Comparative Study on GA Treatment to Promote the Seed Germination of Different Eggplant Varieties

Shuchun MENG，Zhenzhou YU，2，Shunhua SONG*，Lianping MA

1.Beijing Vegetable Research Center，Beijing Academy of Agriculture and Forestry，Key Laboratory of Biology and Genetic Improvement of Horticultural Crops（North China），China，Key Laboratory of Urban Agriculture（North），Ministry of Agriculture，Beijing 100097，China；

2.Horticulture College，Anhui Agricultural University，Hefei 230036，China

Comparative Study on GA Treatment to Promote the Seed Germination of Different Eggplant Varieties

Shuchun MENG1，Zhenzhou YU1，2，Shunhua SONG1*，Lianping MA1

1.Beijing Vegetable Research Center，Beijing Academy of Agriculture and Forestry，Key Laboratory of Biology and Genetic Improvement of Horticultural Crops（North China），China，Key Laboratory of Urban Agriculture（North），Ministry of Agriculture，Beijing 100097，China；

2.Horticulture College，Anhui Agricultural University，Hefei 230036，China

Eggplant （Solanum melongena L.）is the world's fourth largest vegetable crop，but the dormancy phenomenon is common.This experiment selected 7 varieties of eggplant，which are widely used in the production at present in Beijing area，including Jing Qie No.5，Jing Qie No.10，Jing Qie No.3，Jing Yan No.2，Damingqie，Kuaiyuanqie and Jingqie No.1.After sterilization with 1.2%hydrogen peroxide for 5 minutes，the seeds were soaked with 300 mg/L GA for 30 minutes，and the test temperatures were in the range of 20-30℃.Experimental results showed that the germination rate of GA treatment increased the maximum of 18%，indicating GA treatment can promote seed germination.Meanwhile，GA treatment can improve the speed of germination of eggplant，and shorten germination days，so that it is conducive to rapid germination of seed after sowing.

Eggplant Seeds；Germination Capacity；GA

S eed germination capacity is an important index evaluating seed quality，and it is necessary to correct technological factors available for seed germination from different aspects in order to illustrate the capacity in a precise way.For melon and vegetable seeds with germination obstacles，such as seeds of eggplant and aspermous watermelon，it is hardly to obtain measurements of germination rate even with references of Rules for Agricultural Seed Testing［1］or International Rules for Seed Testing［2］.Recently，germination difficulty of seeds of some melons and vegetables has been resolved as new technology of foreign seed germination and promotion technology of seed germination develop.However，researches are unavailable on how to correctly select and use technologies to obtain seed germination capacities.

Eggplant（Solanum melongena）is the world’s fourth largest vegetable crop，native to southern and eastern Asia.It is a vegetable popular in summer and autumn，and the most extensively grown in China，characterized by high yield and adaptability，with a long fruit-bearing stage［3］.The endo pleura is poor in water permeability and seed coat is covered with colloids. Therefore，seed coat material and inner hormonesmake contribution to difficulty of eggplant seeds in water absorption and oxygen uptake，affect ing seed germination［4］.At a proper temperature，seed germination rate is just 50%10 d after sowing，and about 15 d after sowing would all seedlings germinate.It becomes common in production that seedlings grow in different sizes.Therefore，pretreatment before sowing is a crucial way for promoting seed germination and improving seedling quality［5］.

It is notable that the treatment of eggplant seeds with gibberellin solution before sowing would accelerate seed germination and improve germination rate，which has been researched by Wang［4］，Si［5］，and Wang［6］et al.However，seed dormancy characters of eggplant seeds tend to be volatile upon eggplant cultivars，and whether the treatment effects differ upon eggplant cultivar with gibberellin solution is not explored yet.The research selected 7 eggplant cultivars available in market in Beijing and conducted research on seed germination capacity with treatment with gibberellin solution in order to provide references for seed detection and seedling production.

Materials and Methods

The test was carried out in a malting floor of Vegetable Seed Monitoring and Testing Center of Ministry of Agriculture and the test materials included Jingqie No.5，Jingqie No.10，Jingqie No.3，Jingyan No.2，Damingqie，Kuaiyuanqie and Jingqie No.1.The seeds were provided by Beijing Jingyan Yinong Sci-tech Development Center， and gibberellin was by Guangmo Organic Agricultural Chemistry Industry.

