Forage production and longevity of alfalfa (Medicago sativa L.) are reduced by the effect of the fungus Phytophthora megasperma Drechs. in irrigated alfalfa fields located in Central Mexico. There are no resistant alfalfa cultivars adapted to this region. Phytophthora root rot was found in irrigated fields at elevations between 1600 to 2000 m. Strains of this fungus isolated from soil collected in Mexico were more virulent than one strain from Arizona. Four alfalfa cultivars of Mexican origin, Certified Hayden, and Hayden PX-III, an experimental cultivar resistant to strains of P. megasperma from Arizona, were susceptible to P. megasperma Bajio strain collected in Central Mexico. Following two cycles of phenotypic current selection, the level of resistance to Phytophthora root rot was increased from 5.6% to 22.8% in the new population originating from the cultivar INIA-76, and from 12.8% to 30.6% in the new population originating from the cultivar Hayden PX-III.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/281975 |
| Date | January 1981 |
| Creators | Aguirre Rascon, Jaime |
| Contributors | Schonhorst, M. H. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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