Varietal Improvement

Following the introduction of the Norin dwarfing gene-based high yielding varieties of spring wheat Sonora 64 and Lerma Rojo in the early sixties and the Dee-Geo-Wu-Gen dwarfing gene-based high yielding rice varieties Taichung (Native) 1 and IR8 in the mid-sixties, a major breakthrough in yield was achieved. Whereas high level of response to applied fertilizer combined with non-lodging habit ensured high yields, photo-insensitivity conferred wide adaptability and early maturity helped increase the cropping intensity.

India is one of the few countries to take immediate advantage of the phenomenon of hybrid vigor for improving the productivity of as many as 10 field crops. India's more than four decades long experience in hybrid technology prompted the ICAR to explore the possibilities of exploiting hybrid vigor in non-traditional crops like cotton, rice, rapeseed-mustard, safflower, sesame, pigeonpea etc., in addition to extending the hybrid technology of traditional crops like maize, pearl millet, sorghum, sunflower etc. to new and still underexploited niches. India has become the second country, after China, to make hybrid technology in rice a field reality. Now hybrids in rainfed crops like safflower and pigeonpea are also on the ground.

Success of hybrid technology in any crop plant depends on the efficiency of producing and supplying adequate quantity of quality seed. In spite of a wide choice of productive hybrids available in several crops, desired pace of growth in terms of area coverage is yet to be achieved. As hybrid culture in agriculture, cutting across crops and commodities and ir respective of the nature of the crop, is likely to prevail in the 21st century, accelerated hybrid research and development efforts are on. Intensified efforts through interdisciplinary modes of operation on tailor-made varietal development, with tolerance to multiple biotic and abiotic stresses, continue to be the priorty. In the chain of events, environmental impact assessment for realizing enhanced and sustained crop productivity are considered of importance. Biotechnology has emerged as an indispensable tool globally for crop improvement. It is essential that it become fully integrated with the conventional breeding program for achieving rapid growth in agricultural production. Recognizing this fact, resources are being mobilized to establish infrastructure facilities in different institutes/universities in the country for undertaking biotechnology research and education. Over the years, there has been rapid growth in this area and a number of organizations have graduated from tissue culture technology to recombinant DNA biotechnology.

Sustaining the enhanced production potential would be possible by engineering the plants against biotic and abiotic stresses. Sterility systems, derived from alien cytoplasms by genetically engineering male sterility in crops in a non-specific manner, would enhance the exploitation of hybrid vigor. Apomixis, as an extension of hybrid technology, would offer new promise in realization of hybrid advantage on a sustainable basis. Molecular markers could be linked to apo-mixis, which would facilitate marker-aided selection. Reduction in cost of production by replacing costly inputs like chemical fertilizers and pesticides would be possible. Genetic modification for better processing and storage, mechanical agriculture, and appropriate size, shape, color, flavor, texture, taste etc. of the useful part would open possibilities of an icing on the cake for a holistic approach in crop improvement and production.

Identification of physiological and biochemical determinants of metabolism, growth and development would be another essential component for research. Crop growth models linked with GIS and remote sensing would provide new opportunities to design eco-region specific plant type designs to extrapolate performance across different regions. The renewed emphasis on quality of food would make it imperative to understand plant regulation of nutrient uptake as it affects tissue composition and crop nutritional quality, including the efficiency of utilization of nutrients in the soil and plants by genetic and agronomic means.

Protected cultivation would be far more important, and it would be important to determine optimal environmental factors and desired crop characteristics for maximizing the production of greenhouse crops. For water-deficit environments, understanding the physiological effects of water stress and response to water availability would be necessary in order to manipulate genetically different crops for greater adoption and productivity. Understanding the mechanism of crop/ weed competition, allelopathy and host/parasite relationships to develop crop production strategies will contribute to sustainable crop management practices.

The vast majority of marine microorganisms have yet to be identified. Even for known organisms, there is insufficient knowledge to permit commercial exploitation. Oceanic organisms constitute a major share of the earth's biological resources and often possess unique structures, metabolic pathways, reproductive systems and sensory and defense mechanisms. They have adopted to extreme environments, ranging from the cold polar seas to the great pressures and temperatures of the ocean floor. Enzymes produced by marine bacteria are important in biotechnology due to their range of unusual properties. Some are salt resistant, a characteristic that is often advantageous in industrial processes. An unusual group of microorganisms from which enzymes have been isolated are the hyperthermophilic archae (archaeobacteria), which can grow at temperatures of over 1000°C and produce enzymes that are stable at high temperatures. Transferring genes of interest from marine into non-marine microorganisms would be an another area with unfathomed prospects.

Knowledge of the mechanisms underlying carbon allocation and sink-source relationships could help to modify the size of desired organs in a crop. Rhizobium strains with improved symbiotic properties for efficient nitrogen fixation, even in non-leguminous plants, is another possibility. Optimization of mineral nutrition, transport and assimilation in stressed environments to make the most of limited fertilizer input will contribute to efficient crop production. Engineering of oils for modern human diet and for use as feedstock for chemical industry is a real possibility. Production of enzymes in forage crops that will enhance the efficiency of their digestion by the livestock is another area with great promise.

The value of incorporating the shortlisted physiological traits has first to be demonstrated before recommending them as selection criteria. New opportunities using biotechnology approaches are now available to create genetic variation for physiological and biochemical traits, including those for realizing enhanced photosynthetic efficiency. Water is a major constraint in many parts of India. Hence, efforts to manipulate genetically different crops for greater adaptation and productivity in water-deficit environments would be important. Water deficiency coupled with salinity/alkalinity is another paradigm for research. Abrupt weather/temperature fluctuations is yet another challenging research area.

Was this article helpful?

0 0
Organic Gardeners Composting

Organic Gardeners Composting

Have you always wanted to grow your own vegetables but didn't know what to do? Here are the best tips on how to become a true and envied organic gardner.

Get My Free Ebook

Post a comment