Development of tissue culture and transplanting techniques of avocado and its application to mutation breeding
2015
Avenido, R.A. | Pateña, L.F. | Carandang, J.M. | Pamiloza, R.P. | Dimaculangan, J.G. | Barba, R.C.
Conventional breeding of avocado is impeded by its long juvenile period, low fruit set and inefficient breeding techniques, among others. Biotechnology, including genetic engineering and mutation breeding, has great potential for improving and facilitating the development of new avocado varieties. The success of biotechnology for improving avocado is highly dependent on efficient in vitro plant regeneration system and soil and field transplantation scheme of tissue-cultured plants. This paper presents the complete micropropagation system of avocado from somatic embryogenesis to field transplant and its application to mutation breeding. Somatic embryogenesis using immature fruits in Woody Plant (WP) medium was up to 10-40% depending on the variety. Plantlet regeneration increased from subculture cycle 1, SC1, (1.73%) to SC3 (7.80%). Prolonged maturation period and exposure to dark condition had no significant effect. Proliferation of embryogenic cultures was significantly reduced when exposed to 20 and 30 gamma-irradiation. Growth of regenerated shoots was very low, thus, micrografting was done with low success. In vitro rooting of shoots was found as best alternative to produce complete plants. The best rooting medium for non-irradiated and gamma-irradiated (50 and 83% rooting, respectively) shoots was the Barba and Pateña medium. Faster root induction was observed in gamma-irradiated shoots. Dipping the shoots and rooted plants in BIOTECH's BioGroe powder had no significant promotive effect on root development and survival. Five regenerations were successfully transplanted to the field. However, one regenerant was destroyed by typhoon Glenda. Surviving regenerants are being prepared for evaluation of characters using both molecular and horticultural markers.
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