Search Results

You are looking at 51 - 60 of 305 items for :

  • Carya illinoinensis x
Clear All
Authors: and

In vitro germination of freshly collected pollen and pollen stored 1, 10, 11, 12, and 13 years in liquid nitrogen was examined for `Desirable' pecan [Carya illinoinensis (Wangenh.) C. Koch]. Viability of pollen stored in liquid nitrogen for 1, 10, 11, 12, and 13 years was not diminished in comparison to that of fresh pollen. Morphology of stored pollen grains and the germ tube was normal. Thus, liquid nitrogen may offer a means of haploid preservation of pecan.

Free access

Fungal leaf scorch, a potentially devastating disease in pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards, was influenced substantially by irrigation and genotype. Three years of evaluating 76 pecan cultivars revealed that all cultivars exhibited scorch symptoms and that at least three classes of scorch susceptibility existed. Severity of symptoms was also much greater in nonirrigated than irrigated trees, and there were substantial differences in the concentrations of free nitrogenous compounds and free sugars in leaves between irrigated and nonirrigated trees.

Free access
Author:

Abstract

At the meeting of the Crop Advisory Committee for Pecans and Hickories held on 24 Sept. 1984 in Albany, Ga., a question was raised concerning the legitimate scientific name of the pecan tree. Two names are currently in use: Carya illinoensis (Wang.) K. Koch (3, 6, 7, 10, 12, 19) and Carya illinoinensis (Wang.) K. Koch (1, 2, 11, 18, 21). Current usage is heavily in favor of the former epithet. When the 2 names were used as key words in the BIOSIS Previews computer search file for articles written between 1977 and the present, 199 were retrieved under C. illinoensis, whereas only 1 was found under C. illinoinensis. Since Hortus Third uses the latter epithet, articles on pecan submitted for publication in horticultural journals are occassionally returned to their authors for revision. The purpose of this paper is to trace the history of the nomenclature of the pecan as it relates to this dispute and in the process, demonstrate that the strict rules of scientific nomenclature and common sense can both be satisfied by the use of the epithet Carya illinoensis.

Open Access

In vivo pollen tube growth of pecan [Carya illinoinensis (Wangenh.) K. Koch] was estimated to be ≈ 150 μm·hour-1 from 3 to 8 hours postpollination. Pollen tubes averaged 47, 194, 405, and 946 μm after 2, 3, 4, and 8 hours postpollination, respectively. Pollen tube growth was strongly influenced by temperature, and in vitro studies demonstrated pollen germination and tube growth were optimal at 27C for `Cape Fear' pecan. In in vivo studies, tubes of cross-pollen did not grow significantly faster than tubes of self-pollen. Pollen tubes of water hickory [C. aquatica (Michx. f.) Nutt.] grew significantly faster than those of C. illinoinensis. Bitternut [C. cordiformis (Wangenh.) K. Koch] and mockernut hickory (C. tomentosa Nutt.) pollen tubes grew significantly slower on pecan stigmas than did pecan pollen. Pollen arriving first on the stigma has a decided advantage for fertilization success of pecan. The fertilization success rate of pecan pollen arriving 24 hours after first pollen arrival was <3%.

Free access

Pecans [Carya illinoinensis (Wangenh. C.) Koch] were harvested weekly for 9 and 7 weeks until normal harvest time during 1986 and 1987, respectively. Kernels were tested for chemical, physical, and sensory properties. Moisture decreased from 13% at initial harvest time to 4% to 6% by normal harvest. Free fatty acids decreased from 0.5% to 0.2% by the third week before normal harvest. Tannins fluctuated, but averaged about 0.8%. Hue angle remained constant from the fourth week to normal harvest. Shear force increased from 90 to 135 N by the second week before normal harvest. Pecans can be harvested about 2 weeks before normal harvest without significant quality deficiencies.

Full access

Pecans [Carya illinoinensis Wangenh. K. (Koch)], grown in western Texas, New Mexico, Arizona, and California, are usually planted at a spacing of 9.1 × 9.1 m (30 × 30 ft). At this spacing, orchards begin to crowd in about 20 years. This crowding results in reduced yields and nut quality, Strategically removing trees over a period of years is the best alternative to avoid tree-crowding problems. Establishing a new orchard with transplanted mature trees can show a profit 3 years earlier than if using nursery-produced trees.

Full access
Author:

Pecan (Carya illinoinensis) scab was evaluated following unusually extended rains in 1994. Strengths and weaknesses of a variety of scab management practices were studied in five orchards, Scab control was more effective on trees with adequate sunlight exposure than in dense orchards or with fungicide applied after rain than by preset intervals. Triphenyl tin hydroxide, a nonsystemic fungicide, was most effective when applied within 24 h after rain; but, the systemic fungicide, propiconazole, was effective when applied within 6 days after rain. Fungicides must be applied consistently after rain for maximum scab control.

Full access

Genetic variation among pecan [Carya illinoinensis (Wangenh.) C. Koch] cultivars was studied using randomly amplified polymorphic DNA (RAPD) markers. Using a combination of primers, a unique fingerprint is presented for each of the pecan genotypes studied. The genetic relatedness between 43 cultivars was estimated using 100 RAPD markers. Genetic distances, based on the similarity coefficient of Nei & Li, varied from 0.91 to 0.46, with an average value of 0.66 among all cultivars. The phenetic dendrogram developed from cluster analysis showed relatively weak grouping association. However, cultivars with known pedigrees usually grouped with at least one of the parents and genetic similarity estimates appear to agree with known genetic relationships.

Free access
Author:

Of 18 commonly used adjuvants evaluated on pecan [Carya illinoinensis (Wangenh) K. Koch], a few exhibited potential for substantially suppressing net photosynthesis (A) and the conductance of foliage to water vapor (g sw ) when used within their recommended concentration range; however, most provided no evidence of adversely influencing A or g sw . Suppression of gas exchange by certain adjuvants persisted at least 14 days after a single application. The recently developed organosilicone-based surfactants generally exhibited the greatest potential for suppression. These data indicate that orchard managers should consider the potential adverse influence of certain adjuvants when developing orchard management strategies.

Full access

Abstract

Single-node cuttings obtained from 2-month-old seedlings of pecan [Carya illinoinensis (Wang.) K. Koch] were induced to break buds and form multiple shoots in liquid, woody plant medium (WPM) and 2% glucose supplemented with 6-benzylamino purine (BA) at 3 mg/liter. In vitro-derived shoots soaked in 1-3 mg/liter indolebutyric acid (IBA) produced adventitious roots in vitro; when soaked for 8 days in 10 mg/liter IBA, they were rooted successfully in soil and acclimated to greenhouse conditions. Etiolation of stock plants did not improve shoot proliferation or rooting under in vitro culture.

Open Access