Factors and risk Analysis on the formation of Seedless Grape

Factors and risk Analysis on the formation of Seedless Grape

1 forming factors of seedless grape

Seedless grape has always been the direction of grape breeding in the world, but also the consumption trend of table grape in the world. According to the statistics of the World Food and Agriculture Organization, the cultivated area of seedless grape in the world is about 1/5 of the total cultivated area of table grape. At present, there are more than 100 seedless grape varieties in the world. There are two situations in the formation of seedless grapes on the market: one is the cultivation of seedless varieties, and the other is for diploid or tetraploid varieties with more parthenocarpy or triploid or early maturing varieties with poor commercial natural results. it is formed after being regulated by plant growth regulators.

1.1 Seedless varieties

The common seedless varieties on the market are Jing Zaojing, Seedless Zaohong, Brown Seedless, Flame Seedless, Summer Black, Emerald Seedless, Venus Seedless, wonderful Seedless, Seedless White Chicken Heart, scarlet Seedless, Ruby Seedless, Red face Seedless, Royal Autumn, Purple Seedless, Bixiang Seedless, Jintian Royal Seedless, Honey Seedless, Ruifeng Seedless, etc. Among them, Brown Seedless, Flame Seedless, Summer Black, Emerald Seedless, Venus Seedless, wonderful Seedless, Seedless White Chicken Heart, scarlet Seedless, Ruby Seedless, Red face Seedless, Royal Autumn introduced from abroad Jing Zaojing, Seedless Zaohong, Zixiang Seedless, Bixiang Seedless and Jintian Royal Seedless are Chinese cultivars [Yoshanhua Yao].

The grape variety Jingzaojing [5] was bred by the Botanical Garden of Institute of Botanical Research, Chinese Academy of Sciences, and its parent was the cross between vineyard queen and seedless white in 1960. It was identified by peer experts in 1984 and approved by Beijing crop Variety approval Committee in August 2001.

The grape variety Xiahei [6] (black summer and summer black seedless) is an European and American hybrid, originally from Japan, with the Japanese name "Yamanashi". It was bred by the fruit tree test field of Yamanashi Prefecture, Japan in 1968 with Jufeng × Yamashi prefecture fruit tree test ground in 1968. It was registered in August 1997 and was introduced into China by the Japanese Garden Grape Research Institute in 2000. At present, it is one of the main varieties in the south of China.

Seedless grape variety Ruby, also known as Ruby Seedless, Rube Seedless, Eurasian species, native to the United States. Bred by the cross between Emperor and Pirovan075, China was introduced from California in 1986 and is now planted in Shandong, Hebei, Henan, Liaoning, Hunan, Guangxi and other provinces (autonomous regions).

Seedless Zaohong [7] is a triploid seedless variety with breeding number 8611. It was bred by Changli Fruit Tree Research Institute of Hebei Academy of Agricultural and Forestry Sciences. It was crossed in 1986 and approved in Hebei Province in April 1998. its parent is Zhengzhou Zaohong (2n=38) × 2n=76. It is the first triploid seedless variety bred by diploid as female parent and tetraploid as male parent in the world.

1.2 denucleation of plant growth regulators

For diploid or tetraploid with more unisexual fruit, or triploid with poor commercial nature of natural fruit, or early mature varieties, soaking or spraying inflorescences with plant growth regulators before and after flowering of grape can effectively hinder the occurrence of fertilization process and obtain seedless fruit. The varieties with the largest cultivated area in China, such as Zaotian, Yuxuan 1, Jingya, Fujiminori, Zuijin Xiang, Hutai 8, Pioneer, Cuifeng, Jufeng, Anyun Queen, Tama Peak, Gao Rubi, Xinnongxiao, Yidoujin and so on, can be seedless when they are dipped in flower with 12.5 mg ·L-1 GA3. It can also be seedless when it is used on other grape varieties, and GA3 can also be seedless when soaking the flower ear (ear) of Rose fragrant grape in full bloom.

2 relationship between plant growth regulators and contraceptive

Plant growth regulators are a kind of chemical substances with the same or similar biological activities as natural plant hormones, also known as plant exogenous hormones. It has the functions of regulating and controlling plant growth and development, increasing yield, improving quality, promoting early maturity, prolonging shelf life and so on. This is fundamentally different from what we understand as hormones or contraceptive. Contraceptive only acts on people and animals, and its principle is to achieve the purpose of contraception mainly by inhibiting ovulation or hindering the transport of fertilized eggs, which is completely different from plant hormones in chemical structure, object, function and mechanism. Using contraceptives on plants doesn't work at all. Compared with animal hormones, plant hormones are very different in terms of chemical structure and target proteins, just like opening a lock with a key. if the key does not match the structure of the lock, of course it cannot be opened. As a result, plant hormones do not work in the human body, and animal hormones cannot interact with plant cells.

