Abstract— Selection is one of the best breeding approaches in silkworm breeding. An investigation was conducted for study of relationship between season and efficiency of individual selection in six peanut and oval pure lines of silkworm. Silkworm rearing technique included single batch rearing system. Feeding and other conditions of larval rearing were conducted following the standard procedure. Individual selection system based on cocoon weight was conducted as selected group in the zero generation. For each pure line, in zero generation, about 500 individuals recorded for each line from point of cocoon weight trait and the one percentage of individuals in each sex lines which had the highest cocoon weight selected as parents of selected group at next generation. These individuals mated together and formed selected groups of first generations. Meanwhile for each pure line in zero generation, individuals who had the cocoon weight averages equal to population average were selected as random groups. Individuals and offspring in selected and random groups selected and mated randomly without any phonotypical and genotypic selection in first, second, third and fourth generations. Twelve full sib families from each group and pure line were reared in each generation. Totally, 27 economical traits were recorded and analyzed. In each pure line and generation, 12 families were reared so that 25 male and 25 female full sib cocoons were individually recorded for cocoon traits per family. Thus, there are 15552 family data included 4 generations × 6 pure lines × 2 treatments (random and selected groups) × 12 families (replications) × 27 family traits. These data recorded in two autumn and spring seasons. Their records analyzed at four successive generations. From obtained results, it was showed lines at spring had higher response than autumn from point of most important traits. For resistance characters, responses to selection for alive larvae number were 23.08 and 19.72 at spring and autumn respectively. Responses to selection for pupae vitality percentage in best cocoon were -0.304 and -1.486% at spring and autumn respectively. Responses to selection for pupae vitality percentage in middle cocoon were 0.074 and -2.627 at spring and autumn respectively. It is concluded responses to selection for important resistance traits in silkworm pure lines at spring is higher than autumn significantly (P<0.05). Thus, commercial pure lines showed higher phenotypic response in spring rearing period compared to autumn one for production traits.
Index Terms—Bombyx mori, performance, season, selection
Alireza Seidavi is with the Animal Science Department, Islamic Azad University, Rasht Branch, Rasht, Iran. (Corresponding author phone: 0098-9113313073; fax: 0098-1318828387; e-mail: email@example.com)
Cite: Alireza Seidavi, "Relationship between Season and Efficiency ofIndividual Selection in Six Peanut and Oval Lines of Silkworm," International Journal of Engineering and Technology vol. 2, no. 2, pp. 211-214, 2010.