Correlation studies to facilitate the selection of bread wheat varieties for the marginal areas of Kenya

Abstract

The development of wheat varieties for marginal areas is gaining importance in Kenya as 83 of the country is classified as marginal. Furthermore, Kenya imports about half of the national requirement for wheat and wheat products, taking a high proportion of the foreign exchange available. The selection of varieties to be grown in stress and non-stress environments can either be based on the mean yield in both environments or the yield difference between stress and non-stress environments (i.e. tolerance to stress). Eight wheat genotypes were grown in seven environments (three favorable and four marginal), and the relative yield losses were analyzed. Selection for tolerance to stress environments, using components of yield, could be effective when these components are highly correlated with yield. Plant height, tillers per plant, spikelets per head, seeds per head and ear length were found to be significantly correlated with grain yield. However, selection using yield components could not be recommended as a routine procedure since, in some situations, the correlation coefficients were small. The stability of these components was also variable