Predictive approach to optimize the number of visual graders for indirect selection of high-yielding Urochloa ruziziensis genotypes

• Published in: Crop breeding and applied biotechnology Vol. 20; no. 3
• Main Authors: Fonseca, Jales Mendes Oliveira, Nunes, José Airton Rodrigues, Gonçalves, Flavia Maria Avelar, Souza Sobrinho, Fausto de, Benites, Flávio Rodrigo Gandolfi, Lima Teixeira, Davi Henrique
• Format: Journal Article
• Language: English
• Published: Vicosa Crop Breeding and Applied Biotechnology 2020
• Subjects: AGRONOMY; BIOTECHNOLOGY & APPLIED MICROBIOLOGY; Genetic diversity; Genetic variance; Genotypes; Optimization; Phenotyping; Plant breeding; Urochloa ruziziensis; accuracy; forage breeding; visual selection; Brachiaria ruziziensis
• ISSN: 1518-7853; 1984-7033; 1984-7033
• DOI: 10.1590/1984-70332020v20n3a48

Forage plant breeders often use visual scores to assess agronomic traits because of the costs associated with in-depth phenotyping in the initial stages of breeding cycles. The aim of this study was to investigate the impact of the number of graders on the effectiveness of indirect selection of high-yielding genotypes and determine an optimal number of graders in the early-stage trials of Urochloa ruziziensis. For that purpose, five graders assessed 2.219 U. ruziziensis genotypes in an augmented block design. Biomass production and vigor scores were evaluated in two cuts and were analyzed using a linear mixed model approach. Vigor scores were analyzed considering each grader’s score and the combinations of two, three, four, and five graders. Genetic variance was significant for both traits. Visual evaluation was effective in identifying productive genotypes based on the statistical criteria. The optimal number of graders for indirect selection of high-yielding U. ruziziensis genotypes is three.