The genetics of selfing with concurrent backcrossing in breeding hybrid sugar beet (Beta vulgaris altissima L.) |
| |
Authors: | I J Mackay J P Gibson P D S Caligari |
| |
Institution: | (1) Department of Agricultural Botany, The University of Reading, Reading RG6 6AS, and Lion Seeds Ltd, Woodham Mortimer, Maldon, Essex CM9 6SN, UK, GB;(2) Centre for Genetic Improvement of Livestock, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada, CA;(3) Department of Agricultural Botany, The University of Reading, Reading RG6 6AS, UK E-mail: p.d.s.caligari@reading.ac.uk, GB |
| |
Abstract: | Sugar beet hybrids are produced by crossing a cytoplasmic male-sterile (CMS) line with a pollinator. New CMS lines are produced
by crossing a fertile plant to an existing CMS line. The fertile plant is also selfed. In the following generation, one of
the selfed, fertile progeny is paired and isolated with one of the crossed, CMS progeny, to give a second generation of selfing
and crossing. Over a series of such crosses and selfs, a new fertile inbred line and its corresponding, near-isogenic CMS
partner are produced. Selection among lines takes place at one or more stages of the backcrossing programme. A method is presented
here for calculating the genetic variances and covariances within and between lines and generations based on a derivation
of additive genetic relationships modified from an approach widely employed in animal breeding. The genetic variances and
covariances are used to predict response to selection from varying strategies, from which optimum schemes can be determined.
Results suggest that selection should generally take place after three generations of backcrossing when the fertile plant
used to initiate the backcrossing process is not inbred, but can take place after generation two when the fertile plant is
inbred. Doubled haploid production is unlikely to provide an extra advantage that would be worthwhile in such a system. The
method developed here can be used to explore a wide range of more complex breeding systems.
Received: 27 July 1998 / Accepted: 19 October 1998 |
| |
Keywords: | Hybrid selection Concurrent backcrossing Additive genetic relationship Doubled haploids Inbreeding |
本文献已被 SpringerLink 等数据库收录! |
|