The pol cytoplasm is a male sterile cytoplasm with potential for use in hybrid summer rape (Brassica napus L.) seed production while the nap cytoplasm is the one most commonly encountered in summer rape cultivars. The objective of this study was to compare the performance of three cultivar-derived summer rape isoline pairs in the nap and pol cytoplasms to determine the relative effect on performance of these two cytoplasms. One nap line yielded significantly more than its corresponding pol line, three nap lines had significantly higher oil content than their corresponding pol lines, two nap lines had significantly higher protein content than their corresponding pol lines, and two nap lines produced significantly more seed energy than their corresponding pol lines. There are pleiotropic negative effects (biological costs) associated with the pol cytoplasm. These negative effects are affected by nuclear genotype and appear to be related to the depth of male sterility expressed in the derived pol A-line. Key words: Cytoplasm cost, Brassica napus L., cytoplasmic male sterility
The Characteristics of Isozyme in Male Sterile Rape (Brassica napus L.)