First Report of Recurrent Genomic Selection with Real Data in Popcorn and Genetic Gain Increases

Abstract

Recurrent Selection increases the frequencies of favorable alleles for economically important traits, which in the case of popcorn are popping expansion and grain yield. However, is time-consuming, since each selection cycle consists of three stages: progeny development and evaluation, and recombination of the best families. With the Recurrent Genomic Selection use, the time required for each selection cycle can be shortened, as it allows the evaluation and recombination phases to be performed simultaneously, reducing the time needed to complete one selection cycle to only one growing season. In this respect, the objective of this study was to determine the selection accuracy and genetic gains for different selection strategies: PhEN = estimates based exclusively on the phenotypic data of 98 plants; PhEN + GEN = estimates based exclusively on the phenotypic and genotypic data of 98 plants; and GEN = estimates based exclusively on SNP marker genotyping. The following traits were evaluated: 100-grain weight, ear height, grain yield, popping expansion, plant height, and popcorn volume. Field trials were carried out with 98 S1 progenies, at two locations, in an incomplete block design with three replications. The parents of these progenies were genotyped with a panel of ~ 21K SNPs. From the results based on the predictions by strategy GEN, at different selection intensities, the average annual genetic gain for the different traits was 29.1% and 25.2% higher than that by the strategies PhEN and GEN + PhEN for 98 selection candidates; 148.3% and 140.9% higher for 500; and 187.9% and 179.4% higher for 1,000 selection candidates, respectively. Therefore, recurrent genomic selection may result in a high genetic gain, provided that: i) phenotyping is accurate; ii) selection intensity is explored by genotyping several plants, increasing the number of selection candidates, and iii) genomic selection is used for early selection in recurrent selection.

Enhancing genetic gains through marker-assisted recurrent selection: from phenotyping to genotyping

“…RGS was first reported in popcorn to enhance genetic gain in a breeding population. It has been observed that the recurrent genomic showed higher genetic gain provided that the selection intensity along with genotyping helps in increasing the number of individuals for selection (Schwantes et al 2018). In regarding to RGS, more studies are required, to determine that the genomic prediction model can be applied for how many recurrent selection cycles to predict the genomic estimated breeding value (GEBV) precisely.…”

Long-term selection of biparental crosses: a comparison among genomic methods and phenotypic selection

“…However, as usually the evaluation step requires the synthesis and evaluation of progenies of each individual on a experimental trial, this leads to a low genetic gain per unit of time, as it might take too much time to accomplish a cycle. But, with genomic selection it is possible to combine evaluation and recombination into a single step, where the genomic estimated breeding value is used to select the individuals and cross them, without the need to evaluate their progenies (Schwantes et al, 2018).…”