Ubon Ratchathani 60-35 ,a Bi x Polyvoltine Silkworm Hybrid

Abstract

Ubon Ratchathani 60-35 , a bi x polyvoltine silk worm hybrid, was selected from the hybrid lines of Ubon Ratchathani 60 and Nangnoi Srisaket-1. It was promising for good viability and rearing performance and was suitable to Thailand envionment. The characteristics of Ubon Ratchathani 60-35 hybrid were of plain larva, medium cocoon size, yellow filament, higher productiveity than the native parents and higher popularity among th esericulturists. However, the limitation of this hybrid was the unsuitability to reeling by the autometic reeling machine due to the filament length. The biological and agricultural characteristics were as followed; eggs oviposited 388 per female moth, larval duration 18.5 days, weight 28.1 g per 10 mature worms, sound pupa yield 95 per cent, cocoon weight 1.4 g, cocoon sheel weight 22.5 cg., shell yield 16.1 per cent, reelability 63 per cent, filament size 2.4 denier and mean filament length 519 m per cocoon.