| Feijoa sellowiana is a subtropical species, belonging to the Myrtaceae family. It is native to South Brazil with a secondary dispersion in Uruguay. The fresh fruit is enjoyed for its characteristic flavour and aroma, which are similar to pineapple. For this reason it is also called 'pineapple guava'. Owing to its easy adaptability in subtropical regions, nowadays it is extensively cultivated in America, France, Spain, Russia, Australia, Japan and especially in New Zealand, where the fruits are popular. In China, this species was introduced at the end of the 20th century, initially as an ornamental plant. Recently, the species has assumed some economic relevance, with orchards planted in the southern regions of the country, such as Jiangsu, Shanghai, Sichuan and Zhejiang. As a newly rising species for its edible fruits, ornamental and medicinal properties, feijoa shows great potential in being foods, drugs and cosmetics. Supported by the Overseas Intellectual Resource Introduction Program of Sichuan Bureau of Foreign Experts Administration, Professor Wang Dan in Southwest University of Science and Technology(SWUST) introduced a small number of fruit seedlings from New Zealand in 2004. She considers that feijoa has great potential for being developed as ornamental trees and edible fruits because it retains its fine qualities in Sichuan climatic conditions.The feasibility and the adaptability of introductiing feijoa to Mianyang were studied, and at the same time, a comparison test about the propagation methods of feijoa including seeding, layering, grafting, tissue culture, cutting was conducted. Cutting was selected as the appropriate propagation methods for feijoa and the propagation technique, physiology and anatomy of cutting were studied in this paper.The results from the studies would provide a significant basis and practical technologies for the development and utilization of the species, which detailed as following:1,The climatic conditions in Mianyang is similar to the main fruit producing areas in New Zealand. Feijoa can be introduced successfully in Mianyang and consumed as an edible and ornamental fruit tree. Feijoa can be introduced to subtropical parts of our country, but the feijoa in the areas with extreme minimum temperature below -10℃should be used as a kind of ornamental trees, meanwhile in other areas it may be used as both edible and ornamental tree.Feijoa is strongly capable to tolerate extremely high temperature. No sunburn happen after over 30 days's extreme maximum temperature above 35℃. In open field cultivation, the feijoa can withstand the sustained low temperatural(-5℃) rain and snow without freezing. It is not easy to breed the diseases and insect pests in feijoa.2,The introduced feijoa grew well in Mianyang. The bud breaking and shoot growth could occur in each season, four to seven times a year. Spring shoots occur in mid to late of March to early of May, Summer shoots occur in mid-May to early-July, Autumn shoots occur in mid to late of September to early-November, and Winter shoots occur in early-November to end-February. June and July were the two faster growth phases for branch length and diameter.The growth of trunk diameter, crown diameter and tree height followed by the Autumn> Summer> Spring> Winter.Cultivated in the open field in Mianyang, the period of prophase alabastrum, intumescence, petal appearance, prophase flower, metaphase flower and telophase flower of feijoa is in early April, mid-April, late April, early May, early to mid-May and mid-June,respectively. The period of Shed, Rapid fruitGrowth, Slow fruit growth, Shed pre-harvest and Ripening of feijoa is late June, late July to late September, early October, mid- October and late October to early November, respectively.3,The fruit-shaped of feijoa varieties 'Unique' in Mianyang and Auckland, New Zealand, is oval back and it has an excellent uniformity. The average weight in Auckland is greater than that in Mianyang. The soluble solids content, total soluble sugar content, titratable acidity, vitamin C, and pectin of 'Unique' in Mianyang is 12.8%, 9%, 0.65%, 28mg. 100g-1, and 2.8%, respectively, which have little difference with 'Unique' in Auckland, New Zealand. The soluble solids content, total soluble sugar and vitamin C in Mianyang are slightly lower than that of New Zealand, the titratable acid and pectin content in Mianyang is higher than that of New Zealand.The major constituents are: esters 50.64%,aldehydes 26.04%,alcohols 5.84%, hydrocarbons 3.85%, ketones 3.14% and phenol 0.77%. Methyl benzoate is of the highest content 36.56%, followed by (Z)-3-hexenal 17.44%,Hexanal 5.07%, Ethyl butanoate 4.21%, Ethano 13.60%, (E)-2-hexenal 3.53%, Ethyl benzoate 1.50%, 3-octanone 1.44%, linalool 1.40%, (Z)-3-hexenyl butanoate 1.30%, Ethyl acetate 1.21%, and Caryophyllene 1.04%. The major aromatic compounds of feijoa are the same as that in New Zealand. 