بررسی معرفی لاین های کرم ابریشم پر تولید مقاوم به بیماری گراسری(فازاول)

Grasserie (Nuclear Polyhedrosis Virus) is one of the most important diseases of silkworm which can cause remarkable damages. There is no proper curative method for this disease up to now. Therefore employing of breeding plans to introduce more resistant silkworm lines against the disease is of the most essential remedy. In this study the high resistant lines were selected to be used for transferring their resistance controlling genes. Twenty one different silkworm varieties including 11 Japanese varieties named as Xihangl, Xihang2, Xihang3, 101433, M-1-1-31, 31-M-1-1, M-1-1-103, 103-M-1-1, 31, 103 and 107, and 10 Chinese varieties named as Koming1, Koming2, Y, 32-110, 110-32, 104-110, 110-104, 32, 104 and 110 were tested for their resistance by means of spraying of grasserie pathogen suspension with 107 density of N.P.V. particles. Consequently 2 Chinese varieties i.e. Koming1 and 110-104 and 2 Japanese varieties i.e. M.1.1.103 and 103.M.1.1 were distinguished as resistance genes provider varieties. The commercial Japanese line named as 107 also showed high resistance (and weak cocoon characters performance). The females of selected Chinese varieties were mated with the males of commercial Chinese varieties (110, 104 and 32) and females of selected Japanese varieties were mated with the males of commercial Japanese varieties (107, 103 and 31). The crosses of 10731ا and 107 103ا were also generated. Twenty separate families were obtained from each 14 obtained combinations. Furthermore 3 families with random mating were produced from each variety (Control treatment). On this basis during 2nd, 3rd, 4th and 5th years of study 14 combinations were reared. Every year after data analyzing and selection of superior family (from the aspect of grasserie resistance) the females of these families were back crossed with the males of high productive lines. This study could not cover two times rearing per year according to its proposal due the some overlapped programs with silkworm gene bank and breeders stock maintenances at the Silkworm Research Center. So at the end of studying period (1385) five steps of backcrosses were accomplished and the eggs of step 5 should be reared for more 4 years (1386-1389) to complete the 7 steps of backcrossing as well as one step of comparison of obtained varieties with the initial lines. Therefore it is necessary to extent the study for 4 more years.

Keywords:

کرم های ابریشم , بیماری گراسری , ویروس پلی هیدروسیس , اصلاح نژاد بی مهرگان , نتاج , پاشندگی ها (محلول) , ارقام