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Genetic Diversity and Heterosis of Spring Wheat Crosses
Author(s) -
Fabrizius Martin A.,
Busch Robert H.,
Khan Khalil,
Huckle Linda
Publication year - 1998
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1998.0011183x003800040036x
Subject(s) - heterosis , biology , transgressive segregation , genetic diversity , genetic distance , transgressive , cultivar , pedigree chart , inbred strain , genetics , agronomy , genetic variation , hybrid , gene , quantitative trait locus , population , demography , sociology , sedimentary depositional environment , paleontology , structural basin
Genetic diversity between parents may contribute positively to both heterosis and transgressive segregation. The objectives of this study were to determine (i) whether genetic diversity in spring wheat ( Triticum aestivum L.) affected F 2 bulk heterosis and (ii) whether genetic diversity affected the amount of transgressive segregation among progeny from a cross. Genetic diversity was measured by pedigrees, morphology, and gliadin seed proteins. Heterosis was evaluated for 137 F 2 bulks tested at two Minnesota locations in 1993 and three locations in 1994. These bulks were developed from crosses among 91 cultivars. No linear relationship between genetic distance and F 2 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 two 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. Expression of greater‐than‐average heterosis by the highest yielding bulks, without an increase in genetic distance, suggested additional factors were influencing the expression of heterosis. Transgressive segregation was evaluated for six of the 137 crosses; 30 to 40 inbred lines from each of the crosses was evaluated in three environments. Data for these populations were consistent with an additive genetic model. The expression of heterosis was due in part to genetic diversity but was unpredictable and also depended on factors not elucidated by this study.