Soybean (Glycine max L. Merr.) response to the loss of part of its hypocotyl - radicle axis in the production of secondary and/or adventitious roots

The aim of this work was to determine soybean potentiality to generate secondary and/or adventitious roots and to produce a normal seedling when seeds have lost part of their hypocotyl-radicle axis. Three vigor levels, represented each one by four lots were used for this study. Seeds were preconditioned between humid towel papers for 18 hours; then, the hypocotyl-radicle axis was cut with a scalpel and was divided in 1/3, 1/2 and 2/3. Afterwards, seeds were sowed in humid towel papers and were placed in germination chambers at 25°C for 7 days. The length of the hypocotyl and the number of adventitious roots greater or equal to 10mm were evaluated. The length of the hypocotyl was more affected by the cutting intensity than the number of adventitious roots. The production of adventitious roots was, for a loss of 1/3 of the hypocotyl-radicle axis, 3 roots, for a loss of 1/2, 2 roots and for a loss of 2/3, 1 root. The presence of 3 adventitious roots may be considered enough to produce a normal seedling. The loss of 1/3, 1/2 and 2/3 of the hypocotyl-radicle axis was not an obstacle for the production of adventitious roots, but a loss tolerance up to 1/3 of the hypocotyl-radicle axis would be acceptable for the production of a normal seedling.