Comparison of response to selection in three peanut cocoon lines of silkworm during spring and autumn seasons

Abstract

The aim of this experiment was to study the season effect on response to selection in three Iranian silkworm pure lines. In the first year, a parental group was selected, recorded and coded for each 3 lines of 31, 103 and 107, which had further weight average than the population average. These parents were crossed with each other and a selected group was made for these three lines. Also, a parental group was chosen, recorded and coded for each of the three lines which include the weight average equal to population average weight. These parents also were crossed with each other and a coincidental group was made for these three lines in two spring and autumn seasons. The members of each group were grown up and crossed during three successive generations coincidentally with out any re selection. The 27 average records were registered and analyzed in two spring and autumn seasons. The data analysis showed that in spring, among three studied lines for larva vitality, the highest response to selection was shown by line 31 (2.706%) and line 103 (-4.489%),  respectively and the least response belonged to line 107 (-5.064%). The comparison of response average to selection in these three lines also had no significant difference statistically (P > 0.05). In the same season, the highest response to selection for the number of produced cocoons was observed in line 103 (51.19 cocoon) and line 31 (25.56 cocoon), respectively in the base population. Also, the least response to the selection in the base population belonged to line 107 (22.44 cocoon). The comparison of average response to selection in these three lines showed no significant difference statistically (P > 0.05). Among these three studied lines for the best cocoon total weight in spring, the highest response in the base population belonged to line 103 (67.09 g) and line 31 (40.16 g), respectively and the least response to selection in base population belonged to line 107 (19.58 g). The comparison of response to selection in these three lines showed that there was no significant difference statistically (P > 0.050). Among the line for best single cocoon weight in spring, the highest response to selection in the base population belonged to line 31 (0.05888 g) and then line 103 (0.04075 g), respectively and the least response to selection belonged to line 107 (0.03863 g). The comparison of response average to selection among three lines showed that the difference of response to selection in lines was not significantly statistically (P > 0.05). Among lines for cocoon weight resulted from 10000 larva and in spring, the highest response to selection in the base population belonged to line 31 (728.3 g), then line 107 (401.9 g) and the least response was observed in line 103 (289.7 g). The comparison of response average to selection in lines shows that there is no significant difference statistically among these three lines (P > 0.05). Among the lines in autumn, for best single cocoons weight, the highest response to selection in base population belonged to line 107 (0.07700 g) and line 31 (0.05513 g), respectively and the least response to selection in line belonged to line 103 (-0.04657 g) in the base population. The comparison of response average to selection in these three lines has shown that there is a significant difference statistically for response to selection in lines (P < 0.05).

Key words: Silkworm, genotype, season, selection, performance.