Inter specific hybridization to introduce useful genetic variability for pigeonpea improvement1

Pulses occupy an important place in Indian agriculture. Within this protein-rich group of crops, red gram or pigeonpea occupies an important place among rainfed resource poor farmers because it provides quality food, fuel wood, broom and fodder.
Hybrids are plants that result from controlled cross-breeding of two different but specific varieties or breeding lines of the same species of plant. Wild species are important sources of resistance to biotic and abiotic stresses as they have evolved to survive droughts, floods, extremes of temperature (heat/ cold) and have the capability to with stand damage by insect pests and diseases. Ten alleles reported unique to inter-specific derivatives of Cajanus cajan × C. scarabaeoides. The presence of alleles unique to specific population or group indicates an inimitable genetic variability at certain loci. This information is valuable to categorise interspecific hybrids with exclusive genetic variability, whose selection can increase the allele richness of breeding population (Saxena, 2015).
High levels of resistance is available in wild Cajanus species, these are not being utilised adequately in pigeonpea breeding programs. The major limitation is due to the linkage drag and different incompatibility barriers between cultivated and wild species. Under such situations, pre-breeding provides a unique opportunity to expand primary gene pool by exploiting genetic variability present in wild species and cultivated germplasm and will ensure continuous supply of new and useful genetic variability into the breeding pipelines to develop new cultivars having high levels of resistance and broad genetic base (Sharma et al., 2013). The major limitation in successfully using Cajanus platycarpus for the improvement of cultivated pigeonpeais embryo abortion in the BC1 generation from the cross C. Platycarpus × C. cajan. This Cajanus platycarpus, although placed in the tertiary gene pool of pigeonpea, is now amenable to gene transfer with the development of suitable embryo rescue techniques (Mallikarjuna et al., 2011).

1. INTER-SPECIFIC HYBRIDIZATION TO INTRODUCE USEFUL GENETIC VARIABILITY FOR PIGEONPEA IMPROVEMENT Speaker: Vipin Kumar Pandey (Ph.D. Scholar) DOCTORAL SEMINAR I (GP-691) Presentation Date: 4-5-2018 Time:12 noon

2. Contents Introduction Genetic resources of pigeonpea Pigeonpea domestications bottlenecks Distant hybridization Use of interspecific hybridization Problems associated with interspecific hybridization I nterspecific hybridization techniques for pigeonpea improvement Useful genetic variability from interspecific hybridization Case study 1 Case study 2 Case study 3

3. INTRODUCTION ‘ P igeonpea ’ name was coined in Barbados ( Gowda et al ., 2011 ). Red Gram or Pigeonpea [ Cajanus cajan (L.) Millsp .] an ideal plant for sustainable agriculture It is a diploid ( 2n=22 ) It’s genome size is 808 Mbp . ( Varshney et a l., 2012)

4. It have large variation for days to maturity (97days to 299 days) ( Remanandan , 1990) I t is an excellent source of protein 20-22% ( S axena et al., 2010) In India 2015-2016 its area around 3.96 m ha, production of 2.56 million tons and productivity of about 646 kg/ha ( Source : Ministry of Agriculture and Farmers Welfare, Govt. of India, 2015-2016) INTRODUCTION

5. Genetic resources of P igeonpea Source Sharma et al., 2016

6. Diversity in genus Cajanus Cajanus cajan only domesticated species in C ajaninae. In RS Paroda gene bank at ICRISAT, Patancheru , india about 13,220 accessions of cultivated, 526 accessions of wild pigeonpea organised/ colected pigeonpea. 18 species from Asia, 15 species from Australia, and one species from W est Africa. Of these 13 are found only Australia, 1in the Indian subcontinent, 1 in West Africa. Source S harma and Upadhyaya , 2016

7. Wild Cajanus species identified as promising donors for important biotic/abiotic stress and agronomic traits Source Sharma et al., 2016

8. Pigeonpea Domestication Bottleneck/s Source - Mallikarjuna et al. , 2011

9. Hybridization Crossing between two genetically dissimilar parent is called hybridization . Hybridization between individuals from different species belonging the same genus (interspecific hybridization ). By using hand emasculation

