ROLE OF SEXUALITY IN RESPONSE OF GUINEA GRASS POPULATIONS TO HEAT-STRESS

Six populations of Guinea grass, varying in levels of sexual reproduction, were studied for genetic variation in the response of seedlings to high temperature stress. Mortality rates varied between 13 percent and 77 percent and appeared to be associated with the gene frequency changes at loci governing pubescence of ligule and leaf sheath and alcohol dehydrogenases. Sexual populations with greater heterozygosity and higher levels of polymorphism responded differently, presumably because of certain interlocus gene frequency associations. This study suggests that with more loci and more generations of treatment, genetic control of heat response and the role of sex in population structure could well be investigated. © 1978 AMERICAN GENETIC ASSOCIATION.