Selection of families obtained from caryopsis in a polyploid species (Saccharum spp.) using multicategory model

Abstract

Genetic diversity analysis is essential for sugarcane (Saccharum spp.) breeding programs. Crossbreeding based on genetic distances between the parental plants is one of the tools to increase genetic variability and enhance plant selection. The present study aimed to evaluate diversity within and between twelve families (A, B, C, D, E, F, G, H, I, J, K, and L) of sugarcane, derived from caryopses, using primers for sixteen microsatellite loci, five SSR (Simple Sequence Repeats) loci, and eleven EST-SSR (Expressed Sequence Tag-SSR) loci. Similarity calculations used the Bruvo`s distances among individuals and RST distances among families. The analysis of molecular variance (AMOVA) indicated that the majority of genetic variability is within families (72%), with only 28% found between families. The highest genetic similarity was observed between families E and I, while the lowest genetic similarity was between families K and D. Despite the high genetic similarity observed among the twelve sugarcane families in this study, the percentage of genetic variation within families in the 16 SSR and EST-SSR loci was high (72%), showing promise for exploitation in breeding programs to expand or restrict genetic variability in the selection of desirable morpho-agronomic traits in the crop. Furthermore, the study highlights the importance of using appropriate distances for diversity studies with co-dominant markers such as microsatellites in polyploid species.