Search Results

You are looking at 91 - 100 of 565 items for :

  • Refine by Access: All x
Clear All
Full access

Marisa Y. Thompson, Jennifer Randall, Richard J. Heerema, and Dawn VanLeeuwen

Alternate bearing (AB) poses a major challenge for the pecan [ Carya illinoinensis (Wangenh.) K. Koch.] industry ( Wood, 2003 ). AB refers to a tendency for wide season-to-season fluctuations in cropping intensity. This is often expressed as a

Free access

Michael W. Smith and Bruce W. Wood

Allometric equations were developed for orchard-grown pecan [Carya illinoinensis (Wangenh.) C. Koch] trees. Trees, ranging in size from 22 to 33 cm in trunk diameter 1.4 m above the ground, were destructively harvested from two sites. The entire aboveground portion of each tree was harvested and then divided into leaves, current season's shoots, and branches ≥1 year old plus trunk. Roots were sampled by digging a trench beginning beneath the trunk and extending to one-half the distance to an adjacent tree, then separating the roots from the soil. Roots were then divided into those less than 1 cm in diameter and those ≥1 cm in diameter. Equations in the form Y = eaXb were developed to estimate dry biomass of most tree components and the whole tree, where Y is the dry weight, e is the base of the natural logarithm, X is the trunk diameter at 1.4 m above the ground, and a and b are coefficients. A linear equation provided the best fit for estimating the weight of the current season's growth. Power equations were also developed to estimate the weights of inner bark and wood for different size trunks or branches.

Free access

Madhulika Sagaram, Leonardo Lombardini, and L.J. Grauke

Pecan has been known for centuries for its edible nuts and is the most valuable nut tree native to North America ( Hall, 2000 ). It is a species distributed over an area of geographical and climatic variation extending from northern Illinois and

Open access

Haijun Zhu and Eric T. Stafne

Due to the strong vegetative nature of relatively young pecan trees and the absence of dwarfing rootstocks or cultivars, controlling tree size is a major problem in high-density pecan orchards. Paclobutrazol, an effective inhibitor of gibberellin

Full access

M. Lenny Wells

Pecan trees and orchards occasionally suffer damage as a result of cold or freezing temperatures. In the southeastern United States, this is most likely to occur in the autumn before trees have become acclimated to cold temperatures ( Madden, 1978

Free access

Richard J. Heerema, Dawn VanLeeuwen, Marisa Y. Thompson, Joshua D. Sherman, Mary J. Comeau, and James L. Walworth

The native range for pecan extends through much of the south-central United States and into scattered locations in Mexico. Native pecan groves are found growing in deep, sandy, alluvial soils in river bottoms. The soils that cover most of the native

Free access

Leonardo Lombardini, Astrid Volder, Monte L. Nesbitt, and Donita L. Cartmill

Pecan is native to North America ( Thompson and Grauke, 1991 ) and has been used since prehistoric and early historic times as an important source of food and timber ( Hall, 2000 ). It has been commercially cultivated since the mid-1800s and is

Free access

Bruce W. Wood and Charles C. Reilly

Foliar feeding by the black pecan aphid [Melanocallis caryaefoliae (Davis)] can cause tremendous economic losses. Evaluations of black aphids on pecan genotypes indicates that both antixenosis and antibiosis-like resistance mechanisms exists. Tests for antixenosis indicated that aphids possess clear preferences for certain genotypes over others and that this preference can be dependent on a water-soluble chemical component of the leaf surface. Aphids also exhibited a “conditioning preference,” in which they preferentially feed on genotypes from which they originated. Antibiosis tests indicated that pecan genotypes influence the reproductive success of aphids already possessing a feeding adaptation to those same pecan genotypes; therefore, an evaluation of 30 cultivars for antibiosis indicated that populations developed only 20% as fast on `Choctaw' and `Alley' as on `Desirable' and `Success'. No cultivar was observed to essentially prevent aphid reproduction.

Free access

Amir M. González-Delgado, Manoj K. Shukla, and Brian Schutte

Pecan [ Carya illinoinensis (Wangenh.) K. Koch] is an important crop of southern New Mexico, USA. Appropriate management practices are required to maintain the quality and yield of pecan while conserving water resources ( Andales et al., 2006

Full access

Juan L. Silva, Estuardo Marroquin, Frank B. Matta, and Esteban A. Herrera

in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. We thank the Western Pecan Growers Association for their partial support