Quality of Seeds of Upland Rice Lines Adapted to the State of Minas Gerais, Brazil

In the final stages of a plant breeding program, a crucial step is the multiplication of seeds in production fields. Besides a solid planning, the seeds multiplication needs a special attention to guarantee seeds with high quality, genetic integrity, high germination and vigor to the farmer. The aim of this study was to evaluate the physiologic quality, enzymatic expression and respiratory activity of seeds of 20 elite upland rice lines adapted to the state of Minas Gerais, Brazil, from the upland rice breeding program from three Brazilians research institutions. The quality parameters evaluated were root protrusion, number of normal seedlings in the germination test, number of normal seedlings in the germination first count, initial stand from emergence test, speed of emergence index, seedlings shoot and root length, percentage of O2 and CO2 from respiratory activity and the expression pattern of the enzymes alcohol dehydrogenase (ADH) and malate dehydrogenase (MDH). The seeds quality varied among lines, allowing the selection of lines with best performance. The respiratory activity was lower in seeds of lines with high quality. The enzyme ADH was an excellent marker to infer about the quality of seeds, and the variation in the expression of MDH did not depend on the quality of rice seeds. The lines BRS Esmeralda, CMG1896 and CMG1509 showed high physiologic quality in their seeds, and therefore, they should receive higher attention in rice breeding programs.

Phenotypic and Enzymatic Analyses of Upland Rice Lines Seeds under No-Tillage

Over 40% of the agricultural area in Brazil corresponds to no-tillage farming. Although it is evident the importance of obtaining upland rice cultivars adapted to this cropping system, researches in this sense are still incipient and breeders do not have cultivars available to recommend with enough security. The aim of this study was to evaluate phenotypic characters favorable to the no-tillage system in order to establish the basis for upland rice breeding programs interested in this cropping system. The seeds of twenty elite inbred lines from the Upland Rice Breeding Program from the Brazilian research institutions UFLA, EMBRAPA and EPAMIG were evaluated at the Central Seeds Lab from the Agriculture Department of UFLA following a randomized block design with four replicates. The characters evaluated were seedlings emergence (SE), green matter yield (GM), dry matter yield (DM), photosynthetic activity (PA), and superoxide dismutase activity (SOD). The quality parameters evaluated were obtained by a germination test (GT), germination first count (GFC), emergence test (E), initial stand (IS), and alpha-amylase expression. The lines CMG 2074, CMG 1967, CMG 2017, BRSMG Caravera and CMG 2097 showed higher SOD content in the enzymatic analyses, and consequently higher tolerance to abiotic stresses that could be caused by no-tillage. Considering the evaluation of agronomic traits, the line CMG 1967 showed the best performance in no-tillage soil and, therefore, should receive higher attention in Upland Rice Breeding Programs.