This is especially so as more oil expression is tending to occur in producing countries. Germplasm resources are perhaps unique among our human resources in that their utilisation and exploitation does not necessarily exhaust them, and ideally should never do so. The evolutionary history of the legume family sheds some light on the problem. The legumes have a vital role to play in both the developed and developing worlds by providing an alternative nitrogen source to the artificial fertilizers, which, although boosting cereal yields, often have had adverse environmental effects. These considerations may, in particular circumstances, be outweighed by economic factors, but they should not be overlooked in policy formulation.
A more detailed breakdown is given in Aykroyd and Doughty 1982. Differentiation of genomes within a section can occur and has obviously progressed in section Arachis. Natural or artificially induced hexaploidy restored a relatively high level of fertility Kumar et al, 1957; D'Cruz and Chakravarty, 1961; Smartt and Gregory, 1967. The latter possibility makes good phytogeographic sense in that both putative genome donors have been found in north-western Argentina and adjacent parts of Bolivia. The editors are to be congratulated in bringing together a range of authorities and combining their contributions to produce a work that is broad but still has sufficient depth.
Immature pods Pulses which produce pods that remainfleshyfor two or three weeks after setting can be picked green and used as a vegetable. Certainly the problem of low yields appears to be very intractable to the breeders of many grain legume species, but so it did to those working forty years ago in East Africa on the groundnut scheme. Cytology and cytogenetics 55 These are less plausible on phytogeographic grounds but credible morphologically, biochemically and cytogenetically. Introduction - biosystematics of the legumes; 2. In the Old World it seems that a pastoral phase either pre-existed or co-existed with the early phases of arable agriculture, and so domesticated animals which could be used both as beasts of burden and sources of food meat and milk have been a long established feature of agricultural systems. However, this should provide some incentive to those taxonomists who are also interested in the broader and deeper ecological and genetical aspects of species differentiation to interest themselves in economic plants.
It is interesting to note that all selections made by Stalker et al. Smith and Dr Ray O. It appears that pulses have evolved not by producing novel characters under domestication, but rather novel combinations of characters already expressed in wild forms. For example there is strong morphological resemblance between A. The major variable in these three situations is the wild species genome. Provided that there are nitrogen reserves in the plant, these can be mobilised and translocated to the sink of developing pods.
The first inter-specific hybrid between wild species reported in the literature was produced by Raman and Kesavan 1962. It can be seen that taxonomically they comprise a small number of groups of rather closely related species. It would be of great interest to have more detailed surveys of the pattern of utilisation of pulses in Latin America. The role of genera in the Trifolieae has been particularly well studied in enhancing soil nitrogen status. Variation of pod morphology within A.
A high hybridization efficiency was achieved when P. Thus, the soybean is paired with rice in China; peas,lentils and chickpeas with wheat and barley in the Fertile Crescent; beans withmaize in the New World; and cowpeas with sorghum in Africa. Arachis provides an insight into a probable mode of evolution for the cultivated groundnut. Resslar and Gregory 1979 and Stalker and Wynne 1979 have reported additional hybrids between species of sect. Additive inheritance of flavonoids has been shown in an inter-specific hybrid derivative, A. These range from highly toxic alkaloids Laburnum anagyroides Med.
Arguably the most practically useful germplasm resources are in the main those which have evolved subsequent to domestication. Lima bean Peru Phaseolus vulgaris L. Wild bean North America Tylosema esculentum Burchell Schreiber Marama bean South Africa Fig. Hitherto, empirical approaches to screening germplasm for phenological events such as times to flowering have predominated in food legume breeding programs. Where genetic isolation is complete we have no difficulty in distinguishing taxa at the species level or above. The work is arranged in 15 Chapters including a relatively brief Introduction by the editors.
However, in meiotic preparations of A. . The Old World pulses - Vigna species; 6. The grain legumes are a valuable crop possessing the ability to fix nitrogen by Rhizobium biosynthesis and thus contribute to the natural nitrogen cycle. Primitive rhizomatous forms are diploid; the more abundant and more robust forms are tetraploid Gregory et al. Some exploitation of this large resource may be possible through the use of bridging inter-sectional crosses, for example sect. Scientific name, common name and regions of diversity ofprimary grain legumes.