IDENTIFICATION OF DROUGHT TOLERANT WHEAT (Triticum aestivum L.) GENOTYPES USING MULTIVARIATE ANALYSIS UNDER WATER STRESS CONDITIONS

Abstract

An investigation was carried out with 25 wheat genotypes composed of land races and cultivars to screening bread wheat genotypes using multivariate analysis. The experiment was conducted at Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh during rabi season of 2016-17 in Split Plot Design with three replications. The experiment was conducted in a plustic tunnel using control and drought block. The results of analysis of variance revealed significant differences among the genotypes and treatments for all the characters studied viz. plant height, flag leaf collar height, flag leaf length, flag leaf breadth, chlorophyll a, chlorophyll b, proline content, number of tillers per plant, root fresh weight, shoot fresh weight and root shoot ratio. The genotype x treatment interaction was significant for most of the characters except number of tillers per plant. Comparing the mean values, control blocks appeared superior performances than drought blocks in most of the traits except proline content. High heritability was observed for all the traits except flag leaf length, flag leaf breadth and number of tillers per plant. High heritable characters can be further used for selection of superior genotypes. Based on the genetic distance, all the 25 genotypes were grouped under three different clusters. In control conditions, cluster number I holding most tolerant genotypes (BARI21, BARI22, BARI23, BARI24, BARI25, BARI26, BARI27, BARI28, BARI29, BARI30, SATYN2, SATYN4, SATYN11, SATYN12, SATYN18 and SATYN24) with the highest number of relative mean for plant height, flag leaf collar height, chlorophyll b, proline content and shoot fresh weight. Among the three clusters for drought condition, cluster number III holding most tolerant genotypes (BARI27, SATYN19, SATYN24) with the highest number of relative mean value for chlorophyll a, chlorophyll b, number of tillers per plant, shoot fresh weight, root fresh weight. The results of the principal component analysis showed that the first 6 principal component axes explained 97.22% in controls condition and 97.25% in drought condition of the total variations in the wheat populations. Considering overall PCA, the highest genetic diversity was contributed by PC1 and PC2 in both control and drought conditions for plant height, flag leaf collar height, root fresh weight, shoot fresh weight and root shoot ratio. Therefore, these characters should be given emphasis for further selections in wheat breeding. The results of drought susceptibility index (DSI) indicated the superiority in the genotype BARI24 closely followed by the genotypes SATYN12, BARI27, BARI23, BARI25, SATYN17, SATYN4, SATYN2, SATYN24, BARI21, BARI30 and SATYN26. The drought susceptibility index (DSI) indicated that the genotype BARI24 and SATYN9 exhibited highly drought tolerant genotype in the present piece of investigation. These genotypes might carry genes for drought tolerant and might posses novel plant material for further drought tolerant breeding.