The agronomic data for derivatives from these two interspecific crosses showed that none of the derivatives was significantly superior in yield or TKW but all of them had much better protein content, especially the line derived from (Haurani/Kotschyi-SY 20224//Haurani,) cross which had a protein content of 16.1 per cent, compared to 11.8 per cent and 13 per cent for Waha and Haurani, respectively. Ibis particular cross was also resistant to yellow rust, although one of its parents, Haurani, is not.

The durum x kotschyi derivatives also had far greater cold tolerance and were significantly taller than the parents, which is a desirable trait for sever moisture stress situations. The durum x< zhukovskyi derivatives also showed a higher level of cold tolerance. There was a significant difference in plant height, which ranged from 110 to 130 cm compared to 90 cm for Waha's and 145 cm for Raspinegro, the two durum wheat parents employed in the cross.

Through the use of locally adapted germplasm of WANA and wild forms of Triticum a large number of cultivars (Table 4) in Triticum aestivum, T. durum and Hordeum vulgare have been released in a number of countries.

However, with the release of improved cultivars with better tolerance to prevalent biotic and abiotic stresses and with their wide adoption by the farmers in the stressed environments has put up a threat to the elimination of naturally occurring genetic diversity. This diversity is further threatened by the expansion of wheat cultivation to marginal areas to meet the ever increasing food demand due to high population growth in the WANA countries covering fertile crescent which is the primary center of genetic diversity.

The conservation of this immensely important natural resource for the future generations is beyond the concepts and means of any single nation. Therefore an international approach to conserve the biodiversity in situ, which ultimately will also help in preservation of fast deteriorating environments is urgently warranted.


Conclusions

1. West Asia and North Africa is still the richest source of genetic diversity in wheat.
   
2. Diversity is related to source of origin.
   
3. Significant differences occur between various traits at different evaluation sites.
   
4. Characters associated with stress tolerance are in high frequencies in certain regions.
   
5. Considerable diversity in certain traits was observed within a location.
   
6. Though there is still great unexploited diversity in cultivated forms but wild species provide a rich reservoir of desirable genes.
   
7. Modern agriculture is eroding naturally occurring diversity. There is a need to create safe havens to conserve biodiversity in its natural habitat.
   
8. International Networking in Conservation, Evaluation and Utilization of naturally occurring diversity will be the right approach to save the natural resource and conserve the environments.
   
9. Internationally coordinated efforts are needed to enhance and expand genetic diversity.

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