Selecting Drought Tolerant Endemic Coriander Ecotypes Based on Fruit Yield and Related Traits Using Univariate and Multivariate indices

Abstract

Coriander is an annual plant belonging to Apiaceae family that its yield is affected by drought stress. Three experiments (normal irrigation regime, sudden drought stress and gradual drought stress) were conducted according to a randomized complete block design with three replications in 2015 to introduce the most drought tolerant Iranian coriander ecotypes based on several economical traits, aiming at improving them in next generations, using univariate and multivariate tolerance indices. The economic traits having high heritability and high correlation with the yield and fruit essential oil content were used to calculate multivariate index of the Membership Function Value for Drought Stress (MFVD) and multivariate graphical analysis based on Principal Component Mediated Multivariate Index (PCAMMI). Also, genotype by environment interaction was traced for normal and stress experiments. The ecotypes, traits and indices were categorized and their occurrence in the environments was showed using a Heatmap graphical mapping. Stable genotypes and suitable indices were identified. High variation was observed among ecotypes. Stress Tolerance Index and Geometric Mean Productivity indices were suitable for identification of genotypes belonging to group B, and Tolerance Index and Mean Productivity indices were suitable for identification of genotypes belonging to group C. The multivariate index of MFVD and thousand fruit weight was categorized into the same group. Therefore, this index was not effective for separating ecotypes. Ecotypes were grouped using the PCAMMI graphical technique. In sudden drought stress, ecotypes 6, 12 and 14, and in gradual drought stress, ecotypes 1, 2, 3, 5, 8, 11 and 13 were grouped in group A.

Keywords

• biplot
• drought stress adaptation
• heatmap graphical mapping
• multivariate index
• tolerance index