Effect of genotype and rainfall on yield and quality of forage barley and wheat varieties in a semi-arid region

Abstract

SummaryThe effect of rainfall on dry-matter (D.M.) yield, D.M. content and crude protein (CP) content of eight barley and three wheat varieties was studied under semi-arid conditions in Cyprus for 5 years. The best variety was 628 barley, which gave the highest mean yields (6·7 and 0·69 t/ha of D.M. and CP respectively), showed the highest response to annual rainfall (33 g D.M./mm rainfall) and gave high yields in all environments, D.M. yield was not affected significantly by earliness but late varieties had higher D.M. and lower CP contents than early varieties. All varieties showed around average stability. Regression coefficients between D.M. yield and mean yield of varieties for all environments ranged from 0·81 to 1·14 and were not related to D.M. yield of varieties.The fraction of the variation in D.M. yield explained by the variation in annual rainfall varied with variety from 25% to 67%. Multiple regression analysis using the annual rainfall and the rainfall 1 and 2 months before harvesting produced a slightly, but not significantly, higher correlation over the simple correlation between D.M. yield and annual rainfall. Varietal response to annual rainfall, as expressed by the regression coefficient between D.M. yield and annual rainfall, was positively related to D.M. yield (r = 0·84, P < 0·01).The correlation coefficients between D.M. content and annual rainfall ranged from −0·46 to −0·92 while that of CP content and annual rainfall, though not significant in most cases, also tended to be negative.