Types and performance of main Citrus rootstocks in Zhejiang Province

Types and performance of main Citrus rootstocks in Zhejiang Province

1 types of citrus rootstocks in Zhejiang Province

At present, the main types of citrus rootstocks in Zhejiang Province are trifoliate orange, Goutou orange and local early. In addition, in the long-term study of rootstock selection and cultivation, there are sporadic planting of other rootstocks.

1.1 Trifoliate orange

Trifoliate orange is the main rootstock type of citrus in Zhejiang and even in China. it can be divided into two types: large leaves and small leaves according to leaf shape and size, and can be divided into four types according to leaf shape and flower size. The production performance of small leaves and large flowers is the best. There are two kinds of fruit shape: round shape and pear shape. As the rootstock of Wenzhou mandarin, it is cold-resistant, drought-resistant, barren-resistant, early fruiting, high and stable yield, good fruit quality, dwarf tree shape, resistance to foot rot, gum disease and nematode disease, but not resistant to split skin disease. The experiments of grafted rootstocks for many years show that the grafted rootstocks of Fructus Aurantii are not resistant to waterlogging and saline-alkali, so they are suitable to be used as rootstocks in mountainous acid red and yellow soil. As the rootstock of Wenzhou mandarin, the big leaf and flower type is better.

1.2 Goutou Orange

Produced in Huangyan, Zhejiang Province, belongs to limes. It grows fast at seedling stage, has developed root system, is resistant to stickiness and moisture, and has a better effect as sweet orange and wide-skinned citrus rootstocks. It has wide adaptability to soil. Wenzhou mandarin with Goutou orange as rootstock grows well on the coastal reclaimed land along the coast of Zhejiang, and there is no iron deficiency yellowing. Huangyan has always been used as the traditional rootstock of early orange, tangerine, milk orange, scarlet and other citrus varieties. As a sweet orange rootstock, the tree is strong, drought-resistant, moisture-resistant, saline-alkali resistant, foot rot resistant and high-yielding, but the tree grows slowly.

1.3 Local Morning

Produced in Huangyan, Zhejiang. The seedling growth is slow, the root system is developed, drought and cold resistance, as Wenzhou mandarin rootstock, the tree is strong, the crown is round, the branches are compact, high and stable yield, good quality. As tangerine and early orange rootstock, the crown is slightly dwarfed; as navel orange rootstock, the crown is dwarfed. The rootstock is saline-alkali-resistant and acid-resistant, and can be used in both coastal and mountainous areas.

1.4 Zhu Kui

Produced in Wenzhou, Zhejiang Province, it is synonymous with the small red orange produced by Huangyan. The seedling grows fast in the early stage, the root system is developed, the distribution is dense, there are more whisker roots, and the adaptability to soil is wide. When Wenzhou was used as the rootstock of ou orange, ou orange and Wenzhou mandarin, the crown was higher, but the fruiting period was a little later. Huangyan as a local early rootstock, the early growth is good, the fruiting period is early, after the tree age is slightly older, the ear is large, the rootstock is small, the growth potential is weak, and it is easy to rot roots and cause fallen leaves in rainy season, so it is not suitable to be used as local early rootstock. As sweet orange rootstock, the tree has strong potential, developed root system, drought resistance and high yield, but the fruit is late.

1.5 fragrant orange

Produced in Jiangsu, Anhui, Hubei, Sichuan and other provinces. After grafting with wide-skinned citrus such as Wenzhou mandarin, the tree is strong, drought-resistant, cold-resistant, high-yield in the later stage, excellent fruit quality and resistance to foot rot. When grafted with sweet orange, the crown is dwarfed. The rootstock of Liangping pomelo shows strong affinity, early fruit and prosperous growth.

1.6 Wenlinggao orange

The local orange hybrid in Wenling and Yuhuan area of Zhejiang Province is suitable for the rootstocks of pomelo and wide-skinned oranges. It grows fast in seedling stage. Wenzhou mandarin with high orange rootstock shows strong growth potential in coastal land, and its root system is deeper than that of Fructus Aurantii.

2 comparison of resistance of different rootstocks

It is generally believed that trifoliate orange is the most hardy rootstock, the grafted tree has a dwarf crown, easy field management and good quality; it has strong waterlogging tolerance. In 1987, compared with Goutou orange rootstock, Wenzhou mandarin showed stronger waterlogging tolerance after the typhoon. Trifoliate orange is resistant to gum disease, foot rot, decline disease and nematode disease, but it is the only susceptible rootstock to split leaf disease. Lime is the earliest and most widely used type of rootstock before the promotion of Zhejiang citrus root. at present, it is also second only to trifoliate orange and is suitable for almost all citrus varieties. compared with the rootstock, it belongs to strong rootstock with large crown, strong tree potential, high yield and high yield, but the fruit quality is not as good as that of citrus rootstock. Suitable for clayey soil, alkali-resistant soil, cold-resistant, resistant to blight, but sensitive to nematodes, its biggest disadvantage is that it is very sensitive to decline disease. According to the literature, the salt and alkali tolerance of different citrus rootstocks is in the following order: fragrant orange > citrus orange > red orange > Goutou orange > Zhu Yi > local early > trifoliate orange. The salt tolerance test of Weng Maidong to citrus seedlings showed that trifoliate orange was the most sensitive to salt, Goutou orange and local early was moderately sensitive.