10. Why use Interspecific hybridization

11. TECHNIQUES TO MAKE INTERSPECIFIC HYBRIDIZATION SUCCESSFUL

12. Pre-breeding using wild Cajanus species and pigeonpea cultivars for broadening the genetic base for pigeonpea improvement Source SHARMA et al., 2016

13. CMS system derived from wild pigeonpea CMS system Wild species A 1 C. Sericeus ( Ariyanayagam et al., 1995 ) A 2 C. Scarabaeoides ( Tikka et al., 1997 ; Saxena, and Kumar 2003 ) A 3 C. Volubilis ( Wanjari et al., 2001 ) A 4 C. Cajanifolius ( Saxena et al., 2005 ) A 5 C. acutifolius ( Mallikarjuna & Saxena, 2005 ) A 6 C. lineatus A 7 C. platycarpus ( Mallikarjuna et al., 2011 ) A 8 C. reticulatus

14. USEFUL GENETIC VARIABILITY FROM INTERSPECIFIC HYBRIDIZATION OF PIGEONPEA

15. ROLE OF INTERSPECIFIC HYBRIDIZATION IN CROP IMPROVEMENT

16. IMPACT ON UTILIZATION OF WILD SPECIES FOR PIGEONPEA IMPROVEMENT Source- Sharma et al. 2016

17. Pod formation in the cross ( Cajanus acutifolius × C. cajan ) × C. cajan . Case study 1 Immature seeds seen in BC1F1 hybrid pods ( C. acutifolius × C. cajan ) × C.cajan ;

18. INTROGRASSION LINEs (ILs) derived from Cajanus acutifolius having varieties for pod and high 100 seed weight Source – Sharma and Upadhyaya , 2016

19. Female parent , wild species Cajanus platycarpus . Male parent , cultivated pigeonpea Cajanus cajan . Case study 2

20. Embryo rescue in recurrent backcrosses

21. Female parent, wild species Cajanus platycarpus . Male parent , cultivated pigeonpea Cajanus cajan . F1 ( tetraploid ) hybrid between C . platycarpus × C. cajan . In- ovulo embryo culture to save aborting hybrid embryos. Hybrid embryo culture. Multiple shoots from hybrid embryo. In vitro rooting of hybrid shoots .

22. Case study 3 Fertile Cajanus cajan , completely male sterile F1 partially fertile F1 hybrid Morphology of pods ( Cajanus cajan on the left , C . lanceolatus on the right and in the center are the BC1 pods produced on male sterile F1 hybrid. Seed color in ( Cajanus cajan on the left and C . lanceolatus on the right and in the center are the BC1 seeds produced on male sterile F1 hybrid .

23. Anther sterile green contents . Degenerated microspores inside the anther at anthesis Sterile anthers devoid of pollen

24. ( L.S) of fertile bud at pre- anthesis stage . (T.S ) of fertile bud at pre- anthesis stage . L.S of sterile bud at pre- anthesis stage . T.S of sterile anther at pre- anthesis stage. Sporangium with tetrads . Anther wall layers showing epidermis, tapetum and inner wall layer Sterile anther lobe showing normal tetrads. Sterile anther lobe showing tapetal layer.

25. L.S of sterile anther at staminate stage showing intact tetrads. T.S of sterile anther with degenerating tetrads. Sterile anther shriveled and indehiscent at anthesis .

26. ACHIVEMENTS OF INTER-SPECIFIC HYBRIDIZATION Derived from Cajanus cajanifolius A 4 CMS Derived from Cajanus scarbaeoides A 2 CMS Derived from Cajanus volubilis Derived from Cajanus scarbaeoides Derived from Cajanus scarbaeoides Derived from Cajanus scarbaeoides Derived from Cajanus scarbaeoides Derived from Cajanus scarbaeoides Source K . B. Saxena et al., 2013

27. CMS LINES FROM INTERSPESIFIC HYBRIDIZATION

28. Conclusion

29. 8 Thank you