4,Feijoa is easy to propagate by seeds, which leads to a higher germination rate (95%), far higher than its asexual reproduction. However, seeds were generally not used for propagation of seedlings because it was not easy to maintain the original characteristics of the same species. Layering had a high rooting rate, but its propagation coefficient was lower and would injure the mother tree, the roots are also underdeveloped. Grafting should be an important method to propagated the seedlings, but the technical requirements are high, grafting operation is relatively cumbersome. Grafting had a lower survival rate, and it took a long time to bear fruit after grafting. Tissue culture had a high propagation coefficient and generation, less material consumption and high reproduction efficiency, but because of high investment, high cost and complexity of technical steps, especially the production should not be directly used in vitro.Till now, there was no successful cultivate seedlings by tissue culture.5,The rooting ability of feijoa is obviously influenced by substrates, growth regulators and treatment concentration.From strong to less, the influencing order of factors to rooting length is substrates>type of growth regulators>treatment concentration, factors to rooting number is type of growth regulators>treatment concentrationand>substrates and factors to rooting rate is treatment concentration>type of growth regulators>substrates. The best combination selected was pearlite+humus soil, the DBA, 1000mg.L-1 and 10 s treatment. The rooting rate reached 95.2%. The average root number was 4.4 and the root length was 14.3 cm.The rooting ability of feijoa is obviously influenced by the age of the ortet, cutting period and cutting position. In terms of the influencing intensity, the influencing order of factors to rooting length is the age of the ortet > cutting position > cutting period, factors to rooting number is the age of the ortet > cutting period > cutting position and factors to rooting rate is the age of the ortet > cutting period > cutting position. The best combination selected was one-year old ortet, downside and June 20 treatment. The rooting rate reached 97.7%. The average root number was 5.6 and the root length was 17.1 cm.The rooting ability of feijoa is obviously influenced by reproduction methods and maturity. The rooting ability of semi-lignified cutting from 2-year-old was the best. The rooting rate reached 78.95%. The average root number was 6.67 and the root length was 15.80 cm.It is suitable for cutting of feijoa in Summer, and quickly dipping the cuttings into 1000 mg.L-1 of IBA with 10s befor cutting has a good result. The suitable combination of hormone is IBA 1000mg.L-1 + NAA 500mg.L-1.6,No significant correlation could be found between the rooting rate and anatomical structure of the cutting from mother trees of different age, but there are differences in anatomical structure between hardwood and softwood cuttings from mother trees of the same age, which may be the reason that hardwood is different from softwood in rooting characteristics.The adventitious root primordium of feijoa cuttings is a type of induced root primordium. This adventitious root primordium originates from the junction of the vascular cambium and pith rays. There were cyclical and sequential sclerenchyma cells in the phloem and no root primordium in the stems. The adventitious roots generated from the verge of the cut section to 0.1 to 2 cm above the cut. Callus does not differentiate into root primordia.These structural features may be one of the main reasons that feijoa cuttings had low rooting rate.7,During the cuttage, the content of soluble protein, soluble sugar, tannin rose firstly and then dropped, rose firstly and then dropped, rose all the time, respectively. The activity of POD and PPO enzyme rose firstly and then dropped, took on double peak curve, respectively.During the cuttage, the content of soluble protein, soluble sugar and tannin, the activity of POD and PPO enzyme consumption were consonant with the time of callus and variable roots production, respectively. The results showed that there was a close connection between the indexes of physiologyand the production of callus and adventitious roots.
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