Modern agriculture and conventional breeding and the liberal use of high inputs has resulted in the loss of genetic diversity and the stagnation of yields in cereals in less favourable areas. Increasingly landraces are being replaced by modern cultivars which are less resilient to pests, diseases and abiotic stresses and thereby losing a valuable source of germplasm for meeting the future needs of sustainable agriculture in the context of climate change. Where landraces persist there is concern that their potential is not fully realised. Much effort has gone into collecting, organising, studying and analysing landraces recently and we review the current status and potential for their improved deployment and exploitation, and incorporation of their positive qualities into new cultivars or populations for more sustainable agricultural production. In particular their potential as sources of novel disease and abiotic stress resistance genes or combination of genes if deployed appropriately, of phytonutrients accompanied with optimal micronutrient concentrations which can help alleviate aging-related and chronic diseases, and of nutrient use efficiency traits. We discuss the place of landraces in the origin of modern cereal crops and breeding of elite cereal cultivars, the importance of on-farm and ex situ diversity conservation; how modern genotyping approaches can help both conservation and exploitation; the importance of different phenotyping approaches; and whether legal issues associated with landrace marketing and utilisation need addressing. In this review of the current status and prospects for landraces of cereals in the context of sustainable agriculture, the major points are the following: (1) Landraces have very rich and complex ancestry representing variation in response to many diverse stresses and are vast resources for the development of future crops deriving many sustainable traits from their heritage. (2) There are many germplasm collections of landraces of the major cereals worldwide exhibiting much variation in valuable morphological, agronomic and biochemical traits. The germplasm has been characterised to variable degrees and in many different ways including molecular markers which can assist selection. (3) Much of this germplasm is being maintained both in long-term storage and on farm where it continues to evolve, both of which have their merits and problems. There is much concern about loss of variation, identification, description and accessibility of accessions despite international strategies for addressing these issues. (4) Developments in genotyping technologies are making the variation available in landraces ever more accessible. However, high quality, extensive and detailed, relevant and appropriate phenotyping needs to be associated with the genotyping to enable it to be exploited successfully. We also need to understand the complexity of the genetics of these desirable traits in

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Determination of germplasm diversity and genetic relationships among breeding materials is an invaluable aid in crop improvement strategies. This study assessed the breeding value of tomato source material. Two commercial hybrids along with an experimental hybrid and four cultivars were assessed with cluster and principal component analyses based on morphophysiological data, yield and quality, stability of performance, heterosis, and combining abilities. The assessment of commercial hybrids revealed a related origin and subsequently does not support the identification of promising offspring in their crossing. The assessment of the cultivars discriminated them according to origin and evolutionary and selection effects. On the Principal Component 1, the largest group with positive loading included, yield components, heterosis, general and specific combining ability, whereas the largest negative loading was obtained by qualitative and descriptive traits. The Principal Component 2 revealed two smaller groups, a positive one with phenotypic traits and a negative one with tolerance to inbreeding. Stability of performance was loaded positively and/or negatively. In conclusion, combing ability, yield components, and heterosis provided a mechanism for ensuring continued improvement in plant selection programs.

to compensate for the declining native variability by deliberate maintenance. This study is an attempt to describe a functional breeding andMajor breeding objectives in snap bean (Phaseolus maintaining program of intraselection in a traditional snap bean vulgaris L.) concern the development of cultivars com-(Phaseolus vulgaris L.) cultivar. The program was applied in three bining high productivity, stable yields, earliness, pest stages. The first thing examined was the existing genetic variability of source material for earliness and pod yield potential. Single-plant and disease resistance, tolerance to environmental frequency distributions with positive skewness for earliness showed stresses, and desirable agronomic-horticultural attrithat the frequency of unfavorable alleles was high. For total pod butes (Silbernagel, 1986; Singh, 1992). The achievement yield, distribution was found normal. Thus, the end-target should be of such objectives should take into account the cropping selection for early maturity, keeping, and stabilizing high yield. The systems, the ecological conditions, and the preference seed shape uniformity was added as third criterion of selection. Secof consumers in the target areas. In temperate areas ondly, combined pedigree intraselection, based on widely spaced sinof monocropping and intensive cultivation, mechanical gle-plant performance, for the prementioned traits was applied for cultivation, and industrial processing of the final product three successive generations. The evaluation of the third-generation have directed efforts to breed varieties with determinate families revealed progenies with high yield, earliness, and stability of bush type, short duration, concentrated pod maturation, performance. Thirdly, the end-product of the program applied was and uniformity in plant height, seed shape, and size. to restore or even improve the cultivar. The evaluation of improved selections of fourth-generation families and of the source material, Much of the genetic improvement of snap bean has at dense stand, showed that all families were the only ones producing been achieved through the selection of varieties by high and stable early fresh pod harvest, even 53 d after planting applying conventional breeding techniques of self-polli-(53.25-80 g/plant, compared with 0 g/plant of the control). The total nated crops (Singh, 1992) such as bulk, pedigree, backpod yield of all the families was 219 to 276% superior compared cross, and their modifications (Brim, 1966) such as the with source material. Conclusively, the widely spaced single-plant single seed descent method. Conventional pedigree secombined pedigree intraselection was proved reliable and effective lection based on visual evaluations may be difficult, in restoring or even improving the local cultivar of snap bean according especially for traits with low to moderate heritability to update demands.such as seed yield (Patino and Singh, 1989). Bulk breeding methods were effective for endowing genotypes with a better yield stability (Allard,...

In this work, the part of the squash core collection, maintained in the Greek