I. Breeding Objectives:

KSSRDI set the objectives to develop races with high survival rate and worked in the line of - Addressing Changing Scenario of the Industry.

  • Development of Bivoltine-hybrid combinations for the promotion and production of quality bivoltine raw silk.
  • Development of races to replace Pure Mysore in cross-breed combination.
  • Development of races to replace Male parent in cross-breed combination.
  • Development of suitable cross-breed combination for water constraint conditions.

II. Working Germplasm Bank of KSSRDI:

Working germplasm accessions are maintained at the following stations.

  • Silkworm Breeding Station, Bidadi.
  • Germplasm Bank. Ooty
  • KSSRDI sub-station, BR Hills

The genetic resources maintained at different stations are detailed in the following Table-1

Table-1. Silkworm Genetic resources of KSSRDI
Bivoltine Multivoltine
Silkworm Breeding & Genetics Section 31 6
Silkworm Germplasm Bank, OOTY 6 0
Silkworm Germplasm Bank, BR Hills 8 9
Total 45 15

Some of the special character races maintained at Germplasm Bank are:
KA(ye): non-pigmented but diapausing egg (npd).
KS-10: pigmented non-diapausing, thin denier (1.8)
CC(F): Sex-limited for Flesh colored cocoon.


III. Races developed at KSSRDI:

The list of races developed at KSSRDI and their salient characters are given in Table-1. The hybrid combinations and field data are presented in Table-2 and Table-3.

Table-1: Silkworm Races developed at KSSRDI.

Bivoltine

Sl.No

Race

Larval character

Cocoon Character

Year

1

NP2

Plain

White, Dumbbell

1995

2

SP2

Plain

White, Dumbbell

1995

3

KSO-1

Plain

White, Oval

1997

4

KSD8

Sex Limited

White, Dumbbell

1998

5

NP4

Plain

White, Dumbbell

1998

6

HND

Sex Limited

White, Dumbbell

1998

7

NTCM

Plain

White, Dumbbell

2000

8

CTM

Plain

White, Oval

2000

9

NK2

Plain

White, Oval

2002

10

BRO2

Plain

White, Oval

2006

Multivoltine

Sl.No

Race

Larval character

Character

Year

1

SL-KSPM

Sex Limited

Green, Spindle

1994

2

MH1

Marked

Creamish, Spindle

1996

4

C110

Plain

White, Oval

2003

3

KS10*

Plain

White, Oval

2005

*Anti-diapausing race

combinations developed at KSSRDI.

Bivoltine

Sl.No

Hybrid

Year

CSR%

Features

1

NP2 x KSO1

1995

19.5

Robust, ideal for summer, medium productivity, for average farmers, Advantages in rearing.

2

SP2 x KSO1

1995

19.5

Robust, ideal for summer, medium productivity, for average farmers, Advantages in rearing.

3

NTCM x CTM

2000

21.5

Robust, better productivity, for average farmers, Advantages in rearing

4

NK2 x NP4

2003

23.0

Productive, For rainy and winter, Advantages in rearing.

5

KSO1 x NP4

2003

21.0

Robust, for summer, for average farmers, Advantages in rearing.

6

NK2 x HND

2004

23.0

Productive, For rainy and winter, Advantages in rearing.

7

HND x NK2

2004

23.0

Sex Limited larva, Productive, For rainy and winter, Advantages in rearing.


Multi-Bivoltine

1

SL-KSPM x NB4D2

1995

17.5

Similar to PM x NB4D2, but with sex-Ltd larval markings

2

SL-KSPM x CSR2

2005

19.5

Similar to PM x CSR2, but with sex-Ltd larval markings

3

MH1 x NB4D2

1996

17.5

Robust, throughout the year, creamy-white cocoons. Advantages in rearing.

4

MH1 x CSR2

2005

19.5

Robust, more productive than MH1 x NB4D2, throughout the year, creamy-white cocoons. Advantages in rearing and post cocoon parameters.

