Seed longevity of tropical forage grasses

Abstract

The seed viability of Brachiaria decumbens cultivars IPEAN and australian, B. plantaginea (a weed), Panicum maximum cv. Wurth (panicum Wurthl, P. maximum var. trichoglume cv. Petrie (green panic), Setaria sphacelata ver. sericea cv. Kazungula (Kazungula setaria), ali harvested at the Estação Exerimental Central do Instituto de Zootecnia in Nova Odessa €” State of São Paulo €” Brazil and, B. humidicola seed harvested at a private farm, were followed since the 2^nd_3^rd month up to the 1 7^th_27^th month after the harvest. The seeds were stored in paper bags in a Seed Analysis Laboratory at a daily temperature of 22°C, maintained through the use of a air condictioning or in a cool room (green panic) (15°C €” 30% R.H.). Seeds stored under this condition for 11-12 months did not show significative loss of their viability. For some species (green panic, panicum wurth, B. plantaginea, and hand harvested B. humidicola) periods as long as 20-24 months were found maintaining seed viability. Other conciusions were: a) scarified B. decumbens seeds showed a significative higher germination than the non scarified ones during the entire test period (17 months); b) green panic seeds stored at 15°C and 30% relative humidity (cool room) maintained their viability longer and at hiqher values than seeds stored at the laboratory, although there was a delay for those seeds to loose their dormancy, and c) there was evidency that B. humidicola seeds germinate better at 15-35°C than at 20-35°C alternate temperatures and that hand harvested seeds of that species could be stored maintaining their viability longer and in better condition than machine harvested seeds.