Flower and Fruit Management techniques for Seedling cultivation of tetraploid Jufeng Grape

Flower and Fruit Management techniques for Seedling cultivation of tetraploid Jufeng Grape

1 general situation of Jufeng grape

Jufeng grape was bred by Japanese breeder Kang Oi in 1937 using American grape Ishihara Zaosheng (big grain Cambel, tetraploid mutant variety of diploid Cambel) as female parent. It was bred by crossing with European grape Sentiani (tetraploid mutant variety of diploid Lusaki) as male parent, and was officially named in 1945. The visiting delegation of Okayama University in Japan presented four Jufeng branches to Beijing Agricultural University (now China Agricultural University) in 1956, which began to be bred and planted in China in the 1960s. after that, nearly 100 Jufeng grape varieties were introduced from Japan, and some Jufeng grape varieties were selected in China one after another. at present, more than 200 Jufeng grape varieties have been introduced from abroad and bred in China. From 1970s to early 1990s, a large number of Jufeng grape varieties such as Jufeng, Fujiminori and Jingya were developed in the south and north of China, which promoted the first great development of the national grape industry. At present, Jufeng grape variety has a planting area of more than 300,000 hectares in China, which is the largest grape strain in China.

2 characteristics of grape varieties of tetraploid Jufeng line

Tetraploid Jufeng grape refers to the tetraploid European and American species bred with Jufeng as parent, including Jufeng, Jufeng offspring, Jufeng bud mutation varieties and tetraploid varieties bred by Jufeng as male or female parents. there are triploid seedless grape varieties and the rare diploid variety Hong (Queen), and Jufeng triploid grape varieties include Xiahei, early summer seedless, 8611, 8612 and so on. Pedigree of tetraploid Jufeng grape varieties such as Jufeng, Giant Rose, Zuijinxiang, Hutai 8, Yihong, Liaofeng and so on (figure 1)

Fig. 1 pedigree of Jufeng, Liaofeng, Zhenhong, Giant Rose, Zuijinxiang, Hutai 8 and other varieties

Most tetraploid Jufeng grape varieties have dense hairs on the back of leaves and strong resistance; good flower bud differentiation, high branch rate and fruiting coefficient, high yield and stability; large grains and beautiful appearance; thick pulp, soft flesh, sweet juice, strawberry flavor, astringent fruit when not fully ripe; thick peel and flesh separation; short brush, many pores and large pores in pedicels, easy to stem and thresh after harvest. Some varieties will crack fruit and are sensitive to plant growth regulators such as gibberellin.

Due to the genetic factors of parent Morteni, most tetraploid Jufeng grape has a high rate of abnormal ovule, which affects normal pollination and fertilization; the time of fertilization is relatively long, and it is often affected by undernutrition, over-nutrition or adverse environmental conditions during pollination and fertilization. the failure of fertilization often leads to falling flowers and fruits, poor fruit setting, loose ears, seedless fruits and small grains.

3 key points of flower and fruit management in grape seedless cultivation of tetraploid Jufeng line.

The growth potential of tetraploid Jufeng grape varieties such as Jufeng, Giant Rose, Zuijinxiang, Hutai 8, Yihong and Liaofeng are generally prosperous, and the natural fruit setting rate is often on the low side, which can not meet the requirements of ideal ear. In production, attention should be paid to the cultivation of healthy trees of the mean in order to increase the rate of fruit setting and ensure high and stable yield. In addition, these varieties are sensitive to plant growth regulators such as gibberellic acid, thiobenzuron and pyrifuron. The use of gibberellic acid, thiobenzuron and pyrifuron can increase the fruit setting rate and promote seedlessness. However, in production, the use of thiobenzuron and pyrifuron for seedless and fruit preservation treatment is easy to cause astringent pericarp and affect taste. The author's point of view on the use of plant growth regulators such as gibberellic acid, thiobenzuron and pyrifuron in this kind of grape is: if you can use it or not, use it less if you can use it less, and do not use it twice when you can use it once to meet the production requirements. Do not use high concentration when using low concentration to achieve the goal. The following are the key points of the management techniques of this kind of grape seedless cultivation, and each orchard should be used flexibly according to the actual situation.

3.1 controlled application of nitrogen fertilizer, increased application of phosphorus and potassium fertilizer and organic fertilizer to cultivate the healthy tree potential of the mean.

The control application of nitrogen fertilizer before flowering and later growth stage, the application of phosphorus and potassium fertilizer and organic fertilizer in autumn, the prevention and control of tree potential, the cultivation of robust and moderate tree potential, the control of branch base diameter at 0.8 ~ 1.2 cm, reducing nutrient consumption and increasing fruit setting rate.

3.2 pick the heart in time before flowering

The coring was carried out when the new shoot grew to 6 ~ 8 leaves, and then when each top auxiliary tip grew to 3 ~ 5 leaves. Control vegetative growth, concentrate nutrients on the ear, and promote fruit setting. Too strong trees should not be too strong or too much heart picking, it is recommended to release slowly, too strong or too much heart picking will disrupt the hormone balance in the plant, resulting in serious grain size, irregular spike shape and other problems.

3.3 spraying thalidomide before flowering to increase fruit setting rate

In the period of pre-flowering shoot growth, spraying 500 ~ 750 mg / L metoprolol or 300 mg / 1 500 mg / L chlorpromazine for 2 times can control the shoot length, increase fruit setting and increase yield. For example, Jufeng grape cultivated in flat shed in Fuan, Fujian Province, spraying new shoots 3-5 days before flowering can significantly increase the fruit setting rate and meet the requirements of high yield of Jufeng fruit.

