ORIGIN, GENETIC DIVERSITY, CONSERVATION AND TRADITIONAL AND MOLECULAR BREEDING APPROACHES IN SUGARCANE

CURSI, D; CASTILLO, R.O; TARUMOTO; RACEDO,J; PERERA, M. F.; SAMPAIO C. M.

Genetic diversity, erosion, conservation, and utilization - Cash crops"

Springer

Año: 2021; p. 83 - 116

Modern sugarcane cultivars are highly polyploid and have giant genomes (10 giga-bases (Gb)) derived from interspecific hybridization between the cultivated species S. officinarum L. and the wild species S. spontaneum L. Genetic resources could be useful for developing new varieties, and therefore, plant breeding programs are assembling a germplasm collection to increase the number of possible novel gene combinations. The use of wild relatives in sugarcane breeding started at the beginning of introgression during the nobilization process, and it is still used in breeding programs primarily to search for varieties that are more tolerant to biotic and abiotic stresses. The success of a traditional sugarcane breeding program relies on several factors, among which the appropriate parental selection must be made to maximize the chance of genetic enhancement. This choice will be determined by the short- and long-term goals, the availability of materials, flowering synchronism, breeding values and the amount of data available from any parent or combination. In general, the process of developing a new cultivar is long and complex. Genetic resistance to diseases has been successfully achieved through traditional breeding, although this approach is challenging and takes a long time. Several studies have been conducted to unravel and understand the genetic basis of disease resistance and complex traits (e.g., sugar and fiber, among others) through QTL and association mapping. In recent decades, important advances have been made in understanding the sugarcane genome and the gene expression associated with agronomic traits. Furthermore, transgenic sugarcane has been produced in several countries, and there have been numerous initiatives to employ genome editing technology. New breeding technologies and strategies are required to boost genetic improvements significantly in future crop cultivars. Genomic selection has the potential to increase the rate of genetic gain significantly in sugarcane, primarily by (i) reducing the breeding cycle length, (ii) increasing the prediction accuracy for clonal performance, and (iii) increasing the accuracy of the breeding values for parent selection. This chapter describes the origin, genetic diversity, conservation and traditional and molecular breeding approaches associated with sugarcane.