Selection and fertility of seed producing almond’s hybrids in the context of S-genotype

Almond rootstocks are used for almond's cultivars, and they are the second important rootstocks for peaches. Nurseries in Hungary use mostly seedling types originated from the virus-free nuclear stock. Four clones were used as parents ('C.471', 'C.449', 'C.446' and 'C.431'). They have good graft compatibility with the cultivars; however, the mother trees have some disadvantageous characteristics. As a result of breeding activity 600 hybrids were planted at the test plot between 2003 and 2004. The first yield was in 2007. Six hybrids ('1/117', '2/3', '2/78', '3/48', '3/58' and '4/45') were selected from offsprings of the above mentioned 4 parents between 2007 and 2010, to obtain new seed producing cultivars, that contain the advantageous characteristics of parents. Field pollination experiments were carried out using parchment bags as isolators and cross-breeding method completed with reciprocal cross. Also, the sterility of the hybrids was investigated. Simultaneously blooming cultivars are important prerequisite for pollination; therefore the progress of the blooming was monitored and determined the coverage of the main blooming periods. It was found that hybrids were able to pollinate each other. For S-genotyping PCR was conducted using the degenerate primers EM for the amplification of the second intron region of the S-RNase gene, S₅, S₉, S₁₁ and S₂₄ were found in addition to 3 alleles, which are not identical to the previously known almond S-alleles, therefore are indicated with S_x, S_y, and S_z letters. Incompatible combinations are not found among the hybrids. It was found that the hybridsRSQUO main blooming periods overlap, which can provide adequate pollination.