Karl Hillig

Karl Hillig

BSc, MS, PhD

About

20
Publications
20,334
Reads
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885
Citations
Introduction
Skills and Expertise
Education
September 1989 - March 2005
Indiana University Bloomington
Field of study
  • Plant Science
September 1985 - December 1988
Michigan State University
Field of study
  • Plant Breeding and Genetics
September 1983 - May 1985
Cornell University
Field of study
  • Plant Science

Publications

Publications (20)
Article
The hemp russet mite Aculops cannabicola (Farkas) is a little-known but potentially dreadful pest. It primarily feeds on leaves, petioles, and meristems. The mites quickly spread between plants grown in proximity. They cause a curling of leaf edges, followed by leaf russeting. The mites feed on the inflorescences of both sexes, and on glandular tri...
Article
This study reports on a combined analysis of phenotypic traits and allozyme allele frequencies for 69 accessions from the CPRO Cannabis germplasm collection. Sample populations of each accession were evaluated for achene traits, cannabinoid content, days to maturity, plant height, leaflet shape, fiber traits, and root-knot nematode resistance. Samp...
Article
Full-text available
Sample populations of 157 Cannabis accessions of diverse geographic origin were surveyed for allozyme variation at 17 gene loci. The frequencies of 52 alleles were subjected to principal components analysis. A scatter plot revealed two major groups of accessions. The sativa gene pool includes fiber/seed landraces from Europe, Asia Minor, and Centra...
Article
To determine whether the terpenoid composition of the essential oil of Cannabis is useful for chemotaxonomic discrimination, extracts of pistillate inflorescences of 162 greenhouse-grown plants of diverse origin were analyzed by gas chromatography. Peak area ratios of 48 compounds were subjected to multivariate analysis and the results interpreted...
Article
Cannabinoids are important chemotaxonomic markers unique to Cannabis. Previous studies show that a plant's dry-weight ratio of Δ(9)-tetrahydrocannabinol (THC) to cannabidiol (CBD) can be assigned to one of three chemotypes and that alleles B(D) and B(T) encode alloenzymes that catalyze the conversion of cannabigerol to CBD and THC, respectively. In...
Article
The purpose of this article was to track down the earliest known illustrations of Cannabis. Our in silico search methodology utilized computerized search engines and electronic databases for citation tracking. Many botanists prior to Linnaeus, beginning with Dioscorides, described more than one presumptive type of Cannabis. In some cases they were...
Article
Full-text available
This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring color illustrations of signs and symptoms. The fungus Trichothecium roseum produces a white fuzz that covers branches, leaves, and flowering tops of hemp. These symptoms have been confused with true powdery mildew, caused by Sphaerotheca macularis. We...
Article
This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring colour illustrations of signs and symptoms. The hemp longhorn beetle (Thyestilla gebleri) damages hemp stalks in eastern Asia. The fungus Botryosphaeria marconii causes stalk and twig blight disease of hemp in North America and perhaps western Europe....
Article
This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring colour illustrations of signs and symptoms. The fungus Jahniella bohemica damages hemp stalks in Europe. In the previous issue of “Cannabis Clinic” we illustrated Jahniella bohemica and showed how this fungus has been confused with Leptosphaeria acuta...
Article
This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring colour illustrations of signs and symptoms. The fungus Jahniella bohemica damages hemp stalks in Europe. For 125 years this fungus has been confused with Leptosphaeria acuta, a fungus that infests nettle stalks. The morphology of J. bohemica is descri...
Article
This note continues the “Cannabis Clinic” series, presenting diseases and pests of hemp, featuring color illustrations of signs and symptoms. White leaf spot is caused by a fungus, Phomopsis ganjae. Signs and symptoms of the disease, life history of the pathogen, differential diagnosis, and control measures are discussed. Disease symptoms and fungu...
Article
Plant taxonomy is primarily based on patterns of morphological variation and geographical distribution. Plant-parasite relationships can also offer clues regarding the phylogeny of the host plant. Many obligate parasites coevolve with their hosts, eventually becoming restricted to an individual taxon. Host restriction may take place at different ta...
Thesis
Full-text available
Botanists disagree whether Cannabis (Cannabaceae) is a monotypic or polytypic genus. A systematic investigation was undertaken to elucidate underlying evolutionary and taxonomic relationships within the genus. Genetic, morphological, and chemotaxonomic analyses were conducted on 157 Cannabis accessions of known geographic origin. Sample populations...
Article
Fusarium wilt is caused by two closely-related fungi, Fusarium oxysporum f. sp. vasinfectum and Fusarium oxysporum f. sp. cannabis. The disease was first described on hemp in Eastern Europe about 50 years ago, but is now found throughout the Northern hemisphere. Greenhouse studies demonstrated that all cultivars of Cannabis that were tested are sus...
Article
The Vavilov Institute (VIR) in Russia maintains the world's largest collection of Cannabis sativa hemp germplasm through periodic seed regeneration. Sample populations of 93 accessions from the VIR collection were assayed for allozyme variation at 17 gene loci by starch-gel electrophoresis. The frequencies of 47 alleles were subjected to principal...
Article
This is the second in a series of “Cannabis clinic” notes, presenting diseases and pests of hemp, featuring colour illustrations of signs and symptoms. This note concerns Striatura Ulcerosa, the name of a hemp disease caused by the bacterium Pseudomonas syringae pv. mori. The disease was first described in Italy over 100 years ago, but may have ori...
Article
Morphological traits of 16 sour cherry ( Prunus cerasus L.) cultivars and of hybrid and open-pollinated seedlings of germplasm collected in eastern Europe were evaluated with principal component (PC) analysis. Due to the character loadings of the first three PCs in each analysis, some of the PCs can be interpreted as representing gradations between...