ผลของอุณหภูมิต่ำต่อการชักนำการออกดอกนอกฤดูและการแสดงออกของยีนในสตรอว์เบอร์รีพันธุ์พระราชทาน 80

Abstract

Strawberry is an important economic fruit and classified as a subtropical fruit. Cool temperature controls flowering. Off-season strawberry production may diversify the yield, thereby increasing costs, but the environmental conditions are a limiting factor. This experiment aimed to study the effects of vernalization on off-season flowering and gene expression in sub-tropical strawberry cv. Pharachatan 80. The factorial (2 × 2) + 1 in a completely randomized design was used in this study. Factor A was the vernalization temperatures: 2 °C and 4 °C. Factor B was the vernalization periods: 1 week and 2 weeks, compared with non-vernalization (control). The expression profile of genes was determined after vernalization treatments. The results showed that both factors had an interaction on plant size, leaf size, leaf number per plant and percentage of fruit set. The strawberry plant at 4 °C with one and two weeks and 2 °C with one week had higher plant size and leaf size than 2 °C with two weeks. It was found that 2 °C with one week had higher percentage of fruit set than other treatments. Furthermore, the results revealed an interaction between the two factors on number of flowering days it took the plants to bloom, the percentage of flowering, the number of inflorescences, the number of flowers per inflorescences and the number of flowers per plant. Strawberry plants vernalized for 1 and 2 weeks at 2 °C showed earlier flowering (21.4 and 23.1 days, respectively) than did those vernalized at 4 °C (24.9 and 25.7 days, respectively). On the other hand, non-vernalized strawberry plants took longer to bloom, at 62.2 days. Strawberry plants vernalized at 2 °C for 2 weeks had the highest percentage of flowering, number of inflorescences, number of flowers per inflorescence and number of flowers per plant. In addition, number of stolons per plant, first flower blooming days, Inflorescence length, flower size, fruit number, fruit weight and fruit size have no interaction between two factors. It was found that control treatment had more stolon than all treatments. Two weeks after vernalization had higher number of fruits per plants than one weeks after vernalization and vernalized at 2 °C had higher number of fruits per plants than vernalized at 4 °C. For one week had higher fruit weight and fruit size than two weeks after exposed cold temperatures. The study on gene expression showed that the expression of VRN5, SOC1 and FT genes in two weeks at 2 °C had higher expression level than other treatments. Whereas control treatment had no gene expression. This study demonstrated that low temperature affects gene expression and encourages off-season flowering in strawberry and promoted flowering-related genes.