Banca de QUALIFICAÇÃO: EULINA BRITO MARINHO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : EULINA BRITO MARINHO
DATE: 25/09/2026
TIME: 09:00
LOCAL: Sala 34 do ICBS
TITLE:

Advancement of segregating generations and selection of superior red rice lines based on agronomic traits and genetic divergence using SSR markers

KEY WORDS:

Phenotypic selection; Molecular characterization; Genetic variability.

PAGES: 35
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Melhoramento Vegetal
SUMMARY:

Red rice has attracted growing interest due to its higher nutritional value, distinctive organoleptic characteristics, and market expansion, underscoring the need to develop new lines with improved agronomic performance. Advancing segregating generations and using molecular markers—specifically microsatellites (SSR)—are efficient strategies for exploring genetic variability, identifying superior genotypes, and supporting decision-making in breeding programs. Thus, the objective of this study is to select superior red rice lines derived from the segregating generations of the ‘BRS Esmeralda’ × ‘Vermelho Virgínia’ cross, combining phenotypic selection with molecular characterization. To this end, greenhouse trials will be conducted using a randomized complete block design (RCBD) with three blocks to evaluate 21 morphological traits related to plant stature, yield, and grain characteristics; laboratory analyses will also be performed to confirm existing variability in the segregating generations and complement the phenotypic selection. The trials will be divided into three stages: 1) This stage involves evaluating the genetic control of agronomic traits and selecting individual plants within the segregating generations. The trial will comprise seven treatments: two parents, two checks, the F1 hybrid (5 pots per treatment per block), and the F2 and F3 generations (five rows per generation, with ten pots per row, per block). A total of 375 plants will be evaluated, comprising 75 plants from the parents, checks, and F1, and 300 plants from the segregating generations. Analyses will include ANOVA, Tukey’s test, and the estimation of variances and genetic parameters. Phenotypic selection in the F2 and F3 generations will employ a 20% selection intensity, resulting in the selection of 60 superior plants. These plants will serve as treatments in the subsequent phase of the experiment. 2) Comparison of means across generations, parents, and checks, and management of selected families. In this stage, 60 previously selected families, along with parents and checks, will be evaluated—totaling 64 treatments arranged in a Randomized Complete Block Design (RCBD) with three replications, resulting in 192 experimental units. ANOVA and mean grouping using the Scott-Knott test will be performed. Subsequently, a selection index (Smith, 1936 and Hazel, 1943; Mulamba and Mock; or Pesek and Baker, 1969) will be applied with a 30% selection intensity, resulting in the selection of the 18 superior families. 3) Genetic divergence analysis using SSR molecular markers. Parents and plants from the F2 and F3 generations will be characterized using SSR markers, involving estimates of genetic diversity and polymorphic information content, as well as dendrogram construction via UPGMA (Unweighted Pair Group Method with Arithmetic Mean). The aim is to identify promising genotypes with high yield, improved plant architecture, and superior grain quality, while also confirming their genetic divergence through SSR markers. The superior materials obtained may support subsequent evaluation phases and contribute to the development of future red rice cultivars.

COMMITTEE MEMBERS:
Presidente - 2271445 - BRUNA RAFAELA DA SILVA MENEZES
Externa ao Programa - 2147409 - MARILENE HILMA DOS SANTOS - UFRRJExterna ao Programa - 3470085 - TATIANA DE OLIVEIRA PINTO - UFRRJ