Analysis of high and stable yield characteristics of "Kn199" winter wheat cultivar

"Kn199" winter wheat cultivar is 1RS/1BL translocation line and derivative of octoploid synthetic Triticum aestivum and Elytrigia elongata species. It has excellent frost hardiness, winter survival, drought tolerance, hot/dry wind resistance, onsite adaptability and yield stability. Its robust root system facilitates high water absorption and nutrient uptake at the depth of soils especially under drought stress conditions. In this study, nitrogen and phosphorus use efficiency (NUE, PUE) of "Kn199" under reduced and optimum nutrient supplies were investigated in relation to yield potential under limited irrigation conditions. A field experiment was set up in 2008 where wheat yield traits such as pre-winter tiller number, post greening plant number, filling spike number were investigated. Wheat plant tissues were also taken at different growth stages and the 1000-grain weight, per spike grain, per plant spike, yield index and sterile spikelet measured after harvest. The results showed that "Kn199" accumulated more dry matter with a greater distribution in kernels than the other genotypes under both low 120 kg(N)·hm^-2 and normal 180 kg(N)·hm^-2 nitrogen inputs. Partial factor productivity of applied N (PFP_N) in the nitrogen-saving trial was 54.4 kg·kg^-1 for "Kn199", yielding 6 532.5 kg·hm^-2 under 120 kg·hm^-2 N supply. It was 40.6 kg·kg^-1, yielding 7 312.5 kg·hm^-2 under 180 kg·hm^-2 N supply. Under lower phosphorous input of 60 kg(P₂O₅)·hm^-2 in long-term nurseries, "Kn199" exhibited the most desirable PUE attributes such as high tillering capacity, spike formation and harvest population. With sufficient soil water prior to winter, one or two times of irrigation in spring was enough for "Kn199" to yield 7 500 kg·hm^-2 in North Huang-Huai winter wheat cultivation region. Under the adverse and severe climatic conditions such as extreme frosts, droughts and hot winds, "Kn199" cultivation benefits stable grain yield and food security in the region.