infusing genomics in hybrid breeding program of pigeonpea (cajanus cajan)
TRANSCRIPT
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 A4 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-croppingLocal check
Pigeonpea Hybrid Breeding- ICPH 2671, ICPH 2740 and ICPH 3762
Genomic Initiative in Pigeonpea Hybrid Breeding
Hybrid purity test kitMitochondrial 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 A4 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 profilingStructural variation identificationnad4l