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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #59978
Title: GENETIC DIVERSITY AMONG NORTH AMERICAN SPRING WHEAT CULTIVARS I: ANALYSIS OF THE COEFFICIENT OF PARENTAGE MATRIX

Author
item VAN BEUNINGEN, L - UNIVERSITY OF MINNESOTA
item Busch, Robert - Bob

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Bread wheat has been grown for several thousand years with many parts of the world having locally developed types. In the Western hemisphere, wheat was introduced relatively recently with immigrants bringing seed from their countries of origin. We determined the genetic relatedness of 270 spring wheat varieties released since 1900 in North America. Spring wheats are primarily grown in the Upper Midwestern USA, Canadian Prairie Provinces, and Mexico. In Canada and the USA, they are the main source of high protein bread wheats used for strengthening dough mixes for higher quality bread products. Differences in the genetic constitution of spring wheat varieties are relatively unknown. This research studied the relatedness of 270 spring wheat varieties produced in North America during the last 90 years. Varieties released by Canada during the past 30 years are closely related to each other. US wheat varieties differ from both Canadian and Mexican varieties. The more modern US varieties appear to show less relatedness than earlier varieties. Increased genetic diversity in US varieties is good because it allows plant breeders to select for continued gain in yield and other important traits. These results will allow scientists to develop new varieties that maximize progress in plant breeding.

Technical Abstract: Genetic diversity constitutes the raw material for plant improvement and it can provide protection against genetic vulnerability to biotic and abiotic stresses. Therefore, quantification and classification of diversity in cultivar collections can be useful for germplasm curators and plant breeders. Our objectives were to determine patterns of relatedness using the coefficient of parentage (COP) matrix among 270 spring wheat (Triticum aestivum L.) cultivars and to compute mean COP values for major regional breeding programs. The collection included most important cultivars released during this century from Canada (47), the USA (133), and Mexico (90). Cluster analysis based on the COP matrix resulted in 20 major clusters of four or more entries and six small clusters of two cultivars each. The first three axes from a principle coordinate analysis of the intercluster COP matrix showed: 1) a group of seven clusters including most thard red spring cultivars (HRS) from the USA, and Canada (CWRS), based mainly on a Marquis foundation, 2) a group of nine interrelated clusters including most cultivars from CIMMYT (Mexico), 3) two interrelated clusters including mostly white wheats, and 4) two small clusters including mostly old Canadian cultivars. Mean COP values were computed among cultivars released during three successive time periods. The CWRS cultivars have become progressively more interrelated, with Thatcher as their foundation, and average COP values of 0.58 among modern cultivars. The HRS wheats showed a fairly high, but slowly decreasing interrelatedness (COP equals 0.22) among modern cultivars. CIMMYT cultivars were less interrelated (COP equals 0.15 to 0.20) and comparable to levels reported for soft red winter wheat and barley.