggest that the BW1 gene originated from ‘Turkistan’ and/or ‘Ladak.’ The BW2 and BW3 genes were probably from Chilean origin.
Distribution and Transformation of Soluble Carbohydrates during Germination Growth of Sorghum1
Authors: Newton R. J. , Baltuskonis D. A. , Goeschl J. D. , Meckenstock D. H. , Miller F. R.
Published: July 2010

Soluble components of sorghum (Sorghum bicolor (L.) Moench) seedlings growing in distilled water‐sand media were quantified with gas‐liquld‐chromatography. In light, peak levels of soluble component accumulation occurred in the roots in 4 days, in the endosperm in 8 days, and in the shoots in 10 days. Sucrose (2 µg/mg) was the predominant component in the dry seed. In 4‐day‐old seedlings, glucose and fructose levels were 15 and 20 µg/mg, respectively, in both shoots and roots. At l0 days, dhurrin levels in the shoot were 35 to 40 µg/mg and comprised 51% of the total soluble component while glucose accounted for 21%.

In the dark, dhurrin levels in 10‐day‐old shoots were 27% of the total solubles and glucose levels were 45%. Dhurrin levels were highest in the coleoptile‐shoot primordium region (90 µg/mg) and the upper, growing portion of the mesocotyl (28 µg/mg). Monosaccharide levels were highest in the upper, mesocotyl region with glucose at 74 µg/mg and fructose at 51 µg/mg. In 4‐day‐old scutella, sucrose to glucose ratios were greater than 3.

Dhurrin and monosaccharide levels were reciprocally related; this indicated the precursor roles of both glucose and fructose in glycoside synthesis. The detection of a glycoside with gas‐liquid‐chromatography has several distinct advantanges over the traditional, enzymatic‐colorimetric assay.
A Wheat Stem Rust Resistance Gene Common to 12 Cultivars of the Fourth International Winter Wheat Performance Nursery1
Authors: McVey D. V.
Published: July 2010

The wheat (Triticum aestivum L.) cultivar ‘McNair 701’ (CI 15288) was considered universally susceptible to wheat stem rust (Puccinia graminis Pers. f. sp. tritici) until tested with isolate SBC (72‐45‐1212B). With this isolate, an infection type 2= (IT2=) was produced. Twelve entries of the Fourth International Winter Wheat Performance Nursery gave a similar infection type with the same isolate. Crosses were made between some of these cultivars and three cultivars with no detectable genes for resistance. A cross was made between McNair 701 and an F3 progeny homozygous for IT2=. Genetic analysis using isolate SBC of F2 progenies showed that the gene tentatively designated SrMcN from McNair 701 for resistance to stem rust, was present in the 12 cultivars. These cultivars originated in 10 countries and appeared to have no common parentage. Although SrMcN was widespread, it has little value as a source of resistance against the stem rust population of North America.
Timing Late‐season Fruiting Termination of Cotton with Potassium 3,4‐Dichloroisothiazole‐5‐Carboxylate1
Authors: Kittock D. L. , Arle H. Fred , Henneberry T. J. , Bariola L. A. , Walhood V. T.
Published: July 2010

A plant growth regulator, Pennwalt TD‐11233 (3,4‐ dichlorolsothiazole‐5‐carboxylic acid) was evaluated as a chemical termination agent for reducing fruit set on cotton (Gossyplum spp.) in 32 tests in Arizona and California from 1974 through 1977. A reduction in immature bolls through chemical termination causes a similar reduction in diapausing pink bollworms [Pectinophora gossypiella (Saunders)]. In most tests, TD‐1123 was applied in mixture with a persistent plant growth regulator, which was used to prevent plants from recovering from TD‐1123 effects and renewing fruiting. The timing of TD‐1123 application was found critical for obtaining maximum reduction of immature bolls at harvest and minimum reduction of yield and quality. The formula “harvest date, less average number of days from flowering to boll maturity for that date, plus seven” gave a nearoptimum time for treatment. The ratio of the actual number of days from treatment to harvest to the suggested number of days was used to evaluate treatments used in previous tests. Early application (ratio greater than 1) of TD‐1123 moderately reduced the yield of southeastern Upland (Delta type) cotton (G. hirsutum L.) cuitivars, but greatly reduced yields of Acala (G. hirsutum L.) and American Pima (G. barbadense L.) cottons. With the suggested application date (ratio 1.0), immature bolls were reduced about 95% on southeastern Upland cotton, 75 to 80% on Acala cotton, and 60% on Pima cotton.
Effect of Nitrate Reductase Deficiency upon Growth, Yield, and Protein in Barley1
Authors: Oh Jee Young , Warner R. L. , Kleinhofs A.
Published: July 2010

