The relationship between temperature and blueberry growth and development
Blueberries can tolerate temperatures of up to 40-50°C. Temperatures higher than this can lead to poor absorption of water and poor development of the root system. Dwarf blueberries can produce more rhizomes and grow faster at 30°C than at 18°C. Low summer temperatures are the main limiting factor for blueberry growth and development in the Dwarf Bush blueberry production area. Highbush blueberry growth proportionally increased when soil temperature increased from 13°C to 32°C. Soil temperature also has an effect on the growth habit of blueberries, which shorten their branches and open their growth at soil temperatures below 20°C, thus affecting their tree shape and growth and development. The cold resistance of blueberries varies considerably. Highbush blueberry can resist the low temperature of -30~-25℃; half-highbush blueberry can resist the low temperature of -38~-35℃; and shortbush blueberry can resist the low temperature of more than -40℃. Different varieties of the same species have different cold resistance. Highbush blueberries in the blue abundance, blue line resistance to cold, while Dixie resistance to cold is poor; rabbit eye blueberry itself is less resistant to cold, but there are also better cold resistant varieties, such as Tiffany blue. Dwarf bush blueberry in addition to its own cold resistance is strong, another important factor is due to its tree is short, in the northern cultivation of winter snow can be completely covered it, to ensure that it can be safe overwintering.
Temperature mainly affects the growth and development of blueberry by influencing leaf photosynthesis and respiration. Jilin Agricultural University measured a number of materials, and the results show that: the lower limit of photosynthesis temperature of dwarf bush blueberry, semi-high bush blueberry and high bush blueberry leaves are 2-4℃, 3-6℃ and 3-6℃ respectively; the upper limit of their temperatures are 42-45℃, 44-46℃ and 44-47℃ respectively. From the changes of net photosynthetic rate of three types of blueberry leaves under different temperature conditions, the optimum temperature range for photosynthesis of dwarf bush blueberry, semi-highbush blueberry and highbush blueberry leaves was 20-27°C, 25-30°C and 25-33°C, respectively. Under conditions greater than 30°C, the photosynthetic rate of dwarf blueberry leaves declined the fastest, while the photosynthetic rate of semi-highbush blueberry and highbush blueberry declined slower; below 15°C, dwarf blueberry showed a relatively high photosynthetic rate, while the photosynthetic rate of semi-highbush blueberry and highbush blueberry was lower.
Blueberry seed development is also affected by temperature. Seeds that kept changing temperature (0.5-20°C) during seed stratification had much higher germination rates than those treated with only 0°C. Variable temperature treatments (10-32°C) during seed germination also resulted in higher germination rates than those treated only at room temperature.
Temperature has a similarly important effect in flower bud formation and fruit development. Dwarf bush blueberry formed far more flower buds at 25°C than at 15°C. In addition, diurnal temperature variations affect bud development. The most effective problem for Tiffany blue during dormancy is 15°C for 8 hours during the day and 7°C for 16 hours at night, which is the most favorable for flowering, and if its temperature pattern is changed there is a risk of delaying bud bloom.
Consequently, low temperatures at the time of flower bud formation during the growing season often result in severely reduced yields of dwarf bush blueberries in the coming year. Fruit set in highbush blueberries is nearly a factor of one higher at 16-27°C than at cooler temperatures of 8-24°C. And at high temperatures, the fruit develops quickly, the fruit shape is large, and the ripening period is advanced.
Blueberry to achieve the normal development of flower buds, leaf buds must be a certain amount of cold temperature needs, that is, <7.2 ℃ low temperature accumulation time. The cold temperature requirement varies greatly among different species and varieties of blueberries. Highbush blueberries generally need more than 800 hours to achieve normal growth and development and flowering and fruiting. Flower buds require less cold temperature than leaf buds. Although 650 hours of low temperature can enable blueberries to complete tree dormancy, highbush blueberries will grow well only if more than 800 hours of low temperature are required, and 1060 hours to reach the optimal cold temperature requirement. The cold temperature requirement for normal growth and fruiting of northern highbush blueberries is 800-1200 hours. Application of crossbreeding methods can change the cold temperature needs, the United States Florida crossbreeding triploid highbush blueberry cold temperature needs only 400 hours.
Post time: May-19-2025