**14. Disadvantages**

and good quality [59]. The Southwest China, Guizhou, Yunnan and Guangxi provinces, is one of the largest centers of rice genetic diversity and high-quality germplasm in the world

The genetic variability found within landraces affords the possibility of genetic flexibility; landraces have the potential to adapt to local field conditions, and they can adapt to changing environments, farming practices and specific uses such as animal vs. human consumption [61]. Moreover, the genetic diversity of traditional landrace varieties is the most immediately useful and economically valuable component of rice biodiversity [19]. To efficiently conserve, manage and use such germplasm resources, an understanding of structure, apportionment and dynamics of local landrace variation is required. Several studies have examined genetic variation and differentiation among rice landrace varieties [62, 63]. However, little to no infor-

Local adaptation plays an important role in maintaining yields in traditional agricultural systems. Selection for adaptation to each village environment by the farmer's seed selection enhances overall crop diversity and maintains evolutionary flexibility [64]. Almekinders [21] explained that farmers' selection in combination with natural selection results in landraces with high levels of adaptation to biotic and abiotic stresses and for agricultural traits. For example, the genetic diversity of *Phaseolus vulgaris* landraces in Italy has been shaped by local adaptation to microenvironments [65], and in wheat, selection by farmers has strongly influenced the evolution of neutral loci [66].

**1.** Landraces provide a medium to advertise information about the conservation and use of

**2.** Crop improvement often utilizes landrace diversity in the development of new cultivars [8, 24], particularly when developing cultivars for marginal environments. Although, breeders more routinely focus their efforts on a limited gene pool of advanced cultivars or breeders' lines which are more easily utilized without successive backcrossing to eradicate

**3.** Landraces still present a unique source of specific traits for disease and pest resistance,

**5.** They have become important as sources of genetic variability in the search for genes for

**6.** Knowledge of genetic distance among landraces will help the breeding of high-yielding,

**7.** Landraces may provide new alleles for the improvement of commercially valuable traits. **8.** Global climate change emphasizes the need to use better adapted cultivars of the main

tolerance or resistance to biotic and abiotic factors of interest in agriculture.

mation is available on how genetic diversity is structured within a given landrace.

**13. Advantages of landrace over modern cultivated agriculture**

the undesirable traits introduced with the desirable [67, 68].

nutritional quality and marginal environment tolerance [8].

good quality cultivars that will increase crop production [14].

crops and landraces as potential donors of useful genes.

**4.** Landrace tolerance to advert climatic condition.

[21, 60].

14 Rediscovery of Landraces as a Resource for the Future

crop landraces.

**1.** 1. Landraces are generally less productive than commercial cultivars.