Two nitrate reductase (NR)‐deficient mutants, Az 12 and Az 13, and the ‘Steptoe’ control were grown in the field to determine the effect of NR upon growth, N utilization, yield, and grain protein in barley (Hordeum vulgate L.). Although seasonal in vitro and in vivo NR activities in the mutants were less than 10% of the control, total vegetative dry weight, total reduced N, and percent grain protein in the mutants and Steptoe were not significantly different at maturity. Grain yields of both mutants, however, were significantly lower than the control. A greenhouse study indicated that Az 12 could utilize nitrate as a nitrogen source, although not as effectively as the control. These results indicate that harley mutants with very low levels of apparent NR can utilize nitrate as a N source and that NR activity is not closely associated with percent grain protein. At present it is not known whether the low level of NR in the mutants is sufficient to account for the nitrate reduced or whether there is another mechanism for reducing nitrate in plants that is not detected by conventional NR assay techniques.
A Method for Rating Freezing Inhibitor Activity of Barley Genotypes Using Seed and Crown Tissue Mucilages1
Authors: Olien C. R. , Kuhna A. S.
Published: July 2010

An infrared assay is described for rating activity of cell wall mucilages as inhibitors of freezing kinetics. It requires 1% of the sample needed for the flow freeze assay previously used to rate mucilages extracted from wheat seed (Triticum aestivum L.). The reduction of sample size makes it feasible to assay polymers from crown tissue in genetic and plant breeding research. This is especially important for barley (Hordeum vulgare L.) because assay of seed extracts does not reliably indicate inhibitor activity in crown tissue for this species.

Mucilages from both seed and crown tissues of eight Ethiopian barleys, Introduced into the USDA World Collection as possible sources of genetic diversity, were compared with those from a commercial barley. The introductions did produce more mucilage in their seed than did the commercial barley but did not produce effective inhibitors of freezing kinetics in their crowns.
Second Generation European Corn Borer Damage Relationships in Sweet Corn1
Authors: Andrew R. H. , Mosely P. R.
Published: July 2010

European corn borer [Ostrinia nubilalis (Hubner)] is the most serious insect pest on sweet corn (Zea mays L.) grown for processing in the Midwest. This research was designed to evaluate diallel hybrid combinations of previously identified low‐ and high‐damage inbreds by second‐generation European corn borer following artificial infestation. During 3 years 10 low‐damage and 10 high‐damage inbreds were used in each of two separate diallels consisting of 45 F1 hybrids, without parents and reciprocal crosses. While the year ✕ genotype interactions were highly significant, it was possible to identify two inbreds from the previously identified low‐damage group which consistently contributed to low damage in their progeny and two inbreds from the high‐damage group which consistently contributed to high damage in their progeny. Hybrids of high‐damage parents averaged earlier in maturity and tended to have fewer tillers than those in the low‐damage diallel although there were seasonal differences. If the sample of fines used in this study is representative, selection procedures for additive gene action should be effective. However, the range in specific combining ability effects and the significant year ✕ genotype interactions emphasize the importance of testing a wide range of hybrid combinations in different seasons.
Effect of Temperature and Glandular‐haired Medicago species on Development of Alfalfa Weevil Larvae1
Authors: Johnson Kathleen J. R. , Sorensen Edgar L. , Horber Ernst K.
Published: July 2010

We evaluated annual glandular‐haired alfalfa diploids (Medicago disciformis DC., M. blancheana Boiss.) and tetraploids [M. rugosa Desr., M. scutellata (L) Mill.] for resistance to alfalfa weevil larvae [Hypera postica (Gyllenhal)] under three temperature regimes in growth chambers. Perennial M. sativa L. control cultivars were ‘Arc’ (tolerant to weevil larvae) and ‘Lahontan’ (susceptible).

