The performance of introduced grasses in seasonally dry tropical environments in northern Australia

Abstract

Fifty-two introduced grass accessions from forty species were grown at up to 14 sites in northern Australia for five years to assess their degree of adaptation. To establish the plots small grass plants were transplanted into replicated rows in cultivated strips and the area was oversown with legume seed. The plots were fertilized annually with 100 kg/ha superphosphate and grazed by cattle. Measurements of plant persistence, growth during the wet season, and spread were combined to develop an adaptation index. This varied in value from 0-100 and a value of 50 or more was taken to indicate an adapted grass. According to this criterion Andropogon gayanus CPI 57497, Bothriochloa insculpta cv. Hatch, Brachiaria decumbens cv. Basilisk, B. humidicola cv. Tully, Cenchrus ciliaris cv. Biloela and cv. Gayndah, Chloris gayana CPI 4608 1, Chrysopogon sp. CPI 522 13, Dichanthium annulatum CPI 508 19, Digitaria milanjiana CPI 7920, D. smutsii CPI 14368 and CPI 38869, Paspalum plicatulum cv. Rodd's Bay, Urochloa bolbodes CPI 45607 and 47 122, and U. mosambicensis cv. Nixon and CPI 46876 were found to be adapted to at least one site. The accessions have been placed in performance groups on the basis of their growth at the different sites.