Some Important Achievements
The present day crop plants are very different from the wild species. Mostly weeds, from which they originated. This change has been brought about by man through plant breeding. The extent of this change is often so great that is difficult to realise that the cultivated plants did come from the weedy wild species. This can be appreciated by comparing the cobs of a local variety of maize (S. mays) with those of ‘Ganga 101’ an improved maize variety. Clearly, the present –day crop plants were virtually reconstructed by man from weedy wild plants.
1. Semidwarf Wheat and Rice:
One of the most important developments of modern agiculture has been the production of Semidwarf cereal varieties, particularly of wheat and rice. The Semidwarf wheat varieties were developed by N.E. Borlaug and his associated at CIMMYT (International Centre for Wheat and Maize Improvement, Mexico. They used a Japanese variety Norin 10 as the source of dwarfing genes. In 1963, ICAR introduced several Semidwarf selections from CIMMYT. Kalyan Sona and Sonalika were selected from these materials. For more than one decase, these varieties were the most popular wheat varieties in India. A great majority of the wheat varieties now grown in the country are Semidwarf. These Semidwarf wheat varieties are londging resistant, fertilizer responsive and high yielding. They are generally resistant genes into their genotypes. This has greatly increased and stabilized wheat production in the country. These varieties are photoinsensitive and many of them are suitable for late planting. This has enabled cultivation of wheat in non-traditional areas like West Bengal.
Similarly, the development of Semidwarf rice varieties has revolutionised rice cultivation. These varieties were derived from dee-geo-gen, a dwarf, early –maturing variety of Japonica rice from Taiwan. Taichung Native 1 (TN1), developed in Taiwan and IR8, developed at IRRI (International Rice Research Institute) , Philippines , were introduced in India in 1966. They were extensively grown for few years, but were later replaced by superior semi dwarf varieties developed in India, E.g. Jaya, Rama, etc. The Semidwarf rice varieties are lodging resistant, fertilizer responsive, high yielding and photoinsensitive. Photoinsensitivity has allowed rice cultivation in non-traditional areas like Punjab. Even in traditional areas, rice- wheat rotation has become possible only due to these varieties.
2. Noblisation of Indian Canes:
Another noteworthy achievement is Noblisation of sugarcane. The Indian canes were of Saccharum barberi origin and were largely grown in North India. They were hardy, but poor in yield and sugar content. The tropical noble canes of Saccharum oficinarum origin had thicker stem and higher sugar content. But they performed badly in North India primarily due to low winter temperatures in this region. C.A . Barber , T.S. Venkatraman and others at the Sugarcane Breeding Institute, Coimbatore, transferred the thicker stem, higher sugar content and others desirable character from the noble canes to the Indian canes. This is commonly referred to as Noblisation of Indian canes. They also crossed Saccharum spontaneum, a wild species, to transfer disease resistance and other desirable characteristics to the cultivated species. Several high yielding varieties with high sugar content and well adapted to local climate have resulted from this breeding programme. At present, sugarcane breeding all over the world is based on the Noblisation technique.
3. Hybrid Millets:
The development of hybrid varieties of maize, Jawar and bajara, deserves a special mention. A programme to develop hybrid maize began in India over four decades ago in collaboration with Rockefeller and Ford Foundations. Several hybrid varieties have been released since then. The Ganga series of hybrids, E.g. Ganga Safed 2, and Deccan, are a few examples, similarly, several hybrids have been released in Jowar, E.g. CSH-1, CSH-2, CSH-3, CSH-4, CSH-5, CSH-6, CSH-9, CSH-10, CSH-11, etc. and in bajara E.g. PHB-10, PHB-14, BJ-104 and BK560. For certain reason, hybrid maize varieties could not become popular with the farmers. But in some states like Karnataka, hybrid varieties occupy large areas. More recently, composite varieties are being developed to overcome the difficulties encountered with the hybrid varieties. For Example Manjari, Sona, Vijay and Kisan are some the notable maize composite varieties. Some recently released composite are CO-1, NLD, Renuka, Kanchan, and Diara. The composite varieties often yield as much as the hybrid varieties and do not have the drawbacks of the latter. More notably, the farmers need not replace the seed every year in the case of composite varieties.
4. Hybrid Cotton:
India has achieved the distinction of commercially exploiting heterosis in cotton. The first hybrid variety of cotton was H4; it was developed by the Gujarat Agriculture University and released for commercial cultivation in 1970. Since then, several other hybrid varieties, E.g. JK HY1 , Godavary, Sugana, H6 and AKH468 (all within G.hirsutum), Varalaxmi, CBS 156, Savitri, Jayalaxmi and H2HC ( all G.hirsutum X G.barbadense), have been released for cultivation. The hybrid varieties are high yielding, and have high ginning outturn and good fibre quality. They are becoming increasingly popular with the farmers, according to an estimate, they occupy about 70% of the total area under irrigated cotton (this came to about 1.5 million hectares in 1985- 86). It is noteworthy that the farmers are more than willing to pay the high cost of the hybrid seed (around Rs. 50.00 per kg) which is produced by hand emasculation and hand pollination. Efforts to utilize cytoplasmic male sterility (CMS) for hybrid seed production have been successful and a hybrid based on CMS has been released. Hand pollination is essential for seed set on the CMS line. The cost of seed production is expected to be released to 10% of that incurred by hand emasculation and pollination technique. Recently, two hybrid varieties of desi cotton, viz G.cot, Dh-7 and G-cot, Dh-9, have been released.
These are only a few examples of the achievements of plant breeding in India. If we consider the achievement in other countries as well, the examples will be far too many to be listed.
1) The improved varieties generally yield 50-80 percent more than the existing local varieties, often the yield are much higher.
2) Due to resistance to diseases the improved varieties save the cost of plant protection; they also stabilise crop yields. In addition.
3) They offer numberous other advantages (consider the points listed under objectives of plant breeding). Thus plant breeding is of immense economic importance to a nation, especially to that with agriculture – based economy, like India. This fact is well appreciated by the government of India. This is evident from the elaborate All India Coordinated crop improvement projects for most of the important crop.