Summary of wheat sterility research in Nepal

Wheat sterility in Nepal was first observed in 1964-65. Since then it has been increasingly reported, mainly from the eastern, central and western Terai. Yield losses have been as high as 95%. Cases have also been observed in the foothills as well as the high altitude areas of the eastern, central and western developmental regions. Factors linked with sterility include low or high temperature; dry and hot winds or abrupt change of weather conditions at the flowering period; nutrient deficiencies, particularly nitrogen and boron; genetic or varietal factors; thrips sucking the pollen; and moisture excess or stress at the flowering stage. The inconsistent and irregular trend of sterility occurrence indicates that different factors are responsible in different environments. It is suggested that the problem can be solved by the identification, evaluation and breeding of sterility-tolerant varieties.