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Heterosis in Testcrosses of 27 Exotic Peanut Cultivars 1
Author(s) -
Isleib T. G.,
Wynne J. C.
Publication year - 1983
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/cropsci1983.0011183x002300050006x
Subject(s) - heterosis , biology , epistasis , point of delivery , cultivar , genetic divergence , genetic distance , dominance (genetics) , agronomy , horticulture , botany , genetic variation , genetic diversity , hybrid , genetics , population , demography , sociology , gene
A study was conducted to determine the extent of and genetic basis for heterosis in crosses between 27 exotic peanut ( Arachis hypogaea L.) cultivars and an adapted virginia breeding line. Because their subspecific taxonomy was not always clear, principal components were used to cluster the exotic parents into five morphologically distinct groups roughly corresponding to the botanical divisions of the species. Heterosis (measured as the deviation of F 1 performance from the midparent) was observed for pod yield, pod size parameters, seed yield and other traits. Heterosis up to 19% above the higher parent occurred for pod size and length. A significant portion (27 to 68%) of the variability in heterotic effects was attributable to difference among the parental groups with generally higher levels expressed in intersubspecificcrosses. Heterotic deviations were broken into two components reflecting the relative contributions of dominance and epistasis to nonadditive genetic variation. For pod and seed yield and pod length, dominance was the more important source while epistasis was more important for pod and seed number and meat content. The two sources made approximately equal contributions to heterosis for pod and seed size. The degree of genetic divergence between exotic parents and the adapted line was estimated by a Euclidean distance based on the vegetative and reproductive characters used in the principal component analysis. For characters exhibiting more dominance, the relationship of heterosis to divergence between parents was linear and increasing. The relationship was curvilinear for traits largely influenced by epistasis. An optimum level of divergence was detected for pod number only.