Effects Of Cultivation Techniques On Grain Yield And Quality Of Weak-gluten Wheat

To investigate the effects of sowing date, plant density, nitrogen application amount, basal: top dressing N ratio and NPK ratio on grain yield and quality of weak gluten wheat, two varieties (T. aestivum L.cv.Yangmai l3 and Yangmai l5) were used as test materials, and grain yield and quality formation characteristics were studied. The experiment was carried out on the field of Lixiahe Regional Agriculture Research Institute of Jiangsu in 2002-2003, and on the experimental field of Crop Cultivation and Physiology Key Laboratory of Jiangsu Province, Yangzhou University in 2003-2004. The main results were as follows.1. Grain protein content in all treatments showed a high-low-high change with grain development. Grain protein content declined to the lowest on the 21st day after anthesis(DAA). At early grain filling stage, albumen and globulin contents were relatively high, then declined gradually with grain filling; gliadin and glutenin contents increased gradually with grain development. Albumen and globulin were mainly formed at early stage of grain formation and filling; Gliadin and glutenin contents were relatively high on the 7st DAA, but mainly formed at middle and late stages.2. The contents and the accumulated amounts of amylose, amylopectin and total starch in grains showed "S" type dynamic change with grain development. The results indicated that amylose accumulating rate reached its peak on 21-28th DAA in the treatment with 240kgN/ha and basal: top dressing N ratio 5:1:4, while reached its peak on 28-35th DAA in the treatment with 180kgN/ha and basal: top dressing N ratio 7:1:2 and 9:0:1; amylopectin accumulating rate reached its peak on 14-21th DAA; the accumulation rate of total starch reached its peak on 21-28th DAA.3. N content in plants reached its peak at the beginning of over-wintering, then gradually decreased with growth and development, and sharply decreased from jointing stage to anthesis. Total soluble sugar and sucrose contents reached peaks at over-wintering and anthesis, but declined to the lowest at jointing stage. Increasing plantdensity properly or decreasing N application amount or top dressing N after elongation stage could significantly increase total soluble and sucrose contents and C/N ratio after elongation stage, decrease N content in plants after elongation stage, reduce N absorption and accumulation amount, which resulted in the decrease of grain protein content and the improvement of weak gluten wheat quality.4. Sowing date, plant density, N applying amount and basal: top dressing N ratio had significant effects upon grain yield and quality of weak gluten wheat Yangmail5 and Yangmail3. The results indicated that sowing on suitable date, properly increasing plant density, decreasing N application amount and top dressing N ratio could stabilize grain yield, increase starch content, decrease protein content, protein yield and gluten content. The stability of grain yield and quality of weak gluten wheat Yangmail5 was better than that of Yangmail3. The appropriate sowing date for weak gluten wheat Yangmail5 in Yangzhou area was from October. 27th to November, lth, the suitable planting density was from 21 Ox 104 plants/ha to 245 xlO4 plants/ha, the reasonable application amount of nitrogen fertilizer was from 180kg/ha to 240kg/ha, the ratio of basal: top dressing N was 7:1:2, and proper ratio of NPK was 1:0.6:0.6. The suitable planting density for weak gluten wheat Yangmail3 in Yangzhou area was from 21 Ox 104 plants/ha to 260x104 plants/ha, the reasonable application amount of nitrogen fertilizer was 180kg/ha and the ratio of basal: top dressing N was 7:1:2.