3. Management of plant growth regulators in China.

In our country, the production and sales of plant growth regulators are managed according to pesticides, there are guidelines for production and use, there are limited requirements for agricultural products after application, and the supervision and management are guaranteed by testing methods and monitoring projects. First of all, the management of plant growth regulators in China is carried out in accordance with the Pesticide regulations issued by the Ministry of Agriculture. According to the regulations, manufacturers producing plant growth regulators must have relevant qualifications, and sales units shall apply for business licenses in accordance with the relevant provisions of the State. Only after the pesticide registration and production license have been obtained can the production, operation and use be carried out. China has very strict requirements for the registration of plant growth regulators, and a large number of experiments need to be carried out before applying for registration, and strict examination and scientific evaluation are carried out from the aspects of product quality, efficacy, toxicology, residue, environmental impact, and so on. registration can be approved only when various tests prove that it has good efficacy, safety to human and livestock and harmless to the environment. Secondly, all plant growth regulators approved for registration should formulate safe use techniques, including drug use period, drug dosage, application method, use scope, matters needing attention and safety interval, etc., and clearly marked on the product label to guide farmers to use safely. Thirdly, in order to ensure the safety of the final product, the national food safety standard GB 2763Mel 2014 "maximum residue limits for pesticides in Food" also stipulates the maximum residue limits of plant growth regulators in some foods. In addition, there are a series of detection methods for plant growth regulators, which are also long-term concerned parameters of conventional monitoring projects, which ensure the safety of agricultural products using plant growth regulators from the regulatory level.

(4) the safety of using plant growth regulators to grape.

Although plant growth regulators are included in the category of pesticide management, they are not traditional pesticides for disease control, pest control and weed control. One is that their products are of low micro-toxicity, and some are even listed as exempted substances that do not require establishment of residue limits because they are almost non-toxic, and GA3 is less toxic than salt (LD50 > 5,000 mg kg-1 for GA3 and LD50 for salt is 3,200 mg kg-1). Second, the amount of plant growth regulators is small, for example, GA3 uses an effective concentration of 12-15 mg kg-1 before and after flowering. If excessive use is counterproductive, it will have side effects on grape inflorescences, causing spike thickening, hardening, fruit cracking, threshing, etc., losing commercial value (figure 1). Thus it can be seen that growers can not use plant growth regulators in large quantities. Third, risk assessment results show that grapes that have used GA3 have no potential risk to the human body. In 2015, the Agricultural products quality and Safety risk Assessment Laboratory of the Ministry of Agriculture (Hangzhou) led the implementation of the special project "investigation on the use of Plant growth regulators and Product Safety Assessment of fruits and vegetables" (GJFP2015003). The product safety of plant growth regulators used on grapes in Henan, Shandong, Liaoning and Beijing provinces (cities) were evaluated. A total of 80 samples were sampled, and GA3 detection showed that no GA3 was detected in all samples. Hou Yuru et al reported that 50 days before ripening, the grapes were sprayed with 0,25,100 mg ·L-1 respectively and sampled during fruit ripening. The GA3 residues in the fruits treated with blank samples with GA3 content of 0.002 mg ·L-1 were 0.001 and 0.005 mg ·L-1, respectively, indicating that the residue of GA3 in grapes treated with GA3 was very low during ripening, and there was no significant difference between the grape with GA3 and the blank sample. The limit of GA3 in grape has not been established in China, but the residue is much lower than the residue limit standard of 0.2 mg ·L-1 in Japan.

In the middle of the picture on the left is a normal ear, on both sides is a thick and hard stem caused by excessive use of plant growth regulators, and the picture on the right is a stiff fruit.

Fig. 1 different effects of GA3 on grape

Plant growth regulators are widely used not only in China, but also in other countries. Plant growth regulators such as chloropyruron, abscisic acid and GA3 have been registered in a variety of fruits in the European Union and Japan. Due to the low toxicity of GA3, the European Union has not established a specific standard for residue limits of GA3 in fruits [9].

5 Summary

Plant hormones and animal hormones cannot replace each other. Contraceptive cannot make fruit seedless, nor can plant hormones regulate human growth and development, while seedless grapes are mainly related to varieties and the use of plant growth regulators. In addition, through the risk assessment study on the use of plant growth regulators in grape, it was found that it did not have any dietary risk to the human body. What's more, there are a lot of plant hormones naturally produced in plants, and they do not show any harm to health after eating.