Effect of Scarification, Self-Inhibition, and Sowing Depth on Seed Germination of Lupinus campestris

Abstract

Lupinus campestris Schltdl. & Cham. grows in shallow fields and disturbed areas of Central Mexico. It has potential to improve soil fertility and as fodder. Seeds of L. campestris show dormancy, and the technology needed to increase its potential use requires information about conditions favouring seed germination. The aim of this study was to evaluate the seed germination responseof L. campestris under controlled (laboratory) and natural field conditions. Under laboratory conditions, 2 yr old seeds had a maximum germination percentage (50%) when they were scarified with sulphuric acid for 90 min prior to sowing and when laboratory light (0.5 µmol m-2 s-1) was maintained during the diurnal period. Without scarification, only about 3% of the seeds germinated. Light in laboratory resulted in an increased seed germination as compared to darkness condition. In the field experiment 1 yr old seeds were used testing the following treatments: (a) seed scarification (seeds scarified by 30 min immersion in sulphuric acid vs. not scarified), (b) presence or absence of plants of L. campestris in plots before field experiments, and (c) sowing depth (on soil surface and at 3 cm deep). The scarified seeds showed a germination percentage range between 50 and 64%, whereas non-scarified seeds had 9 to 16% germination. The seeds sowed in plots with or without plants of L. campestris (before the experiment) germinated similarly, indicating no evidence of self-inhibition of germination. Three conclusions come out: (1) Scarification treatment with sulphuric acid effectively breaks dormancy in L. campestris seeds; (2) Direct sowing of scarified seeds (on the soil surface or at 3 cm depth) resulted in a range of 50-64% of germination under field conditions; and (3) no evidence was obtained for self-inhibition or a positive interaction between preceding vegetation and seed germination of L. campestris.