L.F.L. Mescouto, M.R. Piza, J.C. Costa, L.O. Pessoni, A.T. Bruzi, C.E. Pulcinelli, T.T.T. DA Rocha
Published: March 12, 2024
Genet. Mol. Res. 23(1): GMR19232
DOI: https://doi.org/10.4238/gmr19232
Cite this Article:
L.F.L. Mescouto, M.R. Piza, J.C. Costa, L.O. Pessoni, A.T. Bruzi, C.E. Pulcinelli, T.T.T. DA Rocha (2024). Early harvesting: an efficient technique for speed breeding in soybean. Genet. Mol. Res. 23(1): GMR19232. https://doi.org/10.4238/gmr19232
About the Authors
L.F.L. Mescouto, M.R. Piza, J.C. Costa, L.O. Pessoni, A.T. Bruzi, C.E. Pulcinelli, T.T.T. DA Rocha
Corresponding Author
Email: adrianobruzi@ufla.br
ABSTRACT
Autogamous plant breeding programs require the advancement of many inbreeding generations to obtain a line with the most fixed loci. The time requested to obtain a new cultivar can be reduced through speed breeding protocols. This study aimed to evaluate the viability of soybean seeds at different phenological stages of development, at R6 (full developed seed) R7 (beginning of maturity) and R8 (full maturity); estimate genetic and phenotypic parameters associated with the physiological quality of immature soybean seeds; and study the feasibility of early harvesting as an alternative for soybean speed breeding protocol under tropical conditions. Thirty-two commercial and non-commercial soybean lines were utilized, sourced from cultivation and value-in-use trials within the soybean genetic improvement program at the Federal University of Lavras (UFLA). The plants were brought to the field, and the seeds were harvested at various phenological stages. After the plants in each plot reached the desired phenological stage, 10 plants were collected per plot at each evaluated phenological stage. Seed quality was assessed using the standard germination test on germitest paper, and seedling length and emergence tests were conducted in trays maintained in a plant growth chamber at a temperature of 25°C, with subsequent uniform irrigation as needed. The average percentage of cycle reduction gain with early harvest was 18.5% in the experiment aimed at precocity and 17% in the experiment targeting grain yield. The gain in days was 18 days for the early trials and 20 days for the yield trials. It is inferred that with the adoption of an early harvest, up to four generations of endogamy can be performed per year in soybean in a high-altitude tropical climate compared to one generation in the field or 2-3 generations in winter nurseries.
Key words: Generations of endogamy, Germination, Physiological quality seed.