Derived varieties were invented by P. Cohn in [4]. Derived varieties of a given type were invented by the authors in [10]. In the paper we deal with the derived variety Vσ of a given variety, by a fixed hypersubstitution σ. We introduce the notion of the dimension of a variety as the cardinality κ of the set of all proper derived varieties of V included in V. We examine dimensions of some varie...

selection and introduction of superior genotypes from native populations is one of the most common improving methods for fruit trees in the world. iran as a very important origin of apricot has a huge diversity of varieties, so a rich collection of local and imported genotypes of apricot was induced in sahand horticultural research station from 1971. nasiri 90 and other four superior varieties ...

Reputable pig breeding programmes have been very successful in reducing production costs over the last twenty years through significant genetic progress in a wide variety of traits including growth, feed conversion, reduced backfat thickness and, over the last decade, litter size and litters per sow per year [1] . However, with some notable exceptions, genetic progress in many meat and eating q...

Genetic selection in wild living animals favours a variety of different traits that are important for maintenance, and reproduction. In contrast selection in domesticated animals not only favours individuals that can cope best with the modified circumstances of living under human custody but also is artificially influenced by the needs of man, e. g. for fast growth or high reproductivity, but a...

in order to evaluation rice cultivars in different irrigation treatment based on sensitive and tolerance indices in rice , an experiment was conducted as split plot based on randomized completed block design with three replications at rice research institute of iran. main factors were included of five irrigation levels: flooded irrigation (normal treatment), irrigation after banishment, five, e...