Physical and gerrninative characterisation of the seeds of native and naturalised pasture species in southern Chile I: Agrostis capillaris L., Arrhenatherum elatius L. ssp bulbosus (Willd), Bromus valdivianus Phil., Paspalum dasypleurus Kunza ex Desv. and Trifolium dubium Sibth.

Abstract

The physical and germinative features of seeds from native and naturalised pasture specie of the Dominio Húmedo de Chile Bromus valdivianus, Paspalum dasypleurus, Agrostis capillaris, Arrhenatherum elatius ssp bulbosus and Trifolium dubium, were studied. Dactylis glomerata and Trifolium repens, were used as control. The seeds were collected from naturalised pastures of Southern Chile. The germination test was conducted under controlled light, temperature and humidity conditions. The duration depended on the requirement of each specie. The effect of two seed pre-treatment were evaluated: KNO₃ solution at 0.5% applied at the beginning of germination test and seed cooling (4°C during 7 days previous to the gennination test). The genninative development of each specie was studied (percentage and speed of germination). The evaluated parameters were: normal seedlings, abnormal seedlings, dead seeds, latent seeds (using tetrazolium test) and for legumes additionaly hard seeds were measured and after scarification evaluated for germination. Among grass specie the greater percentage of gennination was showed by Arrhenatherum elatius ssp bulbosus (88%), and the lower level was showed by Paspalum dasypleurus (4.75%), This specie also showed the greater level of latent seeds (72.25%). Between the two legume specie no significant differences were founded in relation to genninative development. Both specie had a high level of hard seeds, showing after scarification a great genninative capacity. Among the seed pre-treatinents evaluated, KNO₃ showed a positive effect on Agrostis capillaris, Arrhenatherum elatius ssp bulbosus Bromus valdivianus and Paspalum dasypleurus level of gennination. This is an indication that KNO₃ has an effect of braking the latency, allowing an adequate germinative process.