Date of Award:

5-1967

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Department name when degree awarded

Entomology

Committee Chair(s)

Donald W. Davis (Major Professor) B. Austin Haws (Thesis Director)

Committee

Donald W. Davis

Committee

B. Austin Haws

Committee

Eldon Gardner

Committee

Datus M. Hammond

Committee

D. R. McAllister

Committee

Keith R. Allred

Committee

John T. Simmons

Abstract

Several studies have been made by others to try to find a better method of selecting alfalfa that is resistant to seed injury by the alfalfa seed chalcid. This study investigated the possibility of using seed size as a basis of selection for resistance.

Data in this thesis show that the stage of seed development when chalcid oviposited in the seeds did affect the size of seeds. Larger seeds were infested when alfalfa seed chalcid were introduced early in the development of seeds (five days after pollination), and the total number of seeds produced was slightly greater when chalcids were introduced 10 days after pollination.

The percentage chalcid infestation in second crop alfalfa seed was almost twice as great as that in the first crop seed, but the average size of chalcid-infested seeds was larger in the first crop than in the second even though seeds in all size categories were present in both crops.

This study indicated that seed size would not be a good characteristic to use in selecting alfalfa resistant to alfalfa seed chalcid.

There were differenced in sizes of seeds among varieties and entries. Large seeded entries of alfalfa were above average in chalcid infestation, but the smaller seeded entries were also above average in chalcid infestation.

The original theory proposed at the beginning of this investigation, that alfalfa has a higher percentage of alfalfa seed chalcid infestation in the larger seeds and smaller seeds than in intermediate sizes, is true for most samples evaluated, but there were exceptions.

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 .