Genotypes of burley (cultivars B-21 and B-49), flue-cured (line VA-81 and cultivar PD-4), and Connecticut broadleaf (cultivar C9) tobacco (Nicotiana tabacum) resistant (R) or susceptible (S) to the tobacco cyst nematode Globodera tabacum tabacum were crossed. F1 progeny of burley and susceptible broadleaf were selfed and backcrossed to produce additional progeny for evaluation of resistance in ...

The challenge in tetraploid cotton cultivars is the narrow genetic base and therefore, the bottleneck is how to obtain interspecific hybrids and introduce the germplasm directly from wild cotton to elite cultivars. Construction of genetic maps has provided insight into understanding the genome structure, interrelationships between organisms in relation to evolution, and discovery of genes that ...

Defects in red blood cell (RBC) membrane skeleton components cause hereditary spherocytosis (HS). Clinically, HS varies significantly even among individuals with identical gene defects, illustrating the profound effects of genetic background on disease severity. We exploited a new spontaneous mouse model, wan, which arose on the inbred C3H/HeJ strain, to identify quantitative trait loci (QTL) t...

The leaf number above the primary ear (LA) is a major contributing factor to plant architecture in maize. The yield of leafy maize, which has extra LA compared to normal maize, is higher than normal maize in some regions. One major concern is that increasing LA may be accompanied by increased plant height and/or flowering time. Using an F2:3 population comprising 192 families derived from a lea...

Parameters of bone geometry such as width, length, and cross-sectional area are major determinants of bone strength. Although these traits are highly heritable, few genes influencing bone geometry have been identified. Here, we dissect a major quantitative trait locus (QTL) influencing femur size. This QTL was originally identified in an F2 cross between the C57BL/6J-hg/hg (HG) and CAST/EiJ str...

Yung-Yu Yang, Fei-Jann Lin and Hwei-yu Chang (2004) Sex ratio distortion in hybrids of Drosophila albomicans and D. nasuta. Zoological Studies 43(3): 622-628. A sex-ratio distorter in Drosophila albomicans was uncovered by the hybridization between Japanese Okinawa D. albomicans females and Indian D. nasuta males. The F1 male from this cross produces female-biased offspring. The genic nature de...

Either by selective breeding for population divergence or by using natural population differences, T2 and advanced generation hybrids can be deveIoped vith high variances. We relate the size of the genetic lariance to the population divergence based on a forvard and backward mutation model at a locus with :wo alleles with additive gene action. The effects of Jopulation size and initial gene fre...

Reconstitution of phage-neutralizing activity was observed after admixture of separated L and H polypeptide chains of purified antibodies obtained from single sheep or guinea pigs and directed against f1 and f2 phages. Hybrid mixtures of complementary chains of antiphage antibodies and gamma-globulins of the same animal showed less activity than the homologous mixtures of chains from antibodies...

A procedure is outlined for estimating the minimum number of freely segregating genetic factors, nE, contributing to the difference in a quantitative character between two populations that have diverged by artificial or natural selection. If certain simple criteria are satisfied approximately on an appropriate scale of measurement, nE can be estimated by comparing the phenotypic means and varia...

Garden asparagus (Asparagus officinalis L.) is an economically important horticultural crop, susceptible to pathogenic soil fungi of the genus Fusarium. These fungi cause stem, crown and root rot, a major disease all over the world that is difficult to control by the use of chemicals and cultural practices. The development of resistant/tolerant cultivars appears to be the best alternative for c...