Growing sunflower plants from seed to seed in small pots in greenhouse

Abstract

This paper reports the results of two experiments in which sunflower plants were grown from seed to seed in small pots to utilize greenhouse space efficiently. We used small plastic pots (9.0 × 8.6 × 9.0 cm) filled with approximately half a liter of potting soil in a temperature-controlled greenhouse with a light : dark cycle of 14 : 10 h. In the first experiment, 100 F2:5 plants were grown on a two-square-meter bench in the greenhouse during the winter of 2007. Ninety-eight of the 100 plants survived to maturity and produced an average of 62 viable seeds with a range of 36 to 102 seeds per plant. In comparison to the plants grown in six-liter pots, we observed that all the plants grown in the small pots had a significant decrease in plant size such as height, head diameter, and number of seeds per plant. The plants grown in the small pots flowered on average 9 days later than those in the large pots. No significant difference was observed for germination rate between the seeds harvested from small and large pots. In the second experiment, two oilseed and two confectionery sunflower inbred lines were grown during the summer of 2007 to confirm the observations from the first experiment. The results were essentially the same as those observed in the first experiment. For number of seed produced per plant, an average of 13.0 to 42.2 seeds were obtained per head for each of the four lines grown in small pots, with no significant difference observed between oil and confectionery sunflower. Thus, our results suggest that it is possible to produce viable seeds from plants grown in small pots. This method should be useful for efficient line advancement in the greenhouse for breeding and genetic studies.