The tetraploids, M. scutellata and M. rugosa, were highly resistant over all temperature regimes. Larval mortality was complete during the first instar.

Although the diploids were less resistant than the tetraploid annuals, they caused consistent larval mortality at all three temperatures. Mortality of first instar larvae was higher on M. blancheana than on M. disciformis. However, the mortality of ≽second instar larvae or pupae was highest on M. disciformis. Fewer larvae matured to adults on our diploids than on M. sativa. More larvae matured to adults on M. disciformis than on M. blancheana. The mean weight of adults developing on M. disciformis was less than that on M. blancheana and M. sativa, which did not differ in adult weights.

The rate of weevil development increased with temperature on the resistant diploid annuals and on the alfalfa cultivars Arc and Lahontan. At each temperature, larval development was slower on the glandular‐haired diploids than on the alfalfa cultivars. Plant resistance did not alter the length of the pupal stage. However, this stage was shorter at high than at low temperatures.
In Vitro Responses of Tolerant and Susceptible Lines of Lotus corniculatus L. to 2,4‐D1
Authors: Swanson E. B. , Tomes D. T.
Published: July 2010

A positive relationship was established between the in vivo and in vitro 2,4‐D [(2,4‐dichIorophenoxy) acetic acid] response of two lines of birdsfoot trefoil (Lotus corniculatus L.). Callus cultures were initiated from a line selected for 2,4‐D tolerance in the field (T‐68), and from a susceptible cultivar ‘Leo.’ The response of the two callus lines was compared with 2,4‐D levels lower than the maintenance medium (<1 mg/liter), on progressively higher levels (5, 10, 15, and 20 mg/liter), and on high levels (40 mg/liter) throughout seven subcultures. The Leo callus was more responsive to both decreased, and moderately increased levels of 2,4‐D. Growth of both callus cultures was severely inhibited at high levels of 2,4‐D. In vitro selection for 2,4‐D tolerance appears to be practicable in Lotus corniculatus L. Indications are that 2,4‐D conjugation is one possible mechanism for differential tolerance in this species.
Evaluation of Foreign and Domestic Cotton Cultivars and Strains for Boll Weevil Resistance1
Authors: Lambert Lavone , Jenkins Johnie N. , Parrott William L. , McCarty Jack C.
Published: July 2010

Forty‐four domestic and introduced cotton (Gossypium hirsutum L.) cultivars and strains were evaluated in the laboratory for resistance to the boll weevil, Anthonomus grandis Boh. Opposition by the boll weevil was significantly lower in squares (flower buds) from eight cottons (‘Lasani 11,’ ‘AC 134,’ ‘Albar 627,’ G077‐2, ‘BP 52/NC 63,’ TX‐LY‐18‐72, DES‐HJERB 16, and DES‐ARB 16) than in squares from the commercial cultivar, ‘Deltapine 16.’ Five of the eight were introductions. Oviposition was not significantly lower in any entry than in ‘Stoneville 213,’ another commercial cultivar. There was no significant correlation between terpenoid aldehyde content in squares of 10 entries and rate of oviposition. The potential of the entries in breeding for increased resistance to boll weevil is discussed.
Maize Yield Losses Caused by Southern Corn Rust1
Authors: Rodriguez‐Ardon Roduel , Scott Gene E. , King Stanley B.
Published: July 2010

