Comparison of maize performance between doubled haploids and different selfing generations in the Mexican subtropics

• Published in: Acta agronomica (Palmira) 2024-03, Vol.72 (2), p.168-175
• Main Authors: Vargas Escobar, Ever Andrés, García Dávila, Mario Augusto
• Format: Article
• Language: English
• Subjects: Animal breeding; Climate change; Combining ability; Corn; Developing countries; Efficiency; Genotype-environment interactions; Genotypes; Heritability; Homozygosity; LDCs; Pedigree; Plant breeding; Plot (Narrative); Population; Population growth; Population studies; Statistical analysis; Technology assessment; Zea mays
• ISSN: 0120-2812; 2323-0118
• DOI: 10.15446/acag.v72n2.85349

Maize (Zea mays) hybrid breeding programs are increasingly adopting double haploid (DH) technology to enhance efficiency and meet the growing demand for food in the face of population growth and climate change. However, in developing countries such as those in subtropical regions, the utilization of DH technology is still limited. This study aims to evaluate the potential benefits of incorporating this technology into both new and established maize breeding programs. Using a pedigree selfing population from the CIMMYT Genebank, DH lines were developed and compared to the conventional pedigree selfing method through a line-by-tester evaluation. Fifteen DH lines and fourteen lines from each of the S2, S4, and S6 selfing generations were subjected to multilocation yield trials in the subtropics of Mexico. The results showed that it took three years for the S1 population to identify DH lines with 100 % homozygosity and the highest general combining ability (GCA), which was one year earlier than the S6 lines (98,4 % homozygous). DH lines exhibited more genotype-by-environment interactions (GxE) compared to S2 testcrosses but demonstrated similar heritability to the S6 generation. Significant statistical differences were observed between the DH evaluations and the S4 and S6 testcrosses, while no significant difference was found between the S2 and DH evaluations. Based on these findings, a gradual implementation of DH technology in hybrid breeding programs is recommended. However, the conventional pedigree method should not be abandoned entirely, and testing in selfing generations, particularly in S6, remains crucial. This study provides a statistical comparison of DH versus the conventional pedigree method using a line-by-tester approach, contributing valuable insights for plant breeders and researchers in the field of maize breeding. Los programas de fitomejoramiento de maíz (Zea mays) híbrido están adoptando cada vez más la tecnología de dobles haploides (DH) para mejorar la eficiencia y satisfacer la creciente demanda de alimentos en el contexto del crecimiento de la población y el cambio climático. Sin embargo, en países en desarrollo, como aquellos en regiones subtropicales, la utilización de la tecnología DH aún es limitada. Este estudio tiene como objetivo evaluar los posibles beneficios de incorporar la tecnología DH en programas de mejoramiento de maíz, tanto nuevos como establecidos. Utilizando una población de autofecundación de pedigrí proveniente de