Date of Award:

5-1973

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Department name when degree awarded

Botany

Committee Chair(s)

Orson S. Cannon

Committee

Orson S. Cannon

Committee

W. S. Boyle

Committee

Wade G. Dewey

Committee

Herman H. Wiebe

Abstract

Tests substantiating vector nonpreference as a factor in the ability of certain tomato varieties to escape curly top virus (CTV) infection were conducted and evaluated. Nonpreference is not an effective mode of resistance to CTV in tomatoes under field conditions since leafhoppers feed on and may infect plants before expressing a preference.

Preference of viruliferous leafhoppers was observed on plants of seven tomato varieties arranged both randomly and homogeneously in caged flats. Through observation of curly top symptom development, relative resistance due to vector nonpreference was calculated for each variety.

Up to 23 per cent of the fairly high resistance of Lycopersicon peruvianum var. humifusum (a CTV resistance source) and breeding line C5, the least preferred varieties, was due to vector nonpreference. L. peruvianum var. dentatum (evidently the best resistance source), however, maintained its primacy in CTV resistance even though it attracted three times as much leafhopper feeding. Other varieties were medium in preference and low to medium in resistance.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .