Selling high quality P1 and F1 silkworm eggs

SES – Vratza is one of the few institutes in the world selling silkworm eggs throughout the year even in small quantities. We can provide high quality silkworm eggs for rearing all the year round.

The characteristics of the silkworm hybrids produced by SES – Vratza are:

SILKWORM HYBRIDS, CREATED AND PRODUCED BY THE SERICULTURE EXPERIMENT STATION, VRATZA

White cocoon highly productive F1 silkworm hybrids

As especially promissing and highly productive Bulgarian white – cocoon silkworm F1 hybrids, produced recently and reared not only in Bulgaria but abroad as well (Greece, Italy, USA, Egypt, Ghana, Libya, Rwanda, Syria, Uganda etc.) are the four-way hybrids KK x Hesa 1 x Vesletz 2 x Gergana 2 and SN1 x Iva 1 x Magi 2 x Nova 2 and the single hybrids Super 1 x Hesa 2 and Vratza 35 x Merefa 2.

The four-way hybrid (KK x Hesa 1) x (Vesletz 2 x Gergana 2) and the reciprocal cross is characterized with medium values of the main productive characters. The hybrid is obtained by crossing the single hybrid of Japanese type KK x Hesa 1 and of Chinese type Vesletz 2 x Gergana 2. The larvae are with normal markings and plain.
The silkworm egg hatchability is 98 – 99 %, the pupation rate is 96 – 98 %, and the larval duration is 25 –27 days.
The cocoons are white in color, elongated, big and having a mean weight of 1.85 – 2.00 g. The cocoon shell weight is 0.400 – 0.450 mg, the cocoon shell ratio is 21-22 %, the filament length is 1200 – 1300 m, the reelability is over 90 % and the raw silk percentage is 42 – 44 %.
The fresh cocoon yield by one box of eggs is 35 – 37 kg. This hybrid has been especially selected for higher tolerance to unfavorable rearing conditions as well as shorter 5th instar duration.

The four – way hybrid (SN 1 x Iva 1) x (Magi 2 x Nova 2) has medium to high values of the main productive characters. The hybrid is obtained by crossing the sex limited for larval markings single hybrid of Japanese type SN1 x Iva 1 and of Chinese type Magi 2 x Nova 2.
The egg hatchability is 98 – 99 %, the pupation rate is 96 – 98 % and the larval duration is 26 –28 days.
The cocoons are white in color, elongated, big with a mean weight 1.90 – 2.20 g. The cocoon shell weight is 0.420 – 0.490 g, the cocoon shell percentage is 22 %, the filament length is 1200 – 1300 m, the reelability is over 90 % and the raw silk percentage is 42 – 44 %.
The fresh cocoon yield by one box of silkworm eggs is 36 – 39 kg.
The hybrid is sex limited for larval markings. The females are with zebra marking and the males are with normal markings and plain.

The hybrid Super 1 x Hesa 2 and the reciprocal is obtained by crossing the Bulgarian pure lines Super 1 of the Japanese type and Hesa 2 of the Chinese type. The larvae are with markings. The hybrid is characterized with high values of the main biological characters and the technological traits of the cocoons and silk filament.
The egg hatchability is 98 – 99 %, the pupation rate is 96 %, the larval duration is 28 – 30 days..
The cocoons are white in color elongated, big, with a mean weight of 2.10 – 2.30 g. The cocoon shell weight is over 0.500g, the cocoon shell ratio is 22 – 23 %, the cocoon filament length is 1250 – 1300 m, the reelability is 90 – 92 % and the raw silk percentage is 42 – 43 %.
The fresh cocoon yield by one box of silkworm eggs (20 000 ± 200 viable eggs) is 37 – 38 kg.

The hybrid Vratza 35 x Merefa 2 and the reciprocal cross is obtained by crossing the pure lines Vratza 35 of the Japanese type and Merefa 2 of the Chinese type. The silkworm larvae are both with normal markings and plain. The egg hatchability is 98 %, the pupation rate is 95 - 96 %, and the larval duration is 28 – 30 days.
The cocoons are white in color with elongated shape, big, with a mean weight of 2.35 – 2.40 g, the cocoon shell weight is 0.550 – 0.560 g, cocoon shell ratio is 23 - 24 %, the filament length is 1450 – 1500 m, the reelability is 91 – 92 % and the raw silk percentage is 43 – 45 %.
This hybrid is characterized with a very high yield of fresh cocoons by one box of eggs - 42 – 44 kg.

