The seed varieties listed in this Rispens Seeds, Inc. catalog are variously defined as being "resistant," "intermediately resistant" or "susceptible" to disease. These terms describe the reaction of a plant to a particular disease. Please note that some disease organisms have the ability to change from one year to the next, and may vary their intensity of attack. The aggressiveness of strains of the pathogen to which the plant is subjected will influence the disease reaction. The amount of the pathogen present can also influence the resistance or intermediate resistance of a variety. Environmental conditions are extremely important in disease development. Adverse environmental conditions may allow the pathogen to overcome the resistance or intermediate resistance which is bred into a variety. Finally, new races or strains of the pathogen, or a new pathogen, may occur. Statements in this catalog regarding disease resistance or intermediate resistance are based primarily upon reports by seed producers and experimental research stations. It is important for a grower to understand his particular needs before choosing a variety. As shown in this catalog, pathogens listed under the "disease" or "features" column(s) are considered resistant unless otherwise labeled "IR" or intermediate resistant.
Definition of these terms is as follows:
DISEASE: A condition in which the structure or use of the plant is harmfully affected, due to fungi, bacteria, viruses, nematodes or an adverse environmental condition.
ENVIRONMENTAL STRESS: Adverse environmental conditions such as extreme heat or cold, excess water or drought, or excessive wind that can produce reactions in plants that may render the plant/product unmarketable. Rispens Seeds, Inc. does not assume any responsibility for the quality of vegetable production grown under environmental stress conditions.
VARIETAL DESCRIPTIONS: Varietal descriptions within this catalog have been prepared as a guideline only. It is given for comparison purposes to help growers plan crop planting programs, and can be expected to vary in some degree depending upon geographic location, soil type, climactic conditions, and cultural practices. The information on relative maturity (expressed as "days" or "*days" - days from transplant) in this catalog is given only as a guide, as the actual maturity will vary considerably with conditions.
VARIETAL ILLUSTRATIONS: Varieties illustrated in this catalog are the result of favorable growing conditions and identical results are not guaranteed. Color illustrations may not be 100% accurate.
TREATED SEED: Certain seed listed for sale in this catalog is treated for protection against seed borne and soil borne disease(s). One or more of the following types of chemical treatments may be utilized: bactericide(s), fungicide(s), and/or viricide(s). In addition, hot water treatment may be employed.
Terminology for Defining the Reaction of a Plant Variety to Pest and Pathogen Attack
IMMUNITY: Plant varieties which are not subject to attack or infection by a specific pest/pathogen are considered immune.
RESISTANCE: Not as strong as immunity; two levels of resistance are defined.
RESISTANCE (R): Includes plant varieties that restrict the growth and development of the specific pest or pathogen under normal pest or pathogen attack pressure when compared to susceptible varieties. These plant varieties can exhibit some symptoms or damage under heavy pest or pathogen pressure. Plant varieties with Resistance (R) are not immune to the pest/pathogen.
INTERMEDIATE RESISTANCE (IR): Includes varieties that restrict the growth and development of the specified pest/pathogen, but may exhibit a greater range of symptoms or damage compared to resistant varieties. Intermediate resistant plant varieties will usually show less severe symptoms or damage than susceptible plant varieties when grown under similar environmental conditions and/or pest/pathogen pressure, but may have heavy damage under heavy pressure. Plant varieties with Intermediate Resistance (IR) are not immune to the pest/pathogen.
SUSCEPTIBLE: Defined as the inability of a plant variety to restrict the growth and development of a specified pest/pathogen. Plant varieties that are susceptible will show damage when infected and are more likely to have heavy damage under moderate levels of pest/pathogen pressure.
Terminology to Describe the Reaction of a Plant to ABIOTIC Stresses
Abiotic stresses are those caused by the environment and not by a living organism.
TOLERANCE: The ability of a plant variety to endure abiotic or environmental stress with more limited effect on growth, appearance and yield although, under higher levels of abiotic stress, the plant variety may be damaged.
