Effect of tillage and weed flora on the performance of wheat genotypes and the severity of helminthosporium leaf blight.

M. Sc. Thesis, Department of Agronomy, IAAS, Rampur, Chitwan, Nepal. pp. 82

An experiment was conducted in a strip-split plot design with 8 wheat genotypes at the research block of the Institute of Agriculture and Animal Science (IAAS), Rampur Chitwan during the winter season of 2002/03. The purpose of study was to observe the effect of tillage (surface and conventional seeding) and weed flora on the performance of wheat genotypes and the severity of Helminthosporium leaf blight (HLB). Eight wheat genotypes namely, RR 21, BL 1473, NL 297, Kanchan, BL 2217, Milan/Sh. 7, NL 750 and PBW 343 were sown between two rows of rice stubbles (25 cm) and pressed with bare feet in surface seeding. With the same row spacing same genotypes of wheat were sown by conventional method. For each variety there were plots with and without weeding and fungicide treatment. High weed density was found under surface seeding. Fungicide treatment and tillage systems were found significant enhancing the days to maturity and increasing the test weight, kernel per spike, grain yield, biological yield and harvest index. Milan /Sh 7 was found the most resistant to HLB while RR 21 was the most susceptible genotypes. Higher disease severity was found in conventional method than in surface seeding. Kernel per spike, harvest index, biological yield and grain yield were significantly higher in conventionally tilled wheat but test weight was higher in surface seeded wheat. Among the tested genotypes, Milan/Sh 7 produced significantly higher grain yield (4.4 t/ha) in weed free and disease protected plots in surface seeding and was at par with conventionally tillage. Kanchan produced the lowest grain yield (2.3 t/ha), which was at par with RR 21, BL 1473, and BL 2217 under similar condition in surface seeding. There was no significant effect of weeds on HLB development and yield attributes of wheat.