Effect of monocyanamide on breaking dormancy of blueberry

Effect of monocyanamide on breaking dormancy of blueberry

Fund project: supported by the construction project of key disciplines (ecology) with advantages and characteristics of colleges and universities in Yunnan Province (05000511311).

1 materials and methods

1.1 Materials

The experiment was carried out in the solar greenhouse of blueberry base in Ganyu County, Jiangsu Province in 2016. Lanfeng, a variety commonly planted in northern China, was selected as the test material. The tree age was 5 years old and the row spacing was 2m × 1m. The soil is sandy, the organic matter is 1.2%, the improved pH value is 4.7, and the fertilizer and water conditions and management level are good. The solar greenhouse needs to be cold on November 1 every year, and begins to heat up on December 20. The main test instruments are: PAL-1 sugar meter (Japanese Atago company); Firmtech Ⅱ hardness tester (USA); acid-base titrator; electronic scale; tape measure; ZDR-20 temperature and humidity automatic recorder.

1.2 method

In the experiment, three sheds were selected, and the automatic temperature and humidity recorders were hung in each shed, and the data were called out every 3 days to calculate the cooling capacity. The cooling capacity was controlled by the 7.2 ℃ model, and the cooling capacity was controlled at 500,600,700 (December 13) h, respectively. In each shed, 0.5%, 0.8% and 1.1% concentrations were set with 50% monocyanamide as the test reagent. The random blocks were arranged with 45 plants in 5 ridges per treatment, with 3 repeats. The usual heating time was the control (on December 20, the cooling capacity was about 850 h).

The phenological phases of blueberries under different cold stages and different treatments were recorded. A total of 9 trees were selected for each treatment in the greenhouse with different cooling capacity, and 9 trees were randomly selected in the control greenhouse with normal temperature. Each plant was randomly listed and fixed branches in five directions: East, west, south, north and middle. The fruit setting rate of each branch was counted and the total shoot growth length of each branch was measured before fruit ripening. The yield per plant, fruit quality, hardness, soluble solids and titratable acid were measured.

1.3 data processing

Excel 2007 and data processing software SPSS17.0 were used to analyze the single factor variance.

2 results and analysis

2.1 Phenological Phase of Blueberry after Cyandiamide treatment

The results showed that compared with the control, three spraying stages and three concentrations of monocyanamide could advance the phenological phase of Lanfeng, except for the great difference in mature stage, the phenological phase of other phenological phases were basically similar, after treatment with monocyanamide, the flower bud germination stage, bud and boll stage were 5: 8 days earlier, 5: 8 days earlier, 9: 12 days earlier, 6: 9 days earlier, and 9: 13 days earlier. Among them, the effect of 600 h cold treatment on early maturity is the best (see Table 1).

Table 1 phenological phase of Lanfeng blueberry after monocyanamide treatment

2.2 effects on fruit setting rate and shoot growth

The results showed that the fruit setting rate of monocyanamide treatment was significantly lower than that of other treatments at 500 h, but there was no significant difference between 600 h and 700 h treatment and the control. Except that there was no significant difference in the total shoot growth length between 0.5% and 0.8% monocyanamide treatment and the control, the total shoot growth length of the other cold stages and three spraying concentrations were significantly higher than that of the control (see Table 2).

2.3 effect on yield per plant and fruit quality

The results showed that compared with the control, there was no significant difference in fruit quality, hardness, titratable acid and soluble solids under three spraying stages and three concentrations of monocyanamine. the effect of monocyanamide treatment on blueberry fruit quality was not significantly improved or decreased, but the yield per plant of monocyanamide treatment was significantly lower than that of other cold stage treatments and control (see Table 2).

Table 2 effects of monocyanamide treatment on fruit setting rate, new shoot growth, yield and fruit quality of blueberry

Note: there are significant differences between different lowercase letters in the same column (p ≤ 0.05).

3 conclusion and discussion

The chemical name of monocyanamide is amino cyanide, which is a kind of plant growth regulator used to make up for the lack of low temperature and promote the sprouting of fruit trees. in order to meet the early listing of facility blueberries, experiments on the performance of monocyanamide on facility Lanfeng were carried out in this paper.

Through the observation of phenological phase, when blueberry was treated with monocyanamide at different cold stages, different concentrations could advance the phenological phase of Lanfeng, and the ripening period of Lanfeng was 913 days earlier, and the effect of 600 h cold treatment was the best.

In terms of fruit setting rate, the fruit setting rate of different concentrations of monocyanamide treatment at 500 h was significantly lower than that of other treatments and control, which may be due to the lack of cold capacity. Although monocyandiamide can make up for the deficiency of low temperature, the effect of monocyanamide treatment is not ideal when the cumulative cooling capacity of plants is seriously insufficient, which is obviously manifested by low fruit setting rate. The results showed that monocyanamide could not only break the dormancy of flower buds but also break the dormancy of leaf buds and promote the growth of new shoots, which was consistent with the results obtained by Stringer et al on rabbit eye blueberries and high irrigated blueberries.

The results showed that monocyanamide did not significantly improve or decrease the fruit quality of blueberry, which was not consistent with the conclusion that Wang Xingdong et al treated Spartan and Berkeley varieties with monocyanamide could increase the yield and fruit quality, while Li Bo et al treated sweet cherry with monocyanamide and concluded that monocyanamide could significantly improve the fruit quality. The difference may be related to the types and characteristics of the tested fruits, which need to be further studied. When the chilling capacity is insufficient, even if treated with monocyanamide, the yield per plant can not be increased, and the reason for the low yield per plant is the low fruit setting rate.

Generally speaking, when the facility Lanfeng blueberry was cold for 600 hours, the effect of 0.8% monocyandiamide treatment was the best, the fruit ripening period was 13 days earlier, and the fruit quality was not affected compared with the control.