3.4 Control of Botrytis cinerea and ear rachis brown blight

2-3 days before flowering, the whole plant was sprayed with pyrimidinamide, pyrimidinamide or Pythium to prevent and control Botrytis cinerea and ear axis brown blight, and lay a good foundation for high yield.

3.5 arrange the ear

Panicle shaping is an important part of grape flower and fruit management and a key measure to achieve high quality and simple production.

3.5.1 heading time is generally carried out at flowering time, and if the area of the park is large and labor is scarce, it can be carried out from 2-3 days before flowering to 2-3 days after flowering (before the initial flowering stage).

Fig. 2 full panicle with spike tip

3.5.2 according to the market demand, the whole ear can be carried out in the following two ways. The main results are as follows: (1) the ear tip type of the whole ear (figure 2). The accessory ear and most of the branches in the upper part of the ear were removed, only the tip of the ear was 7-8 cm, and the target ear mass was 600-800 grams at maturity. (2) pinch and branch the whole ear (Fig. 3). Remove the accessory spike and the upper 1-2 branches of the ear, cut the other spikelets into 1.5-2.0 cm, do not pinch the spike tip at this time, and cut it too short when the spike is thinning, and then cut the inflorescence into a cylindrical or cylindrical shape to concentrate nutrition and promote fruit setting. The target ear mass at maturity is 700g to 900g.

Fig. 3 panicle trimming by pinching short branches

3.6 regulator for fruit protection and expansion

If it is found that this kind of grape grows strongly in production (the diameter of the base of the fruiting branch is more than 1 cm at flowering, the distance between the internodes of the ear is much larger than that of the adult fist, the upper and lower leaves of the ear are much larger than the adult palm, the leaves are thicker, the tip of the new shoot is bent heavily, and there are a lot of branches and gland beads) or encounter bad weather during the flowering and fruit setting period, it will often lead to poor fruit setting, and the ear can not meet the requirements of beauty and target yield. Thiazuron or gibberellic acid can be used to protect fruit at the initial stage of physiological fruit drop (figure 4).

Fig. 4 effect of regulator on fruit protection and fruit expansion (left: Jufeng; right: Hutai 8)

The main results are as follows: (1) Thibenuron fruit protection and fruit expansion: using Nongshuo brand thiaburon, 1 pack (15 grams) of 7.5 kg of water, dipped evenly or sprayed once in 3-4 days after flowering (see flower 10-14 days, the initial stage of physiological fruit drop, when the ear begins to drop), can improve fruit setting, increase fruit grains and improve fruit quality. (2) gibberellic acid fruit protection, fruit expansion: use Nongshuo brand 4% (mass fraction) gibberellic acid, 1 packet (5 ml) to water 15 kg, the method is the same as (1). During the treatment, it can be mixed with pyrimidinamide, Pythium, Kaiser, pyrimidine and other agents to control Botrytis cinerea and ear axis brown blight.

3.7 fixed panicle and whole panicle

After setting fruit (see 18-20 days after flowering), the panicle was fixed. Generally, the number of ears retained per mu is no more than 2 500 ears, and 2 ears are selected from 3 branches, and the ears are fixed according to the plant. Cut off the ears with poor panicle shape, late flowering and yellowish grains. After setting the ear length, cut off the over-long ear tip according to the ear length of 16-18 cm (the whole ear with the ear tip is generally no longer needed to cut off the ear tip), the commercial ear is 20-25 cm long and 11-13 cm wide at maturity, and the ear mass is 600-800 grams (ear-tip whole ear) or 700-thousand-900 grams (pinch short branch ear) [Yoshama Huayao].

3.8 thinning fruit

After the grain size is clear (about 22 days after flowering), the fruit should be thinned in time, and the small fruit, deformed fruit, disease and insect fruit and overdense fruit should be removed. Generally, there are 50-80 grains in the ear, the mature ear is loose and tight moderately, and the ear mass is 600-900 grams.

3.9 expanded fruit

When adopting seedless fruit protection cultivation, if the fruit expansion treatment is carried out again, it is easy to cause poor coloring, delayed ripening and astringent taste, and it is not recommended to use regulators to expand the fruit in order to pursue fruit quality in production; but in seedless cultivation, because the seeds are often small, thiaburon treatment can be used again at the initial stage of fruit expansion, and the concentration should be low rather than high, 1 pack (15 grams) to water 7.5 kg.

3.10 Prevention of fruit cracking

If there are more grains in the ear or the fruit is not thinned in time, the fruit will be cracked in the process of fruit expansion. After entering the coloring period, when there is an imbalance of soil moisture, fruit cracking will occur and continue until the fruit is ripe and harvested. Fruit infected with powdery mildew or the use of gibberellic acid, thiobenzuron, pyruron and other doses are too high, the fruit is too large, will aggravate the occurrence of fruit cracking. In the production, the whole ear should be thinned, the yield should be controlled, the sufficient amount of organic fertilizer should be applied deeply, the buffering capacity of root soil should be increased, the application of phosphorus, potassium and calcium fertilizer should be paid attention to, the fruit resistance and pericarp toughness should be improved, and the soil should be kept moist during the cracking period (orchard growing grass, covering the tree disk with film, laying straw or straw), so as to avoid the sudden dryness and moisture of the rhizosphere soil, which can effectively prevent fruit cracking.