Interplot competition and its control in durum wheat genotypes evaluation

Interplot competition may lead to biased yield comparisons in cereal variety trials, especially when varieties differ in plant height. In order to evaluate and control the phenomenon of interplot competition, three experiments were conducted to evaluate the competition effect in relation to border row number, grouping varieties according to their height and plot row orientation. The results revealed a significant effect of interplot competition, mainly manifested on the border rows, when the varieties differed in height. Such a significant effect of interplot competition was also evident when plot rows were shown in the east-west orientation.