Seema BediKulveer Kaur2019-12-162019-12-162019http://krishikosh.egranth.ac.in/handle/1/5810137848Studies on agronomic and morpho-physiological parameters associated with nitrogen use efficiency (NUE) are important for developing high-yielding genotypes and sustaining yield levels. The present study entitled “Effect of wheat semi-dwarfing gene Rht8 on nitrogen uptake and utilization under contrasting nitrogen treatments” was conducted at the experimental area of wheat section, Department of Plant Breeding and Genetics and Department of Botany, Punjab Agricultural University (PAU), Ludhiana during rabi season of 2017-18 and 2018-19. Field experiment on 34 genotypes introgressed with a dwarfing gene Rht8 were evaluated in three N regimes viz., 125Kg ha-1, 62.5Kg ha-1 and unfertilized plots (no nitrogen) taken as control. Various agronomic and morpho-physiological traits under three N regimes were recorded to assess the effect of dwarfing gene Rht8 on root architecture or on nitrogen use efficiency (NUE) of the genotypes. The results revealed that gene Rht8 has a positive role in NUE as observed through agronomic and morpho-physiological traits. Significant differences in grain yield, yield attributes, N uptake and NUE were observed among genotypes having gene Rht8 and the control genotypes without the dwarfing gene. The gene can be used in wheat breeding program for improving NUE and also ensuring less use of fertilizers and environment friendly agriculture. The gene Rht8 has a strong effect on N uptake via improved root vigour and depth. This improvement in root system may also be explored for tolerance to other abiotic stresses, specifically drought conditions.ennullThesis