In this essay we will discuss about:- 1. Distribution of Sorghum 2. Cultivated Species of Sorghum 3. Origin and Evolution 4. Reproduction and Pollination 5. Breeding Objectives 6. Breeding Procedures 7. Breeding Centres 8. Achievements.
Essay on Sorghum
Essay # 1. Distribution of Sorghum:
Sorghum is an important food crop of global significance which belongs to the family Gramineae. It is cultivated in tropical and subtropical climates especially in the semi-arid tropics the world over. Sorghum is a C4 plant and, therefore, has high photosynthetic efficiency.
The major Sorghum producing countries are Africa, India, China, Pakistan, USA, Australia, Argentina and Mexico. In India, major Sorghum growing states are Maharashtra, Gujarat, Tamil Nadu, Karnataka, Rajasthan and Madhya Pradesh. The grain is used as human food in various ways and stalk as animal feed. In south India, where winter is mild, it is also grown in rabi season.
Essay # 2. Cultivated Species of Sorghum:
There is only one cultivated species of Sorghum, i.e. Sorghum bicolour which is diploid (2n = 2x = 20). In Sorghum, the panicle has wide variability ranging from very open and loose to compact. Based on panicle morphology, there are five races of Sorghum, viz. Bicolour (open panicle and elongated grains), Guinea (open panicle and flattened grains), Caudatum (high yield and bright seed colour), Kafir (Semi compact to compact panicle and spherical grain), and Durra (round grains). The races Kafir and Durra have several useful genes. Stem juice of fodder Sorghum is sweeter than grain Sorghum. The important wild species are S. bicolour spp. arundinaceum (2n = 20) and S. halepense (2n = 4x = 40).
Essay # 3. Origin and Evolution of Sorghum:
It is generally accepted that Ethopia is the centre of origin of cultivated Sorghum. From there it spread to other parts of the world. The diploid wild species S. arundinaceum (2n = 20) is considered to be the likely ancestor of cultivated Sorghum. This wild species is still found growing in Ethopia and its adjacent regions.
Essay # 4. Reproduction and Pollination of Sorghum:
The cultivated Sorghum is seed propagated and self- pollinated. Natural cross pollination varies from 5 to 30% depending upon genotype and environmental conditions. Protogyny is common which promotes natural cross pollination. An isolation distance of 200 and 100 metres is essential for the production of foundation and certified seeds. Tillering is an important feature in Sorghum. Wild species propagate by rhizomes also.
Essay # 5. Breeding Objectives in Sorghum:
In grain Sorghum, the main breeding objectives are high yield, better quality, early maturity, wider adaptation and resistance to biotic (diseases, insects and parasitic weeds) and abiotic (lodging, salinity and drought) stresses. Major yield components are panicle size and type, grains per panicle, productive tillers per plant and test weight.
Quality characters include chapati and bread making qualities, protein and lysine contents. Major diseases of Sorghum are leaf blight, zonate leaf spot, downy mildew, rust, ergot or sugary disease and charcoal rot. Important insect pests are stem borer, stem fly and midge. Striga is a root parasite weed of Sorghum.
Essay # 6. Breeding Procedures in Sorghum:
Important breeding methods which are used for genetic improvement of Sorghum crop are introduction, pure-line selection, pedigree breeding, backcrossing, composite breeding and heterosis breeding. Disruptive mating and selection, biparental mating and recurrent selection procedures are effective in population improvement.
Biotechnology is expected to play significant role in future in genetic improvement of Sorghum. Somaclonal variation will help in developing resistant cultivars to biotic (diseases, insects and parasitic weeds) and abiotic (lodging, salinity and drought) stresses, besides early maturing cultivars.
Essay # 7. Breeding Centres of Sorghum:
International Sorghum improvement work is carried out by ICRISAT, Hyderabad. This centre also maintains global gene pool of Sorghum. ICRISAT has testing centres in different countries. New varieties are developed by multi-location testing in different countries. Testing centres are located in Nigeria, Kenya, Zimbabwe, Mexico and India.
In India, Sorghum breeding work is carried out by National Research Centre for Sorghum, Hyderabad and State Agricultural Universities. New varieties are developed after multi-location testing in coordinated project for 3-5 years.
Essay # 8. Practical Achievements of Sorghum:
In India, several high yielding varieties and hybrids have been developed for different states. Hybrids are developed by using cytoplasmic genetic male sterility. Kafir 60 is the source of male sterility. High lysine Ethiopian mutants (IS 11167 and 11758) are used for quality improvement.
Some important varieties and hybrids of grain Sorghum developed in India are listed below:
1. Hybrids:
CSH 1, CSH 2, CSH 3, CSH 4, CSH 5, CSH 6, CSH 9, CSH 10 and CSH 11 for kharif and CSH 7, CSH 8, CSH 12 and CSH 13 for rabi season.
2. Varieties:
CSV 1, CSV 2, CSV 3, CSV 4, CSV 5, CSV 6, CSV 7, CSV 8, CSV 9, CSV 10, CSV 11, CSV 12, CSV 13, M 35-1 and Swati for Kharif and CSV 7 R and CSV 8 R for rabi season.
Two varieties, viz. CSV 13 and SAR 1 have been released by ICRISAT. Variety SAR 1 is resistant to Striga, a parasitic weed of Sorghum in Andhra Pradesh and parts of Maharashtra.
No comments yet.