title: The effects of seed size on hybrids formed between oilseed rape (Brassica napus) and wild brown mustard (B. juncea).
abstract: BACKGROUND
  Seed size has significant implications in ecology, because of its effects on plant fitness. The hybrid seeds that result from crosses between crops and their wild relatives are often small, and the consequences of this have been poorly investigated. Here we report on plant performance of hybrid and its parental transgenic oilseed rape (Brassica napus) and wild B. juncea, all grown from seeds sorted into three seed-size categories.
  
  
  RESULTS
  Three seed-size categories were sorted by seed diameter for transgenic B. napus, wild B. juncea and their transgenic and non-transgenic hybrids. The seeds were sown in a field at various plant densities. Globally, small-seeded plants had delayed flowering, lower biomass, fewer flowers and seeds, and a lower thousand-seed weight. The seed-size effect varied among plant types but was not affected by plant density. There was no negative effect of seed size in hybrids, but it was correlated with reduced growth for both parents.
  
  
  CONCLUSIONS
  Our results imply that the risk of further gene flow would probably not be mitigated by the small size of transgenic hybrid seeds. No fitness cost was detected to be associated with the Bt-transgene in this study.
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
authors: Yong-Bo
authors: YB
authors: Liu
authors: Zhi-Xi
authors: ZX
authors: Tang
authors: Henri
authors: H
authors: Darmency
authors: C Neal
authors: CN
authors: Stewart
authors: Kun
authors: K
authors: Di
authors: Wei
authors: W
authors: Wei
authors: Ke-ping
authors: KP
authors: Ma
mesh_terms: D029688:Brassica napus / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*; D006824:Hybridization, Genetic / Q000502:physiology; D009149:Mustard Plant / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*; D012639:Seeds / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*