Inheritance of Sterile Traits in Fifth Generation Chinese Cabbage and Evaluation of Yield Components

Chinese cabbage is a popular vegetable in Thailand and internationally. In Thailand, the majority of seeds used by farmers for cultivation are imported, a trend driven by increasing demand from both farmers and consumers. To reduce reliance on imported Chinese cabbage seeds and develop varieties suited to Thailand's environment, experiments have focused on transferring the genetic traits of Chinese cabbage into regular varieties through backcrossing methods. A randomized complete block design (RCBD) with seventeen treatments, including five fertile varieties, six backcrossed varieties, and six commercial varieties, was used in our experiments. Results from the experiments indicated that, by the fifth generation, backcrossed Chinese cabbage varieties showed no pollen staining, distinguishing them from other varieties that exhibited normal pollen staining. In terms of yield components and desirable horticultural traits, two backcrossed (BC) varieties, BC5 142-6-5 and BC5 142-7-12, demonstrated statistically similar pre-trimming and post-trimming weights compared to commercial varieties, along with a shape index close to the desired market standard of 1.6. Additionally, other potential varieties, such as BC5 23-9-3 and BC5 27-8-7, alongside fertile varieties, 23-9-3, 23-8-7, 27-8-7, and 142-6-5, showed promise as male lines. These findings underscore several promising varieties for further breeding. These new backcross lines could serve as female lines for developing hybrids in Thailand, exhibiting high post-trimming yields and desirable head characteristics that align with consumer preferences.