COMPARISON OF SOMATIC AND SEXUAL BRASSICA-NAPUS - SINAPIS-ALBA HYBRIDS AND THEIR PROGENY BY CYTOGENETIC STUDIES AND MOLECULAR CHARACTERIZATION

Reciprocal crosses were performed between Brassica napus (AACC, 2n = 3 8) cv. Brutor and Sinapis alba (SalSal, 2n = 24) cv. Carine. Using fer tilized ovary culture, 2.2 and 1.9% of interspecific hybrids were prod uced when white mustard was the female and the male parent, respective ly. On S. alba cytoplasm, three plants with a BC1-like structure (SalS alAC, 2n = 43) were obtained and ACSal (2n = 31) and AACCSal (2n = 50) hybrids on reciprocal crosses. At the same ploidy level, no differenc es in meiotic behavior were observed. The amphidiploids (AACCSalSal, 2 n = 62), produced after colchicine treatment of ACSal hybrids, were co mpared with the somatic hybrids previously obtained from the same pare ntal varieties. Only two somatic hybrids differed and one of them lost Idh-2 rapeseed isozymes, whereas all the plants presented an hybrid p attern for all the other molecular markers. The plants with 50 chromos omes (AACCSal) from sexual hybrids were similar whatever their origins . Their comparison with backcross progeny of somatic hybrids revealed that the latter one differed either by chromosome number, ranging from 42 to 54, or by the percentage of cells with less than 12 univalents and with multivalents. From our results, the efficiency of protoplast fusion compared with sexual crosses as a tool to introduce new traits in a crop is discussed.