RECURRENT BACKCROSS - A METHOD FOR TRANSFERRING ERUCIC-ACID ALLELE INTO BRASSICA OILSEED CULTIVARS, BRASSICA-CAMPESTRIS L YELLOW SARSON AS AN EXAMPLE

Recurrent backcrossing was used to incorporate the zero-erucic acid al lele from a brown-seeded Canadian Brassica campestris cultivar, Tobin, into a high-erucic acid, white-flowered, Yellow Sarson (B. campestris ), line M-91. Seeds heterozygous for erucic acid were identified by th e half-seed technique and subsequently grown for backcrossing or selfi ng. Backcrossing, followed by selfing, led to the production of both z ero- and high-erucic acid, yellow-seeded, yellow- or white-flowered Ye llow Sarson types. Agronomically, the zero- and high-erucic acid genot ypes were comparable to the recurrent parent. These results suggested that the half-seed technique can be used to identify those seeds heter ozygous for erucic acid alleles, after which the zero- or high-erucic acid alleles can be incorporated into Brassica oil crop cultivars by r ecurrent backcrossing.