Relationship of morphological traits in tall fescue genotypes grown in normal and drought stress conditions

Relationships between different morphological traits were assessed on 75 tall fescue genotypes under moisture stress and non-stress conditions, using several multivariate statistical methods including regression analysis, path analysis and factor analysis during 2011 and 2012. Results showed that drought stress significantly affected all the studied traits except for days to ear emergence and plant height. There were significant differences among the genotypes for all the studied traits indicating a broad genetic diversity in the germplasm. Correlation coefficients of dry forage yield of the first and second cuts with most of the recorded traits under moisture stress and non-stress conditions were significant. The results of stepwise regression showed that crown diameter, days to pollination and the number of fertile spikes contributed in 63% of observed variation for forage production under non stress condition. Under stress condition, the number of fertile spikes, crown diameter and plant height contributed in 73% of the observed variation for forage production. Path analysis indicated that crown diameter and number of fertile spikes had the strongest direct effects on forage yield. Factor analysis for all of the traits revealed four factors under non-stress and stress conditions which justified 80 and 77 percent of the total variation, respectively. In factor number 1 traits such as forage yield, number of fertile spikes and crown diameter and in factor 2, days to ear emergence and pollination had the highest factor loads.