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For further information on the Electronic Forum on Biotechnology in Food and
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Note, participants are assumed to be speaking on their own behalf, unless they state otherwise.]
Sent: 15 December 2003 12:54
Subject: 84: Re: Integration of molecular markers with plant breeding
This is from Dionysia Fasoula, Agricultural Research Institute, Cyprus.
It has been very interesting to follow the thoughts shared by colleagues from many countries during this FAO conference, culminating with the recent message from David Reece (no. 83, December 13), which also prompted the following contribution:
The issue of integrating molecular markers with plant breeding activities is essential. An inherent limitation remains the fact that while molecular analysis, by its very nature, has the capacity to focus on and evaluate the individual genome, conventional plant breeding evaluation works not at the level of the individual plant, but at the level of multiplant plots. The possibility to use a breeding methodology that enables the breeder to establish the individual plant as the unit of evaluation and selection from the earliest segregating generations in the actual fields of his or her choice, can enhance the efforts to identify useful markers.
In this regard, it is helpful to consider the essence of honeycomb breeding, which is a breeding methodology conceived to evaluate individual plants at distances that minimize the CV (coefficient of variation) of individual plant yields, while maximizing the yield per plant, in the arrangement of one of the several so-called honeycomb designs.
Following are some points that I believe will be of value to participants seeking to enhance their relevant programs, both in developing as well as in developed countries: What is needed for marker development and validation, as well as for successful QTL studies, is the most accurate phenotyping possible, particularly for traits that have economic impact (e.g. yield, stability of performance, tolerance to density and the various biotic and abiotic stresses, responsiveness to inputs). These traits are usually inherited in a polygenic manner, and therefore, are difficult to score reliably with conventional field or greenhouse techniques. Reliable phenotyping for the above traits is possible in all segregating generations in honeycomb trials, which are designed for accurate phenotypic (not visual) evaluation and place equal emphasis on selection both among and within the progeny lines.
Our experience with the honeycomb trials so far indicates that, encouragingly, success in plant breeding may not approach its theoretical limit yet, once we have methodologies to exploit the ability of the genome for self-restructuring.
Accordingly, developing countries can play an active role in the development of MAS, particularly in the detection of associations between molecular markers and traits of interest. These countries can develop their own dual-purpose honeycomb breeding programs, which will lead to the release of superior breeding germplasm or end-cultivars, and at the same time produce accurate phenotypic data to be used for the development of molecular markers, in collaboration settings. This will also produce useful information on the range of the validity of various markers across the different production environments.
Details about the construction of the appropriate honeycomb designs and the establishment of honeycomb trials are found in: Fasoulas, A.C. and V.A. Fasoula, 1995. Honeycomb selection designs. Plant Breeding Reviews 13:87-139. This article provides also illustrations of several honeycomb designs.
The rationale and the benefits stemming from the coupling of molecular breeding activities with the capabilities of the honeycomb breeding are found in: Fasoula, V.A. and D.A. Fasoula, 2000. Honeycomb breeding: Principles and applications. Plant Breeding Reviews 18:177-250.
The concept and the criteria for whole genome phenotypic evaluation are found in: Fasoula, V.A. and D.A. Fasoula, 2002. Principles underlying genetic improvement for high and stable crop yield potential. Field Crops Research: 191-209. It also presents a unifying genetic basis connecting vigor, degeneration and response to selection.
Dionysia A. Fasoula
Molecular Genetics and Breeding
Agricultural Research Institute
P.O. Box 22016
e-mail: dfasoula (at) arinet.ari.gov.cy dionysia_fasoula (at) yahoo.com
Sent: 15 December 2003 12:56
Subject: 85: marker assisted introgression in cattle
From Delphin Koudande, Benin.
