Detailed Explanation of Garlic Seed Selection and Purification-Rejuvenation Techniques

Because garlic reproduces asexually, and the garlic clove is a modified lateral bud that forms part of the mother plant, long-term asexual reproduction inevitably leads to the accumulation of viruses within the plant as well as the buildup of other undesirable traits, causing degeneration of the garlic's varietal characteristics. Degenerated garlic plants are short and small, have low photosynthetic capacity, produce smaller bulbs, and decline in quality, seriously affecting garlic yield and profitability. The key techniques for garlic seed selection and purification-rejuvenation are introduced below:

1. Establish off-site garlic seed-production fields

Establishing garlic seed fields with a certain degree of regional and cultivation difference can prevent garlic degeneration, improve the varietal characteristics of garlic, and provide a certain off-site growth advantage. For example, exchanging between mountainous areas and plains, between dryland areas and rice-growing areas, between vegetable-growing areas and grain-growing areas, and exchanging between off-site locations in different directions within a certain range, such as south and north, east and west — all of these can improve the varietal characteristics and yield of garlic to varying degrees.

2. Select disease-free and pest-free garlic bulbs with the characteristics of the variety as seed garlic

During the garlic harvest period, go to the seed field to select seed garlic. The selection criteria are plants with the morphological characteristics of the variety, leaves free of disease spots, large and plump bulbs, uniform color, a moderate number of cloves, no insect sources, and disease-free, virus-free seed garlic. After selection, tie them into small bundles and harvest and store them separately. Be sure to dry the bulbs thoroughly and store them under cool and ventilated conditions; high temperature and humidity will reduce the viability of the cloves' scale buds and may even cause the seed to rot.

3. Use aerial bulbils as seed

To improve the varietal characteristics and vigor of garlic seed, aerial bulbils of garlic can be used for propagation. The method is: after the garlic bolts in the late growth stage, do not harvest the garlic scapes; delay the bulb harvest period by 15-20 days, and harvest when the scapes turn yellow and the aerial bulbils are mature. Select those with a diameter greater than 0.4 cm and store them through the summer. In early to mid-September, open furrows on level beds for drilling in rows or broadcast sowing, with 120,000-150,000 seedlings per 667 sq m, then cover with about 2 cm of soil, press down, and water. Subsequent management is the same as for garlic sown with cloves. When aerial bulbils are sown, generally in the first year they produce single-clove garlic; store the single-clove garlic well, and when planted in autumn it will grow into normal bulbs, with the bulbs noticeably enlarged, good quality, and strong growth vigor. Using this method to propagate garlic seed is the main method for improving garlic's varietal characteristics and preventing garlic degeneration. This method is not suitable for some varieties; for example, garlic without scapes, or with thin and small scapes that do not produce bulbils, cannot be propagated by this method.

4. Select and breed virus-free seedlings, and introduce virus-free garlic seed

In recent years, research institutions have adopted virus-free measures for garlic seed production, and virus-free garlic seed has a clear yield-increasing effect. However, it must be foundation seed or certified seed; beyond 3 generations, the yield-increasing effect becomes insignificant. Virus-free garlic must not be harvested too late, otherwise the cloves easily split apart, affecting the garlic's commercial value.

5. Garlic that has undergone secondary growth cannot be kept for seed

Fields where garlic has undergone secondary growth, i.e. "horsetail garlic," due to cultivation and climatic conditions cannot be used for seed selection. Secondary growth in garlic is itself a form of degeneration that affects garlic yield and quality; if such garlic is selected for seed for another season, it will cause even more secondary growth and severe yield reduction.