Diversity characterisation of broccoli (Brassica oleracea L.) landraces for their on-farm (in situ) safeguard and use 4 in breeding programs

Brassica oleraceaL. is an importantspecies that originated in the eastern Mediterraneanarea. From there,B. oleraceaL. subsp.capitata(L.)DC. convar.botrytis(L.) Alef. var.italicaPlenck(broccoli) was introduced into Italy where consider-able diversification took place. Several landraces ofbroccoli, which are highly appreciated by local peoplefor their organoleptic traits, are presently cultivated inboth large fields and home gardens. In this study, 10landraces, 4 synthetics derived from landraces and 4 ofthe most used F1 hybrids were characterised formorpho-physiological and molecular traits with theprincipal aim of feeding information into the landraceprotection schemes being developed in Italy and intobreeding programs. The landraces and derivedsynthetics are well differentiated from each otherand from the F1 hybrids for important agronomic andgenetic traits. The principal component analysis basedon analysis of morpho-physiological traits showed thatoverall the 2 main components accounted for 67.74 %of the total variation. The neighbour joining tree,based on 23 microsatellite markers, grouped acces-sions into 2 main clusters. One includes one syntheticvariety and 2 F1 hybrids, while the other clusterincludes all the other accessions. There were alsoseveral sub clusters. Most of the materials examinedshowed within-accession diversity. The informationgathered in this study can be used to protect landracesthrough the schemes presently being developed inItaly and to register them in the European commoncatalogue of ‘‘conservation varieties’’.In situ(on-farm) conservation of landrace diversity is discussedwith reference to landrace use.