Abstract:
Calamansi (× Citrofortunella microcarpa Bunge.), also called ‘calamondin’ or ‘kalamansi’ in Tagalog and ‘limonsito’ in Cebuano, is the most important citrus fruit crop of the Philippines. A system for somatic embryogenesis and plantlet regeneration of this crop was developed for use in micropropagation, genetic transformation and in vitro conservation. Somatic embryos were induced using nucellar tissues from immature seeds cultured onto BP, Barba and Pateña, and MS, Murashige and Skoog, media, each with 20g/L sugar and 100 ml/L coconut water. Highest somatic embryo formation was observed in cultures in BP medium. Somatic embryo induction decreased as the fruit diameter increased. Somatic embryos were also induced from nucellar tissues cultured onto LMr medium (MS macro and micro, MT vitamins and amino acids with 1.0 mg/L each of kinetin and NAA, 2.0 mg/L BAP and 50 g/L sugar). Proliferation of somatic embryos was enhanced when subcultured onto Gp, Mp and Rp media (Gamborg’s B5, MS and BP media, respectively, with 0.5 mg/L 2,4-D, 400 mg/L glutamine, 60 g/L sugar and 100 ml/L coconut water). Maturation and germination of somatic embryos were observed in BP and MS media with 20g/L sugar and 100 ml/L coconut water. Plantlets developed in 3-5 weeks, were acclimatized and transplanted to soil. This system on somatic embryogenesis and plantlet regeneration in calamansi can now be used for micropropagation, genetic transformation and in vitro conservation studies.
Calamansi (× Citrofortunella microcarpa Bunge.), also called ‘calamondin’ or ‘kalamansi’ in Tagalog and ‘limonsito’ in Cebuano, is the most important citrus fruit crop of the Philippines. A system for somatic embryogenesis and plantlet regeneration of this crop was developed for use in micropropagation, genetic transformation and in vitro conservation. Somatic embryos were induced using nucellar tissues from immature seeds cultured onto BP, Barba and Pateña, and MS, Murashige and Skoog, media, each with 20g/L sugar and 100 ml/L coconut water. Highest somatic embryo formation was observed in cultures in BP medium. Somatic embryo induction decreased as the fruit diameter increased. Somatic embryos were also induced from nucellar tissues cultured onto LMr medium (MS macro and micro, MT vitamins and amino acids with 1.0 mg/L each of kinetin and NAA, 2.0 mg/L BAP and 50 g/L sugar). Proliferation of somatic embryos was enhanced when subcultured onto Gp, Mp and Rp media (Gamborg’s B5, MS and BP media, respectively, with 0.5 mg/L 2,4-D, 400 mg/L glutamine, 60 g/L sugar and 100 ml/L coconut water). Maturation and germination of somatic embryos were observed in BP and MS media with 20g/L sugar and 100 ml/L coconut water. Plantlets developed in 3-5 weeks, were acclimatized and transplanted to soil. This system on somatic embryogenesis and plantlet regeneration in calamansi can now be used for micropropagation, genetic transformation and in vitro conservation studies.
Authors: L.F. Pateña, L.E. Endonela, L.C. Refuerzo, R.C. Barba
Keywords: calamondin, tissue culture, immature seeds, nucellus, micropropagation
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