Research On Transfer Cytoplasmic Male Sterility Lines And Genetic Diversity In Flowering Chinese Cabbage

Flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilissen. et Lee) is a variant of Brassica and its tender flower stalk was the edible organ. Although the Flowering Chinese Cabbage has strong heterosis, the early breeding was mainly focused on the conventional cultivar selection, purification, rejuvenation or cultivated technology, and has few studies on its cross-breeding. In this study, we used the Purple Cai-Tai cytoplasmic male sterile line (Eru-5A) as the female parent and the flowering Chinese Cabbage Hua15and Hua16as the male parents to breeding the Flowering Chinese Cabbage cytoplasmic male sterile lines. The agronomic traits, physiological and biochemical indexes of each generation were investigated in order to obtain their variation. The Flowering Chinese Cabbage cytoplasmic male sterile lines were researched through both morphological and molecular marker. Meanwhile, SSR markers was used to analyze the genetic diversity of the40Flowering Chinese Cabbage from Hunan, Hubei and Jiangxi Province. The mains results are as follows:1. The sterile source, pollination time and the method of cultivate after pollination were investigated. An efficient transfer system was explored that hybridize three generations in one year, and successfully obtained two Flowering Chinese Cabbage cytoplasmic male sterile lines Eru-15A, Eru-16A.2. The agronomic traits, physiological and biochemical indexes of the F1and BC1to BC3of Purple-Caitai X Flowering Chinese Cabbage were investigated. The results showed that the traits of the two crosses hybrids (Fl) were excellent, and some traits have heterosis. The change can be divided into two situations:(1) With the increase of the backcross generation, the characters were close to the recurrent parent gradually.(2) Heterosis occurred in the early generations, and then closed to the recurrent parent gradually.3. Both morphological and molecular markers were carried out to investigated the cytoplasmic male sterile lines Eru-15A, Eru-16A. The results showed that the floral organs grow as normal besides the stamens, and the sterility was stable. Through PCR amplification, With the orf138primers, a specific band was amplified in the two Flowering Chinese Cabbage sterile lines and Eru-5A. After cloning and Blast analysis, we found the sequence homology was100%, the sterility gene of Eru-5A has been transferred into the Flowering Chinese Cabbage.4. The40Flowering Chinese Cabbage cultivars were divided into four groups at the place that genetic similarity coefficient was0.69through SSR markers. Group I including12varieties which are mainly early-maturing varieties with dark green leaves. They are B1、B21and B5et al. Group II including19varieties, which are mid-maturing or late-maturing, and they have strong growth potential, large leaves and high yield. They are B3、B12and B33et al. Group III including B9、B22、B28and B34. Most of them are early-maturing varieties with light green leaves besides B28. Group IV including B4、 B16、B37、B39and B41. Most of them are early-mature with good quality and yellowish green leaves. But their resistances are weak and the yields are low.