Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract only
Publication Acceptance Date: 3/3/2006
Publication Date: 6/1/2006
Citation: Edme, S.J., Suman, A., Kimbeng, C. 2006. Temporal changes of genetic diversity in sugarcane breeding populations. [abstract]. American Society of Sugar Cane Technologists. 26:44 2006 Interpretive Summary:
Technical Abstract: Concerns about decline of genetic diversity in sugarcane (Saccharum spp.) breeding programs need be addressed to define better breeding strategies aimed at achieving greater genetic gains. The objectives of this study were to reconstruct the divergence in the Canal Point breeding populations as temporal changes from early (1960) to recent (1999) years. A replicated field test was established in March 2005 at the Canal Point Station with 61 sugarcane genotypes, encompassing historical cultivars released from 1960 to 2000 along with a set of wild relatives included as representative founders of this population. These genotypes were divided into five populations or decades and characterized phenotypically and with molecular markers as sucrose-related target region amplification polymorphism (TRAP). A multivariate nonparametric approach was used to assess the spatial (temporal) autocorrelation of genetic divergence based on the TRAP profiles. An increase in % polymorphism was detected from the first decade (26.4) to the last decade (56.15) using the TPAP markers with an overall polymorphism of 58.3%. Genetic distance ranged from 0.04 (CP 95-1039 and CP 70-1133) to 0.30 (CP 99-1542 and CP 98-1335) with an average of 0.22. Significant and positive genetic structure was detected up to the second decade of breeding when spatial autocorrelation revealed a decline in genetic diversity. The CP breeding population has maintained a relatively constant (but a negative spatial autocorrelation) level of genetic diversity since then. Marker-trait associations will be presented and spatial autocorrelation relating genetic distance with the phenotypic data will be also investigated. These results will be discussed in the context of sugarcane breeding strategies, relating introgression breeding with the size of the genetic diversity.