The final purpose is to get both line completely inbred?

The "classical way" is described extensively by Jackson Lab using 20 incrossing (did not found the original link)

http://ko.cwru.edu/info/breeding_strategies_manual.pdf

Here a paper often quoted on the statistic

Abiola et al. 2003 PMID: 14634638

http://www.ncbi.nlm.nih.gov/pubmed/14634638

AND

Welsh et al. 2012 DOI:10.1534/g3.111.001784

http://www.g3journal.org/content/2/2/191.full

Newer methods using 5 inbreed was established using genetic matching:

Discuss here http://www.informatics.jax.org/greenbook/chapters/chapter2.shtml

I'm not competent to answer the question, sorry.

Hi Cleopatra.

Probably the Diallel Analysis (or Diallel Cross) is the most used mating design for studying general combining ability (GCA) and specific combining ability (SCA) of those inbred lines over the environments. You may need to grow at 3 different locations, and each location with 2-3 replications, plus couple of seasons [you should talk to your project leader about the 'numbers'].

The following website will direct you to a real-life example:  http://www.scielo.br/scielo.php?pid=S0103-90162000000100021&script=sci_arttext#t6

Combining ability of maize inbred lines evaluated in three environments in Brazil

 Luciano Lourenço Nass1*; Marlene Lima2; Roland Vencovsky3; Paulo Boller Gallo2

1Embrapa Recursos Genéticos e Biotecnologia, SAIN Parque Rural - CEP: 70770-900 - Brasília, DF.

2IAC, C.P. 28 - CEP: 13001-970 - Campinas, SP.

3Depto. de Genética - USP/ESALQ, C.P. 83 - CEP: 13400-970 - Piracicaba, SP.

*Corresponding author  

Good luck on your research,

@ Nicolas, the final purpose of Combining ability study is to find out which (two) inbreds are the best/suitable parental lines for hybridization (hybrid production) over a specific environment. Combining ability analysis also helps in the identification of superior hybrid combinations which may be utilized for commercial. The gene action evaluated from the experimental analysis also help plant breeders' breeding approaches and directions.

Thank you all for the answers and links to articles

I think the most suitable is partial diallel mating design or also the line by tester mating design. software that can do the analysis is genstat