DO PLANTS DERIVED FROM SEEDS THAT READILY GERMINATE DIFFER FROM PLANTS DERIVED FROM SEEDS THAT REQUIRE FORCING TO GERMINATE - A CASE-STUDY OF THE DESERT MUSTARD LESQUERELLA-FENDLERI

We compared the performance of plants of the desert mustard Lesquerell a fendleri derived from seeds that readily germinated (''natural'' pla nts) with plants originating from seeds forced to germinate by the app lication of gibberellic acid which required an extended germination pe riod (''induced'' plants). Before transplanting from the green house, induced plants were significantly larger in diameter but had significa ntly fewer leaves than natural plants. There were also significant dif ferences between seed source populations, as well as seed source by ge rmination treatment interactions, for both plant diameter and number o f leaves. After transplantation to a desert shrubland site, there were highly significant differences in survivorship of natural and induced plants. Five months after transplantation, survival of natural plants (43.3%) was twice that of induced plants (21.3%). Natural plants tran splanted beneath creosote bush shrubs were also larger in diameter tha n induced plants, while the converse was true for plants transplanted in the open intershrub areas. We argue that these results may be, at l east partially, the result of genetic differences between seeds that r eadily germinate and seeds that remain dormant but viable under the sa me environmental conditions.