Hybridization between Camelina sativa (L.) Crantz and common Brassica weeds

Abstract

The movement of genes between crops and closely-related weeds has the potential to create economic and environmental problems. Camelina sativa (L.) Crantz is a promising oilseed crop and minor weed in North America, but ecological risk assessment is needed to predict crop-weed gene flow. In this study, reciprocal crosses between C. sativa cultivars and 17 Brassicaceae species in the genera Arabidopsis, Arabis, Barbarea, Camelina, Cardamine, Erysimum, and Lepidium were performed. F1 hybrids were formed between C. sativa cultivars and three species: Camelina alyssum (Mill.) Thell., Camelina microcarpa Andrz. Ex DC., and Capsella bursa-pastoris (L.) Medik. None of the other Brassica species formed hybrid offspring. F1 hybrids from C. sativa × C. alyssum showed the same pollen viability and fecundity as the parents, while hybrids from C. sativa × C. microcarpa had reduced pollen viability, silicle (pod) number and seed production. Intergeneric F1 hybrids from Camelina sativa × Capsella bursa-pastoris were sterile and this correlated with large decreases in pollen viability and number of ovules/flower. In addition, the SSR markers could be applied to identify progenies in C. sativa breeding programs as well as auxiliarily assess possibility of gene flow between C. sativa and weedy relatives. Principle coordinate analysis (PCoA) made from SSR markers clearly divided into 12 species into five groups of species. Especially, C. sativa was classified into one group with those two interfertile C. microcarpa, and C. alyssum but distinctly separated from Camelina hispida var. grandiflora (Boiss.) Hedge, Camelina laxa C. A. Mey and Camelina rumelica Velen. This division among the Camelina species was consistent with their capacity to produce fertile F1 hybrids with C. sativa. The hybridization results suggest that gene flow is likely between cultivated C. sativa and the North American weeds C. alyssum and C. microcarpa.