| he time and mode of gene expression of the Semigamy mutant was examined by developing a genetical-statistical analysis based on a novel application of joint-scaling tests. A 3 x 3 factorial mating of genetically-marked parents was used to produce 9 populations, each of which was subsequently evaluated for haploid/chimera frequencies. These data were analyzed by use of joint-scaling tests based on genetic models that distinguished among various types of parental sporophytic, gametophytic, and zygotic genetic source effects. Chi-square tests of the genetic effects models demonstrated their validity, and that the Semigamy gene was qualitatively inherited. The regression and associated t-tests indicated that the Semigamy gene was expressed at the sporophytic level as an incompletely dominant allele, and that maternal genotypic influence was strong, whereas paternal genotypic influence was moderate.;A modified method of deficiency mapping was used to associate the Semigamy locus with a chromosome and/or chromosome segment. Semigamous hypoaneuploid F;To more efficiently recover Semigamy induced haploid progenies, a statistical selection technique, based on seed weight, was devised. Seeds from 4 populations, 2 homozygous semigamous lines and the reciprocal crosses between them, were weighed and divided into discrete weight classes. Both raw and transformed seed weights were analyzed, and plotted against the numbers in each weight class per population and against haploid and chimera frequencies. The results indicated that a truncated selection regime based on... |
