what are characterstics of mexian varieties of wheat which is used for hybridisation
Answers
Until the 1960s breeding new varieties of wheat and other plants was confined to research institutions. This changed with the introduction of the 1964 Plant Varieties and Seeds Act, which allowed breeders to be paid royalties for the varieties they developed, known as plant breeders rights. As a result, most plant breeding is now carried out in the private sector, while the basic research is still carried out by institutions. Breeding new wheat varieties is also funded by a system of payments collected from farmers who collect and save seed from one year to the next. Patents are sometimes used to fund research, for example when a technology has been applied to more than one variety. Collection of payments and government representation is carried out by the British Society of Plant Breeders, founded in 1966.
Creating new wheat varieties is achieved using conventional artificial selection. In artificial selection breeders cultivate wheat plants and select only the specimens with the features deemed to be desirable for further cultivation. The first generation of offspring, the F1 generation, are uniform but F2 and later generations show an enormous diversity of different gene combinations. Therefore, generations of wheat plants are cultivated and with each generation the plants with the best combination of characters are selected for further breeding. This continues until only those with the best traits remain and undesirable features cease to emerge, a process that can take up to 12 years. Characteristics that might be selected for include crop yield, physical characteristics like height, the timing of crop maturation and resistance to disease, pests and environmental stress. The efforts of breeders have resulted in the recent appearance of ‘Alternative Wheats’ that can be planted in both winter and spring growing seasons. Artificial selection has also been used to shorten the life cycle of wheat, allowing it to be grown at higher latitudes with shorter growing seasons;
Some genetic technologies are now being used to streamline the process of artificial selection. Mapping the location of a desirable gene in wheat allows breeders to work out from an early stage whether or not it is present in an individual. Marker assisted breeding uses genes to label a desirable characteristic and determine whether or not it is present in a plant.
Genetic modification offers precise manipulation of characteristics by changing or deleting genes, or inserting new genes from other organisms. This allows the inclusion of desirable traits in the genome of a cultivated plant without other less desirable traits that might be introduced.
High Yielding Variety Seeds (HYV seeds) are seeds are of better quality than normal quality seeds. The produce from these seeds is a bit more compared to the normal ones. These seeds are a better option of seeds in order to obtain a healthy and surplus crop. These seeds have good immune system to fight with insects and other diseases. Another goods feature of these seeds is they needs very less irrigation care. These seeds played a very prominent role in the introduction of green revolution of India.
Under the new agricultural strategy, special emphasis has been placed on the development and widespread adoption of high-yielding varieties of seeds. Though the government had been paying attention to induce qualitative improvements in seeds ever since the initiation of planning process in the country, yet the real impetus to these efforts were given by the adoption of the new agricultural strategy in the Kharif season of 1966. In Mexico, Prof. Norman BorIaug and his associates developed new varieties of wheat which were early-maturing, highly productive and disease resistant during the mid-1960s and these varieties were imported and planted in selected regions of India having adequate irrigation facilities. Within a year of their introduction, it was conclusively demonstrated that the yields from the new varieties exceeded 25 to 100 per cent compared to the yields from traditional varieties. The Seventh Plan kept a target of 70 million hectares for coverage in area under HYV. As against this, the actual area under HYV by the end of Seventh Plan was only 63.1 million hectares. In 1998-99, the coverage rose to 78.4 million hectares.
Production of improved seeds and especially high- yielding varieties of seeds was encouraged on the farms of the Centre and the State governments and by registered seed growers. Side by side, Indian Council of Agricultural Research, Punjab Agricultural University at Ludhiana, G.B. Pant Agricultural University at Pantnagar and several other research institutes were engaged in the task of developing new hybrid varieties suitable to Indian conditions and in adopting imported varieties to Indian requirements. While in selected regions of the country Mexican varieties of wheat like Lerma Rojo-64-A and Sonara 64 were directly introduced in the initial period, considerable attention was later given to hybridisation of Mexican material with Indian varieties. Introduction of such high-yielding varieties of wheat depends crucially on the availability of fertilisers, adequate water supply, pesticides and insecticides. Therefore they have to be launched in the form of a 'Package Programme'. Because of their dependence on irrigation, they could be adopted only in areas having proper irrigation facilities. Indian seed programme includes the participation of Central and State Governments, ICAR, State Agriculture Universities, public sector, cooperative sector and private sector institutions.
Seed sector in India consists of two national level corporations, i.e., National Seeds Corporation (NSC) and State Farms Corporation of India (SFCI), 13 State Seed Corporations (SSCs) and about 100 major private sector seed companies. For quality control and certification, there are 22 State Seed Certification Agencies (SSCAs) and 101 State Seed Testing Laboratories (SSTLs). Though the private sector has started to play a significant role in the production and distribution of seeds particularly after the introduction of the New Seed Policy of 1988, the organised seed sector particularly for food crops and cereals continues to be dominated by the public sector. As far as the distribution of certified/quality seeds is concerned, it increased from 25 lakh quintals in 1980-81 to 277.3 lakh quintals in 2010-11. Unfortunately, the seeds revolution of 1960s and 1970s appears to have tapered off after encompassing only the cereal segment. Improved seeds technology continues to elude vital segments of the farm economy such as pulses, oilseeds, fruits and vegetables. As a result, the country has to import nearly 2 million tonnes of edible oils and about a million tonnes of pulses every year so as to meet the domestic demand. In the above context, the National Seeds Policy 2001 provides the framework for growth of the Seed Sector. It seeks to provide the farmers with a wide range of superior quality seed varieties and planting materials.