International Germplasm Collection, Conservation, and Exchange at ICRISAT

Germplasm is the most important raw material for any crop improvement program, and yet humankind continues to be faced with the extinction of this invaluable and irreplaceable resource. One of the best descriptions of genetic resources is given by Mehra and Arora (16) who stated, "Plant genetic resources represent the sum total of diversity accumulated through years of evolution under domestication and natural selection". Genetic manipulation (3) is advancing at a fast pace and the process may be even more accelerated by the application of genetic engineering techniques. But nothing can be achieved, even by genetic engineering, unless those desirable genes are at our disposal. Jain (11) considered germplasm as part of human biological heritage without whose free exchange present-day farm productivity would not have been possible. In this regard, the International Agricultural Research Centers strategically located at regions of rich crop diversity are in a unique position to collect and conserve germplasm and make it readily available to all scientists throughout the world

Genetic Resources Activities at ICRISAT

Established in 1979, the Genetic Resources Unit (GRU), ICRfSAT, is implementing short and long-term work plans in areas ofgermplasm collection, evaluation, maintenance, documentation, conservation and utilisation. The GRU has assembled 93,951 accessions in its gene bank from 125 centres which pertain to sorghum, pear/millet, chickpea, pigeonpea and groundnut. The status of these collections and the collaborative role ofGRU in collection and conservaiion of genetic resources in national and international context is stressed. Future lines ofactivity are indicated. There is a need to have duplicate germplasm conservation centres and collection of wild relatives is stressed. ICRISAT has developed short-term, medium-term and longterm conservation facilities and its gene bank is now operational

Study on the seroprevalence of small ruminant brucellosis in and around Bahir Dar, North West Ethiopia

A cross sectional study was carried out from October 2008 to April 2009 to determine the sero-prevalence of brucellosis in small ruminants in and around Bahir Dar, northwest Ethiopia. The sampling method used was purposive sampling technique for districts and simple random for the study animals. A total of 500 serum samples (270 from sheep and 230 from goats) were collected from extensive management system with no history of vaccination. All serum samples were initially screened by Rose-Bengal-Plate Test (RBPT) and positive reactors to RBPT (n=6) were further tested by complement fixation test (CFT) for confirmation. Accordingly, the overall prevalence of brucellosis in small ruminants was 0.4 % (2/500). Rose Bengal Plate Test detected 6 (1.2%) of the samples as seropositive. Up on further testing by CFT only 2 (0.4%) were positive which were adult goats. The seroprevalence of brucellosis was found higher in females (0.4%) than males (0%). Although seropositive animals are low in number, it was found out that animals more than 1 year of age were more affected than others. The result of the present study revealed that the seroprevalence of small ruminant brucellosis in the study area was very low. However, the existence of the disease in the study area has possible risk of spread in the future. Accordingly, elimination of positive seroreactors has been recommended to control the spread of brucellosis in these species of animals

Ultrastructural and molecular characterization of altered plastids in nuclear gene controlled yellow stripe mutant of Pennisetum americanum

The ultrastructural and molecular biological studies were conducted to elucidate the changes in the nuclear gene controlled plastid alterations in yellow stripe mutant of Pennisetum americanum. The plastids in yellow tissue were bound by a double membrane envelope and no internal thylakoid membrane differentiation, whereas plastid development was normal in the green tissue. The nuclear gene apparently influences the individual plastids as evidenced by the presence of heteroplastidic cells. Ribosomal RNAs were extracted from green and yellow seedlings with homozygous recessive and heterozygous genotypes. Plastid specific 23S and 16S rRNAs were absent in the yellow seedlings irrespective of the genotype. The presence of disorganized lamellar membranes in the rRNA/ribosome deficient plastids indicate that they are synthesized outside the plastid compartment. Restriction endonuclease analysis revealed no detectable differences in fragmentation pattern of the plastid DNAs from green and reverted green seedlings. This is consistent with the suggestion that the nuclear gene is not inducing any change in the plastid genome size and in the restriction enzyme recognition sites

Inheritance of stripe in pearl millet

A nonlethal chlorophyll-deficient mutant named stripe was detected in a pearl millet (Pennisetum americanum (L.) Leeke) accession IP-5009 collected from Nigeria. The stripe plants showed longltudinal yellow stripes alternating with green stripes on leaf blades, leaf sheaths, stems. peduncles, inflorescences, and spikelets. The stripe plants segregated yellow, stripe, and green depending on the number and size of the yellow stripes on the leaf blade. Segregation data from crosses of green and stripe plants did not fit a definite Mendelian ratio. The spikes of the stripe plants have yellow and green spikelets and when yellow spikelets were crossed with green spikelets, segregation data indicated that the yellow spikelet color was monogenic recessive to the green color. Since the yellow and green sectors that are genetically different from each other lie adjacent to each other, the stripe plants are considered to be chimeras

Germplasm Exchange and Plant Quarantine Systems at ICRISAT

The germplasm is considered as a pan of human biological heritage without whose free exchange and availability, present day farm productivity would not have been possible (Jain. 1982). Therefore. collection, evaluation, utilization, conservation and exchange of genetic resources assume considerable significance, especially in view of the rapid degradation and exploitation of the available biodiversity all over the world (Mehra and Arora, 1982; Mengesha. 1984; Paroda and Arora. 1986; Paroda, 1989). Considerable efforts are being made worldwide to conserve the genetic resources of important crop plants. Free exchange of diverse germplasm is essential. Genetic manipulation is advancing at a fast pace and the progress may even be more accelerated by the application of genetic engineering techniques in the future (Law, 1986)

World germplasm collections and their potential in crop productivity

Effective and imaginative utilization of the large variability assembled in the collection of genetic resources of cereals and legumes determines the potential and adaptation of future varieties. Modem method of characterization such as restricted fragment length polymorphism (RFLP)…………………….

Seed drying for germplasm conservation

Orthodox seeds can be dried to low moisture contents with considerable advantage to longevity. Seed drying involves the evaporation of moisture from seed surface into the outer atmosphere ana is influenced primarily, by the gradient in relative humidity between the seed and drying environment. The various methods of drying seeds to reduce moisture content for subsequent storage were discussed. Sun-drying, although is the cheapest method usually practiced, affects seed quality and is impractical in humid tropics due to the prevailing high relative humidity. While using commercial seed dryers for artificial during, proper control of the air temperature is essential to minimize seed deterioration. A low temperature-relative humidity drying is recommended to reduce the moisture content to 5±2 per cent for long-term conservation of the germplasm seeds. The relative advantages and the associated problems in drying seeds to such low moisture content are discussed