TY - JOUR
T1 - Genetic basis of heterosis explored by simple sequence repeat markers in a random-mated maize population
AU - Lu, H.
AU - Romero-Severson, J.
AU - Bernardo, R.
PY - 2003/8/1
Y1 - 2003/8/1
N2 - The genetic basis of heterosis in crop plants has not been completely resolved. Our objective in this study was to determine the level of dominance for quantitative trait loci (QTLs) that underlie heterosis in maize (Zea mays L.). An F2 population of an elite maize single cross, LH200 x LH216, was random mated for three generations in an attempt to break up repulsion linkages that might lead to pseudo-overdominance. The population was analyzed with 160 simple-sequence repeat markers. Phenotypic data analyses indicated overdominance for grain yield and partial dominance for plant height, grain moisture and stalk lodging. A total of 28 QTLs were identified for grain yield, 16 for grain moisture, 8 for stalk lodging, and 11 for plant height. For grain yield, 24 QTLs (86%) showed overdominance. In contrast, most of the QTLs for plant height, grain moisture and stalk lodging showed partial to complete dominance. Little epistasis was detected among the QTLs for any of the traits. Our results can be interpreted in one of two ways, or a combination of both: (1) QTLs for grain yield in maize exhibit true overdominance, or (2) QTLs for grain yield show partial to complete dominance, but they are so tightly linked such that three generations of random mating failed to separate their individual effects.
AB - The genetic basis of heterosis in crop plants has not been completely resolved. Our objective in this study was to determine the level of dominance for quantitative trait loci (QTLs) that underlie heterosis in maize (Zea mays L.). An F2 population of an elite maize single cross, LH200 x LH216, was random mated for three generations in an attempt to break up repulsion linkages that might lead to pseudo-overdominance. The population was analyzed with 160 simple-sequence repeat markers. Phenotypic data analyses indicated overdominance for grain yield and partial dominance for plant height, grain moisture and stalk lodging. A total of 28 QTLs were identified for grain yield, 16 for grain moisture, 8 for stalk lodging, and 11 for plant height. For grain yield, 24 QTLs (86%) showed overdominance. In contrast, most of the QTLs for plant height, grain moisture and stalk lodging showed partial to complete dominance. Little epistasis was detected among the QTLs for any of the traits. Our results can be interpreted in one of two ways, or a combination of both: (1) QTLs for grain yield in maize exhibit true overdominance, or (2) QTLs for grain yield show partial to complete dominance, but they are so tightly linked such that three generations of random mating failed to separate their individual effects.
KW - Heterosis
KW - Maize
KW - Overdominance
KW - Quantitative trait loci (QTLs)
KW - Random mating
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U2 - 10.1007/s00122-003-1271-7
DO - 10.1007/s00122-003-1271-7
M3 - Article
C2 - 12759730
AN - SCOPUS:0041975060
SN - 0040-5752
VL - 107
SP - 494
EP - 502
JO - Theoretical and Applied Genetics
JF - Theoretical and Applied Genetics
IS - 3
ER -