Performance of Lotus corniculatus L. genotypes submitted to cutting interval : subsidies to a breeding program

The objective of this work was to evaluate the response of five birdsfoot trefoil populations (Lotus corniculatus L.), selected under severe and intense grazing (P38, P37, P9 and P3) or cutting (population Corte), one rhizomatous population from Morocco and two cultivars, São Gabriel (Brazil) and ARS 2620 (USA), to different cutting intervals (20 and 40 days). The trial was carried out in a greenhouse for 224 days. The plants were submitted to the treatments during four months, when it was made four and two cuttings for the 20 and 40 day intervals, respectively. In the following months, aerial part of the plants was totally removed and after 70 days of regrowth, evaluation of roots and aerial section were performed. Analysis of variance and multivariate analysis was performed, obtaining the Mahalanobis distance (Md), dendogram by UPGMA method and the relative contribution of the characters for genetic divergence. There was no genotype × cutting interval interaction and the genotypes presented a reduction on dry matter yield of roots, crown and aerial sections, number of stems and plant height when submitted to frequent cuttings. The most divergent genotypes were Marrocos and P9 (Md = 108.7) and the most similar ones were São Gabriel and P37 (Md = 7.8). The results suggest exclusion of the population P9 because of its weak performance and the utilization of the populations Corte and P37 as progenitors in the birdsfoot trefoil breeding program. Root dry matter accumulation and plant height were the characters that contributed most to genetic divergence and they can be used for selection works