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Title: Breeding and selection of sugar cane (Saccharum hybrids) for specific adaptation to two contrasting marginal environments
Author: Bissessur, D.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 1997
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The study investigates the potential to breed and selective highly productive sugar cane varieties for specific adaptation to the two contrasting marginal environments, the extremely dry and wet zones. A partially balanced square lattice design with three replicates was used to evaluate 154 genotypes representing four families across the plant cane and first ratoon crops. The F x E and G x E interactions were determined using the mixed model analysis of variance. The genetic potential of the population was estimated in terms of genetic and phenotypic variances and coefficient of variations, broad-sense heritability, genetic advance, phenotypic correlation and multiple regression analysis. One-tailed tests at 25% significance level were used to select varieties more productive than a pool of controls. The F x E and G x E interactions for cane and sugar yield parameters were significant although the F x E less so than the G x E. The families and the genotypes were at their best under different conditions showing that the genetic background of a family is suited to one environment or to another. Consequently, the results suggest that selection strategies should aim at directed breeding as well as selection of families at each specific site. Mass selection was found to be more effective than family selection. Cane yield was the major determinant of sugar yield and stalk number the main component of cane yield. A multi-trait selection criteria comprising stalk number, height and diameter was found appropriate. The most suitable combinations for the dry environment had at least one parent adapted to the dry zone whereas for the wet zone previous adaptation of either one or both parents to the zone was of no advantage. Promising varieties, specifically adapted to each environment were successfully selected indicating that further improvement of sugar productivity is possible.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available