The hybrid B1 x Svila 2 and the reciprocal. The hybrid is characterized with high values of the main biological characters and the technological traits of the cocoons and silk filament.
The egg hatchability is 98 – 99 %, the pupation rate is 96 %, the larval duration is 28 – 30 days..
The cocoons are white in color elongated, big, with a mean weight of 2.50 – 2.70 g. The cocoon shell weight is 0.600 – 0.650g, the cocoon shell ratio is 24 %, the cocoon filament length is 1350 – 1450 m, the reelability is 90 – 92 % and the raw silk percentage is 43 – 45 %.
The fresh cocoon yield by one box of silkworm eggs (20 000 ± 200 viable eggs) is 43 – 45 kg.

The hybrid Hesa 1 x Svila 2 and the reciprocal cross. The silkworm larvae are with normal markings. The egg hatchability is 98 %, the pupation rate is 95 - 96 %, and the larval duration is 28 – 30 days.

The cocoons are white in color with elongated shape, big, with a mean weight of 2.55 – 2.65 g, the cocoon shell weight is 0.612 – 0.650 g, cocoon shell ratio is 24 %, the filament length is 1450 – 1500 m, the reelability is 91 – 92 % and the raw silk percentage is 43 – 45 %.
This hybrid is characterized with a very high yield of fresh cocoons by one box of eggs - 43 – 45 kg.

Silkworm F1 hybrids with some special characteristics

Black – yellow hybrid: This is a F1 silkworm hybrid that has black silkworm larvae and the cocoons are yellow in color. The fresh cocoon weight is 1.80 – 2.00 g, cocoon shell weight – 0.300 – 0.320 g and silk shell ratio is 16 %.

Pink hybrid: The larvae have normal markings, the cocoon color is pink. The fresh cocoon weight is 2.00 - 2.2 g, cocoon shell weight – 0.380 – 0.420 g and silk shell ratio is 19 %.

Green hybrid: The larvae have normal markings, the cocoon color is green. The fresh cocoon weight is 2.00 - 2.20 g, cocoon shell weight – 0.370 – 0.410 g and silk shell ratio is 18.50 %.

Zebra – yellow hybrid: This is a F1 silkworm hybrid that has zebra silkworm larvae and the cocoons are yellow in color. The fresh cocoon weight is 2.20 – 2.40 g, cocoon shell weight – 0.400 –0.430 g and silk shell ratio is 18 %.

Silkworm P1 crossed lines and hybrids

KK x Hesa 1 and the reciprocal: Bivoltine Japanese type single hybrid. The egg serosa color is brown (straight cross) and gray (reciprocal cross), chorion color is white or yellow, and the eggs are sticky. The last instar silkworm larvae are bluish-white and with normal markings. The body shape is thinner and longer. The cocoons are white, elongated with high constriction. The hybrid is used as initial form of (КК × Hesa 1) × (Vesletz 2 × Gergana 2) F1 four-way hybrid and reciprocal cross.

Vesletz 2 x Gergana 2 and the reciprocal: Uni-bivoltine Chinese type single hybrid. The egg serosa color is greenish gray, chorion color is yellow and eggs are sticky. The last instar silkworm larvae are bluish-white in color and plain. The body shape is thicker and shorter. The cocoons are white and oval. The line is used as initial form of (КК × Hessa 1) × (Vesletz 2 × Gergana 2) F1 hybrid and reciprocal cross.

SN1 x Iva 1: Bivoltine Japanese type single hybrid. The egg serosa color is gray, chorion color is white and the eggs are sticky. The last instar silkworm larvae are bluish-white in color, the female individuals have zebra marking and the male ones are with normal markings. The body shape is thinner and longer. The cocoons are white in color, elongated with high constriction.
The hybrid is used as initial form of the four – way F1 hybrid (SN 1 x Iva 1) x (Magi 2 x Nova 2) and the reciprocal.

Magi 2 x Nova 2: Uni-bivoltine Chinese type single hybrid. The egg serosa color is gray, chorion color is white, and the eggs are sticky. The last instar silkworm larvae are bluish-white in color, the females are zebra marked and the males are plain. The body shape is thicker and shorter. The cocoons are white in color, with oval shape. The hybrid is used as initial form of the four – way F1 hybrid (SN 1 x Iva 1) x (Magi 2 x Nova 2) and the reciprocal.