Root immersion in antimitotic solutions and exposure times in obtaining doubled haploid super sweet corn
Juliana Moraes Machado de Oliveira, Vitor Joaquim de Lucena, Iran de Azevedo Duarte, João Otávio Gonçalves dos Santos, Maria Eduarda Alves de Oliveira, Lucas Alves Camilo, Guilherme Cunha do Carmo, Helton Silva Alves Ferreira, Gabriel Henrique Molina, Igor de Santi Santos, Enzo Dessunti Pagnan, Josué Maldonado FerreiraAbstract
Chromosomal doubling of haploids, through exposure to antimitotic agents for specific periods, is crucial for obtaining doubled haploids. The objectives of this study were (a) to determine the potential for chromosome doubling by immersing the roots of haploid super sweet corn ( Zea mays L. var. saccharata ) seedlings at 17°C in solutions of colchicine, pronamide, and amiprophos‐methyl + pronamide for different exposure times; and (b) to compare the doubling effectiveness of these antimitotic solutions, for different exposure times at greenhouse and field cultivation. Putative haploid seeds from eight super sweet populations, obtained by crossing with the hybrid inducer CIM2GTAIL‐P1 × CIM2GTAIL‐P2, were used. The first experiment used exposure times of 5–12 h for colchicine and pronamide solutions and 5–16 h for amiprophos‐methyl at 17°C. In the second experiment, exposure times of 5, 6, and 7 h were chosen for pronamide and amiprophos‐methyl solutions, and 10, 11, and 12 h for colchicine, at 17°C. The hybrid inducer promoted a mean real haploid induction rate of 9.7%. Greenhouse treatments promoted greater success in obtaining doubled haploids. The pronamide solution led to greater lethality of seedlings but obtained mean overall success rates of 11.2%–12.7%, not differing from treatments using a solution containing amiprophos‐methyl. Colchicine treatment with 10 h of exposure at 17°C resulted in the best performance, with overall success rates of 32.3% in the greenhouse and 20.3% in the field, making it the best treatment for obtaining DHs in super sweet corn.