Seleção de famílias e clones de Saccharum spp. para obtenção de cana energia

Abstract

Sugarcane biomass has gained attention due to its versatility in uses and is seen as a sustainable source of energy, highlighting the generation of energy by burning sugarcane bagasse and fuel ethanol, which together represent 17.5% of the energy consumed in Brazil. Sugarcane biomass is considered one of the most profitable for generating electricity, reducing the use of fossil fuels and the emission of greenhouse gases. However, the development of varieties of energy cane has not yet reached large scale by producers and large improvement programs. Given this reality, the objective of this work was to identify the best combinations of parents and optimize the process of early selection of energy cane clones and select clones with high fiber contents to introduce them into the active germplasm bank. Twenty-seven crossings were performed, nine of which were biparental, nine were crossroads and nine were self-made. Comparison studies were carried out between methods and obtaining, planting and conducting seedlings. Genotypic values and variance components of families and individuals were estimated from the main production components and agro-industrial characteristics, using the mixed model methodologies REML / BLUPIS and BLUP-seq as a genetic-statistical tool. Correlation studies were also developed using the Spearman and Pearson methods, and the Hamblin and Zimmermann coincidence index estimates to verify the efficiency of early selection. It was verified that: the height of the plants can be used as a parameter for early selection of the best families still in the seedlings production phase; conducting populations by the classical method favors the growth and greater uniformity of the plants; in the SA method, plants are more vulnerable to competition for space, water, light and nutrients. However, it allows greater use of area, seeds and greater exploitation of genetic variability; the crossroads with the female parents IN 84-58 (C14) and PRBIO 371 (C13), as well as the two-parent crossings PRBIO 353 x PRBIO 273 (C8) and PRBIO 264 x PRBIO 182 (C7) are the most indicated among those studied for new sugarcane crossing campaigns. The indirect selection to increase the fiber contents via soluble solids content is not efficient; there was little difference between the genotypic expression of the variables evaluated in the classical methods and the advance selection; there was little difference between the genotypic expression of the families evaluated between the classic methods and the advance selection; there is an indication of greater genetic gains from the previous selection of families and subsequent individual selection; the grouped planting of seedlings in the advance selection method favors the selection of a larger number of individuals within families in the same physical space; the C1, C2, C4, C5, C7, C10, C12, C15 and C16 families are the most suitable for genotypic selection to increase fiber levels; the accessions Co285, PRBIO150, PRBIO163, PRBIO215, PRBIO221, PRBIO273, PRBIO298, PRBIO353, PRBIO371 and PRBIO392 are the most suitable for genotypic selection to increase fiber levels, and may have their combinations repeated and / or recombined among themselves.