GALLO, C1.; ENRICO, J.M.2; CRAVIOTTO, R.1; ARANGO, M.1
Temperatures over 32 ºC combined with hydric stress during soybean seed filling can lead to green seeds.
These seeds can cause occasional failures in lot germination, problems during conditioning and storing. The goals of the present investigation were to determine the physiological quality of soybean seed lots belonging to different maturity groups sown in two planting dates and with different contents of green seeds, and to estimate the viability and vigour of green seeds. Five seed lots from early planting maturity groups III and IV cultivars were utilized, with different % of green seeds (4, 11, 16, 38 and 53%) and 5 lots of late planting maturity groups VI and VII, with 3, 7, 11, 13 and 19% of green seeds. Physiological quality was evaluated using the Topographical Tetrazolium Test (TTT). Four repetitions of 50 seeds were used for each cultivar. The percentage of environmental damage was ≥ 52% in all cultivars. In seeds from early planting maturity groups, environmental damages were extensive and located in the embryonic axis. In seeds from late planting maturity groups, environmental lesions were less extensive and superficial. Green seeds that were not stained in the TTT were classified as non-viable. All the evaluated material displayed high percentage of environmental damage, but the MG III and IV cultivars presented the greatest critical damage values. Green seeds are viable if the embryonic axis and the proximal area where it joins the cotyledons do not present deep or physiological damage.
Keywords: quality, seed, Glycine max, tetrazolium, environment