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Breeding Cycles Expedited by FT ‐mediated Reduction in Generation Time
Author(s) -
Eickholt David P.,
Lewis Ramsey S.
Publication year - 2013
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/cropsci2013.03.0150
Subject(s) - biology , inbreeding , transgene , cultivar , nicotiana tabacum , allele , locus (genetics) , genetics , crop , epistasis , genetically modified crops , genotype , plant breeding , microbiology and biotechnology , botany , agronomy , gene , population , demography , sociology
ABSTRACT Methods for rapid inbreeding are desirable for reducing the time required to complete a breeding cycle and to increase genetic gain per year. Constitutive expression of FLOWERING LOCUS T ( FT ) derived from Arabidopsis has previously been shown to reduce generation time in tobacco ( Nicotiana tabacum L.) and other crop plants. Here, we used tobacco as a model system to investigate the utility of a modified single‐seed descent (SSD) breeding method where transgenic expression of 35S : FT was used to reduce generation time during inbreeding. The transgene was maintained in hemizygous condition during inbreeding, and null segregants were isolated in the F 4:5 generation to create nontransgenic F 5:6 lines that were produced in nearly half the time that would have been required using conventional SSD. Opportunities for selection among 35S : FT plants during inbreeding were demonstrated by selecting for quantitative levels of resistance to the soil‐borne pathogen Phytophthora nicotianae . Populations of selected lines exhibited significantly higher levels of resistance relative to random lines, greater frequencies of highly resistant genotypes, and lower frequencies of highly susceptible genotypes. The system outlined here could lead to more rapid commercialization of improved cultivars in crop species amenable to manipulation of flowering time via transgenic expression of FT ‐like genes. Strategies to enhance the frequency of favorable alleles in resulting populations can be incorporated into the method.