Among several environmental factors (light, moisture, temperature) that can affect bulb development, temperature has been established as playing a predominant role in controlling growth and flowering in bulbs [1]. For most of them, a “warm-cold-warm” sequence is required to complete their lifecycle. Different genera and species demand various temperature optima, but, in general, the
SPRING
WINTER
AUTUMN
SUMMER
flowering
summer dormancy
leaf and root senescence
aboveground growth: bulb enlargement
−18 to −2 °C
12 to 26 °C
−2 to 17 °C
−2 to 17 °C
flower maturation and shoot development
flower induction and organogenesis
dormancy optimal temperature for the initial organogenesis ranges from 15 to 21 °С, while low positive temperature is required for the development of a flower stalk and well-formed flowers (Table 1) [1]. This period of autumn-winter cooling seems to be extremely important for flower development, as its absence leads to slow shoot growth and severe flowering disorders [4–13].