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Genetic Factors Conditioning Resistance in Alfalfa to the Stem Nematode 1
Author(s) -
Grundbacher F. J.,
Stanford E. H.
Publication year - 1962
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/cropsci1962.0011183x000200030011x
Subject(s) - library science , citation , resistance (ecology) , biology , agronomy , computer science
AS EARLY as 1923 the stem nematode, Dhylenchus •**• dip sad (Kiihn) Filipjev, was reported to occur on alfalfa in California (12). To date the parasite is found in several alfalfa producing areas of the state, especially in coastal regions, the Antelope Valley, and certain parts of the Central Valley. Frequently, great destruction is observed in fields on dairy farms where alfalfa has been grown repeatedly on the same land, thus favoring the build-up of large populations. In stem nematode-infested fields, if alfalfa is grown after alfalfa, the seedlings may become damaged. If alfalfa follows another crop, the damage generally appears in the second year in the form of barren patches which may increase in size in succeeding years. The alfalfa stand on entire fields may be destroyed. Stem nematode attack of seedling plants results in swelling of the cotyledonary node. The subsequently-developing leaves have swollen and stunted petioles. Susceptible seedlings seldom recover under field conditions. Infested older plants show swollen stems, buds, and petioles, as well as distorted leaves and petioles. The surface of the swollen plant parts is rough and frequently shows brown discolora-