Wheat varietal investigation for terai, tars and lower valleys under timely-sown irrigated conditions (1998/99 to 1999/2000)

Normal sown irrigated wheat is one of the most important production environments in the terai. Wheat varieties with high yield potential and resistant to major diseases are essential to increase production and productivity in such environment. Sixteen different activities were carried out during 1998/99 and 1999/2000 wheat season to develop and identify suitable varieties. Altogether 155 and 137 crosses involving specific parents were made during 1999 and 2000 wheat season respectively. Segregating generations from F1 to F6 were planted and appropriate selections were made. A total of 346 new Bhairahawa Lines (BLs) were bulked from F6 generations for multilocation screening during the period. Screening nurseries like Nepal Advanced Lines consisting of 242 and 220 genotypes each year was evaluated at four locations and selected lines were promoted to Initial Evaluation Trial in each year. International screening nurseries and yield trials like IBWSN, IDSN, BWON, EGPSN, Elite lines, EGYPT, ESWYT, AVTs were received as in the previous years from CIMMYT, ICARDA, DWR, India and were successfully conducted at NWRP, Bhairahawa during both the years. Several selections were made for specific purposes. A mass screening of genotypes were carried out at Kankai Farm during 1999/2000 wheat season to search genotypes resistant to sterility. Thirty-one out of 308 genotypes have been observed completely free from sterility. Several new genotypes like BL 2033, BL 2071, BL 2037, BL 2067, BL 2015, BL 2043, BL 2030, BL 2075, BL 2049 and others with high yield potential, better grain type, resistant to leaf rust and foliar blight have been identified from IET-TTL during the two wheat seasons. From CVT-timely-sown irrigated, genotypes, BL 1887, BL 1923, BL 1999, BL 1981, NL 867 and BL 1968 have been identified as promising ones. Previously identified genotypes, NL 792 and NL 781 have grain yield advantage of more than 7 and 5 percent respectively over check variety Bhrikuti under timely-sown irrigated conditions. NL 792 could be proposed for release for western Terai.