The low glucosinolate Brassica juncea breeding line 1058 was derived from a
BC1F3 plant of an interspecific cross between high glucosinolate Indian B.
juncea (genome AABB, 2n = 36) line 60143 and B. rapa (genome AA, 2n = 20)
canola strain CZY. Line 60143 had 2n = 36 chromosomes (18 bivalents at meta
phase I) and strain CZY had 2n = 20 chromosomes (10 bivalents). Line 1058 w
as nullisomic, with 2n - 2 = 34 chromosomes, with 17 bivalents formed at me
taphase I and an even chromosomal segregation of 17:17 at anaphase I. In F-
1 hybrid plants of the cross 1058 x CZY, 98.3% of the pollen mother cells h
ad 10 bivalents and seven univalents. This is evidence that plants of line
1058 are nullisomic, missing one pair of B-genome chromosomes.