Intergeneric hybridization between Diplotaxis siettiana and crop brassicas for the production of alloplasmic lines

Intergeneric hybrids were produced between Diplotaxis siettiana and Brassica campestris through embryo rescue. The hybrids were completely pollen sterile and backcrosses with pollen of B. campestris did not yield any seeds. Induction of colchiploidy restored pollen fertility and backcross pollinations yielded viable seeds. Cytological details of the hybrid, amphidiploid and backcross progenies were studied. Both pollen-sterile and pollen-fertile plants have been obtained in backcross 2 progeny. This hybrid (D. siettiana x B. campestris) was used as a bridge cross to transfer the cytoplasm of D. Siettiana to two other incompatible cultivars of Brassica - B. juncea and B. napus. Pollinations of the amphidiploid (D. siettiana x B. campestris, 2n = 36) with pollen of B. juncea/B. napus readily produced seeds without embryo rescue. These hybrids were grown to flowering and their cytological details were studied. Seeds have been produced from backcross pollinations of both these hybrids with the pollen of the respective cultivars. The results clearly show the feasibility of producing alloplasmic lines in all the three oilseed brassicas.