Genetic variation among and within united states collard cultivars and landraces as determined by randomly amplified polymorphic DNA markers

A collection of collard (Brassica oleracea L,, Acephala group) germplasm, including 13 cultivars or breeding lines and 5 landraces, was evaluated using randomly amplified polymorphic DNA (RAPD) markers and compared to representatives of kale (Acephala group), cabbage (Capitata group), broccoli (Italica group), Brussels sprouts (Gemmifera group), and cauliflower (Botrytis group), Objectives were to assess genetic variation and relationships among collard and other crop entries, evaluate intrapopulation variation of open-pollinated (OF) collard lines, and determine the potential of collard landraces to provide new B, oleracea genes, Two hundred nine RAPD bands were scored from 18 oligonucleotide decamer primers when collard and other B. oleracea entries were compared, Of these, 147 (70%) were polymorphic and 29 were specific to collard, Similarity indices between collard entries were computed from RAPD data and these ranged from 0.75 to 0.99 with an average of 0.83, Collard entries were most closely related to cabbage (similarity index = 0.83) and Brussels sprouts entries (index = 0.80), Analysis of individuals of an OP cultivar and landrace indicated that intrapopulation genetic variance accounts for as much variation as that observed between populations, RAPD analysis identified collard landraces as unique genotypes and showed them to be sources of unique DNA markers, The systematic collection of collard landraces should enhance diversity of the B, oleracea germplasm pool and provide genes for future crop improvement.