5

CSR2 x KS10

2007

21.0

Overcomes hiberanation character of CSR2, high productive. Whte cocoons similar to Bivoltines.

6

PM x NK2

2008

19.0

Similar to PM x CSR2, Advantages in seed production.

Multivoltine

1

MH1 x C.Nichi

1996

14.5

Suitable for water stress areas. Superior to PM x C.Nichi

2

PM x CN2

2000

14.0

Suitable for water stress areas. Superior to PM x C.Nichi

3

PM x C110

2004

13.5

Suitable for water stress areas. Superior to PM x C.Nichi

Table-3: Field data of Hybrid combinations developed at KSSRDI.

Bivoltine

Control

Sl.No

Hybrid

Area (Districts)

Year

No. of dfls

Av. Yield (kg)

Av. Rate (Rs)

Av. Yield (kg)

Av. Rate (Rs)

1

NP2 x KSO1

Bangalore(U), Bng ®, Tumkur, Kolar

1999-2002

>10.0 Lakhs

42.00

153.16

42.0 (CB)

121.19

2

NTCM x CTM

Bangalore(U), Bng ®, Tumkur, Kolar

2001-2002

>50,000

47.00

148.15

44.0 (CB)

126.15

3

BRO2 x NP4

Bangalore(U), Ramnagar, Mandya, Kolar

2007- ongoing

> 25,000

59.00

138.23

52.3 CB, 42.0 BV

129.98 CB, 138.18 BV

4

NK2 x HND

Bangalore(U), Ramnagar, Mandya, Kolar

2007- ongoing

> 25,000

62.00

153.87

55.0 CB, 45.0 BV

132.97 CB, 146.11 BV

Multi-Bivoltine

Control

1

SL-KSPM x NB4D2

Bangalore(U), Bng ®, Tumkur, Kolar

1996-2002

> 102.00 Lakhs

41.50

110.50

41.00

110.50

2

SL-KSPM x CSR2

Bangalore(U), Kolar

2005-2007

>60000

58.40

133.80

57.00

131.80

3

MH1 x NB4D2

Throughout Karnataka

1997-2003

> 30.00 Lakhs

46.00

Rs 10-20 higher than PM x NB4D2

41.00

107.5

4

MH1 x CSR2

Throughout Karnataka

2005-2008

> 2.1 Lakh

60.00

123.83

55.00

103.32

5

CSR2x KS10

Ramanagara, Kolar

2007

>25000

63.00

141.00

57.00

131.8

6

PM x NK2

Bangalore(U), Ramanagara, Tumkur, Kolar, Mandya

2008- ongoing

>1.5 Lakhs

57.00

129.55

57.00

127.45

Multivoltine

Control

1

MH1 x CNichi

Chamaraja nagar, Mysore

1997-2003

> 3.00 Lakhs

44.50

Rs 10-20 higher than PM x Cnichi

32.00

Rs 80-100

2

PM x CN2

Chamaraja nagar, Mysore

2000-2002

>65,000

36.00

Rs 30 higher than PM x Cnichi

32.00

Rs 80-100

3

PM x C110

Chamaraja nagar, Mysore

2005

20000

38.00

Rs 10-20 higher than PM x Cnichi

32.00

Rs 80-100

It is well known that white cocoon spinning cross breeds have an edge over colored cocoon spinning cross breeds with respect to productivity and quality. Accordingly, white cocoon spinning productive polyvoltine race MH1 was bred during 1992-1996. During 1997-2003, the new cross breed MH1 x NB4D2 was popularized extensively across the state of Karnataka (Table-3). Department of Sericulture, Government of Karnataka had established separate seed area at H.D. Kote of Mysore district and Aurad of Bidar district for multiplication and supply of MH1 seed cocoons to Government grainages and LSPs. MH1 x NB4D2 hybrid has registered higher crop stability, productivity as well as improved tenacity and neatness. The raw silk is also suitable for use as warp. During 2003-08, MH1xCSR2 cross breed combination registering higher crop stability productivity and quality was popularized. Acceptability of this cross breed among farmers, graineurs, reelers, weavers and DOS, GOK is expected to catalyze the stepwise transformation of the industry from polyvoltine colored raw silk to polyvoltine white raw silk before shifting to all bivoltine raw silk as materialized in Tropical China.

