Life Sciences Commons^™

Use Of Monolploid Solanum Phureja In Cell And Tissue Culture Techniques For Potato Improvement, Henry R. Owen

Henry R. Owen

Monoploid genotypes (2n = x = 12), derived by anther culture of a diplandrous genotype of Solanum phureja, a South-American diploid potato species, were examined for their utility in germplasm development.

Nine monoploid genotypes and the diploid anther-donor plant were grown in photoperiod chambers at The Southeastern Plant Environment Laboratories (SEPEL) at North Carolina State University to examine the effect of photoperiod on tuber yield and to determine the variability for critical photoperiod for tuberization. Significant differences were found among the monoploid genotypes for total tuber weight and tuber number. Longer photoperiod treatments both decreased and delayed tuberization. Axillary tuber …

The Lin-14 Locus Of Caenorhabditis Elegans Controls The Time Of Expression Of Specific Postembryonic Developmental Events, Victor R. Ambros, H. Robert Horvitz

Victor R. Ambros

The lin-14 locus of Caenorhabditis elegans plays an important role in specifying the normal timing and sequence of developmental events in the lateral hypodermal cell lineages. The results of gene dosage, complementation, and temperature-shift experiments indicate that the fates expressed by cells at successive stages of these cell lineages are specified by the level of lin-14 activity and that lin-14 acts at multiple times during development to control stage-specific choices of cell fate. Our observations suggest that during normal development a reduction in the level of lin-14 gene function causes the sequential expression of stage-specific cell fates.

Molecular-Marker-Facilitated Investigations Of Quantitative-Trait Loci In Maize. I. Numbers, Genomic Distribution And Types Of Gene Action, Jonathan F. Wendel, M. D. Edwards, Charles W. Stuber

Jonathan F. Wendel

Individual genetic factors which underlie variation in quantitative traits of maize were investigated in each of two F 2 populations by examining the mean trait expressions of genotypic classes at each of 17-20 segregating marker loci. It was demonstrated that the trait expression of marker locus classes could be interpreted in terms of genetic behavior at linked quantitative trait loci (QTLs). For each of 82 traits evaluated, QTLs were detected and located to genomic sites. The numbers of detected factors varied according to trait, with the average trait significantly influenced by almost two-thirds of the marked genomic sites. Most of …

Genetic Compatibility Of Aedes (Protomacleaya) Triseriatus With A. (P.) Brelandi And A. (P.) Hendersoni (Diptera: Culicidae)., David B. Taylor

David B Taylor

Interspecific hybridization was used to examine reproductive compatibility of Aedes (Protomacleaya) triseriatus (Say) with Aedes (P .) brelandi Zavortink and Aedes (P.) hendersoni Cockerell. Most male progeny were sterile intersexes when A. brelandi or A. hendersoni males were crossed with A. triseriatus females. Female hybrids, and males from the reciprocal crosses, were morphologically normal and fertile. Varying percentages of intersex males were observed among progeny when normal F1 hybrids were crossed to either parental species or with other hybrids. Egg and female sterility resulting from a partial incompatibility between A. triseriatus cytoplasm and A. brelandi male-determining chromosome was observed. No …

Genetic Compatibility Of Aedes (Protomacleaya) Triseriatus With A. (P.) Brelandi And A. (P.) Hendersoni (Diptera: Culicidae)., David B. Taylor

David B. Taylor

Interspecific hybridization was used to examine reproductive compatibility of Aedes (Protomacleaya) triseriatus (Say) with Aedes (P .) brelandi Zavortink and Aedes (P.) hendersoni Cockerell. Most male progeny were sterile intersexes when A. brelandi or A. hendersoni males were crossed with A. triseriatus females. Female hybrids, and males from the reciprocal crosses, were morphologically normal and fertile. Varying percentages of intersex males were observed among progeny when normal F₁ hybrids were crossed to either parental species or with other hybrids. Egg and female sterility resulting from a partial incompatibility between A. triseriatus cytoplasm and …