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A Plant Pathologist's View of Germplasm Evaluation and Utilization 1
Author(s) -
Hooker A. L.
Publication year - 1977
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1977.0011183x001700050004x
Subject(s) - germplasm , biology , resistance (ecology) , agriculture , microbiology and biotechnology , plant disease resistance , crop , plant breeding , biological dispersal , genetic diversity , plant disease , agronomy , genetics , gene , ecology , environmental health , medicine , population
Plant diseases represent important preventable hazards to crop production. Genetic or cytoplasmic uniformity greatly increases vulnerability to disease when the crop is a) widely grown, b) has resistance to an aggressive pathogen that has an efficient means of dispersal and the potential for frequent genetic shifts from avirulence to virulence, and c) is grown in an environment favorable for disease. While there are risks to crop uniformity, the advantages to agriculture outweigh the disadvantages. Since epidemics are rare, present germplasm evaluation and utilization schemes are quite good but improvements are possible. Better monitoring of pathogens and germplasm relative to genes and cytoplasms for resistance is needed. Many germplasm collections have not been adequately evaluated for disease reaction and the available genes for resistance have not been transferred to plant types suitable for agriculture. Stable resistance to most diseases can be achieved by means of breeding and gene deployment. General resistance, multicomponent resistance, zonal deployment, and multilines are alternatives, each with advantages and limitation relative to plant breeding and agricultural objectives. International testing against a diversity of pathogen biotypes in a range of environments is a powerful tool in breeding for disease resistance. Germplasm diversity affords some protection against the unknown.