Influence of shade and scarification on the germination of Ischaemum rugosum Salisb.

Aspectos biológicos de la germinación de Ischaemum rugosum

Abstract

Introduction. The percentage of shade and scarification can influence the germination of Ischaemun rugosum Salisb. Knowledge of these aspects would allow establishment of successful measures for an integrated management of this species. Objective. To compare the influence of different percentages of shade on the germination of scarified and not scarified I. rugosum Salisb. Materials and methods. This experiment was carried out in micro-tunnels during the dry season and the transition to the rainy season, at Fabio Baudrit Moreno Agricultural Experimental Station, Alajuela, Costa Rica, during 2016. In the dry season, the following shade percentages were used 0 %, 30 %, 50 % (green saran), and 100 % (black saran). In the transition to the rainy season, the same percentages of shade were used, but the black saran was changed to 70 % white saran, in both experiments scarified and non-scarified seeds of the weed were used and germination was counted. The data were analyzed with logistic regression and a hypothesis test for the regression coefficients with a significance level of 5 %. Results. In the dry season there was greater germination with non-scarified seeds and 50 % shade. During the transition to the rainy season the highest germination occurred at four days after sowing (dds), under 50 % shade and with scarified seed, and fifteen days after sowing the highest germination (odds ratio 8.67 to 1) occurred with 70 % shade, green saran and scarified seed. Conclusion. Scarification allowed an increase in germination in the transition to the rainy season, not in the dry season. In both seasons there was a positive influence on germination with the shade percentages of 50 % and 70 %.