Growth and yield of doubled haploid lines of oilseed Brassica rapa

Abstract

The production of doubled haploid (DH) lines of Brassica rapa could be an efficient procedure for the development of inbred parents for hybrid production. A total of 162 B. rapa DH lines were evaluated in field tests at Saskatoon, Canada, in single row, replicated tests and 10 DH lines were tested in four-row plot, multilocation, replicated tests. Seed of DH lines was produced by bud selfing in the greenhouse. Approximately one-fifth of all DH lines tested were chlorophyll deficient, presumably due to the expression of recessive alleles. Inbreeding depression was evident in low seed and biological yields, low number of seeds per pod and delayed flowering. Seed yield of DH lines was positively associated with the number of seeds per pod, early flowering and a long pod-filling period. One DH line was equal in yield to its donor population (DP), suggesting that dominance deviation was the genetic basis for high seed yield in this species. The consistent performance of DH lines over years and locations indicated that DH lines may be selected after 1 year of evaluation for combining ability testing. Higher yielding DH lines of B. rapa must be selected before they can be used as parents for hybrid development. Key words: Brassica rapa, doubled haploid, field evaluation