Methods

Standard germination test After purity analysis，the seeds were selected randomly to get 4 samples and every sample contained 100 seeds，with four replications.The germination test was conducted at 20-30℃［1］.Specifically，the seed bed was prepared on August 10，2014 and the number of germinated seedlings was recorded since the 2ndd［7］.Then，germination potential was computed after 7 d and the last calculation was conducted af-ter 14 d concerning the days required by 70%seeds’germination.If the germination rate reaches 80%，it suggests that seed growth has passed dormancy.If the germination reached the highest，it suggests that the dormancy is broken［6］.

Effects of gibberellins treatment on improving seed germination capacity The seeds were sterilized with hydrogen peroxide （1.2%）for 5 min，and then soaked with 300 ppm gibberellins for 30 min.Subsequently，the seeds were collected and dried until the moisture content was close to standard content at initial stage.Then，germination test was conducted at 20-30℃［6］.The seed bed was prepared on August 10，2014 and the number of germinated seedlings was recorded since the 2ndd.Then，germination potential was computed after 7 d and the last calculation was conducted after 14 d concerning the days required by 70%seeds’germination.If the germination rate reaches 80%，it suggests that seed growth has passed dormancy.If the germination reached the highest，it suggests that the dormancy is broken.Every treatmenthad four replications and every replication involved 100 seeds.

Results and Analysis

Dormancy characters of seeds of different eggplant cultivars

Seed dormancy is quite common for eggplant.The test results showed that of the 7 eggplant cultivars，except of Jingqie No.1 （85%），germination rates of the rest all kept in the range of 60%-80% （Table 1）.It can be concluded that Jingqie No.1 was free from seed dormancy and the rest cultivars underwent shallow dormancy.

Effects of gibberellin treatment on seeds of different eggplant cultivars

According to germination test treated with gibberellins，germination rates of Jingqie No.3 and Damingqie were both lower than 80%，showing little differences with the rates of the treatment with gibberellins.For Jingqie No.1，the treatment with gibberellins also improved the germination rate from 85%to 92%，and the germination rates of rest cultivars all kept higher than 80%，12%higher than that of control.These indicated thatgibberellins treatment has broken seed dormancy of eggplant.It is notable that the treatment effects on Jingyan No.2 were the most significant，for the germination rate increased from 68%to 86%.

Table 1 Germination of seeds without treatments

Table 2 Seed germination of eggplants treated with gibberellins

Comparisons of the days required by eggplant seeds in reaching 70% of seed germination

The treatmentof gibberellins proved significantly in promoting seed germination.Forexample，ittook about 6-9 d for seed germination rate to reach 70%of the seeds not treated with gibberellins.Still，the rates of Jingyan No.2 and Damingqie did not reach 70%.In contrast，for seeds treated with gibberellins，except of Damingqie，seed germination of the rest cultivars all achieved 70%in 4-5 d（Fig.1-Fig.7）.It can be concluded that the treatmentwith gibberellins increases germination rate of eggplant seeds and reduces germination period，which is conductive to seed germination after sowing，but Jingqie No.3was not so sensitive to gibberellins，so that it took 8 d for germination rates reached 70%in both treatment with gibberellins and the control group.As for Jingyan No.2，the treatment with gibberellins proved the best.For example，the seeds in control group did not reach 70%in terms of germination rate，but the treated seeds reached 70%only in 5 d.

Conclusions

Seed dormancy is quite common of newly harvested eggplants，and decided by genetic characters.For instance，germination rate of Jingqie No. 1 exceeded 80%，and seed dormancy was not so significant.The germination rates of Jingqie No.5，Jingqie No.10，Jingqie No.3，Jingyan No.2，Damingqie and Kuaiyuanqie all kept in the range of 60%-80%，characterized by shallow dormancy.Still，if the seeds are sown without treatment，the wastes would be as high as 10%.The research has demonstrated that the treatment with 300 mg/L gibberellins would break eggplant seed dormancy and the treated seed germination increased the highest by 20.93%.Except of Jingqie No.3 and Damingqie，the germination rates of rest cultivars all increased by more than 12%. Meanwhile，the treatment would improve germination speed and reduce germination days，which is conductive to seed germination.However，the differences of effects of treatments with gibberellins at different concentrations should be further explored.

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Responsible editor：Xiaoxue WANG

Responsible proofreader：Xiaoyan WU

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*Corresponding author.E-mail:songshunhua@nercv.org

Received:July 3，2015 Accepted:August 16，2015