Assessing Reniform Nematode Resistant Cotton Lines Using Classical Growth Analysis

Development of reniform nematode resistance in cotton germplasm that could provide a long-term solution to cotton losses due to reniform nematode is in progress in Cotton Belt of the US. Classical growth analysis was conducted to evaluate reniform nematode resistance in cotton germplasm lines (Gossypium barbadense accessions; 08SS110-NE06.OP and 08SS100) and selected commercial cotton cultivars (Deltapine 16 and PHY 490 W3FE). The study was conducted over two years at two different field locations that were infested with reniform nematodes exceeding the economic thresholds. Growth and development traits such as plant height, node numbers, and dry biomass were taken at every two weeks intervals following emergence from harvesting two-meter row length. Fiber yields were recorded at the end of each season for all four genotypes. Also, soil samples were extracted from top 15 cm depth at planting, flowering, and harvesting for reniform nematode counts. Among four genotypes, the resistant line 08SS110-NE06.OP showed significantly higher values for most of the measured growth traits, derived growth indices, and yields in both the years. While the commercial cultivars PHY 490 W3FE showed significantly lower values. Unlike commercial cultivars, the reniform nematode counts significantly declined below thresholds in plots grown with germplasm lines in both the years. The information from the study will be helpful to develop cotton cultivars with resistance to reniform nematode in Cotton belt of the US.