Crop Germplasm Conservation and Developing Countries

Abstract

Loss of the genetic diversity of some of the world's crops has accelerated in recent decades, with many crops becoming increasingly susceptible to diseases, pests, and environmental stresses. A global network of gene banks has therefore been established to provide plant breeders with the genetic resources necessary for developing more resistant crops that will enable farmers to maintain high yields. Most of these gene banks now store the germplasm of only the major crops such as cereals, potatoes, and grain legumes. Cultivated varieties of these crops are conserved as well as wild species that might otherwise become extinct. Tropical cash crops such as bananas and coconuts are also important food crops in many Third World countries, and more effort needs to be made to conserve the germplasm of these crops as well as of other important plants such as plantation crops, medicinal herbs, and fruit and timber trees.

Genetic diversity and environmental associations of wild emmer wheat, in Turkey

“…Modern plant breeding practices have reduced the genetic diversity in cultivated plants, including wheats, making them increasingly susceptible to diseases, pests, and environmental stresses (Plucknett et a!., 1983). Consequently, the maintenance of high world food production is severely threatened.…”

Artificial introgression of a large chromosome fragment around the rice blast resistance gene Pi-ta in backcross progeny and several elite rice cultivars

“…The surviving progeny with superiority on yield after disease epidemics were selected, and seeds were saved for next year. Thus, landraces have been a choice of breeding because they were selected from the field after years of adaptations, and can therefore offer a good package of disease resistance (Plucknett et al, 1983). The landraces, Tetep from Vietnam and Tadukan from the Philippines, have been used as donors for blast resistance worldwide.…”

“…Physical differences between wild relatives, landrace and cultivated rice can be easily determined with as few as 25 simple sequence (SSR) markers (Ram et al, 2007). In rice, blast disease caused by the filamentous ascomycete fungus Magnaporthe oryzae (formerly Magnaporthe grisea (Hebert) Barr) has been a limiting factor for production, and blast resistance (R) genes have been commonly bred into diverse elite rice cultivars from landrace varieties and wild relatives (Shigemura and Kitamura, 1954;Plucknett et al, 1983;Brar and Khush, 1997;Tanksley and McCouch, 1997). In the Southern US, blast epidemics occurred in the 1980s due to the widespread deployment of the susceptible cultivar Newbonnet (Lee, 1994).…”

J Trevor Williams (1938–2015): IBPGR director and genetic conservation pioneer

“…There would never have been an IPGRI, Bioversity [International] or [Global Crop Diversity] Trust if it wasn't for Trevor. ' During his IBPGR tenure and afterwards, Trevor authored or contributed to some important publications on the issues and challenges around plant genetic resources, including environmental concerns, climate change, food security, and future directions, among others (Plucknett et al 1983;Holden and Williams 1984;Plucknett et al 1987;Williams 1988;Williams 1990;Cohen et al 1991;Williams 1991). In his early writing, Trevor discussed the role of in situ conservation of crop wild relatives (Ingram and Williams 1984), and later on, models for in situ conservation (Maxted et al 1997), and the link between ex situ and in situ conservation in a cuttingedge commentary in Diversity (Williams 1993 (Smith et al 1992), and through the TTP became a scientific and policy adviser to the Bamboo and Rattan Research Network in Asia, initially an informal network supported by Canada's International Research Development Centre (IDRC).…”