Registration into the JIC Pisum Germplasm Collection

of near isogenic lines at the rugosus R and Rb loci


Ambrose, M. J.  and Hedley, C.L.                                                           John Innes Centre, Norwich , UK

       The development of near isogenic lines are important in allowing the effects of single genes or combinations of genes to be investigated while maintaining essentially a common genetic background. Three pairs of near isogenic lines for the rugosus loci R and Rb have been submitted to the JIC Pisum collection for long term maintenance and distribution. The accession numbers and allelic status of this material are presented in Table 1.

 JI 3316 and 3317

      The BC1 pair of isolines for the rugosus (R) locus were the result of an initial cross between JI 430 (rr) and JI 145 (RR) followed by 6 backcrosses  to JI 430 and a further 19 rounds of reselection from the heterozygote (1).

 JI 3318 and 3319

      The BC2 pair of isolines for the rugusus (Rb) locus were the result of an initial cross between BC1/6 (RRRbRb) and JI 1156 (RRrbrb). Six rounds of backcrossing to the BC1/6 parent were performed followed by 10 rounds of reselection from the heterozygote (2).

 JI 3320 and 3321

      The CMR pair of isogenic lines were selected from an early flowering heterozygous BC2 line after the 6 rounds of backcrossing. The node to flowering of JI 430 and the BC 1/6 recurrent parent was 16. The early flowering variant flowered some 3-4 nodes earlier than the recurrent parent BC 1/6 (flowers at node 16). The genetic basis of the early flowering of this material has not been explored but the trait is stable in this material.  No subsequent reselection from heterozygotes was performed.


Table 1. JI accession numbers of three pairs of near-isogenic lines

JI Accession Number



BC1/19 RR


BC1/19 rr


BC2/10 RbRb


BC2/10 rbrb


CMR RbRb- early flowering


CMR rbrb- early flowering

All accessions are available from the John Innes Pisum Collection (3).


1.       Hedley, C.L. Smith, C.M. Ambrose, M.J, Cook, S. and Wang, T.L. 1986. Annals Botany 58: 371-379.

2.       Hedley, C.L., Lloyd, J.R., Ambrose, M.J., and Wang, T.L. 1994. Annals of Botany 74: 365-371.