Identification of iron deficiency chlorosis tolerant sources from mini-core collection of groundnut (Arachis hypogaea L.)
Iron deficiency chlorosis (IDC) is common among groundnut grown in calcareous and alkaline soils in India, China and Pakistan and causes considerable reduction in pod yield. To identify genetically diverse IDC tolerant accessions, the mini-core collection of groundnut representing geographical diversity was evaluated for IDC response over 2 years in iron-deficient calcareous soils. Enormous genetic variability was evident in the mini-core collection for IDC tolerance-related traits such as a visual chlorotic rating (VCR) and SPAD chlorophyll meter reading (SCMR) across five growth stages. Several IDC tolerant sources belonging to different botanical varieties such as hypogaea bunch (ICG # 5051, 6766, 5286, 6667, 4538, 14008, 5663, 9842, 11855), hypogaea runner (ICG 10479), fastigiata (ICG 10890) and vulgaris (ICG # 11651, 118) were identified. Among the six botanical varieties of groundnut, hypogaea bunch types were found most tolerant to IDC and this is the first report in groundnut. The IDC tolerant sources identified were irrespective of their country of origin. The principal component analysis based on VCR, SCMR, pod yield and its related traits revealed five major principal components that explained 80% of the total variation. The biplot generated using PC1 and PC2 revealed a distinct separation of IDC tolerant genotypes from the susceptible ones. The hierarchical clustering using five major principal components revealed seven major clusters that were mainly based on IDC response of the accessions.