# Diversity in Selected Grain Mineral and Protein among Pigeonpea Landraces
## 3 Results
### Principal Component and Cluster Analysis for Selected Grain Mineral and Protein Contents  
The first three principal components (PCs) accounted for 76.50% of the variation among the pigeonpea genotypes with eigenvalues of more than one (Table 5). Three variables, namely Mg, Mn and P, were associated with PC1 with Mn, contributing the most variation to this component. The second principal component (PC2) explained 22.84% of the variance, reflecting positive loadings of protein and P but negative correlations for Fe and Zn. However, the third principal component (PC3) explained only 12.49% of the variance, with negative loadings for both Zn and protein. The pigeonpea landraces were scattered randomly across all the quadrants on the biplot (Figure 1). Nevertheless, the improved genotype 'G-10' along with the local 'G-03' and exotic 'G-04', 'G-01', 'G-14' and 'G-09' were clustered at the extreme margins of the cartesian plane. Genotypes 'G-05', 'G-04' and 'G-03' were closely associated with P, Ca, Mg and Mn. In addition, protein as well as K and Cu appeared to be associated markedly with five landraces, namely 'G-01', 'G-02', 'G-06', 'G-08' and 'G-10', which were located in the top-left quadrant (Figure 1). In contrast, <30.0% of the landraces ('G-07', 'G-11', 'G-12' and 'G-13') were closely associated with both Fe and Zn. Moreover, a negative relationship was detected between protein and each of these two micro-elements as indicated by the obtuse angle between the vector for protein and that of Fe and Zn. Furthermore, both 'G-09' and 'G-14' were positioned conspicuously far away from the origin, suggesting that they were the most genetically divergent landraces for the eight elements and grain proteins that were evaluated. Several nutritional traits including Ca, Mg, Mn, P and Zn revealed a negative and significant association with traits such as Cu, protein and K, as indicated by a large angle between the traits (Figure 1). Three genotypes ('G-01', 'G-08' and 'G-10') were associated with high levels of protein and K. Furthermore, both 'G-09' and 'G-14', which were positioned distantly from the origin, also suggested that they possessed unique alleles for the grain mineral elements and protein contents that were evaluated. \begin{table} \begin{tabular}{c c c c c c c c c c} \hline
**Variable** & **Ca** & **Cu** & **Fe** & **K** & **Mg** & **Mn** & **P** & **Zn** & **Protein** \\ \hline Ca & \(1.000\) & & & & & & & & & \\ Cu & \(-0.541\)* & \(1.000\) & & & & & & & & \\ Fe & \(-0.148\) & \(0.157\) & \(1.000\) & & & & & & & \\ K & \(-0.139\) & \(0.704\)** & \(0.074\) & \(1.000\) & & & & & & \\ Mg & \(0.557\)* & \(-0.573\)* & \(0.021\) & \(-0.523\) & \(1.000\) & & & & & \\ Mn & \(0.424\) & \(-0.646\)** & \(0.011\) & \(-0.592\)* & \(0.507\) & \(1.000\) & & & & \\ P & \(0.348\) & \(-0.514\) & \(-0.275\) & \(-0.579\)* & \(0.647\)* & \(0.377\) & \(1.000\) & & \\ Zn & \(-0.105\) & \(0.246\) & \(0.502\) & \(-0.171\) & \(0.223\) & \(0.287\) & \(0.043\) & \(1.000\) & \\ Protein & \(-0.086\) & \(0.347\) & \(-0.575\)* & \(0.332\) & \(-0.04\) & \(-0.532\)* & \(0.104\) & \(-0.226\) & \(1.000\) \\ \hline \end{tabular}   
* **:* *The cluster analysis revealed three clusters out of fourteen pigenopea landraces (Table 6). 'G-01' was clustered together with the local landrace 'G-08' in sub-cluster I-a, but sub-cluster I-c consisted of 'G-02' as a singleton joining the two subclusters at a similarity level of 81.70%, based on Euclidean and correlation distance, using complete linkage clustering. Compared to other landraces in the cluster, a singleton is the most superior within the cluster. The improved check genotype 'G-10' was clustered together with 'G-06' in subcluster II-a and 'G-13' was the most diverse member of the cluster. Cluster III consisted of five landraces including 'G-03' and 'G-14'.