Saturday, May 16, 2015
MICROPROPAGATION OF BANANAS
MICROPROPAGATION OF BANANAS is considered a new technology introduced in banana industry. The scientist has reported in vitro culture of banana. Shoot-tip culture in combination with heat therapy was successfully used to produce virus-free banana plants as well as for mutation induction. Several reviews have been written on the in vitro culture techniques for different applications. The shoot-tip meristem culture technique is used routinely for large-scale propagation of bananas in Malaysia. Currently, commercial production of micro-propagated banana plants in Malaysia is estimated at around 1.3 million. The commercial micro propagation protocol has been successfully modified to bring soma-clonal variation down to 0.5%. There are several advantages of tissue culture-derived banana plants, such as vigorous growth, high survival rate, uniformity, and high flowering rate (90% of plants flower compared with 59% of plants produced from suckers). This shortens the harvesting period by about 2 months. Reduction in the cost of micro-propagation has been achieved by using locally made culture containers, and by replacing tissue-culture grade sucrose with commercial cane sugar, and Gelrite with locally available agar. We also found that the multiplication rate could be enhanced by 33% by using liquid or semi-liquid media instead of solid medium. We could also achieve rooting by placing plantlets in a hydroponic system in the greenhouse; the resulting rooted plantlets needed a shorter period of hardening. Other cost reduction strategies particularly the use of sunlight, should be pursued to reduce the current production cost further.
EXPLOITATION OF SOMACLONAL VARIATION
The occurrence of off-type plants, commonly known as soma-clonal variants is relatively common in in vitro plants. Usually, most of the soma-clones are undesirable from agronomic point of view. Nevertheless, the phenomenon is useful in generating genetic variation for banana improvement with continuous selection of soma-clones for earliness from tissue culture-derived commercial plantings of Pisang Berangan, the proportion of plants showing earliness in flowering increased gradually from 16% to over 60% at 8 months of planting. This means that at about 11 months after planting, 66% plants were ready for harvest compared with 4% for sucker material and 16% for unselected tissue-cultured plants. Secand by using tissue-culture-derived plants, 27% of Pisang Rastali (one clone) survived for more than 3 years in the Fusarium wilt-infested field, while all other clones planted at the same time had succumbed to the disease. Dissection showed the symptoms of Fusarium infection at the base of the corm tissue. The vascular discoloration was arrested 20-30 cm above the base. The continuous selection of tolerant plants has resulted in the release of a Fusarium wilt-tolerant clone of Pisang Rastali called Mutiara. This report obtained from few result from lab and commercial lab producing planting material in banana industry.