No abstract

Brazil is the world’s largest producer of sugarcane and one of the leading suppliers of sugar and ethanol worldwide. In the 2019–2020 crop season, the country produced 642.7 million tons of sugarcane in a harvest area of 8.44 million hectares. Historically, sugarcane breeding has contributed continuously to increasing yields by regularly releasing superior cultivars for use by the Brazilian industry. In the last 40 years, an average annual increase of 155.7 kg ha−1 of sugar yield has been reported, about half of which may be attributed to breeding programs. However, due to the size of the country, the intensive expansion of the crop to low-fertility soils in the last few years, especially in degraded pasture areas, and the widespread adoption of mechanization, new challenges have been imposed on national breeding programs. This review covers the current situation with sugarcane breeding in Brazil and the main advances that have allowed the country to maintain world leadership in developing the industry. Additionally, the history of sugarcane breeding, current national breeding institutions, germplasm development, key breeding objectives, selection stages and methodologies are summarized. An overview is also presented of biotechnological approaches which have become key tools for improving Brazilian traditional breeding programs. The adoption of strategies to increase Brazilian sugarcane yield, aiming to consolidate crop production in a food and energy matrix, is also discussed.

Sugarcane orange rust was recently introduced into Brazil and its control is based on the use of resistant varieties. This study aimed to determine the reaction of Brazilian sugarcane varieties to the disease in the field and to compare artificial inoculation methods. Rust severity was assessed in 17 varieties at a 15-day interval. The maximum disease severity (MS%) and the area under the disease progress curve (AUDPC) were determined for each genotype. The artificial inoculation methods tested were: spraying of a spore suspension on 60-day-old plants in the greenhouse, or placing the spore suspension into the leaf whorl of 5-month-old fieldgrown plants. Nine out of the 17 varieties studied were resistant to the disease, including the most widely grown in new plantings, RB867515 and RB966928. Varieties RB72454, SP89-1115 and SP79-2233 were susceptible, while RB925211 and SP81-3250 were moderately susceptible. Varieties RB855156, RB92579 and SP83-2847 showed an intermediate reaction. Both inoculation methods correlated well with field results. Spray inoculation discriminates better the responses of the varieties and enables the evaluation of more disease variables. Leaf whorl inoculation allows the use of field-grown plants and generates results in a shorter time.

Sugarcane is the main source for sugar production and the most important crop for energy production, as well as for byproducts like ethanol and fibers in the world. With a complex genome, the plant has its species from crosses between species of the genus Saccharum, which were the basis for sugarcane breeding programs worldwide. The production of sugarcane has increased worldwide due to breeding programs that have developed more productive clones for specific uses and adapted to different climatic conditions. The future objective of breeding programs is to develop sugarcane with high productivity, high sucrose content, drought tolerance, and high production of ethanol and biomass, i.e., plants with high fiber content and with cell walls easily broken to favor the production of ethanol from bagasse, efficient plants with low nitrogen fertilizer use, and others, and consequently to reduce environmental impacts. Currently, the demand for products derived from sugarcane is consistently increasing; the ethanol byproduct has been pointed out as one of the important sources to feed the demand for renewable energy in fossil and nonrenewable fuel substitution programs in different countries around the world. This chapter describes the genetic improvement of sugarcane and its current goals.