PHYSIOLOGICAL STUDIES ON BANANA PLANT USING MODERN BIOTECHNOLOGY

Abstract

Bananas and plantains are important staple food crops for people living in tropical and subtropical countries (Lee et al., 1997). In Egypt, the overall average of banana reached about 53607 feddans produced about 72899 tones of edible fruits (Ministry of Agric., A.R.E., 1999).

Banana and plantains are herbaceous monocots belonging to the genus Musa, most are seedless, sterile and clonally propagated by suckers. The genus Musa contains many members and has a complicated taxonomy (Kshanika and Niranjali, 1997). Edible cultivars are inter-specific hybrids of the two wild diploid species (2n -2x=22), Musa accuminata (AA) and Musa balbisiana (BB) (Simmonds and Shepherd, 1955 and Rowe, 1984). The interspecific hybrids (cultivars) have been grouped according to the contribution to the ploidy of the two wild species. Musa accuminata providing the "A" genome and M balbisiana providing the "B" genome. The resulting hybrids are designated (AA, AB, BB, AAA, ABB, BBBB and AAAA) (Stover and Simmonds, 1987). Williams, however, is belonging to AAA genomic group (2n- 3x=33) (Okole and Schulz, 1996). In addition, almost all edible bananas are triploid (Kshanika and Niranjali, 1997). Environmental stress in arid and semi-arid areas, mainly drought and salinity limit growth and productivity of most species (Shin et al., 2000). The excess of salt in the soil or in the irrigation water is one of the biggest problems in agriculture since almost all cultivated plants are sensitive to it (J6se et aL, 2000). In addition, a large percentage of the world's crops are exposed to chronic or sporadic period of drought (Boyer, 1982) even in the absence of drought the limiting amount of rainfall are primary determinants of crop selection and yield (Ludlow and Muchow, 1990). Thus, water deficit is one of the most common environmental