Fibre analysis of wheat genotypes and its association with lodging: Effects of nitrogen levels and ethephon

Present study involved 12 lodging tolerant/ susceptible spring wheat (Triticum aestivum L.) genotypes grown at 180, 300 kg N/ha and 480 g/ha ethephon application in latter N rate at CIMMYT (Centro Internacional de Mejoramiento de Maiz y Trigo), Mexico during 1997-98 and 1998-99 under disease free and irrigated condition. During both the years, crop lodged 25 to 30 days after anthesis in varying degrees at different N levels whereas, ethephon application at DC 38 prevented lodging and decreased the ADF (acid detergent fibre), cellulose and lignin content by 8.47, 8.81 and 5.56 %, respectively in the basal internode and increased K content of 2(nd) internode by 9.6 % as compared to without its application, However, increasing N rates from 180 to 300 kg/ha determined non-significant difference for ADF, cellulose, lignin and K concentrations in the 2(nd) and 3(rd) internodes. ADF and cellulose concentrations of 3(rd) internode were higher by 3.2-3.8 % and 4.7-5.3 %, respectively when compared with 2(nd) internode whereas 2(nd) internode determined 1.9-4.2 % higher lignin and 12.3-13.4 % more potassium contents than the 3(rd) internode at different N levels. Pooled analysis indicated that genotypic differences for ADF, cellulose, lignin and K contents were significant for both the internodes. ADF, cellulose and lignin contents for the 2(nd) and the 3(rd) internodes were negatively correlated with lodging score and in combined analysis of 3(rd) internode its phenotypic correlation was - 0.53, - 0.57 and - 0.61 with lodging score, respectively. Also, from multiple correlations study it was observed that ADF, cellulose and lignin contents had a positive impact among themselves and their cumulative effect in turn might be preventing lodging. Therefore, it could be said that higher ADF, cellulose and lignin content of basal internode were important parameters in developing a lodging resistant cultivar under irrigated and high N conditions.