番木瓜扦插繁殖及生長結實特性之研究

Studies on the Propagation and Growth, Fruiting Characteristics of Cutting of Papaya (Carlca papaya L.)

番木瓜（Carica papaya L.）以其30～40cm之側枝，經2,000ppm IBA處理所培育之扦插苗，於秋作九月種植後，經63天的生長即可開始陸續開花，比實生苗提早133天，始花高度僅33公分，而實生苗則為115公分，所結果實性狀與原來母株一樣，但平均單果重增加100公克，甜度相近，可達16.1°Brix，植株之生長，於定植後126天以內比實生苗旺盛，之後即無差異。側枝之培養及發根，以夏季最容易，秋冬季較困難，周年生產供應有問題，且1株母株側枝的繁殖率1年平均僅24支。如以組織培養扦插苗種植栽培，除可與側枝扦插苗的生長特性一樣外，其繁殖相當快速，由莖頂培養初生叢生枝做為增殖體後，增殖體再行繼代培養，可依6X14n（n為繼代數）之速率增加，繼代間相隔約3星期，由增殖體繼代培養過程中所生長之叢生枝，可取其1.5～2.0公分長的頂梢進行扦插，依0.5PPm IBA之誘導生根可有80%的發根率，則組織培養扦插苗的繁殖可依2.4X14n的速率增加，其繼代期間為3星期。本研究將針對番木瓜以側枝扦插及組織培養扦插二種繁殖方式，分別探討並說明其方法、生長特性及比較其優劣點。

The papaya cuttings, propagated from lateral shoot with 2,000 ppm IBA treatment for rooting, were grown in September to elucidate the plant characteristics, fruit yield and quality. Field cutting plants have been characterized by excessive vegetation within 126 days after planting and reduced juvenile stage for 133 days. Young trees have grown vigorously and set flower and fruit at 33 cm above ground or 63 days after planting. Seedling, when planted in this environment in September, have a juvenile section of 115 cm high before flowering. Daughter plants are same of the sex and should also have the same fruit of excellent quality as the parent plants from which the cuttings are taken. Comparied with autumn or winter season, parent trees can be cut back in summer to encourage lateral shoot production and hasten root formation easily. However, only a total of 24 lateral shoots can be taken from parent tree per year. The microcuttings on the other hand, obtained from 1.5~2.0 cm shoot tip of tissue culture multiple shoot with 0.5 ppm IBA treatment for rooting, were also grown in September and have the same plant growth characteristics with higher fruit yield as cutting. The micropropagation effeciency of papaya was the best on this studies than before. The primary multiple shoot in vitro 6 cm high, cultured from apics of field growing plant on transplanting medium, were dissected into double-node segment and culture for 3 weeks on multiplication medium. 5~7 multiple shoots that have developed from segment were dissected into double-node segment and culture on the multiplication medium again, giving a multiplication rate of 6 X 14n (n = no. of subculture) in 3 weeks. Meanwhile, the shoot tips 1.5~2.0 cm long can be cut from multiple shoot and cultured on rooting medium containing 0.5 ppm IBA for 3 weeks, giving a rooting percentage of 80% and multiplication rate of 2.4 X 14n in 3 weeks. Ultimately, the papaya microcuttings with tissue culture were more available than lateral cuttings and seedlings.