3 performance of nutrient uptake by different rootstocks

There are differences in the absorption of minerals and other nutrients by different rootstocks, because the mechanism of nutrient ion absorption and root morphology of different citrus rootstocks will affect the absorption capacity of mineral elements. Many researchers at home and abroad believe that rootstocks have significant effects on the contents of mineral elements in the leaves of scion varieties. Zou Yuming's research shows that rootstocks have significant effects on the contents of most nutrient elements in the leaves of Wenzhou mandarin, the effects on major elements are Ca, N, K, Mg, P, and the effects on trace elements are Cu, Fe, Zn and Mn. Zhou Xuewu and others analyzed the mineral nutrients of several commonly used rootstocks. The results showed that the content of K, Mn and Cu in trifoliate orange was the highest and the content of Fe was the lowest. On the contrary, the content of Fe was high and the content of K and Cu was lower. Wenzhou mandarin on the anvil of trifoliate orange has obvious yellowing phenomenon of element deficiency on the beach, and it is easy to have the symptoms of iron deficiency, manganese and zinc deficiency. In acid soil, magnesium deficiency and boron deficiency are easy to occur whether Gutou orange or Fructus Aurantii is used as rootstock. The local early cropping Wenzhou mandarin rootstock not only overcame the yellowing of element deficiency (lack of iron, manganese, zinc) of using trifoliate orange as Wenzhou mandarin rootstock, but also provided a new excellent rootstock variety for coastal citrus. The local early rootstock Wenzhou mandarin has developed root system, large and thick leaves, compact and round crown, strong load capacity, strong stress resistance, saline-alkali resistance, yellowing resistance and so on.

4 performance of different rootstock types on different soils

Chen Qishou and others carried out comparative experiments with four kinds of rootstocks of Gutou Orange, Zhuzao, Trifoliate Orange and Local early. The results showed that Goutou Orange rootstock Wenzhou mandarin had the strongest growth potential and the tallest tree body, showing tolerance to drought, waterlogging and saline-alkali tolerance. Zhu Luan rootstock ranked the third early, the early growth of Fructus Aurantii rootstock was good, but the saline-alkali resistance was poor, the yellowing phenomenon appeared after delivery, and the tree potential became weaker. Tang Weiying et al used citrus rootstocks for sowing and grafting experiments, and preliminarily considered that Goutou orange and Zhuzhu were suitable for coastal citrus rootstocks. High orange rootstock Wenzhou mandarin also showed strong salt tolerance. From the crown investigation, there was no significant difference in tree height and crown diameter between Wenzhou mandarin and orange rootstock, but the crown volume and projection area of 7-year-old Wenzhou mandarin showed that the high orange rootstock was superior, the branch structure and its growth were similar, the affinity was strong, and the base of Wenling high orange rootstock protruded obviously, showing a strong growth trend, and the leaf size was similar. The whole leaf area of high orange rootstock was larger, there was no significant difference in fruiting performance and fruit index, and the yield was similar. However, compared with trifoliate orange, high orange rootstock has developed roots and deeper roots, and has the characteristics of drought tolerance, waterlogging resistance, wind resistance, wide adaptability and so on.

Therefore, at present, Wenzhou mandarin cultivated in mountainous areas generally uses trifoliate orange as rootstock, while Gutou orange and local early rootstock are the main rootstocks in coastal areas.

5 differences in fruit quality of Wenzhou mandarin among different rootstock types

Compared with Gutou orange and local early rootstock, Wenzhou mandarin with trifoliate orange as rootstock had better fruit quality, thinner pericarp and higher sugar content, and the yield of Gutou orange rootstock was the highest in Gutou orange rootstock, but the fruit ripening period was later than that of other rootstocks. Since 1961, Linhai County, Zhejiang Province has grafted satsuma mandarin, which is planted in coastal areas, mountains and plains. After nearly 20 years of practice, its fruit quality is good, mainly manifested in its thin pericarp and more edible parts. The sugar content is generally higher, and the flavor of Wenzhou mandarin is better.

In a word, citrus production mainly makes use of the characteristics of rootstocks, such as Arbor, dwarfing, drought resistance, cold resistance, waterlogging tolerance, saline-alkali tolerance and disease and insect resistance, to enhance the excellent characters of scion varieties, so as to maintain their inherent biological characteristics and fruit economic characters. The effect of rootstock varies not only with different site conditions, but also on the quantitative and quality characters of scion in the whole growing season. the effects of different years, climate and soil tillage methods on tree growth and fruit quality were greater than those of rootstocks. In the cultivation of satsuma mandarin in Zhejiang Province, after years of practice, trifoliate orange, Goutou orange and local early were gradually formed as the main rootstocks of Wenzhou mandarin mandarin. According to the soil type, the distribution of rootstocks of Wenzhou mandarin is generally as follows: trifoliate orange is generally used as rootstock on acidic soil and flat neutral soil, so Wenzhou mandarin is more resistant to poor soil. Gutou orange and local early are generally used as rootstocks in plain gardens with alkaline soil and high groundwater level, so Wenzhou mandarin is more resistant to salt and waterlogging.