Authors
1
Department of Animal Science, College of Agriculture, University of Guilan, Rasht, Iran
2
Iran Silkworm Research Center, Rasht, Iran
3
Department of Animal Science, College of Agriculture, Rasht Branch, Islamic Azad University, Rasht, Iran
Abstract
At this research it was investigated the effects of three prevalent environmental stresses in Iranian silkworm rearing farms on 6 kinds of Iranian silkworm hybrid performance. The climate stresses included warm/humid, warm/dry and temperature fluctuating conditions which compared with standard rearing climate conditions. The trail carried out within spring and early autumn rearing conditions. Some economic characters such as the percentages of good, middle, low and double cocoons, larval, pupal and total mortality, weight of total and good cocoon per 10000 larvae, number and weight of cocoon per liter, single cocoon weight, single cocoon shell weight and single cocoon shell percentage were surveyed. The obtained results of ANOVA showed the rate of larval, pupal and total mortalities at spring rearing season (3.0, 3.84 and 6.49% respectively) were higher under warm/humid condition compare to warm/dry (2.16, 3.47 and 5.33) and temperature fluctuating (2.22, 4.33 and 6.2) conditions (P˂0.05). Similarly at autumn rearing season warm/humid climate resulted to higher larval, pupal and total mortalities (10.18, 20.66 and 28.07% respectively) compare to warm/dry (5.72, 16.73, and 21.28 %) and temperature fluctuating (3.93, 2.58 and 6.41 %) rearing conditions (P˂0.05). Furthermore at spring and autumn seasons, respectively 2.22 and 6.11 % at larval mortality, 4.07 and 11.0 % of pupal mortality and 5.97 and 16.09 % at total mortality were observed (P˂0.05). According to the results of this study, humidity had no effect of pupal mortality while warm/humid condition increased the larval mortality (P˂0.05). Therefore silkworm hybrids would demonstrate better performance under warm/dry rearing condition compare to warm/humid climate (P˂0.05). Under humid rearing climate the apparent weight of cocoon will increase which is due to higher pupal weight (P˂0.05). The results further showed the existence of negative genetic correlation between resistance and productive characters. It is cleared that the hybrids performances varies based on different environmental condition (P˂0.05).
Keywords
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