**17. Conclusion and future perspective**

Loss of genetic diversity has been recognized as a genetic bottleneck imposed on crop plants during domestication and through modern plant breeding practices. Allelic variation of genes originally found in the wild but gradually lost through domestication and breeding has been recovered only by going back to landraces. Landraces with increased biomass and total photosynthesis have potentially new allelic variation that should be exploited in plant breeding.

Landraces are heterogeneous with variable phenology, are low to moderate but stable edible yield and are often nutritionally superior. Traditional agricultural production systems in the past have played a vital role in the evolution and conservation of on-farm diversity, allowing farmers to circumvent crop failure by reducing vulnerability environmental stresses. A systematic evaluation of landraces for assessing the pattern of diversity is urgently needed to identify alleles for enhancing yield and adaptation to abiotic stress for raising the productivity of the staple food crops in stressful environments.
