Isozyme marker based estimation of genetic diversity
among 49 parental clones used in sugarcane varietal
development was carried out using peroxidase, esterase
and phosphorylase systems. Based on similarity index
values, all 1176 possible parental combinations were
categorized into high, medium and low diversity groups.
Maximum number of combinations showed medium
diversity (51 = 0.60 to 0.80) reflecting the existence of
moderate genetic diversity in sugarcane parental clones.
Selection percent per cross, based on H.R. Brix, cane
diameter and single cane weight, calculated in 14 crosses
belonging to all the three groups in the 1st clonal trial,
was correlated with similarity index. A significant negative
correlation (-0.6221) was observed between them.
Selection percent was lower in the combinations with
high 51 values (above 0.80) compared to the other two
groups indicating the importance of diversity information
in indirectly identifying less productive combinations.
Moderate levels of diversity. were sufficient to generate a
higher proportion of selectable types, as selection % did
not improve with increasing diversity. Thus isozyme
analysis of parental clones provided useful information
in identifying and thereby avoiding genetically more similar
combinations, which would otherwise lead to close
breeding. Use of more efficient marker systems is needed
to identify heterotic cross combinations and to predict
progeny performance in sugarcane.
Keywords: Sugarcane, isozyme diversity. parental clones, cross combinations, selection per cent, similarity index
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906
G. Hemaprabha, U. S. Natarajan and N. Balasundaram info_circle