There were identified 5 variety designs of alfalfa developed during breeding
history: improved population, synthetic variety not reproduced from initial parental components (type
1), synthetic variety reproduced from initial parental components (type 2), hybrid variety on CMS base
and self-pollinating variety.
A new design of alfalfa synthetic variety of second type has been created, whose parental
components cross pollination is going to be controlled by self-incompatible genes. High level of
heterosis of the breeding constitution will be achieved by including in a tetrahaploid plant of alfalfa
four sets of haploid chromosomes well combining with each other and with haploid sets of
chromosomes of other tetrahaploid plants of the same variety.
Building of proposed construction will include the following steps: a) coherent derivation of
diploid and dihaploid plants from tetraploid plants of alfalfa responding to breeding goals; b)
formation of group of dihaploid plants of the future variety base on their haploid set of chromosomes
aptitude to provide high grade of combining abilities with every haploid set of chromosomes of the
group; c) rebuilding tetrahaploid plant by crossing four dihaploid plants from the same group (A x B)
and (C x D), and performing somatic hybridization of the obtained crossbreds (AB+CD); d)
concatenation of new synthetic variety by multilevel mating a number of tetrhaploid plants. High
level of General Combining Abilities of each set of haploid chromosome of a group provides
expectation of forming high share of tetra allelic loci and as result achieving high grade of heterosis in
every possible combination and sequence of crossing. In this case multilevel mating will be a
mechanism of transferring of hybrid vigor from parental tetrahaploid plants to F1 seeds of complex
hybrid, so synthetic variety of alfalfa might be implemented by 2[A x B], 4[(A x B) x (C x D)], 8 [(A x
B) x (C x D)] x [(E x F) x (G x H)] or more tetrahaploid plants.