Drought tolerant wheat varieties developed through mutation breeding technique
AbstractIn search for higher yielding drought tolerant wheat varieties, one of the Kenyan high yielding variety 'Pasa' was irradiated with gamma rays (at 150, 200, and 250gy) in 1997 so as to induce variability and select for drought tolerance. Six mutants ((KM10, KM14, KM15, KM18, KM20 and KM21) were selected at M4 for their drought tolerance screening. The six mutants and 2 checks, Duma and Pasa were tested for their performance in a National performance trial. The study was carried out as a National Dryland Wheat Performance Trial in 4 sites in Kenya and selection done for two seasons, 1999 and 2000. The sites were Katumani, Naivasha, Lanet and Mogotio, which represent marginal rainfall areas in Kenya. Randomised complete block design was used and replicated three times. Data on plant height, yield and hectolitre weight were taken. The results showed that mutant line KM21 and KM14 performed significantly (P<0.05) better than the other elite lines in yield performance. They also yielded significantly higher (P<0.05) than the parent 'Pasa' in most of the sites while KM14 had the highest average yield across sites in both years. In Lanet and Katumani they performed better than variety 'Duma', which was used as the check variety in the dryland. The two mutants were presented to the National technical release committee in the year 2001, to be considered for release. KM14 was accepted and has now been released for commercial production in the marginal areas of Kenya as Njoro BW1. This study clearly demonstrated the usefulness of mutation as a tool of creating variability in wheat especially for complex traits like drought tolerance.
Keywords: mutation, drought tolerance, bread wheat and yield stability
Journal of Agriculture, Science and Technology Vol. 7(1) 2005: 18-29