Peach Tree Technology Home-Study Manual: A Practical Guide for Fruit Growers

1. Variety Introduction

1.1 Early Red Flat Peach (Zaohong Pantao)

Single fruit weight 110-200 g; the fruit surface is pink-red, beautiful and vivid, firm-fleshed, crisp and juicy, intensely sweet and fragrant, of the highest quality, storage- and transport-tolerant, ripening in mid-June.

1.2 Okubo

Average single fruit weight 250 g, large fruit weight 700 g, good flavor, sweet-tart and palatable, freestone, ripening at the end of July.

1.3 Jingyu (Beijing No. 14)

Fruit elliptical or nearly round. Single fruit weight 195 g, maximum fruit weight 233 g, fruit surface light green-yellow, with a small amount of red blush on the sunny side and a small amount of red stripes on the shaded side. Flesh white, sweet, freestone. Fruit ripening period is early to mid-August.

1.4 Chongyanghong

The fruit is extra-large, single fruit weight 250-350 g, maximum 700 g, nearly round, fruit apex flat, skin slightly thick, bright red and vivid, with few hairs, flesh white, fine, crisp and juicy, fiberless, good palatability, containing 11.9% soluble solids, 0.46% acid, vitamin C content 3.62 mg/100 g, storage- and transport-tolerant, storable 10-15 days at room temperature. Ripening period is mid-September to early October.

1.5 Ruiguang No. 5

Fruit short elliptical, average single fruit weight 145 g, maximum fruit weight 158 g. Skin ground color yellow-white, not easy to peel. Flesh white, fine in texture, hard-melting, sweet, relatively strong flavor, clingstone. Contains 7.4%-10.5% soluble solids, 7.0228% soluble sugars, 0.3624% titratable acid, vitamin C 7.6828 mg/100 g. Ripens in early to mid-July in the Beijing area.

2. On-Tree Management

2.1 Pruning

2.1.1 Key Points of Summer Pruning Techniques

(1) Bud rubbing and sprout removal: promptly rub off useless water sprouts inside the tree canopy and competitive buds below the pruning cut. Sprout removal means promptly rubbing off newly sprouted peach shoots once they grow to about 5 cm; generally, for young trees, remove the strong and keep the weak, which can moderate tree vigor, improve light exposure and save nutrients.

(2) Pinching and shoot twisting: pinching means removing a small section of the tender shoot tip together with several tender leaves from a growing branch. This can control the branch's elongation growth, promote the formation of plump, well-developed flower buds in the lower part of the branch, and delay the upward shift of the fruiting zone. It controls excessive growth, moderates tree vigor, and transforms the shoot into a well-developed fruiting branch; if a vigorous shoot emerges again at the twisted point, twisting can be done again. Apart from selected extension branches and their side branches, other competitive shoots of extension branches, shoots on the upper side of scaffold branches, water sprouts and vigorous shoots after heading back, and vigorous shoots near large wounds can all be twisted. The best time for twisting is when the new shoot has grown to about 30 cm and is not yet lignified. The twisting point is best at about 5-10 cm above the base of the shoot.

(3) Branch pruning and branch bending: summer pruning of peach trees is divided into two situations. (1) Heading back new shoots in May-June can not only improve light conditions but also promote two fruiting branches to emerge from the lower part; the heading-back length is best done leaving 3-5 buds at the base. (2) Because peach trees do not bear fruit twice (that is, a branch that has already borne fruit will not bear fruit again), after the peach fruit is harvested, the section of branch that has already borne fruit should be cut off, and the two branches left at the base serve as reserve branches, which can lay a good foundation for a bumper harvest the following year. In this way, pruning after harvest each year can not only improve ventilation and light penetration and save nutrients, but also effectively control the outward shift of the fruiting zone, making nutrient supply convenient and fruiting growth robust. Branch bending is a key measure to moderate tree vigor, advance fruiting, and prevent the lower part of branches and trunk from becoming bare and branchless. For large branches more than 3 years old, in May-June when the sap is flowing and the branches and trunk become soft, methods such as "pulling, propping, hanging, and wedging" can be used according to the angles required by the tree shape to pull the branches open and fix their form. In this way, branches can emerge from the middle and lower parts of the bent branch, avoiding an empty, bare lower part (bare legs). However, when bending branches, be sure not to pull the branch to horizontal or drooping into an arch shape. Otherwise, the tip of the bent branch will weaken, and vigorous shoots will easily emerge on the upper side or at the bend, failing to achieve the purpose of branch bending. Conversely, if the bending angle is insufficient, it is still easy to produce strong upper growth and weak lower growth, with the lower part becoming bare. According to many years of practical experience, a branch-bending angle of about 80 degrees is appropriate.

