B. B. Singh

Genetic improvement of mungbean and urdbean and their role in enhancing pulse production in India

The initial varietal development in mungbean and urdbean focused mainly on selection from landraces or the germplasm samples collected, purified and evaluated. However, systematic efforts were made by National Agricultural Research System comprising Indian Council of Agricultural Research and State Agricultural Universities through All India Coordinated Pulses Improvement Project for varietal improvement. National Bureau of Plant Genetic Resources and AICPIP centres collected over 8,000 Vigna genetic resources and also introduced germplasm from other countries and made them available for evaluation. Several resistant donors were identified and used to transfer gene(s) for biotic stresses. As a result, a number of high yielding varieties were developed through intraspecific hybridization. Large numbers of these varieties are resistant to one or more major diseases of the specific agro-eclogical niches. Six varieties in mungbean and two in urdbean were also developed through inter-specific hybridization which had new plant type and resistance to prevalent diseases. However, limited success has been achieved for the development of varieties with resistance to insect-pests and abiotic stresses. There is a need to intensify research in these areas through introgression of desirable alleles from secondary and tertiary gene pool into the cultivated type for yield, photo period and temperature insensivity and insect pest tolerance. The onset of genomics provides massive amount of information, but the success will depend on precise phenotyping to achieve desired restructuring in existing plant type.

Enhancing pulses production in India through improving seed and variety replacement rates

India is the largest producer, consumer and importer of pulses in the world. Pulses are important for the nutritional security of the cereal based vegetarian diet of large population of India. Due to ever increasing population, rising income of people and pulses being the major source of protein in Indian diet, the demand for pulses continues to grow at 2.8% per annum. It is estimated that 27.5 million tonnes of pulses would be required by 2025. Since more than 80% of the area under pulses is under stressed rainfed environment, the quality seed of improved varieties has emerged as the most vital input for enhancing pulses production in India. For ensuring availability of quality seed it was estimated that 39.38 lakh q and 46.87 lakh q quality seed of improved varieties would be required in 2020 and 2025, respectively, at increased seed replacement rate (SRR). The SRR of all the pulses under study showed an increasing trend during the last decade. This could be further increased with vibrant formal and informal seed system involving public and private seed industries and promotion of participatory seed production programmes. Since pulses are grown in diverse agro-climatic situations under severe biotic and abiotic stresses, the varietal diversity in seed chain also assumes greater importance. Seed chain is currently being maintained with 236 improved varieties of six major pulses. However, only 44 of them occupied prominence in seed chain and could contribute significantly to increased pulse production in recent times. There is further need to bring sufficient number of high yielding and disease resistant varieties in seed chain which should adequately represent all pulse growing areas in the country. The present paper discusses the options of yield enhancement in pulses through increased availability of quality seed and strategy for enhancing variety replacement, rate (VRR) and seed replacement rate (SRR) of major pulses, viz., chickpea (Cicer arietinum L.), pigeonpea (Cajanus cajan L.), mungbean (Vigna radiata L. Wilczek), urdbean (Vigna mungo L. Hepper), lentil (Lens culinaris L.) and fieldpea (Pisum sativum L.)

Molecular Strategies for Fungal and Nematode Resistance

Fungal pathogens and plant parasitic nematodes are prominent in causing diseases in legume crops. Chemical control of nematodes and fungi are not very effective and also cause product contamination. Molecular biology has made it possible to identify and clone genes associated with pathogenesis related proteins, anti-fungal proteins and compounds, phytoalexins and enzymes controlling oxidative burst, etc. which lead to a number of transgenic plant developments. It has also been possible to overexpress them constitutively in several transgenic crop systems. In a majority of cases it was proved that these anti-fungal proteins are very effective against various fungal pathogens. RFLP (Restriction Fragment Length Polymorphism) has made it possible to generate high-density maps of various commercially important crops including peas. However, progress of molecular mapping and gene tagging is limited due to availability of low degree of polymorphism using conventional DNA markers like RAPD and RFLP. In recent years, development of microsatellite based markers and AFLP has produced adequate polymorphism in a number of grain legumes like chickpea which otherwise was shown to be low polymorphic. Besides, there are also some successful examples of gene tagging using these markers for fungal diseases and nematode resistance in grain legumes.