Cultivation of Rootstock Seedlings of Sichuan Pepper and Management Techniques Before and After Grafting

Sichuan pepper (scientific name: Zanthoxylum bungeanum Maxim.), also known as hui, da jiao, Qin pepper, Shu pepper, Chuan pepper, or mountain pepper. It is a deciduous shrub or small tree of the genus Zanthoxylum in the family Rutaceae, and can be planted as a solitary specimen or used as a protective thorn hedge. Its fruit peel can be used as a seasoning, and aromatic oil can also be extracted from it; it can also be used as medicine, the seeds are edible, and they can also be processed into soap. Sichuan pepper can remove the gamy odor of various meats; promote saliva secretion and increase appetite; and dilate blood vessels, thereby helping to lower blood pressure. It can generally be eaten by most people, but pregnant women and those with yin deficiency and excess fire should avoid eating it. The fruit is round, the size of a mung bean, and its outer skin is a commonly used spice. When the fruit matures, the red or purplish-red peel is called pepper red, and the seed is called pepper eye; both are Chinese medicinal materials and commonly used household seasonings. It is mostly seen on slopes at an altitude of 2500 m, and is also cultivated. It is drought-tolerant and likes sunlight, and is cultivated in many places.

Cultivation of Rootstock Seedlings

From mid-to-late August to the end of September, collect fully mature wild Sichuan pepper seeds. After collecting them, spread them in a ventilated and dry indoor area and let them dry naturally in the shade. After the fruit peel splits open and the seeds fall out, soak the seeds in a 30% alkaline water solution for 24 hours, and rub and wash them repeatedly by hand to remove the oil, then rinse them clean with clear water, and then mix the seeds with 2% potassium permanganate for disinfection. In early to mid-November, choose a plot with loose, fertile, and moist soil as the seedbed for sowing. Before sowing, apply sufficient farmyard manure, make a bed 1 m wide and 30 cm high, open furrows for drilling, with 4 rows per bed. After sowing, sift a 2 cm thick layer of farmyard manure over the surface to cover the seeds, and cover with grass to retain moisture. When seedlings emerge in spring, remove the covering in time. When the seedlings reach 10 cm in height, thin them to a plant spacing of 10 cm, about 20,000 plants per mu. After that, combine weeding, fertilizing, and bud removal to promote robust growth of the seedlings.

Preparation Before Grafting

1. Selection of rootstock. Choose healthy, disease-free seedling plants with a basal diameter of more than 0.5 cm as rootstock. Practice has shown that the thicker the rootstock, the higher the survival rate of grafting. In addition, remove the leaf thorns within 10 cm of the ground to facilitate operation.

2. Collection of scions. Cut one-year-old branches with excellent variety, no pests or diseases, plump buds, and a thickness of 0.4—0.6 cm as scions. After collecting them, remove the leaf thorns, wrap them in wet burlap, and sprinkle water in time to keep them moist for later use. They can also be grafted as soon as they are collected.

Grafting

1. Grafting time. Around Jingzhe, when some rootstock leaf buds begin to sprout, is the best grafting period.

2. Grafting method. Single-bud side grafting is mainly used.

Specific operation steps: choose a smooth spot 5—6 cm above the ground on the rootstock and make a downward flat cut, slightly into the xylem, about 2 cm long, leaving 0.5 cm of cortex and cutting away the upper half of the cortex. Cut off the scion at a 45-degree angle on the side of the graft bud, then make a long cut 2 cm long on the back side, and use pruning shears to cut off the scion 0.5 cm above the bud body to remove the graft bud. Quickly insert the graft bud into the rootstock cut, align the cambium, and tie it tightly with plastic film.

Management After Grafting

25—30 days after grafting, the graft bud can sprout. At this time, use a grafting knife to break the plastic film and expose the graft bud to let it grow naturally, then cut the rootstock 1 cm above the graft bud in 2—3 times. Other management also includes removing sprouts, weeding, fertilizing, and controlling pests and diseases. In the autumn of the same year, they can be taken out of the nursery for field planting.

Seedling Stage Management  Field planting is key. The survival rate is highest when planting is done just as the buds begin to sprout. After planting, water thoroughly, apply topdressing 2-3 times during the growing season, and combine it with watering during drought.