Banana Male Flower In Vitro Regeneration
Abstract
The present study was undertaken with a view to establish a protocol on in vitro regeneration of plants by using young male flowers of banana (Musa sp. cv. Sabri) as explant. Appropriate developmental stage of immature male flowers for inoculation, medium composition for induction of calli, regeneration of plants, rooting of in vitro regenerated shoots, acclimatization of in vitro regenerated plantlets and ex vitro establishments of plantlets were worked out. Young male flowers obtained by striping away the bracts in between 24 to 26 were found suitable as explants for induction of callus. The isolated male flowers were cultured on MS (Murashige and Skoog) medium supplemented with different concentrations and combinations of three auxins viz. 2, 4-D (2,4-Dichlorophenoxyacetic acid), NAA (Napthaleneacetic acid) and IAA (Indole-3-acetic acid) for induction of callus. Only two of the two medium composition yielded calli. The better response (20%) was recorded in MS medium containing 2.0 2, 4-D + 0.5 NAA + 0.5 IAA (Indole-3-acetic acid) (mg/l). The calli were cultured on MS medium fortified with different concentrations of BA (Benzyladenine), NAA, IAA and Glutamine or Caesin hydrolysate (CH) to regenerate shoots. MS medium having the supplementation of 1.0 BA + 0.5 IAA + 500 CH (mg/l) was appeared best for regeneration of shoots. Single isolated regenerated shoots were implanted on MS medium supplemented with three different concentrations (0.5, 1.0 and 2.0 mg/l) of IBA or NAA to induce root. IBA at a concentration of 1.0 mg/l produced best rooting. The plantlets were gradually acclimatized and transferred to the soil. The survival percentage was about 90%.
Introduction
Banana is one of the most important and remunerative cash crops grown round the year in Bangladesh. The energy and nutritional status of banana are much higher than other common tropical and subtropical fruits. The average yield of banana is 14 t/ha, which is lower compared to other banana-producing countries in the world (Islam and Hoque, 2004). Higher yield of banana can play a pivotal role in the economy of Bangladesh. It is possible to increase the yield of banana by using disease free high yielding variety, modern technology of production as well as post harvest management. Banana (Musa spp.) is one of the most important nutritious fruit crops of the world and grown in many tropical areas where they are used both as a staple food and dietary supplements (Assani et al., 2001).
In our country, Sabri (AAB) is the second important commercial cultivar of banana after Amritsagar (AAA) (Islam and Hoque 2004). However, cultivar Sabri is highly susceptible to panama disease (Fusarium wilt) caused by Fusarium oxysporum ssp. cubense. So, there is a scope to improve this variety by the development of somaclonal variant through indirect oraganogenesis. Most of the edible bananas are sterile polyploids and must be propagated vegetatively. So, genetic improvement of this plant through cross breeding is an insurmountable task. Tissue culture technique using shoot or meristem tips are suitable for large-scale production of uniform and vigorously growing propagules for field establishment. The combination of mutation breeding and in vitro culture has been suggested as an alternative approach for banana improvement (Novak et al., 1990). However, the main limitation of this technique is the high degree of chimerism. Repeated vegetative propagation is needed to dissociate chimeras, but the minimum requiring number of cycles is unknown (Roux, 2004). So, somaclonal variation may be an alternative option for the improvement of banana ( A.H. Kabir et al., 2008; Nasrin,S. et al., 2003; Denise M. Seliskar et al., 2000; Larkin, P.J. et al., 1981;). Keeping the above significant points in mind, the present research aimed at regenerating plants through indirect organogenesis in banana by using young male flower buds as explants. The specific objectives of the present study are (i) to find out suitable stage of development of male flower bud as explant, (ii) to optimize growth regulators in culture medium for induction of calli and for shoot regeneration from calli, (iii) to optimize auxins in the culture medium for induction of root in regenerated shoot, and (iv) to acclimatize, harden and establishment of the plantlets in the soil.
Source : Banana Male Flower In Vitro Regeneration | InformativeBD
