There is a relatively balanced relationship between the reproductive and nutritional growth of Tea plants. Modern tea gardens, employing techniques such as clonal propagation of superior cultivars combined with dense planting and canopy cultivation, have effectively resolved issues related to reproductive growth, which thus requires little attention from garden operators. However, with the rise of cold-sensitive albinos tea and the promotion of three-dimensional picking canopy models, reproductive growth has again become a technical issue that must be addressed for high-quality and high-yield cultivation.

I. Reproductive Phenomena

Cold-sensitive albinos tea generally exhibits strong capabilities for Bud formation and flowering, but weak abilities for seed setting and inheritance of albinism traits.

1. Early onset of Reproductive Growth

Sexually propagated tea plants typically enter the reproductive growth stage after reaching the age of 3 years, while clonally propagated conventional tea plants start budding and flowering at the age of 2 years. However, albinos tea often begins to flower in large quantities starting from the first year, and even shows strong capability for bud formation and flowering in the same year it is cuttaged.

2. Large Bud Formation and Flowering, Few Seeds Set, Weak Seed Inheritance of Albinism Trait

In general, albinos tea displays a budding and flowering capability that surpasses that of conventional varieties. The budding and flowering capability of White Leaf No.1 is particularly strong, followed by Thousand Year Snow, while Siming Snow Bud essentially shows a level similar to that of conventional tea plants. However, their capabilities for seed setting and inheritance of albinism traits are relatively weak. White Leaf No.1 basically only flowers and sets few seeds, while Thousand Year Snow and Siming Snow Bud have slightly stronger seed setting capabilities. The strength of the seed inheritance of albinism traits, in descending order, is: Siming Snow Bud, Thousand Year Snow, White Leaf No.1. The proportion of albino plants obtained from the offspring of Siming Snow Bud seeds is approximately 50%, whereas that of White Leaf No.1 seeds is less than 5%.

3. Little Correlation Between Reproductive Growth Ability and Albinism

In terms of albinism performance, the Siming Snow Bud strain is the most distinct, achieving the highest degree of albinism, which exceeds that of other varieties. However, its plants are tall and robust, and their capability for bud formation and flowering is significantly lower than that of the White Leaf No.1 strain.

II. Reproductive Rhythms and Their Influence

The bud formation, flowering, and seed setting of tea plants are mainly determined by five factors: tea variety, garden model, garden age, tea shoots, and cultivation techniques.

Tea Variety: The order of strength for budding and flowering ability is: albinos tea, sexually propagated populations, and conventional clonal superior cultivars. Among albinos tea varieties, the order of strength for budding and flowering ability is: White Leaf No.1, Thousand Year Snow, and Siming Snow Bud, while the weakest seed setting ability is found in White Leaf No.1.

Tea Garden Model: Three-dimensional picking tea gardens are more likely to form buds than flat-picking tea gardens, and sparse planting tea gardens are more likely to form buds than densely planted tea gardens.

Tea Plant Age: Generally, the older the plant, the more likely it is to flower, but in mature tea gardens with dense canopy branching, due to insufficient light within the canopy, the capability for flowering can drop significantly. This can result in younger tea gardens or those not yet closed row showing more severe flowering than mature, closed row tea gardens.

Tea Shoots: Among the spring (first round), summer (second and third rounds), and autumn (fourth and fifth rounds) shoots that sprout each year, the first and second rounds are the shoots that form buds, while the third to fifth rounds generally cannot form buds. When buds appear on the second round shoots, they constrain the sprouting and development of shoots in subsequent rounds, and may even lead to a halt in the sprouting of the next round of new shoots.

Cultivation Techniques: Different pruning times and degrees, fertilizer types and application times, affect the reproductive growth capability of tea plants. During the annual cycle of tea plants, the period for bud formation is from June to July, the flowering period is from October to December, and the seeds mature during the following autumn and winter seasons. The first and second rounds of shoots that have matured in the current year, from June to July, can form buds, and a large amount of bud formation and flowering can lead to a shift in the advantage from nutritional growth to reproductive growth. Firstly, when a large number of buds form on shoots and turn into flowering shoots, it suppresses the sprouting and growth of subsequent shoots, reducing the sprouting and growth of shoots in the third and subsequent rounds, and lowering the position of high-quality tea buds sprouting the following year. Secondly, flowering and seed setting consume the nutrients within the plant, thus exacerbating the weakening of the plant and reducing the yield of tea buds the following year.

III. Control Measures

Based on the growth rhythms of nutritional and reproductive growth during the annual cycle of tea plants, the control measures to inhibit reproductive growth are:

1. Adjust the Canopy Pruning Method

In three-dimensional picking tea gardens, after the Spring Tea harvest, the canopy pruning employs a two-step pruning method. The method involves: performing comprehensive harvesting of the spring shoots while leaving the fish leaf, and then positioning the pruning 10 cm above the previous year's cutting point after the spring tea harvest. For the second round shoots, controlled positioning pruning is carried out when the shoots reach a height of 15-20 cm and are semi-woody. The canopy is then level pruned or only the protruding branches are cut, 10 cm above the spring tea pruning position. The remaining part of the second round shoots is left to sprout the next round of shoots, forming the foundation shoots for the picking production layer.

2. Focus on Promoting the Fourth Round Shoots

After the second step of pruning, the third round shoots are naturally reserved. Since July and August are typically hot and dry, the third round shoots are naturally constrained in their growth. The fourth round shoots that sprout in early September are focused on and cultivated as the main target for the next year's production shoots.

3. Increase Nutrient Supply for Autumn Shoots

Ten to fifteen days before the sprouting of the fourth round shoots, nitrogen fertilizers are applied to promote their growth, forming the backbone of the production shoots for the following year. For uncropped young tea gardens, apply 10-15 kg of urea per mu; for mature tea gardens, apply 20-25 kg of urea per mu.

By applying these control techniques, focusing on the controlled positioning of the second round shoots and the cultivation of the fourth round shoots as the main autumn shoots, a picking production layer primarily composed of autumn shoots without buds is formed. The effective picking layer depth is 20-55 cm, with a branch density of 180-450 per m2, and the ratio of non-flowering shoots to second round shoot lengths is 6:1 to 8:1. This can effectively control the bud formation and flowering of tea plants, ensuring high-quality, high-yield, and efficient production of albinos tea.

This article is excerpted from “Cold-Sensitive Albinos Tea,” written by Wang KaiRong, Wu Ying, Liang YueRong, Li Ming, Zhang LongJie, and Han Zhen, published by Zhejiang University Press.