Abstract:

In order to improve the yield of hybrid seeds of Tagetes erecta and Tagetes patula per unit area, different concentrations of glucose, sodium chloride, boric acid, and gibberellin were sprayed on the stigma of male sterile marigold maternal plants before pollination. The seed setting rate of individual inflorescences under different treatments was statistically analyzed, and the correlation between the seed setting rate and environmental factors such as temperature and humidity were analyzed. The results showed that the application of T₁₀ (37.5 mg/L GA₃) resulted in the highest seed setting rate of single inflorescence, reaching 64.95%, slightly higher than that of control (59.97%); the treatment with the lowest seed setting rate was T₅ (3.0% NaCl), which was 30.72%. Excessive NaCl concentration could damage the stigma of marigold inflorescence. There was significant difference between T₅ and other treatments. Different pollination dates resulted in different seed setting rates, which exhibited a trend of 'low-high-low' depending on the pollination time. The correlation between seed setting rate and air temperature and humidity was analyzed, and it was found that the seed setting rate had medium-negative correlation with daily maximum and average temperatures, but did not reach a significant level.

Key words: Tagetes erecta, Tagetes patula, distant hybridization, male sterile line, seed setting rate, gibberellin