Multivariate approach to identify and characterize bread wheat (Triticum aestivum) germplasm for waterlogging tolerance in India

An experiment was conducted for evaluating the performance of 149 elite Indian and Australian germplasm lines under normal and waterlogged soil conditions over two years (2014-15 and 2015-16), revealed significant differences for all the studied traits under waterlogged as well as under normal soil conditions. Waterlogging adversely affected thousand kernel weight, tillers per meter, biological yield and grain yield. The three morphological traits namely; biological yield, tillers per meter and plant height significantly contributed towards waterlogging tolerance. The geometric mean productivity (GMP), harmonic mean (HM), stress tolerance index (STI), mean productivity (MP) and mean relative performance (MRP), were significantly and positively correlated with grain yield under waterlogged (Ys) as well as under normal soil conditions (Yp). Whereas, yield stability index (YSI) was found positively correlated with grain yield only under waterlogged soil conditions (Ys) in both years as well as over the years. Besides, GMP, HM, MP, MRP and STI were also significantly correlated with each other in individual year as well as across years, indicating thereby that any one of these parameters might be used as an alternative option to each other for selecting high yielding genotypes under both the conditions (waterlogging and normal). The promising lines identified based on GMP, STI, MP, HM and MRP could also be rated as tolerant being high yielding particularly for waterlogging condition. The two parameters (YSI and reduction percentage) identified as effective selection indices clearly discriminated the per se performance of genotypes based on stable performance under waterlogged conditions, and thus these could be used an indicative approach of gennplasm lines possessing waterlogging tolerance genes. The correlation values also supported results and indicated strong association of biological yield with yield stability index. The germplasm lines namely; UP 2584, TINCURRIN, SSD-C2-172, SSD-C2-151, SSD-C2 204, SSD-C2 140, RW 3684, NW 4098, KRL 105, K 307, HD 3086, HD 2329, DUCULA 4 and CUNDERIN were identified to be capable of producing highest biomass and also higher values for YSI among all lines taken for this study. Based on both YSI and biological yield, lines CUNDERIN, DUCULA 4, HD 3086, KRI, 105 and RW 3684 were identified to as tolerant and could be utilized as potential donor for increasing waterlogging tolerance of future wheat genotypes. Our research findings also imply that tolerant lines eventually would lead to higher productivity under stress situations, where heavy rainfall and stagnation of water for a prolonged period adversely affect the wheat crop. The results of the present study based on field screening technique and the selection criteria based upon indices will be rewarding for increasing grain yield of wheat under such harsh environments.