Diversity of Sex Types and Seasonal Sexual Plasticity in a Cucumber Germplasm Collection

• Main Authors: Dou Xinxin, Shen Di, Zhang Xiaohui, Cheng Jiaqi, Li Sigeng, Song Jiangping, Wang Haiping, Zhang Wei, Li Xixiang
• Format: Article
• Language: English
• Published: KeAi Communications Co., Ltd. 2015-09-01
• Series: Horticultural Plant Journal
• Subjects: cucumber; germplasm; sex type; diversity; pistillate flower; sex stability
• Online Access: http://www.sciencedirect.com/science/article/pii/S2468014115010109

The sex type of a cucumber plant is determined by the proportion of male, female and hermaphrodite flowers that it bears and is an important factor that affects fruit yield. In this paper, the sex types and seasonal sexual stabilities of 322 accessions of cucumber germplasm were identified. This germplasm collection displayed a great variety of sex types. We used an updated 10-type sex classification system based on the flower types present and the proportion of nodes with pistillate flowers (PNPF). The PNPF ranges of all the accessions were 2.12%–100% in spring and 0–100% in autumn. A total of 81.37% of the accessions had PNPFs of 10%–50% in spring, but most (84.78%) accessions were reduced to 0–20% PNPF in autumn. The range of reduction of PNPF from spring to autumn was 0–67.91%. In other words, most of the germplasm was normal monoecious (31.68%) or subandroecious (62.73%) in spring, but 94.10% of the accessions were subandroecious in autumn. According to the statistical evaluation of the difference in PNPFs between the two seasons, each accession could be classified into one of three groups: seasonally stable, seasonally sensitive and highly seasonally sensitive, accounting for 10.56%, 20.50% and 68.94% of the accessions, respectively. With a few exceptions, the seasonal PNPF differences were positively correlated with the PNPFs in a given season for most accessions. These results provided useful information and materials for sex expression mechanism research and for breeding cucumbers with high and stable yields.