GROUND WATER-TABLE LIMITS THE IRRIGATION REQUIREMENT OF TALL AND DWARF WHEATS (TRITICUM-AESTIVUM)

A field experiment was conducted on several diversified wheat (Triticu m aestivum L. emend. Fiori & Paol.) genotypes under varying shallow wa ter-table depth (57 cm to 280 cm) from 1988-89 to 1990-91 on Typic Ust ochrept sandy-loam soil at Hisar. The genotypes were sown after pre-so wing irrigation with canal water. Thereafter these were subjected to 2 irrigation treatments, viz. no-post solving irrigation (I-0) and full irrigation at irrigation depth : cumulative pan evaporation (ID : CPE ) ratio of 0.9 (I). Irrigation (I) increased soil-moisture content and transpirational cooling but the improvement in leaf water potential a nd relative water content were non-significant over (Io) treatment. Ap plication of irrigation reduced the yield attributes, grain yield and harvest index. Reductions in grain yields were generally greater in ta ll genotypes ('C 306', 'C 306 M'). The genotypes 'WH 147' and 'P 20237 ' yielded more than 5 tonnes/ha even without post-sowing irrigation (I -0). Under irrigated condition, 'PBW 175', 'P 20237' and 'WH 147' outy ielded other genotypes, but their grain yields were also lower under I treatment than under I-0.