ROOT LENGTH DENSITY AND YIELD TRAITS OF BROCCOLI (BRASSICA OLERACEA L. VAR. ITALICA PLENCK) AS AFFECTED BY DIFFERENT TECHNIQUES OF SEEDLING GROWING AND TRANSPLANTING

The research was carried out in Ofanto plain (southern Italy, Lavello, Basilicata region, 41°03’N, 15°42’E, 180 m a.s.l.), in order to study the response of broccoli (‘Marathon F1’) both root length density (RLD) and yield traits as affected by: 1) different techniques of production of seedlings (volume containers equal to 13, 46, 90 and 180 cm3), 2) different periods of transplant (24/08/2005 and 26/09/2005) and 3) different procedures of transplantation (with or without biodegradable container). A double rows lay out of planting, for a crop density of 2.94 plants m-2 was performed. The harvest started on 02.11.2005 and 12.12.2005, and ended after 30 and 45 days, respectively for the two transplantation times. Along with harvests, soil samples were taken at different positions (close to the plant, between the rows, between the doubled rows) and at different depths (0-20, 20-40, 40-60 cm) in order to measure RLD according to Newman’s method (1966). The results showed that the RLD and the heads (corymbs) yield (as so as all the main yield components) were significantly influenced by: 1) the volume of containers, from 1.9 to 2.4 cm cm-3 and from 9.7 to 13.5 t ha-1, respectively for the smallest and the largest container; 2) the time of transplant, with values of 2.4 , 1.9 cm cm-3 and 14.6, 10.9 t ha-1, respectively, for the first and the second time; 3) the presence of the container at transplant, with values of 2.0, 2.3 cm cm-3 and 12.9, 13.5 t ha-1 for the transplant with and without container, respectively. Moreover, with reference to the RLD, were observed, as expected, a reduction with: 1) increasing distance from the plant (values from 3.3 to 1.3 cm cm-3, respectively for samples collected near the plant and between the doubled rows) and 2) with increasing depth (values from 3.7 to 0.8 cm cm-3, respectively for the 0-20 and the 40-60 cm layer)