以20個不同花椰菜及青花菜品種(包含8個親本及12個商業栽培種)為材料，並以黃花芥藍、白花芥藍及小白菜為對照，進行逢機增殖DNA片段的分析。共篩選出32個逢機引子可產生多型性條帶，結果總共產生了399個條帶，90條為對所有花椰菜和青花菜都只具有單型性之條帶，另外309個是具有多型性(polymorphic)的條帶，其中有73條是對花椰菜具單型性(monomorphic)但對青花菜具多型性之條帶、16條是對花椰菜具多型性而對青花菜具單型性之條帶、96條對花椰菜與青花菜皆具多型性之條帶、23條為花椰菜所特有之條帶、101條為青花菜所特有之條帶。利用Jaccard方法所求出不同樣品之間的相似度及利用UPGMA、NJ及Maximum parsimony方法所建立出來的親緣關係圖，顯示青花菜和花椰菜可分為兩群，其F1品種和親本之間的關係也可以由此結果顯現出來。而不同樣品之間的遺傳變異雖然亦可見其相關性，但並不能完全由外觀型態上可分別出來。
另一方面，至少有10個以上和耐熱性青花菜有關聯的條帶標記被找出來，針對部分分子標記在回交子代的遺傳與高溫形成花球的關係，在本論文中也有所探討。

Twenty accessions of broccoli (Brassica oleracea L. var. botrytis L.) and cauliflower (B. oleracea L. var. italica) were analyzed using random amplified polymorphic DNA (RAPD) markers with B. olercea var. alboglabra as an outgroup. Three hundred and ninety nine DNA markers were generated by thirty two oligonucleotide primers and three hundred and nine markers are polymorphic. Among them, seventy three markers are monomorphic to all the samples of cauliflower but polymorpic to the samples of broccoli ; sixteen markers are polymorphic to the samples of cauliflower but are monomorphic to the samples of broccoli; ninety six markers are polymorpic to the samples of cauliflower and broccoli; twenty three markers are specific only to the samples of cauliflower; one hundred and one markers are specific to the samples of broccoli. Using cluster analyses based on three different methods (UPGMA, NJ and Maximum parsimony), twenty accessions can be divided into two groups with one belonging to cauliflower and the other belonging to broccoli. Phylogenetic relationship was clearly correlated to morphological difference. However, some accession of broccoli was showed to have greater genetic distance to other accessions of broccoli than to some accessions of cauliflower.
Also, at least 10 molecular markers which may be linked to special characteristic of heat tolerance of an F1 broccoli were found. Some selected molecular markers were analyzed in the progenies of backcross between this F1 and its female paren