Research On Cytology & Combining Ability And Isozymes For Cytoplasmic Male Sterility In Radish (Raphanus Sativus L)

Radish (Raphanus sativus L) is one of most important vegetable in world-wide horticultural crops. Utilization of CMS lines is much more effective and economical in producing commercially hybrid seeds. Therefore, it has important meanings to studying on morphology during its reproductive stage and combing ability during its vegetable stages for selecting new cultivars and producing seeds by male sterile lines of radish.This experiment selected an introduced male sterile origin and male sterile lines, morphology of flower organs and heterosis performance and combining ability and other aspects about inheritance were studied. Furthermore, system research on cytology & isozymes for cytoplasmic male sterility in radish; in order to provide theoretical help for studying on mechanism of male sterility in radish. The results are listed as follows:1. According to the performance of flower organs radish male sterile plants can be classified into two types:①yellow degeneration corolla;②form of abortive pollen. As far as the stigma is concerned, the form of abortive pollen includes emerged stigma, half-emerged stigma and non-emerged stigma forms as well as anther. Most of radish male-sterile plants belongs to form of abortive pollen, emerged stigma also anther. But there was a special form in abortive pollen, the color and size of anther were less than male fertile type, the stigma was bundled by its anthers and the color of anthers became white during anaphase; the anther has a little pollen sometimes. The study also showed the vigor of micro-pollen flower are less than half of normal pollen.2. Hybrids of radish performed heterosis very obviously. The trait of single root weight performed positive heterosis over parents, positive heterosis are also occurred in other traits and cytoplasmic gene have no obvious affection on heterosis'performance. The study of combining ability showed that general combining ability was different between male sterile lines and maintainer lines, but their absolute values are the same. the general combining ability of P7&P12 (in father lines) performed best, the specific combining ability of P1×P11,P1×P14,P2×P14 performed well. The study of inheritance showed that the expansion of plant, the length of leave, the width of leave, the quantity of leaves were controlled by additive effect mainly and the height of plant, single root weight were controlled by dominant & mutual effect between non-equal-genes mainly.3. The results of cytological experiment revealed the microsporogenesis of the male sterile lines began abortive at uni-nucleate stage, the tapetal cells swelled abnormally and highly vacuolated, performs hypertrophy and double-nucleate and occupied the locule. With degeneration of the tapetal cells, the pollen aborted. The locule finally deformed and shrunk, only left little material which stained dark.4. In this research, activity of two isozymes were studied during their development of vegetable and reproductive stages. The results showed that during vegetable stage, trends of POD activity in leaves of male sterile lines were ascend persistently; while the activity of POD were firstly ascend then descend in the maintainer lines. Trends of SOD in male sterile lines were firstly descend then ascend, while trends of SOD in maintainer lines were firstly descend then ascend and descend finally. During reproductive stage, the results showed that values of POD activity in flower buds of male sterile lines was higher than that of maintainer lines, and trends of POD activity were reverse as flower buds development between male sterile lines and maintainer lines; Trends of SOD activity showed opposite change as that of POD activity, and gaps of the values of SOD activity were smaller as flower buds development between two lines.