Hybrid sterility (HS) belongs to reproductive isolation barriers that safeguard the integrity of species in statu nascendi. Although hybrid sterility occurs almost universally among animal and plant species, most of our current knowledge comes from the classical genetic studies on Drosophila interspecific crosses or introgressions. With the house mouse subspecies Mus m. musculus and Mus m. dome...

Genetic control of the induction of gastric tumors by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was studied in susceptible ACI rats, resistant Buffalo rats, and their F1 and F2 offspring. Both sexes of all strains, initially 7 to 9 weeks old, were given MNNG at a concentration of 83 micrograms/ml in their drinking water for 32 weeks and were sacrificed at experimental Week 72. The incidence o...

abstract effect of selection index in four iranian commercial lines (107, 110, 153 and 154) on performance of their hybrids including 107 ×110, 110×107, 153×154 and 154×153 was investigated. selection index program was performed on all 3p commercial lines during 9 generations. next generation parents of 3p lines were selected in each generation, by construction of selection matrix based on heri...

Experiments evaluated both noise vulnerability and the extent of protection from noise by sub-chronic low-dose kanamycin in young F1 hybrids resulting from a cross between C57BL/6J and CBA/J inbred mice.

SENCAR mice are selectively bred for hypersusceptibility to two-stage chemical skin carcinogenesis. They are also hypersusceptible to UV radiation tumorigenesis with single high-dose, but not chronic low-dose, exposures. In addition, SENCAR mice exhibit an exaggerated and persistent epidermal hyperplasia (due to sustained proliferation of the basal cells) in response to UV-induced tissue damage...

Predation may be a signi® cant factor in the divergence of sympatric species although its role has been largely overlooked. This study examines the consequences of predation on the ® tness of a pair of lacustrine stickleback species (Gasterosteus aculeatus complex) and their F1 hybrids. Benthic sticklebacks are found in the littoral zone of lakes associated with vegetation and bare sediments, w...

quantitative valuations of observed heterosis for 11 traits of 15 f1 hybrids generated by half diallel crosses of six diverse rice cultivars (domsefid, hashemi and binam, three iranian local cultivars; dorfak, kadous and ir30, three improved cultivars), were made in this study. fifteen f1 hybrids and their parents were evaluated in a randomized complete block design with three replications at t...

As a result of the conducted research, it was established that varietal characteristics influence interphase periods white cabbage and its yield. The duration period "stairs – beginning formation heads" varied in studies. During cultivation Slavia Slava 1305 varieties, "seedlings 88 89 days, respectively, but plants variety are characterized by more pronounced early maturity compared to varieti...

The application of heterosis (hybrid vigor) has brought great success to plant breeding, particularly of hybrid rice, achieving significant yield increases. Attempts to explore the heterosis of inter-subspecific hybrids between indica and japonica rice, which result in even greater yield increases, have greatly increased in the past decades. However, because of the reduced seed setting rate in ...

This study focuses on the possibility of experimental hybridization among host snail species for Schistosoma mansoni in Brazil, with morphological characterization of the hybrids found. By using albinism as a genetic marker, intraspecific crossbreedings were performed between two strains of each species involved, in addition to interspecific crossbreedings; the only viable crossbreeding was bet...