For realizing better economic advantage in the cross-breed production, a sex-limited multivoltine race, similar to Pure Mysore, SL-KSPM was developed. The Department of Sericulture, Government of Karnataka took up the seed multiplication at the Pure Mysore seed area and, therefore, a large quantity of seed of SL-KSPM could be produced along with the Pure Mysore. SL-KSPM x NB4D2 entered the mainstream of cross breed production along with PM x NB4D2 with Government grainages and LSPs. Subsequently, CSR2 replaced NB4D2 in both the combinations (Table-3).

To improve the productivity of PM x C-Nichi in rain-fed zone of Karnataka, three cross breed combinations have been developed by KSSRDI viz. MH1 x C-Nichi, PM x CN2 and PM x C110 and are popularized (Table-3).



IV. Race authorization and Registration

The hybrid combinations that are authorized, submitted for authorization and patented are listed in the Table-9.

Table 9A: Hybrids Authorised by CSB

Sl.No

Hybrid

Voltinism

Year

Remarks

1

KSO1 x SP2

Bivoltine

1999

Fopr summer season, South and N. India

2

NK2 x NP4

Bivoltine

2010

For favorable seasons, N. and East India

3

KSO1 x NP4

Bivoltine

2010

For summer season, S. and N. India

4

MH1 x CSR2

Multi-Bivoltine

2010

For all Seasons, Throughout India.

5

PM x C110

Multivoltine

2010

For rainfed areas, S.and N. India

Table 9B: Hybrids under Authorization trials.

Sl.No

Hybrid

Voltinism

Year

Remarks

1

NK2 x HND

Bivoltine

2011-12

Productive, for favorable seasons

2

PM x NK2

Multi-Bivoltine

2011-12

For all seasons

3

BRO2 x NP4

Bivoltine

2011-12

Robust, For summer season

Table 9C: Patented Race

Sl.No

Race

Voltinism

Year

Remarks

1

KS-10

Non-diapausing

2005

Patented for Preventing diapause

KS-10, which has a unique character of overcoming diapause in bivoltines was developed during 2005. For the first time in the sericulture history of the world, KSSRDI has discovered a phenomenon wherein, by crossing the male parent of a non-diapausing race (KS-10) with the females of bivoltines, the diapause of the resulting F1 eggs can be overcome. This breakthrough technology of prevention of diapause through this method has been patented and new breeding concept in ‘Voltinism breeding’ has been initiated. Subsequently, similar phenomenon in working germplasm accessions of KSSRDI having pnd and npnd type of eggs was also observed.

Utilization of this technology is under field trial using the available bivoltines as females (that are rejected in the preparation of cross breed combination PM x CSR2) in the non-hibernating hybrid combinations, like CSR2 x KS-10 and NK2 x KS-10.

As per the field requirement as proposed by the DOS, Government of Karnataka, a new cross breed combination, PM X NK2 has been identified during 2007. NK2 has revealed better performance with P1 rearers and graineurs. Pathological studies through disease challenging has shown that the race is more robust. PM x NK2 is under field trial.

18 races are registered with CSGRC, Hosur.



V. Future strategies:

Keeping in view of the changing trends, the work is in progress in the direction of breeding of races with specific characters like:

  • High Shell content races.
  • Fine denier races (KS-10).
  • Genetically engineered disease tolerant races (DNA marker assisted NPV resistant).
  • Races for Kenchu virus resistance in multivoltine & bivoltine and Nuclear polyhedrosis virus tolerance in bivoltine donor parents.
  • Races with higher food conversion efficiency.
  • Collaborative work on molecular identification of ‘Id’ gene of KS-10.