Evaluatıon Of Fıfty Irrıgated Sprıng Wheat Genotypes Grown Under Late Sown Heat Stress Condıtıon In Multıple Envıronments Of Bangladesh

Abstract

The experiment was carried out during November to March, 2016-17 in three agricultural research centers/stations of the Bangladesh Agricultural Research Institute (BARI): (i) the Wheat Research Centre (WRC; 23 degrees 11' 14.52 '' N, 89 degrees 11' 11.99 '' E; 10.4 masl), Nashipur-Dinajpur in AEZ-1 (Old Himalayan Piedmont Plain); (ii) the Regional Wheat Research Center (RWRC; 23 degrees 59' 19.21 '' N, 90 degrees 24' 36.65 '' E; 13.1 masl), Joydebpur in agroecological zone (AEZ)-28 (Modhupur Tract) and (iii) the RARS (23 degrees 11' 14.52 '' N, 89 degrees 11' 11.99 '' E; 10.4 msal), Khaertala-Jessore in AEZ-11(High Ganges River Floodplain). Fifty wheat genotypes including two check varieties i.e., BARI Gom 21 and BARI Gom 26 and fourth eight wheat lines from F6 generation were evaluated in nursery of semi-arid wheat yield trial (SAWYT) under irrigated timely sown (ITS) and irrigated late sown heat stress (ILS) conditions to find out the heat tolerant wheat lines for future breeding program to develop heat tolerant wheat varieties. Genotypes specific significant variation was observed between phenology, yield and yield contributing characters of all wheat genotypes when sown at late sown heat stress condition (ILS) in all three locations. Among the genotypes, 16 genotypes (i.e., 'Gen.-7', 'Gen.-9', 'Gen.-11', 'Gen.-13', 'Gen.-14', 'Gen.-16', 'Gen.-19', 'Gen.-22', 'Gen.30', 'Gen.-31', 'Gen.-33', 'Gen.-36', 'Gen.-38', 'Gen.-40', 'Gen.-42' and 'Gen.-48') performed better under ILS condition and the genotypes were selected for future breeding program to develop heat tolerant varieties. Heading and maturity of the selected 16 lines found earlier both in ILS as well as ITS conditions as compared with other non-selected lines. Similarly, higher number of spikes m(-2), TGW and grain yield were also recorded across the locations and genotype in ILS condition.