Heterosis manifestations by survival and larval duration of F Bombyx mori L. Hybrids reared 1 with artificial diet

Abstract

Abstract. The aim of this paper was to study the influence of the degree of heterosis (compared to higher parent value- HP and mean parental values- MP) on the signs, survival and duration of development in F hybrids of Bombyx mori L. from different geographical origin, fed by artificial diet. The study was conducted 1 at the Training Experimental Station of the Sericulture section of the Faculty of Agriculture at Trakia University. A total of 10 hybrids were tested featuring 6 breeds from the genetic bank of Sericulture and Agriculture Experiment Station (SAES)-Vratsa. Silkworms were reared with artificial diet containing 15% powder of dried mulberry leaf produced at SAES-Vratsa and prepared by methods, developed by the manufacturer, whereby 250g of dry substance and 675ml of distilled water are homogenized using a mixer. The mixture is cured thermally in a microwave for 10min. at ~800W. The receptivity of specimens was -st determined based on the results from the survival and the duration in the I age of the larval stage. In heterogeneous crossbreds higher survival rate in the first age is exhibited by hybrids in which a Japanese type breed was used as dam. Homogeneous crossbreds created with the participation of Japanese breeds excel in both analyzed traits those involving a Chinese type. For the survival trait heterosis manifestations to higher parent value (HP) and mean parental values (MP), were detected in the majority of hybrids (90.91%). Regarding the duration of development, heterosis effect to MP was observed in all F hybrids, 1 while to HP heterosis is exhibited by 60% of the tested F hybrids.

Keywords

• Bombyx mori L. hybrids
• artificial food
• heterosis
• receptivity
• survival