Resistance to Meloidogyne arenaria in Arachis spp. and the Implications on Development of Resistant Peanut Cultivars1

1990 ◽  
Vol 17 (1) ◽  
pp. 35-38 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe
Keyword(s):  
Fourth Order ◽  
Wild Species ◽  
Gene Pool ◽  
Egg Mass ◽  
Meloidogyne Arenaria ◽  
Sources Of Resistance ◽  
Third Order ◽  
Nematode Reproduction ◽  
The Third ◽  
Significant Difference

Abstract Peanut root-knot nematode (Meloidogyne arenaria (Neal) Chitwood race 1) is a serious pathogen in commercial peanut (Arachis hypogaea L.) production. There is no peanut cultivar with resistance to this nematode. The primary constraint in the development of resistant cultivars has been the absence of identified sources of resistance in A. hypogaea and related wild species. The objective of this study was to examine the wild Arachis spp. collection of the Coastal Plain Experiment Station for sources of resistance to M. arenaria. Thirty-six wild Arachis spp. genotypes were compared with the susceptible cv. Florunner for resistance to M. arenaria reproduction and galling response in two greenhouse tests. A. monticola Krap. et Rig., a member of the second-order gene pool, was the only wild species tested which did not have a gall index and egg-mass index significantly lower than that of A. hypogaea. There was no significant difference between A. monticola and A. hypogaea for the number of eggs per root system or per gram of fresh root weight. In addition, the host efficiency of A. monticola was 3.49, indicating a high level of susceptibility. All genotypes examined from the third-order gene pool species (A. cardenasii Krap. et Greg. nom. nud., A. duranensis Krap. et Greg. nom. nud., A. helodes Martius ex Krap. et Rig. and A. villosa Benth.) exhibited significantly less plant damage and nematode reproduction than A. hypogaea. Except for one A. villosa genotype, all entries from the third-order gene pool exhibited high levels of resistance to M. arenaria based on a host efficiency less than 1.00. All fourth-order gene pool accessions examined (A. burkartii Handro, A. glabrata Benth., and A. hagenbeckii Harms.) exhibited high levels of resistance to M. arenaria. These results indicate that resistance to M. arenaria is prevalent in both the third- and fourth-order gene pools of peanut. These results increase the probability of success in developing peanut cultivars with resistance to M. arenaria since species in the third-order gene pool are cross compatible with A. hypogaea. Based on genetic theory, these results also increase the probability of resistance to M. arenaria in the first-order gene pool. Therefore, further screening for resistance to M. arenaria in A. hypogaea is recommended.

Children’s Recall of Approximations to English

1973 ◽  
Vol 16 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Elizabeth Carrow ◽  
Michael Mauldin
Keyword(s):  
Language Development ◽  
Fourth Order ◽  
Third Order ◽  
Memory Processes ◽  
The Third ◽  
General Index ◽  
General Linguistic

As a general index of language development, the recall of first through fourth order approximations to English was examined in four, five, six, and seven year olds and adults. Data suggested that recall improved with age, and increases in approximation to English were accompanied by increases in recall for six and seven year olds and adults. Recall improved for four and five year olds through the third order but declined at the fourth. The latter finding was attributed to deficits in semantic structures and memory processes in four and five year olds. The former finding was interpreted as an index of the development of general linguistic processes.

scholarly journals Asymptotic formulae for linear equations

1972 ◽  
Vol 13 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Don B. Hinton
Keyword(s):  
Asymptotic Behaviour ◽  
Fourth Order ◽  
Linear Equations ◽  
Order Equation ◽  
Third Order ◽  
Fourth Order Equation ◽  
The Third ◽  
Asymptotic Formulae ◽  
Image Position

Numerous formulae have been given which exhibit the asymptotic behaviour as t → ∞solutions ofwhere F(t) is essentially positive and Several of these results have been unified by a theorem of F. V. Atkinson [1]. It is the purpose of this paper to establish results, analogous to the theorem of Atkinson, for the third order equationand for the fourth order equation

scholarly journals Volume derivatives of the Grüneisen parameter in the limit of infinite pressure

2019 ◽  
Vol 97 (1) ◽  
pp. 114-116 ◽  
Author(s):  
A. Dwivedi
Keyword(s):  
Boundary Condition ◽  
Fourth Order ◽  
Fundamental Theorem ◽  
High Pressures ◽  
Grüneisen Parameter ◽  
Third Order ◽  
Gruneisen Parameter ◽  
The Third ◽  
Properties Of Materials ◽  
Derivatives Of

Expressions have been obtained for the volume derivatives of the Grüneisen parameter, which is directly related to the thermal and elastic properties of materials at high temperatures and high pressures. The higher order Grüneisen parameters are expressed in terms of the volume derivatives, and evaluated in the limit of infinite pressure. The results, that at extreme compression the third-order Grüneisen parameter remains finite and the fourth-order Grüneisen parameter tends to zero, have been used to derive a fundamental theorem according to which the volume derivatives of the Grüneisen parameter of different orders, all become zero in the limit of infinite pressure. However, the ratios of these derivatives remain finite at extreme compression. The formula due to Al’tshuler and used by Dorogokupets and Oganov for interpolating the Grüneisen parameter at intermediate compressions has been found to satisfy the boundary condition at infinite pressure obtained in the present study.

