Predicting the properties of second cycle hybrids produced by intercrossing random samples of recombinant inbred lines

• Published in: Heredity 1984-10, Vol.53 (2), p.283-292
• Main Authors: de Toledo, J F F, Pooni, H S, Jinks, J L
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Classical and quantitative genetics. Population genetics. Molecular genetics; Classical genetics, quantitative genetics, hybrids; cross-breeding; Crosses, Genetic; Cytogenetics; Ecology; Evolutionary Biology; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetics and breeding of economic plants; Genetics of eukaryotes. Biological and molecular evolution; Human Genetics; Hybridization, Genetic; Inbreeding; Mathematics; Nicotiana rustica; original-article; plant breeding; Plant Genetics and Genomics; Pteridophyta, spermatophyta; Recombination, Genetic; Vegetals
• ISSN: 0018-067X; 1365-2540
• DOI: 10.1038/hdy.1984.87

Distributive properties of the second cycle hybrids that are produced by intercrossing the recombinant inbreds extractable from the F 2 of a cross between two pure breeding lines can be predicted from the early generations of the original cross. Hence the frequency of such hybrids that will outperform the extreme recombinant inbreds or the original F 1 can be predicted. Basic generations and triple test cross families provide the most reliable estimates of the predictors and therefore should be used whenever possible although, in the presence of linkage, randomly mated F 2 's may give improved predictions. Simpler experiments consisting of the parental varieties and their F 1 and F 2 generations, however, provide all the information that is likely to be necessary for most practical purposes. The predictive power of the new approach is demonstrated on material extracted from the cross of varieties 1 and 5 of Nicotiana rustica . The predictors were estimated from the means and variances of V 1 , V 5 , F 1 and F 2 raised in six environments between 1973 and 1983. The predicted frequencies of second cycle F 1 's which outperform the extreme recombinant inbred lines derived from this cross are compared with those observed among 190 second cycle hybrids in a diallel between 20 recombinant inbreds derived from the same cross.