Effect of terminal season water stress on yield, yield component and remobilization different cultivar and lines in bread Wheat

ABSTRACT: In order to investigate the effects of terminal water stress on yield, components yield and assimilate remobilization in wheat cultivars and lines in Markazi province, two experimental separated designs were established using randomized complete blocks with three replications and 8 treatments. A field study was conducted in 2009 in Agriculture and Natural Resource Experiment Station of Markazi province. Genotypes eight that different characteristic investigated include three cultivars current at regions and five lines. One experimental was water stress in stage post flowering and second experimental irrigations the farm was done with normal regime. We measured in research flag leaf length, flag leaf width, number spike maturity, grain number in spike, grain weight in spike, peduncle weight, length awn spike, biological yield, spike weight, 1000 grain weight, yield, harvest index, pre-anthesis photo-assimilate contribution to grain and peduncle to total retranslocation ratio. Results showed that response of cultivars and lines under optimum irrigation and water stress conditions were different. Water stress reduced yield and yield components. In order to stress evaluated indices at cultivars and lines we used six indices such as harmonic mean (Harm), stress tolerance index (STI), tolerance index (TOL), Mean productivity (MP), stress susceptibility index (SSI) and Geometric mean productivity (GMP). Results showed that MP and TOL indices good for optimum condition and SSI, Harm, STI and GMP indices good for water stress condition also STI, GMP and SSI indices good for optimum and water stress condition. Also results showed that some cultivars at water stress condition, tolerant and have relatively high yield for example, lines C-84-4 and C-82-12 more tolerance and Alvand and backcross cultivars susceptible tolerance under optimum irrigation and water stress.