scholarly journals Resistance to the Peanut Root-Knot Nematode (Meloidogyne arenaria) in Arachis hypogaea1

1992 ◽  
Vol 19 (1) ◽  
pp. 35-37 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe
Keyword(s):  
Egg Production ◽  
Economic Losses ◽  
Egg Mass ◽  
Root Weight ◽  
Meloidogyne Arenaria ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Plant Introductions ◽  
Nematode Eggs ◽  
Fresh Root

Abstract The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production area of the southern United States. Chemicals for control of this pest are becoming increasingly limited, and there are no known sources of resistance within the U. S. A. hypogaea collection. The objectives of this research were to screen 1,321 plant introductions for resistance or hypersusceptibility based on egg-mass ratings in greenhouse tests and to conduct more intensive greenhouse studies of selected genotypes to evaluate this method for identifying resistance to the peanut root-knot nematode. Twenty-seven genotypes with low and eight genotypes with high egg-mass ratings were selected and reevaluated in a more intensive greenhouse experiment. Seventeen of the low selections supported fewer (P≤0.05) egg masses, and seven supported less egg production per gram of fresh root weight than Florunner. Three selections for high egg-mass ratings supported more nematode eggs per plant than the cultivar Florunner and had a greater host efficiency. One of these genotypes supported more nematode eggs per gram of fresh root weight than Florunner. These results show that resistance to M. arenaria exists in the cultivated peanut species and can be selected by rating egg-mass production on greenhouse-grown plants.

New bounds on effective elastic moduli of two-component materials

1982 ◽  
Vol 380 (1779) ◽  
pp. 305-331 ◽  
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Fourth Order ◽  
Geometrical Parameters ◽  
Effective Moduli ◽  
Third Order ◽  
Effective Shear Modulus ◽  
The Third ◽  
Two Component ◽  
Order Bounds

Based on the perturbation solution, we derive new bounds on the effective moduli of a two-component composite material which are exact up to fourth order in δ μ = μ 1 — μ 2 and δ K = K 1 — K 2 , where μ i and K i , i = 1, 2, are the shear and bulk modulus, respectively, of the phases. The bounds on the effective bulk modulus involve three microstructural parameters whereas eight parameters are needed in the bounds on the effective shear modulus. For engineering calculations, we recommend the third-order bounds on the effective shear modulus which require only two geometrical parameters. We show in detail how Hashin-Shtrikman’s bounds can be extended and how Walpole’s bounds can be improved using two inequalities on the two geometrical parameters that appear in the third-order bounds on the effective shear modulus. The third- and fourth-order bounds on the effective moduli are shown to be more restrictive than, or at worst, coincident with, existing bounds due to Hashin and Shtrikman, McCoy, Beran and Molyneux and Walpole.

STANDARD NOMOGRAPHIC FORMS FOR EQUATIONS IN THREE VARIABLES

1935 ◽  
Vol 12 (1) ◽  
pp. 14-40 ◽  
Author(s):  
F. M. Wood
Keyword(s):  
Unit Circle ◽  
Fourth Order ◽  
Third Order ◽  
Rectangular Hyperbola ◽  
Practical Utility ◽  
The Third ◽  
Cubic Curve ◽  
Final Adjustment ◽  
Straight Lines ◽  
Suitable Location

Equations of the third and fourth nomographic order in three variables have been dealt with and classified. Equations of the third order may be reduced to one of two standard forms, α + β + γ = 0 and α + βγ = 0, which give alignment charts composed of three straight lines. Equations of the fourth order may also be reduced to one of two standard forms, resulting in charts composed of (a) two straight lines and a curve, or (b) two scales on a conic, and the third on another curve. Transformations of these four standard forms are given which permit of rapid and easy adjustment of the position and length of the scales for any given example, resulting in a chart of practical utility. Although the underlying theory has been studied by other writers, notably Soreau and Clark, it has possibly never appeared before in such a neat form. On this account, and also because of the standard transformations, it is felt that this article is of particular value.Standard forms have also been developed for third order equations leading to charts composed of two scales on a conic and a third straight scale, and in conclusion a third type of chart, in which all three scales appear on a single cubic curve, has been standardized. The practical value of the last type is questionable, but the conic charts are of use since we may arbitrarily choose the unit circle, or the rectangular hyperbola, for our conic scales. Final adjustment forms which permit suitable location of the scales in particular examples have been obtained in every case.

scholarly journals SIMILARITY SOLUTIONS AND CONSERVATION LAWS FOR THE BEAM EQUATIONS: A COMPLETE STUDY

2020 ◽  
Vol 60 (2) ◽  
pp. 98-110
Author(s):  
Amlan Kanti Halder ◽  
Andronikos Paliathanasis ◽  
Peter Gavin Lawrence Leach
Keyword(s):  
Conservation Laws ◽  
Fourth Order ◽  
Singularity Analysis ◽  
Travelling Wave ◽  
Similarity Solutions ◽  
Third Order ◽  
The Third ◽  
Beam Equations ◽  
Complete Study ◽  
Wave Reduction