I sent a reflection on 12 December, starting by approving comment by Ismahane ElOuafi (message 77, December 10), but unfortunately my connection to internet did not work. I have now about ten minutes, so I will just sumarise what I wrote:
Marker assisted introgression (MAI) in cattle should be thought deeply before implementation because:- QTL can be lost during the backcross process,
National Agricultural Research Institute of Benin
01 BP 884 Cotonou
dkoud2002 (at) yahoo.fr
[Thanks very much for these comments about MAI. Delphin's PhD from
Wageningen University, Netherlands in 2000, entitled "Introgression of
trypanotolerance genes" is highly relevant in this context. The abstract is
"Trypanosomosis is the most widespread parasitic disease of great importance in Africa affecting human and animals. There are breeds of cattle that are trypanotolerant. Trypanotolerance is an ability of these breeds to withstand the effects of trypanosome infections. The disease impedes production in Sub-Saharan Africa. In this thesis, the main focus is on marker-assisted breeding to improve trypanotolerance and mouse is used as model organism for cattle. We have concentrated on the opportunities to exploit individual genes (QTL) that affect trypanotolerance. We have shown how the size of a breeding experiment increases with the number and the size of the QTL region to introgress. Biological factors to be considered when estimating the required size of an introgression experiment are also highlighted. Strategies to optimize designs for introgression show that selecting two lines each carrying two of the donor's QTL allele during the backcross (when intogressing three QTL) is more advantageous than monitoring simultaneously the three QTL in terms of number of animals to maintain, number of genotyping and costs involved. An experiment in mice shows that QTL introgression is feasible and successful, and that the background genotype is an important factor to be considered when analyzing the results of such an experiment. This experiment is unique. The general discussion focuses on the introgression of trypanotolerance genes is cattle with an emphasis on Sub-Saharan zones of Africa. The introduction of trypanotolerant cattle in the humid and sub-humid zones of Africa, however, should be done with care to avoid damage to the environment and bio-diversity"...Moderator].
Sent: 15 December 2003 13:05
Subject: End of FAO conference on Marker Assisted Selection
The last message (number 85), from Delphin Koudande, has been posted so Conference 10 of the FAO Biotechnology Forum is now officially closed.
FAO established the Biotechnology Forum in the year 2000 with the aim of providing quality balanced information on agricultural biotechnology in developing countries and to make a neutral platform available for people to exchange views and experiences on this subject. We hope that this conference on "Molecular marker assisted selection as a potential tool for genetic improvement of crops, forest trees, livestock and fish in developing countries" has been both interesting and of value to you.
For your information, we can provide some figures about the conference. It ran for four weeks, from 17 November to 14 December 2003, and a total of 627 people subscribed, the highest number for any of the Biotechnology Forum conferences held so far.
Of the 627 people, 52 (i.e. 8 %) submitted at least one message. Messages were received from all major regions of the world - 28 of the 85 messages posted (i.e. 33%) came from participants in Asia, 26% from Europe, 14% from Latin America and the Caribbean, 9% each from Africa and Oceania and 8% from North America.
Messages came from people living in 26 different countries - the greatest proportion by far was from participants in India (25%), followed by Australia (9%), United States (8%), United Kingdom (7%) and Peru (6%). A total of 50 messages (i.e. 59%) were from participants in developing countries and 35 (41%) from participants in developed countries.
The great majority of messages came from people working in research centres, including CGIAR centres, (52%) and in universities (33%). The remainder worked as consultants, development agencies, farmer organisations, government agencies, NGOs or UN organisations.
[Note that figures about the relative contributions of the developing versus developed world or of the different world regions to the conference are only approximate - people from developing countries may be currently living in developed countries (and vice versa). Similarily, results on participants workplaces are only an approximation - people may have several roles at any one time].
If, in the future, you use material from the conference for your decision-making or refer to it in articles or use it as reference material we would be happy to be know about it (at firstname.lastname@example.org). All the messages posted will remain on the Forum website for future reference, at http://www.fao.org/biotech/logs/c10logs.htm. As is standard practice with conferences in the Biotechnology Forum, we will prepare a Summary Document in the future to provide a summary of the main arguments and concerns discussed during the conference, based on the messages posted by the participants.
Finally, a very special and sincere thanks to all of the 52 individuals who submitted messages and who devoted their time and effort to this excellent exchange of views, insights and experiences about MAS in developing countries.John
John Ruane, PhD
FAO Working Group on Biotechnology,
Moderator, Conference 10
e-mail: biotech-mod2 (at) fao.org
FAO website http://www.fao.org
Forum website http://www.fao.org/biotech/forum.asp
FAO Biotechnology website http://www.fao.org/biotech/index.asp