Bananas and plantains (Musa sp.) are major staple foods in many developing countries of the world. Although bananas are rich in carbohydrate, fiber, protein, fat, and vitamins A, C, and B6 they are largely deficient of iron (Fe), iodine, and zinc (Zn). A small increase in the micronutrient content of bananas could play a major role in combating disorders that are due to deficiency of mineral micronutrients such as Fe and Zn. The objective of this study was to determine the Fe and Zn content of 47 banana genotypes from a germplasm collection in Uganda using atomic absorption spectrophotometry. The Fe and Zn content showed wide variability and highly significant differences (P < 0.001) within and among the different banana categories selected for this study. The highest average Fe content (1.42 mg/100 g) was found in ‘Saba’ (ABB) while the least Fe content (0.06 mg/100 g) was found in ‘Kikundi’ (AAA). The highest average Zn content (1.21 mg/100 g) among the analyzed accessions was found in ‘Kivuvu’ (ABB) while Zn was not detectable in both ‘Kabucuragye’ (AAA) and ‘Grand Naine’ (AAA). Considering these figures, there is a greater than 20-fold variation in the Fe and Zn levels of the banana genotypes used this study suggesting that genetic improvement of genotypes for enhanced micronutrient levels may be achieved by breeding.
Meiotic studies in Musa L. have been hampered by: 1) time-consuming efforts required to find the correct stages of cell division; 2) rigidity of the microsporocyte cell wall that makes preparation of smears difficult; and 3) poor staining of prophase chromosomes. This study describes an improved technique to examine meiosis in Musa. The procedure involves dissection of microsporocytes from the anthers, centrifugation to obtain large number of microsporocytes, enzymatic digestion of cell walls and treatment of cells with acetic-alcohol that results in spontaneous bursting of the protoplasts and release of chromosomes. Previous meiotic studies in Musa used acetocarmine that stained only highly condensed metaphase and anaphase chromosomes easily but not the relaxed prophase stages. In this study, we found that silver nitrate, Giemsa and Leishmans' stain were also effective for staining Musa chromosomes. Silver staining was most effective for the less contracted prophase chromosomes. By providing an improved procedure to examine all the meiotic stages in Musa, this technique will be useful to develop pachytene karyotypes, characterize new hybrids and identify nuclear restitution mechanisms that are important in breeding schemes.