Yield Improvement in Eastern Soft Red Winter Wheat from 1919 to 2009

Periodic evaluation of improvements in yield and disease resistance is necessary to assess breeding progress over time, and the elucidation of underlying traits responsible for yield gains can help direct future breeding. Objectives of this study were: 1) to determine the rate and magnitude of yield progress in eastern soft red winter (SRW) wheat (Triticum aestivum, L.) cultivars released from 1950 to 2009 relative to a historical cultivar Red May (1919) and; 2) to determine effects of leaf rust (Puccinia triticina f. sp. tritici) and powdery mildew [Blumeria graminis (DC.) E.O. Speer f. sp. tritici Em. Marchal] on grain yield components and agronomic traits. Replicated yield trials were grown at Warsaw, VA in 2010 and 2011, and at Holland and Blacksburg, VA in 2011. For objective 1, the genetic progress experiment: flag leaf angle, kernel weight, spikes m-2, lodging, flowering date and harvest index collectively explained the most yield variation in multiple environments on the basis of linear regression analysis. Rate of genetic yield improvement ranged from 0.56% yr-1 at Holland in 2011 to 1.4% yr-1 at Blacksburg in 2011. For objective 2, the disease loss experiment: yield losses ranged from 1% at Holland in 2011 to 21% at Warsaw in 2011. Losses primarily due to powdery mildew and leaf rust were as high as 14% and 33%, respectively. Powdery mildew had the largest negative correlation with harvest index and seeds spike-1, while leaf rust had the largest negative correlation with plant biomass and harvest index.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Crop and Soil Environmental Sciences

Department dc:contributor.department

Crop and Soil Environmental Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2011

Author dc:creator

• Green, Andrew Justin

Chair dc:contributor.committeechair

• Griffey, Carl A.

Committee members dc:contributor.committeemember

• Balota, Maria
• Parrish, David J.
• Thomason, Wade E.

• yield
• wheat
• genetics

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-12122011-112349

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/36086