Root Nodule Categorization and Their Relation with Plant Growth in Peanut Crop Grown in Alfisols

To investigate the relationship between nodule category and plant growth characteristics in peanut, nodules were classified into three categories: large size nodule (LSN) ( greater than 2 mm), medium size nodule (MSN) (1-2 mm) and small size nodule (SSN) ( less than 1 mm) and their position on roots (primary and lateral roots). The number of LSNs on primary roots was found to be much higher than on lateral roots. The number of MSN developed on primary and lateral roots was comparable, whereas, lateral roots had a higher SSN number. In addition, when comparing the LSN and MSN numbers to SSN number, the plant growth parameters showed a high positive correlation. Multivariate regression analysis yielded similar results. This nodule classification technique aids in the identification of peanut nodules and their role in quantification of plant growth characteristics. Further, this technique can be used in identifying/screening of efficient nodulating peanut genotypes.