Southern corn rust, caused by Pucclnia polysora Underw. causes severe yield losses on maize (Zea mays L.); especially on late planted maize in the South. Near‐isogemc crosses were used to determine the extent of yield losses caused by this disease. Susceptible hybrids, in three biweekly plantings (beginning about 25 May) in 1976 and 1978, showed average yield reductions of 4, 23, and 45%. Reduced kernel weight accounted for some but not all of the loss in yield.
Relationship of Sugarbeet Fruit Size to Vigor of Commercially Processed Seed Lots and Cultivars1
Authors: Akeson W. R.
Published: July 2010

Sugarbeet (Beta vulgaris L.) seed is commercially processed and graded to several different fruit sizes. My objectives were first to determine the effect of fruit size on emergence potential and second to determine whether a laboratory packed sand test reliably measures these differences in emergence potential. Commercially processed and graded seed lots and cultivars were evaluated by the standard germination procedure, a laboratory packed sand test measuring percent emergence of seedlings through a 3.3 cm layer of packed sand (4% water wt/wt), and by field emergence trials. Field emergence was highly correlated with laboratory packed sand emergence (r = 0.92, 12 df), but not correlated with standard germination in tests involving three cultivars (‘GWH58,’ ‘GWH93,’ and ‘GWH115’) and four fruit sizes (2.4 to 2.8, 2.8 to 3.2, 3.2 to 3.6, and 3.6 to 4.0 mm diameter) in a 3 ✕ 4 factorial combination. Field and laboratory emergence increased with increase in fruit size from 2.4 to 2.8 to 3.2 to 3.6 ram; however, emergence of the largest fruit size (3.6 to 4.0 mm) was equal to or less than that of 3.2 to 3.6 mm size. Influence of fruit size on field emergence was not affected by planting date. Emergence of seed lots (four sizes per lot) of four cultivars (‘GWH45,’ GWH58, GWH93, and GWH115) was evaluated with the packed sand test in factorial combinations. Each cultivar had seed lots which were significantly different from one another. Emergence of GWH45, GWH93, and GWH115 seed progressively increased with increase in fruit diameter except for the largest size (3.6 to 4.0 mm) which was equal to or less emergence than that of the 3.2 to 3.6 mm size. GWH58 showed a similar trend except that seed size effects were not significant. No seed lot ✕ fruit size interaction was found. Thus all sizes of the superior emerging lots had better emergence than the corresponding sizes in the poorer lots. These tests show that fruit size must be kept constant when emergence potential of seed lots or cultivars is measured. The laboratory packed sand test, utilizing seed lot ✕ fruit size factorial combinations, effectively evaluated the emergence potential of seed lots of commercial cultivars.
Dry Matter Accumulation in Kernels of Maize1
Authors: Frey Nicholas M.
Published: July 2010

Selection in a breeding program for physiological traits should not be initiated without knowledge of critical growth stages for the crop. The granin yield of maize (Zea mays L.) is the integral of kernel dry matter accumulation over time. The rate and duration of kernel fill have been suggested as factors which might be improved through selection and result in yield improvement. The purpose of these experiments was to follow kernel development at three positions on the ear when treatments were imposed which altered assimilate supply to the ear.

Two maize hybrids, Pioneer brand '3388' and '3369A,' which differed in the yield components, kernel rows ear‐1, and kernel weight, were grown in field plots. Treatments were applied at 50% stand density, shoot bagging ears to allow complete pollination on a single day, and 50% leaf area removal. Kernel growth rates were determined for kernels at the base, middle, and tip regions of the ears. Hybrid 3369A had more rapid rates of kernel dry matter accumulation than did 3388 in both years.

Treatments which affected assimilate supply, i.e., thinning and leaf area removal, affected kernel number (ear row)‐1through variations in the cessation of kernel development at the tip of the ears. Rates of kernel dry matter accumulation were similar for kernels from basal and middle regions of the ears, regardless of assimilate supply. Tip kernels may have filled at slower rates than did kernels from the other two regions. Altered duration of the linear phase of kernel dry matter accumulation due to treatments affecting assimilate supply was suggested as one cause of variations in kernel weight on an ear as well as between ears of the same hybrid. A critical stage in the development of maize that is highly dependent on assimilate supply is the 2‐ to 3‐week period after 50% silking; the period when final kernel number is determined.