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Attempts were made for characterizing eleven banana (Musa AAB Plantain
subgroup) clones at molecular level during January 2000 to October 2001 at the
Department of Pomology and Floriculture and the Plant Molecular Biology and
Biotechnology Centre, College of Agriculture, Vellayani. Tissues from fully unfurled
leaves of the clones, were used for isolating DNA, using modified Walbot's method.
Storage of leaves at -SYC did not affect either the DNA yield or purity ratio. Gel
elctrophoresis using agarose concentrations of 0.09 per cent and 1.4 per cent were the
best for visualizing the genomic DNA and RAPD pattern, respectively. The best voltage
level was 75 V. TBE buffer could produce better separation of bands compared to TAE
buffer. Twenty nanogram of DNA, 200 IlM each of dNTPs, 0.6 units Taq DNA
polymerase and 5 pM primer in presence of the assay buffer gave good PCR
amplification results. The programme consisted of an initial denaturation at 95°C
for 3.0 minutes, followed by 45 cycles of denaturation at 95°C for 1.0 minute,
annealing at 36°C for 1.0 minute 30 seconds and extension at 72°C for 2.0
minutes. The synthesis step of the final cycle was extended further by 6.0
minutes. The products of .ampl ification were kept at 4.0°C until attended. One
hundred and six RAPDs were generated when PCR amplification was carried out using
forty decamer primers (Operon Inc., CA, USA) of kit A and kit B. Of these, 100 bands
were polymorphic which accounted to an average of 2.5 polymorphic bands per primer.
Eight primers (OPA-OI, OPA-03, OPA-13, OPB-OI, OPB-06, OPB-lO, OPB-12 and
OPB-IS) produced reproducible banding patterns on at least two runs. These primers
yielded 42 scorable bands with an average of 5.25 bands per primer. The amplification





products ranged in size from 400 to 1500 bp. The number of bands resolved per
amplification was primer dependent and varied from a minimum of three to a maximum
of nine. Reproducible bands were scored for their presence (+) or absence (-) for all the
plantain clones studied. A genetic similarity matrix was constructed u~ng the Jaccard's
coeffecient method. The pairwise coefficient values varied between 0.3333 and 0.9355.
The least similarity coefficient values were those of Zanzibar with Changazhikodan and
Manjeri Nendran (0.3333). The highest value for similarity index was obtained for
Koonoor Ethan - Quintal Banana pair (0.9355), followed by Manjeri Nendran -
Myndoli pair (0.8889). The next value was for the Kaliethan - Koonoor Ethan
pair (0.8529). Based on the similarity coefficients, distances between the clones
were computed using SYSTA T software package. The distance was the least
between Koonoor Ethan and Quintal Banana (0.042), followed by Manjeri
Nendran and Myndoli (0.06). Zanzibar and Mysore Ethan showed the greatest
distance (0.349), followed by Mysore Ethan and Padalamurian (0.167). In the
dendrogram constructed by the nearest neighbour (single-link) method
(Krzanowski, 1988), all the eleven plantain clones were found grouped under
five clusters. Attu Nendran, Changanasseri Nendran, Changazhikodan, Kaliethan,
Koonoor Ethan and Quintal Banana formed the largest cluster. Manjeri Nendran
and Myndoli formed the second cluster. Padalamurian, Mysore Ethan and
Zanzibar formed three separate clusters. Zanzibar, belonging to 'Horn Plantain',
was different from the rest of the clones. Quintal Banana and Myndoli, which
were considered to be identical, got grouped under two different clusters.