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) germpla sm, including 13 cultivars or breeding lines and 5 landraces, was eval uated using randomly amplified polymorphic DNA (RAPD) markers and comp ared to representatives of kale (Acephala group), cabbage (Capitata gr oup), broccoli (Italica group), Brussels sprouts (Gemmifera group), an d cauliflower (Botrytis group), Objectives were to assess genetic vari ation 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, olerace a genes, Two hundred nine RAPD bands were scored from 18 oligonucleoti de decamer primers when collard and other B. oleracea entries were com pared, Of these, 147 (70%) were polymorphic and 29 were specific to co llard, Similarity indices between collard entries were computed from R APD data and these ranged from 0.75 to 0.99 with an average of 0.83, C ollard entries were most closely related to cabbage (similarity index = 0.83) and Brussels sprouts entries (index = 0.80), Analysis of indiv iduals of an OP cultivar and landrace indicated that intrapopulation g enetic variance accounts for as much variation as that observed betwee n populations, RAPD analysis identified collard landraces as unique ge notypes and showed them to be sources of unique DNA markers, The syste matic collection of collard landraces should enhance diversity of the B, oleracea germplasm pool and provide genes for future crop improveme nt.