Inclusive Market-Oriented Development (IMOD) – our approach to bringing prosperity in the drylands. ICRISAT is a member of the CGIAR Consortium. Nad7a_del marker for A 4 derived CMS lines Infusing genomics in hybrid breeding program of pigeonpea (Cajanus cajan) Saxena RK, Sameerkumar CV, Saxena KB, Lekha PT, Sinha P, Singh VK, Katta MAVSK, Kumar V, Hingane A, Srikanth S, Kulshreshtha A, Krishnamurthy L, Varshney RK * International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India *Address for correspondence: [email protected] Pigeonpea is an important pulse crop, well-suited for rainfed and semi-arid cropping system. The released draft genome sequence and commercial cytoplasmic nuclear male sterility (CMS)-based hybrids has been the significant contributions of ICRISAT. The pigeonpea hybrids- ICPH 2671, ICPH 2740 and ICPH 3762 have become popular by outperforming the local varieties with 30-40% higher yield in Asia under rainfed ecosystem. Breeding heterotic hybrids conventionally for different niches is a herculean task. Genomic approaches have been initiated to accelerate the hybrid breeding programs. With the large scale commercial hybrid seed production, ensuring the quality of F1 seed is of utmost importance. Towards this, marker based hybrid purity assessment kit has been developed for ICPH 2671. Identification of potential restorers, marker based purity assessment for hybrids, CMS (A-) and their maintainer (B-) lines derived from A4 systems are being carried out. In this regard, mitochondrial genomes of wild species (C. cajanifolius), the source of CMS, hybrid, A- and B-line have been sequenced and candidate genes (nad4l and nad7a) identified. In addition, a heterotic pool is also being generated using whole genome re-sequencing of parental lines of hybrids which will assist the existing hybrid breeding efforts. The advantage of two line hybrid breeding system has encouraged the evaluation and characterization of a temperature-sensitive male sterile line for its potential use. Various studies are being carried out at the molecular and cellular level to identify putative candidate genes that will help elucidate the underlying molecular mechanism. These efforts promise accelerated hybrid breeding program in Asia and other regions of the semi arid tropics. Abstract Performance of ICPH 2671 at multi-locations over 4 years Advantages of Hybrids More vigour More yield 44% greater shoot mass 40-50% greater root mass Greater drought tolerance Ideal for inter-cropping Pigeonpea Hybrid Breeding- ICPH 2671, ICPH 2740 and ICPH 3762 Genomic Initiative in Pigeonpea Hybrid Breeding Hybrid purity test kit Mitochondrial genome sequencing 9 rearrangements: ICPW 29 v/s ICPA 2039 22 rearrangements: ICPA 2039 v/s ICPB 2039 1 rearrangement: ICPA 2433 v/s ICPH 2039 Identification of putative candidate genes for A 4 derived CMS lines: nad7a and nad4l nad7a 51 genes identified • 34 protein-coding • 3 rRNA genes • 14 tRNA genes Defining heterotic pool EGMS line for 2-line hybrid system Male sterile Male fertile Expression profiling Structural variation identification nad4l