We study the similarity solutions and we determine the conservation laws of various forms of beam equations, such as Euler-Bernoulli, Rayleigh and Timoshenko-Prescott. The travelling-wave reduction leads to solvable fourth-order odes for all the forms. In addition, the reduction based on the scaling symmetry for the Euler-Bernoulli form leads to certain odes for which there exists zero symmetries. Therefore, we conduct the singularity analysis to ascertain the integrability. We study two reduced odes of second and third orders. The reduced second-order ode is a perturbed form of Painlevé-Ince equation, which is integrable and the third-order ode falls into the category of equations studied by Chazy, Bureau and Cosgrove. Moreover, we derived the symmetries and its corresponding reductions and conservation laws for the forced form of the abovementioned beam forms. The Lie Algebra is mentioned explicitly for all the cases.

The mechanism of the Cannizzaro reaction of Formaldehyde

1954 ◽  
Vol 7 (4) ◽  
pp. 335 ◽  
Author(s):  
RJL Martin
Keyword(s):  
Fourth Order ◽  
Kinetic Data ◽  
Order Reaction ◽  
Rate Equations ◽  
Third Order ◽  
The Third ◽  
Hydride Ion ◽  
Cannizzaro Reaction ◽  
Wide Range ◽  
Mechanism Of The Reaction

For a wide range of concentrations of formaldehyde and alkali, the Cannizzaro reaction of formaldehyde can be described as the sum of a third and a fourth order reaction. However, the concentrations which are used for the rate equations must be corrected for the amount of methylene glycol anion present. The dissociation constant of methylene glycol as determined from the kinetic data is the same magnitude as that derived electrometrically. The mechanism of the reaction is interpreted as a reaction between formaldehyde and the hydride ion donors CH2(O-)(OH) and CH2(O-)(O-) It is shown why the third order reaction proposed by previous workers is not always applicable.

New bounds on the effective thermal conductivity of N -phase materials

1982 ◽  
Vol 380 (1779) ◽  
pp. 333-348 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Fourth Order ◽  
Third Order ◽  
Two Phase ◽  
The Third ◽  
Component Material ◽  
Order Bounds ◽  
Correlation Parameters ◽  
Two Parameters

Based on the perturbation solution to the effective thermal conductivity problem for an N -component material, we derive new third- and fourth-order bounds for the effective thermal conductivity of the composite. The new third-order bounds are accurate to third order in | ϵ a — ϵ b |, where ϵ a is the thermal conductivity of phase a and require a total of ½ N ( N — 1) 2 third-order correlation parameters in their evaluation. For two-phase composites, these bounds require only one geometrical parameter and are identical to Beran’s bounds. For N ≽ 3, the third-order bounds use the same information as Beran’s bounds, but always more restrictive than Beran’s bounds. The new fourth-order bounds are accurate to fourth-order in | ϵ a - ϵ b | and require an additional ¼ N 2 (N — 1) 2 fourth-order correlation parameters. For N = 2, only two parameters are needed, and the fourth-order bounds are shown to be more restrictive than the third-order Beran’s bounds and the second-order Hashin-Shtrikman’s bounds. The applica­tion of the third-order bounds to a spherical cell material of Miller is illustrated.

Identification and Evaluation of Additional Sources of Resistance to Peanut Root-knot Nematode in Arachis hypogaea L.1

1996 ◽  
Vol 23 (2) ◽  
pp. 91-94 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe ◽  
Michael G. Stephenson ◽  
William F. Anderson
Keyword(s):  
Arachis Hypogaea ◽  
Field Experiments ◽  
Germplasm Collection ◽  
Economic Losses ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Nematode Reproduction ◽  
Plant Introductions ◽  
Production Areas

Abstract The root-knot nematode (Meloidogyne arenaria race 1) causes significant economic losses throughout the peanut (Arachis hypogaea) production areas of the southern U.S. Chemicals for control of this pest are becoming increasingly limited, and there are no peanut cultivars with resistance. Seven moderately resistant plant introductions have been identified; however, less than 25% of the germplasm collection has been examined for resistance based on nematode reproduction. The objectives of this work were to examine an additional 1000 plant introductions for resistance to the peanut root-knot nematode and to compare the most resistant introductions to previously reported sources of resistance. Preliminary greenhouse screening trials were conducted to rate severity of root galling and amount of egg mass production. Seventeen accessions were selected based on a mean egg mass rating of less than or equal to three. These selections were reevaluated in additional greenhouse and field experiments to quantify levels of resistance and to directly compare these sources of resistance to those previously reported. Eight accessions had a significantly higher level of resistance (lower egg mass rating) than Florunner; however, none had a significantly higher level of resistance than those previously reported. Results of this study identified additional sources of resistance which may provide unique genes for resistance. In addition, two of these new sources of resistance (PI 298848 and PI 311265) exhibited significantly higher yield than those previously identified when grown in soil heavily infested with M. arenaria.

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