2.1.2 Key Points of Winter Pruning Techniques

Winter pruning of peach trees is generally carried out from after leaf fall in autumn to before bud break in spring. Peach trees have strict light requirements, so an open-center form is used for training. Generally, trunk height is about 30-50 cm; upright varieties should have a shorter trunk, while spreading varieties should have a taller one, with 3 scaffold branches arranged alternately on it. Large branch groups are spaced 60-80 cm apart on the same side and are generally developed from strong shoots such as water sprouts, water-sprout-type fruiting branches and vegetative branches; they have strong growth vigor, occupy a large space, bear many fruits, and have a long life. Medium branch groups are spaced 40-60 cm apart on the same side and are developed from water-sprout-type fruiting branches and long fruiting branches; small branch groups are spaced 20-40 cm apart and are generally developed from medium and short fruiting branches, occupying little space, bearing few fruits, and having a short life. Therefore, the spacing of branch groups on the scaffold and side branches should follow the principle of dense at both ends and sparse in the middle; the front should be mainly small and medium branch groups, while the back and both sides should be mainly large and medium branch groups, with small and medium branch groups arranged in the gaps between large and medium branch groups, ensuring ventilation and light penetration, balanced growth, and clear subordination. Fruiting branch pruning: in the young tree stage, tree vigor is vigorous, so fruiting branches should be left long; long fruiting branches and water-sprout-type fruiting branches can be cut to leave 30-40 cm, and water sprouts can be thinned out. In the initial fruiting stage and full fruiting stage, tree vigor is relatively moderate; because flower bud differentiation in the middle of fruiting branches is more complete, the plump middle buds should be retained. Generally, long fruiting branches should be cut to leave 30-40 cm, medium fruiting branches 20-30 cm, and short fruiting branches 10-20 cm. Overly dense fruiting branches should be thinned out; fruiting branches on the upper side and lower side bear poorly, so they can also be thinned out. Mainly retain fruiting branches on both sides and on the oblique upper sides. Pruning of water sprouts: thicker branches growing on the upper side or inside the canopy are called water sprouts, commonly known as "club branches"; they easily cause trees to grow on trees and affect light in the tree body, so they should be thinned out as much as possible. If a water sprout grows in a space where it can be used, it should be trained into a branch group, but attention should be paid to summer pruning. Pruning of branch groups: attention should be paid to combining training and utilization. For large branch groups on the outer periphery of the canopy, pay attention to the direction of the cut bud or extension branch; the extension branch should be cut slightly more heavily than the side branches, and the cut should leave a plump bud. For large and medium branch groups inside the canopy, the method of first heavy cutting and then light pruning should be adopted, removing the strong and keeping the weak, removing the upright and keeping the horizontal; thereafter, each year shorten the terminal vigorous branch, led by an oblique branch, so that it rises in a curved manner, but the height of the branch tip should not exceed the tip of the scaffold branch. For small and medium branch groups in the lower part of the canopy, press the front and invigorate the rear, that is, cut off the terminal 1-2-year-old branches to promote rejuvenation of their base; overly weak small branch groups can be thinned out. Pruning of scaffold extension branches: pay attention to the direction and angle of the cut bud. Ensure the dominance of the scaffold branch and prevent confusion between scaffold and side branches and a chaotic tree shape.

2.2 Flower bud thinning: when the flower buds are the size of soybean grains, leave one flower bud per node and thin out the rest; also remove all flower buds on branches not planned to bear fruit, reserve branches, and bouquet-like branches.

2.3 Flower thinning and fruit thinning: first thin the flowers at the base of fruiting branches, keep the flowers in the middle and upper parts, thin double flowers and keep single flowers, staggered left and right, and thin out all flowers on reserve branches. Fruit thinning is carried out 10 days after flowering and completed entirely before the hard-pit stage. Long fruiting branches retain 2-4 fruits (large and medium fruits retain 1-2, small fruits retain 3-4), medium fruiting branches retain 1-3 fruits (large and medium fruits retain 1-2, small fruits 2-3), short fruiting branches may retain 1-2 or no fruits (large fruits: retain 1 fruit per 2-3 fruiting branches; medium fruits: 1 short branch retains 1 fruit; small fruits: 1 fruiting branch retains 1-2 fruits); weak fruiting branches and bouquet-like fruiting branches generally retain no fruit, reserve branches retain no fruit, and secondary-shoot fruiting branches may retain 1-3 fruits according to growth vigor.

2.4 Bagging

2.4.1 Bag type selection: for single-layer multicolor bags, if single fruit weight is above 1 jin, the 230×190 type can be selected. For half a jin to 1 jin, select the 190×175 type; for flat peaches, select the 190×175 type; for Qingfeng, select the 190×175 type.

2.4.2 Management before bagging: spray once with insecticide and fungicide before bagging. Medication: use low-toxicity or biological pesticides; complete bagging within 3-4 days after spraying; spray one section and bag one section to ensure quality.

2.4.3 Bagging method: take a paper bag, keep the bag opening facing upward, open it with your hands, then pinch flat the two lower corners, then place the young fruit in the middle of the bag, and then fold the bag opening horizontally with both hands and fix it to the peach branch; do not put leaves into the bag.

2.4.4 Bag removal time and method: (1) Bag removal time: for Qingfeng peach, 10 days before ripening, begin removing bags from bagged peaches in positions with good light for observation; when the fruit in the bag reaches seven-tenths ripe and begins to turn from green to white, this is the best time to tear the bag. One to two days after tearing the bag, remove the entire bag. Remove bags from the outer and upper parts first, and from the inner and lower parts later. Harvest at 7.5-8.0 maturity. (2) Bag removal method: bag removal should likewise be done on a clear day at 4 p.m. Or do it after more than 2 consecutive overcast days, when the following days continue to be overcast (without rain). When removing bags, never remove them all at once; do it in two steps. First untie 1/2 of the bag opening into an umbrella shape, allowing the fruit to gradually adapt to the outside climate and temperature, and then remove the bag completely. When bagged fruit is harvested, the fruit surface is bright red and vivid, with very few hairs, and the fruit surface is delicate, smooth, and attractive in color.