Seleção de genótipos de sorgo cultivados sob estresse hídrico

Abstract

Sorghum belongs to the family Poaceae. The genus Sorghum is characterized by spikes that grow in pairs. It is an annual plant, although it is a perennial herb, in the tropics, it can be harvested several times a year. Sorghum is one of the most commonly found cereals in the world, in Brazil it is cultivated in several states, mainly in the Midwest and Southeast regions, 88% of national production. For the total harvest 2020/2021, the estimate is 2, 3 million tons produced, in an area of 864.5 thousand hectares. The objective of this research was to evaluate the development of sorghum genotypes under water stress conditions, through physiological, chemical, and vegetative growth analyses, to select the best-acclimated genotype(s) to stress. The trial was conducted at Embrapa Semiárido, located in Petrolina – PE, from September to November 2020. 112 pots of 21 liters, 38 cm long and 38 cm deep. The experimental design was completely randomized in four blocks with a factorial arrangement of 7 x 2, distributed as follows; seven sorghum genotypes, two water regimes (irrigated and stress), and two collections, four replicates. The following growth variables: plant height (HEIGHT) (cm), shoot dry mass (SDM) (g), root dry mass (RDM) (g), shoot nitrogen content, Fluorescence with the following components, Fv´/Fm´ (Photosystem Effective Quantum Yield), PhiPS2 (Photosystem II Effective Quantum Yield), qP (Photochemical Extinction Quenching) and ETR (Electron Transport Rate) and Gas Exchange with the following components, Photo (Photosynthesis) (μmol CO2 m-2s-1), Cond (Stomatic Conductance) (gs) (mol H2O m-2s-1), Trmmol (transpiration) (mmol H2O m-2s-1) and Vpdl (deficit of water vapor pressure between the sheet and the atmosphere). In a general analysis, the best genotype acclimated to water stress was Volumax, about vegetative growth the best genotypes under water stress conditions were Volumax and IPA SF15 and for nitrogen content, the best genotypes were Agri 002E and IPA SF15.