Introduction to the New Silkworm Variety for Summer and Autumn, Xiafang x Qiubai
Xiafang x Qiubai is a silkworm variety for summer and autumn use bred by Southwest Agricultural University through repeatedly setting up high-temperature environments. In 1992 and 1993, it participated in indoor variety comparison tests and rural trials in Sichuan Province, and all economic indicators reached or exceeded those of the control variety "781 x 7532". In March 1994, it passed the approval of the Sichuan Provincial Silkworm Variety Approval Committee.
The Xiafang x Qiubai variety is a summer-autumn use variety bred by combining hybrid breeding and systematic segregation breeding. Due to reasonable parent selection and a correct breeding scheme, this variety has strong tensile properties, high yield, excellent silk quality, and easy reproduction, reaching the domestic advanced level and gaining the recognition of peer experts. According to provincial-level appraisal, the cocoon yield per 10,000 silkworms is 17.96 Kg, the cocoon filament length is 1268 m, and the reelability rate is 75.9%. The neatness is 95 points, the silk yield from cocoon reeling is 17.22%, and the cocoon shell weight per 10,000 silkworms is 5.8% higher than that of the control.
Large-scale rural production has proved that this variety has good health, is easy to rear, and has high yield. The cocoon yield per gram of silkworm eggs is 2.7% higher than that of the control, and the yield per 10,000 silkworms is 3.6% higher than that of the control. By rearing one sheet of eggs, farmers net an additional 3.1 yuan in cocoon income, improving farmers' @#@250@#@ economic benefits.
This variety is a binary hybrid, and both parents are bivoltine, four-molt, and himé silkworms. The pure lines have the characteristics of being easy to rear, easy to mate, relatively high egg production (Xiafang produces 550 eggs per moth, Qiubai produces 480 eggs per moth), and simple and easy reproduction, so seed farms are willing to reproduce them. Through combining ability testing, this variety has good general combining ability and specific combining ability. The first-generation hybrid has a larval duration 22 hours shorter than that of the control, good health, a cocoon yield per gram of silkworm eggs 6.9% higher than that of the control, high yield, and silk length and reelability rate 8.7% and 16.6% higher than those of the control, with good silk quality.
More than 10,000 sheets were promoted in the Chongqing area. In 1992, 50,000 sheets were promoted, and in the autumn of 1996, 600,000 sheets of seed were used. It has become the leading variety for summer and autumn in Sichuan Province and Chongqing Municipality.
10,000 sheets of the new variety produce 320000 Kg of cocoons. The dry cocoon reelability light discount is 259 Kg, the acceptable rate is 95%, and the drying discount is 243 Kg. The control variety values are 280000 Kg, 272 Kg, 92%, and 250 Kg respectively. Therefore, the new variety produces 1042 Kg more raw silk than the control. At 150 yuan per kilogram of raw silk based on grade 3A, this will increase output value by 1.563 million yuan. Subtracting the additional payment for raw material cocoons of 32,000 yuan, the net increase is 1.24 million yuan. The above totals an increase in income of 1.271 million yuan. At a reduction value of 0.85, the newly added output value is 1.08 million yuan.