Pigeonpea - A unique jewel in rainfed cropping systems

Pigeonpea is a crop for rainfed environments endowed with several features to thrive harsh climate. It adapts well in sole crop and inter cropped conditions (with cereals, millets, oils seeds and pulses) by enhancing the system productivity and net income to the small and marginal farmers across the globe. The range of maturity duration in the crop allows it to grow in diversified cropping systems and patterns in varied ecoregions of the world. Development of cytoplasmic male sterility based hybrids provided an opportunity for enhancing the yields under marginal environments. With recent interventions in addressing the photo sensitivity and maturity have led to evolving super early varieties with less than 100 days duration, provided a scope for horizontal expansion of the crop in different agro ecological systems

Hybrid Technology–a new vista in pigeonpea breeding

Once designated as an ‘orphan crop’ to now being crowned as a mainstream ‘commercial crop’, pigeonpea has evolved over the decades as lifeline for millions of resource poor farmers in the semi-arid tropics, where it is cultivated for both subsistence and commercial purpose.Pigeonpea [Cajanus cajan (L.)] is the sixth most important legume crop, grown predominantly in the tropical and sub-tropical regions of Asia, Africa and Latin America. India is considered as the center of origin of pigeonpea (Van der Maesen, 1980) because of its natural genetic variability available in the local germplasm and the presence of its wild relatives in the country..

Translational Pigeonpea genomics consortium for accelerating genetic gains in Pigeonpea (Cajanus cajan L.)

Pigeonpea is one of the important pulse crops grown in many states of India and plays a major role in sustainable food and nutritional security for the smallholder farmers. In order to overcome the productivity barrier the Translational Pigeonpea Genomics Consortium (TPGC) was established, representing research institutes from six different states (Andhra Pradesh, Karnataka, Madhya Pradesh, Maharashtra, Telangana, and Uttar Pradesh) of India. To enhance pigeonpea productivity and production the team has been engaged in deploying modern genomics approaches in breeding and popularizing modern varieties in farmers’ fields. For instance, new genetic stock has been developed for trait mapping and molecular breeding initiated for enhancing resistance to fusarium wilt and sterility mosaic disease in 11 mega varieties of pigeonpea. In parallel, genomic segments associated with cleistogamous flower, shriveled seed, pods per plant, seeds per pod, 100 seed weight, and seed protein content have been identified. Furthermore, 100 improved lines were evaluated for yield and desirable traits in multi-location trials in different states. Furthermore, a total of 303 farmers’ participatory varietal selection (FPVS) trials have been conducted in 129 villages from 15 districts of six states with 16 released varieties/hybrids. Additionally, one line (GRG 152 or Bheema) from multi-location trials has been identified by the All India Coordinated Research Project on Pigeonpea (AICRP-Pigeonpea) and released for cultivation by the Central Variety Release Committee (CVRC). In summary, the collaborative efforts of several research groups through TPGC is accelerating genetics gains in breeding plots and is expected to deliver them to pigeonpea farmers to enhance their income and improve livelihood

Super early pigeonpea varities and hybrids: New intervener for maximized, time specific dry land production

A neglected crop of yester-years, pigeonpea (Cajanus cajan[L.] Millspaugh) is a multi-purpose, versatile food legume, which has seen greater evolution in its plant architecture, duration and yield pattern as time passed. In rainfed ecologies across the globe, pigeonpea fits in as a remunerative option to the farmers. Frequent droughts in recent past have resulted in losses to crops such as cereals, millets and oil seeds, but pigeonpea in the same cropping niche provided at least minimum assurance to small and marginal farmers, owing to its drought tolerance and ability to withstand harsh environments. The enormous variability and plasticity of the crop provided an opportunity to breeders to develop super early maturity group with the life span of less than 100 days. The existing maturity duration -- early (less than 140 days) and medium (180 to 200 days) -- imposes restrictions on adaptation to drought. The super early genotypes provide the foundation for future pigeonpea breeding because of their earliness, photo insensitive nature, impressive per day productivity, adaptability across the varying range of altitudes, stress escape mechanism and niche to fit well in various agroecologist and cropping systems. Rapid generation turnover is a boon to breeders for faster introgression of traits of interest, to carry out studies on genetics of biotic and abiotic stress by developing mapping population within very short duration. In the above context, “super early varieties and hybrids, is a wonderful breeding material to secure future sustainable dry land pigeonpea production”

Next generation sequencing based transcriptomic studies for crop improvement in pigeonpea

Transcriptomic studies are rapidly evolving as a powerful tool with next-generation sequencing technology to understand gene functions and molecular mechanisms. RNA sequencing (RNAseq) provides a dynamic range for transcript detection and a better quantification of expression levels.With the availability of genome sequence in pigeonpea, RNA-seq was used to link the sequence information to phenotypic traits resulting from specific developmental processes. In pigeonpea, three-line hybrid breeding system is well-established; however, it is technically demanding and cumbersome. In order to explore the possibility of a two-line hybrid breeding system, a coherent transcriptomic approach supported by physiological and cytological data has led to the identification of a temperature-sensitive male sterile (TSMS) line. This line has been characterized for critical (tetrad) stage and temperature (23°C), and the identification of candidate genes involved in abscisic acid signaling for fertility reversion. Furthermore, a gene expression atlas (CcGEA) has been developed and transcriptomic profiles generated for studying pod and seed development with a dataset of 590.84 and 342 million paired-end reads, respectively in pigeonpea. These data have been analyzed for genes with differential, specific, spatio-temporal and constitutive expression. In addition, CcGEA identified a gene network of 28 co-expressed genes, including two regulatory genes, a pollen specific SF3 and a sucrose-proton symporter to be involved in pollen fertility, which has potential implication in seed yield improvement. In summary, this study, especially identification of TSMS and development of CcGEA, will accelerate on-going efforts to enhance genetic gains in pigeonpea

Pigeonpea improvement: An amalgam of breeding and genomic research

In the past five decades, constant research has been directed towards yield improvement in pigeonpea resulting in the deployment of several commercially acceptable cultivars in India. Though, the genesis of hybrid technology, the biggest breakthrough, enigma of stagnant productivity still remains unsolved. To sort this productivity disparity, genomic research along with conventional breeding was successfully initiated at ICRISAT. It endowed ample genomic resource providing insight in the pigeonpea genome combating production constraints in a precise and speedy manner. The availability of the draft genome sequence with a large‐scale marker resource, oriented the research towards trait mapping for flowering time, determinacy, fertility restoration, yield attributing traits and photo‐insensitivity. Defined core and mini‐core collection, still eased the pigeonpea breeding being accessible for existing genetic diversity and developing stress resistance. Modern genomic tools like next‐generation sequencing, genome‐wide selection helping in the appraisal of selection efficiency is leading towards next‐generation breeding, an awaited milestone in pigeonpea genetic enhancement. This paper emphasizes the ongoing genetic improvement in pigeonpea with an amalgam of conventional breeding as well as genomic research