Agriculture Reference
In-Depth Information
(Kunzel et al.
2000
; Wang et al.
2001
). Doubled haploids, combined with marker-
assisted selection, provide a short-cut in backcross conversion, a plant breeding
method for improving an elite line defective in a particular trait (Toojinda et al.
1998
). Expressed sequence tags may help in identification of genes that determine
any trait of interest.
8 Conclusion
The haploid-derived true breeding lines provide a rapid means of achieving ho-
mozygosity, thereby speeding up the usually cumbersome and protracted conven-
tional breeding methods for crop improvement. Today, haploids and doubled hap-
loids have been reported in over 200 plant species (Forster et al.
2007
), however,
less than 10 % of these reports encompass tree species. Thus much work needs
to be done in the field of in vitro haploid production. This may be feasible only
with the development of novel genotype-independent methods through the study
and improvement of existing protocols and by obtaining a better understanding of
the haploid induction process, especially of the two main developmental switches:
the induction of the male/female gametophyte to undergo division, and subsequent
occurrence of embryogenesis. The recent spurt in the development of ultra high
throughput technologies of advanced genomic, transcriptomic, proteomic and im-
aging tools hold great promise for identification and analysis of genes that might be
playing important roles in the haploid induction process. This will immensely help
in the understanding of these processes and towards development of highly efficient
protocols for production of haploids, resulting in the overall improvement of highly
desirable and recalcitrant plant species. Through this chapter, we intend to provide a
clear and simple overview of haploidy with the purpose to stimulate interest among
scientists working in the related area and the potential application of the various in
vitro techniques used in haploid production intended for crop improvement.
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