Morphological and Biochemical Variability in Germplasm in Hot Arid Region of India

Abstract

This study determined the extent of diversity and relationships among 74 Aloe germplasm collected mainly from the Indian arid zone by characterizing 18 morphological traits (8 quantitative and 10 qualitative). High coefficient of variation (CV) was observed in quantitative traits (aloin content [AC] [43.1%], leaf width [LW] [32.0], polysaccharide [30.7], and inflorescence length [18.5]) through CV. Range and mean values for important biochemical traits of Aloe vera were 0.009–10.94 and 5.77, respectively, for aloin and 0.16–0.61 and 0.40, respectively, for polysaccharide (mg 100 mL –1 ) content. Leaf rind thickness (LRT) showed the highest variability (0.8–1.8 mm), followed by leaf length (LL) (30–57.5 mm) and LW (99.2–17.3 mm). Pearson’s correlation study revealed both positive and negative relationships among the quantitative traits of aloe genotypes ranging from −0.19 (AC and LL/LRT) to 0.48 (leaf thickness and LRT). Dendrogram was generated for the six quantitative traits by using Euclidean distance-based unweighted pair group method with arithmetic mean method of cluster analysis which formed four major clusters at coefficient value of 3.7 with two subclusters each. Cluster analysis clearly brought out two groups as non-bitter and bitter ones. The pattern obtained through cluster analysis confirmed by two-dimensional scatter plot of principal components analysis (PCA) accounted for 67.73% of cumulative variance. Despite limitation in estimating the total genetic variation, the present study indicated that morphological and biochemical traits were useful in preliminary evaluation and can be used as a general approach for assessing genetic diversity among morphologically distinguishable aloe genotypes.