UC IPM Online UC ANR home page UC IPM home page

UC IPM Home

SKIP navigation

 

Research and IPM

Grants Programs: Projects Database

Project description

Resistance of alfalfa against silverleaf whitefly: breeding and mechanisms of resistance. (01XA010)
Program Exotic Pests and Diseases Research Program
Principal
investigators
G.P. Walker, Entomology, UC Riverside
L.R. Teuber, Agronomy and Range Science, UC Davis
Host/habitat Alfalfa
Pest Silverleaf Whitefly Bemisia argentifolii
Discipline Entomology
Review
panel
Agricultural Systems
Start year (duration)  2001 (Two Years)
Objectives Determine the mechanism of resistance in alfalfa clones selected for resistance against silverleaf whitefly.

Evaluate material identified as resistant in previous laboratory assays in the field (Imperial Valley) under natural infestation conditions.

Further improve the silverleaf whitefly resistance of advanced genetic materials currently being selected for improved agronomic characteristics and resistance to other economically important pests and diseases.

Second-year
progress
Objective 1. We have systematically narrowed down the mechanisms of resistance in the resistant alfalfa genotypes in accordance with our original planned research approach. We have ruled out difficulty of the whiteflies penetrating the plant tissue with their stylets and difficulty penetrating a phloem sieve element (the type of plant cell that whiteflies upon) as possible mechanisms of resistance. Resistance is expressed AFTER a sieve element is penetrated, and results in the whitefly spending significantly less time in ingestion behavior and a greatly reduced (one fifth) volume of plant sap ingested, and eventually death.

Objective 2. We made the first year evaluation of our alfalfa clones under field conditions in Imperial Valley. Due to high mortality of transplants, we did not get as many individual plants established as we had hoped, so we will fill in the missing plants this spring and repeat the evaluation this summer. Nonetheless, several of the clonal lines that looked good in our greenhouse evaluations performed excellently in the field trial and considerably better than the recently released alfalfa cultivar UC-Impalo-WF with moderate resistance against whiteflies. This means we have identified germplasm that can improve whitefly resistance over what is currently available.

Objective 3. We are continuing to use our greenhouse/laboratory evaluations to screen the potential parent clones for the next generation of whitefly resistant alfalfa. We have conducted at least one replicate on 30 of the potential parent alfalfa clonal lines.

First-year
progress
We are preparing our field plots for this year's field evaluation of different clonal lines of alfalfa for resistance against silverleaf whitefly.

Top of page


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   web template revised: November 21, 2014 Contact webmaster.