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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 111 (1993), S. 0 
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Restriction fragment length polymorphisms (RFLPs) have been proposed for predicting the yield potential of different types of cross. Their has been evaluated in 15 flint and 12 dent inbreds from the European maize (Zea mays L.) germplasm as well as in 68 F1 crosses (21 flint × flint, 14 dent × dent, and 33 flint × dent) produced between them. The materials were evaluated for F1 performance and midparent heterosis of grain yield, dry matter content (DMC) and plant height in two environments in Germany. Genetic distances (GDs) between parental lines, calculated from RFLP data of 194 clone-enzyme combinations, showed greater means for flint × dent (0.67) than dent × dent (0.62) and flint × flint (0.55) crosses. Cluster analysis based on GDs resulted in a clear separation of flint and dent lines and agreed well with pedigree information. For the complete set of 64 crosses analyzed (excluding 4 crosses between closely related lines) correlations of GD with F1 performance and heterosis were significant for all traits except F1 performance of DMC. When separate calculations were performed for individual subjets of crosses, correlations of GD with Fl performance and heterosis were significantly positive (0.48 ≤ r ≤ 0.80) for all traits in the flint × flint crosses, but not significant for the subsets of flint × dent and dent × dent crosses. Our results confirm those of previous investigations in that the predictive value of RFLP data is restricted to crosses between lines from the same heterotic group, and cannot be applied to crosses between lines from genetically divergent heterotic groups.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 83 (1992), S. 1003-1012 
    ISSN: 1432-2242
    Keywords: Zea mays L ; RFLPs ; Genetic diversity ; Heterotic groups
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thirty inbred lines representing a wide range of early-maturing European elite germ plasm of maize (Zea mays L.) were assayed for RFLPs using 203 clone-enzyme combinations (106 DNA clones with restriction enzymes EcoR1 and HindIII). The genetic materials comprised 14 flint, 12 dent, and 4 lines of miscellaneous origin. Objectives were to (1) characterize the genetic diversity for RFLPs in these materials, (2) compare the level of genetic diversity found within and between the flint and the dent heterotic groups, and (3) examine the usefulness of RFLPs for assigning inbreds to heterotic groups. All but two DNA clones yielded polymorphism with at least one restriction enzyme. A total of 82 and 121 clone-enzyme combinations gave single-banded and multiple-banded RFLP patterns, respectively, with an average of 3.9 and 7.7 RFLP patterns per clone-enzyme combination across all 30 inbreds, respectively. Genetic similarity (GS) between lines, estimated from RFLP data as Dice's similarity coefficient, showed considerable variation (0.32 to 0.58) among unrelated inbreds. The mean GS for line combinations of type flint x dent (0.41) was significantly smaller than for unrelated flint lines (0.46) and dent lines (0.46), but there was considerable variation in GS estimates of individual line combinations within each group. Cluster and principal coordinate analyses based on GS values resulted in separate groupings of flint and dent lines in accordance with phylogenetic information. Positioning of lines of miscellaneous origin was generally consistent with expectations based on known breeding behavior and pedigrees. Results from this study corroborated that RFLP data can be used for assigning inbreds to heterotic groups and revealing pedigree relationships among inbreds.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 84 (1992), S. 672-681 
    ISSN: 1432-2242
    Keywords: RFLPs ; Heterosis ; Genetic distances ; Prediction ; Zea mays L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Restriction fragment length polymorphisms (RFLPs) have been proposed for the prediction of the yield potential of hybrids and the assignment of inbreds to heterotic groups. Such use was investigated in 66 diallel crosses among 6 flint and 6 dent inbreds from European maize (Zea mays L.) germ plasm. Inbreds and hybrids were evaluated for seven forage traits in four environments in the Federal Republic of Germany. Midparent heterosis (MPH) and specific combining ability (SCA) were calculated. Genetic distances (GD) between lines were calculated from RFLP data of 194 clone-enzyme combinations. GDs were greater for flint x dent than for flint x flint and dent x dent line combinations. Cluster analysis based on GDs showed separate groupings of flint and dent lines and agreed with pedigree information, except for 1 inbred. GDs of all line combinations in the diallel were partitioned into general (GGD) and specific (SGD) genetic distances; GGD explained approximately 20% of the variation among GD values. For the 62 diallel crosses (excluding 4 crosses of highly related lines), correlations of GD with F1 performance, MPH, and SCA for dry matter yield (DMY) of stover, ear, and forage were positive but mostly of moderate size (0.09≤r≤0.60) compared with the higher correlations (0.39≤r≤0.77) of SGD with these traits. When separate calculations were performed for various subsets, correlations of GD and SGD with DMY traits were generally small (r〈0.47) for the 36 flint x dent crosses, significantly positive (r〈0.53) for the 14 flint x flint crosses, and inconclusive for the 12 dent x dent crosses because of the lack of significant genotypic variation. Results indicated that RFLPs can be used for assigning inbreds to heterotic groups. RFLP-based genetic distance measures seem to be useful for predicting forage yield of (1) crosses between lines from the same germ plasm group or (2) crosses including line combinations from the same as well as different heterotic groups. However, they are not indicative of the hybrid forage yield of crosses between unrelated lines from genetically divergent heterotic groups.
    Type of Medium: Electronic Resource
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