Development of root morphology traits of the Czech lucerne varieties in chernozem over a three year period

Abstract

The root system of plants is generally in relation to important agronomic and ecological characteristics. The aim of this study was to investigate differences in root morphology development of Czech lucerne varieties under chernozem soil conditions. In spring 2007, a field experiment with ten Czech lucerne varieties was established with a regular space of 125 mm between the rows. During the 2008–2010 period, the plants were sampled every autumn after the last cut in five blocks per each variety; the size of the sampling area was 50 × 50 cm and average depth of sampling was 0.25 m. All varieties provided similar trend in root morphology development but some differences could be detected in the rate of this development. From all evaluated root traits, these differences were connected mainly with tap-root diameter, intensity of root branching and lateral root number. Advisable varieties should provide higher density of plant together with higher root diameter and branching which is resulted to higher root weight per m2 and consequently to higher stand productivity. The root-branched plants achieved a significantly higher tap-root diameter of 10.7 mm in comparison with unbranched-root plants with 7.1 mm. Except of plant age, the stand density and tap-root diameter could be considered as a parameter to drive lucerne root morphology development. Within a year, the increase of tap-root diameter was connected with increase of root branching at root-branched plants whilst decrease of plant density caused the beginning of the process of root branching at tap-rooted plants. The range of root traits influenced themselves so their joint presentation is advisable. It must be remembered that soil conditions are a factor which strongly modified the root morphology traits; therefore, these results must be completed with other experiments under various soil conditions. The knowledge of root morphology traits could contribute to the assessment of lucerne varieties specific features.