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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #84161
Title: GENETIC DIVERSITY AND HETEROSIS OF SPRING WHEAT CROSSES

Author
item FABRIZIUS, MARTIN - UNIVERSITY OF MINNESOTA
item Busch, Robert - Bob
item KHAN, KHALIL - NORTH DAKOTA STATE UNIV
item HUCKLE, LINDA - NORTH DAKOTA STATE UNIV

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Wheat breeders need new tools to predict how productive their new varieties of wheat are likely to be. New varieties are made by mating plants from different parental families. The similarities and differences among different parental varieties of wheat influence the way the offspring react to plant diseases, drought, and heat stress. The productivity of the new generation of wheat is profoundly influenced by how closely the parents ar related -- those hybrids of parents that are closely related generally produce less grain than hybrids from parents that are more distantly related. We tested whether a new way of classifying the relationship among wheat varieties, which uses the pattern of proteins in the plant tissue, is better than older methods, such as the actual geneology of the parents. We mated specific pairs of parental varieties and measured the hybrid vigor (improved yield) of the resulting offspring. The new method based on protein patterns was not better than the old method, and even the old method was not very useful in predicting hybrid vigor. Our research showed that some unknown factors other than parental geneology were influencing hybrid performance. This important finding will help plant breeders discover better ways to predict wheat variety performance. This will help them produce new wheat varieties for enhanced and improved food production, which are critically important for our national food supply and for export.

Technical Abstract: Genetic diversity between parents may contribute to both heterosis and potential for developing inbred lines from a cross. The objectives of this study were to use gliadin-banding patterns to estimate the genetic distance among spring wheat cultivars released by North American breeding programs and to determine whether pedigree, morphological, or gliadin diversity affected F2 bulk heterosis or the potential of crosses measured by recombinant inbred line performance. Gliadin-banding patterns were collected for 290 spring wheat cultivars, previously characterized for pedigree and morphological differences, and the genetic similarity coefficient was calculated for each pair-wise combination of cultivars. The genetic similarity coefficient was not correlated to the coefficient of parentage. We developed 137 F2 bulks using 91 different cultivars as parents and tested them at 2 locations in 1993 and 3 locations in 1994. No linear relationship between genetic distance and F2 bulk heterosis was detected. However, when crosses were divided into related and unrelated groups, crosses with parents unrelated by pedigree or morphology expressed greater heterosis than crosses with related parents. Bulks of crosses between cultivars that were classified as unrelated by 2 or more of the distance measures showed more heterosis than related crosses. Thus, part of heterosis seems to be due to parental diversity, though not in a linear fashion. Heterosis was expressed by some crosses between related parents, as well. Expression of greater heterosis than average by the best yielding bulks, without an increase in genetic distance, suggested additional factors influence heterosis expression.