SCREENING OF IN VITRO PRODUCED BANANA PLANTS FOR SOMACLONAL VARIATION

The in vitro mass propagation of banana (Musa spp.) cultivar ‘Grand Nain’ was carried out in this work. Shoot tip explants were cultured on MS (Murashige and Skoog, 1962) basal medium supplemented with BA (3.0 mg/L), sucrose (3% w/v) and solidified with gelrite (0.2% w/v). Axillary buds were proliferated through two recultures and multiplied for 18 weeks (6 subcultures) on the same medium but solidified with phyto-agar (5.5 g/L). Isolated shoots were rooted on MS medium contained IBA (1.0 mg/L), sucrose (3% w/v) and solidified with phyto-agar (6.5 g/L). In vitro produced plants (40000) were screened for somaclonal variation during acclimatization, nursery and open field stages. Screening detected 1800 morphological malformed/abnormal plantlets after 6 weeks in acclimatization, these plantlets were grouped into 12 off-types. However, some of them (3 off-types) were rebounded and another one died in the nursery. Another abnormal plants (8 off- types) was newly appeared after 6 months in the nursery. Also, 3 off-types were rebounded and one died in the open field. Open field growth parameters were taken and survey detected 5 new off-types. Generally in all stages, the total detected variants were 3098 (7.75%), 1000 plant of them (2.5%) were rebounded and 202 plants (0.5%) died. Most of the variants can be screened out at the nursery stage; the remaining off-types (1.28%) only were detected in the open field. Further work using molecular markers will be done to demonstrate the abnormalities at the molecular level.