Studies On Super-high Yielding Technology And Index In Winter Wheat

In this paper, the regularity of high yield in wheat production and the evolution of wheat high yield way were analyzed, and it summarized the characters of all paths and their restrictions. A new wheat super-high yield way was presented through experiment: "more seedling, smaller top leaves and higher biomass accumulation" cultivation method.The main contents of this cultivation method included relatively increasing seeding rate and making top leaves smaller so as to achieve higher photosynthetic accumulation. Its major technological charters as follows:(l) the seeding rate should be increased 15-20% based on the optimum sowing ;(2) the time for first irrigating and fertilizing in spring should be put off to jointing stage in order to reduce the leaf area of top 3 leaves;(3) if the yield goal is larger 700Kg/mu, the varieties with smaller leaves and bigger spikes should be selected .The key technological indexes of this way as follows :(1) Yield component of winter wheat: the characters of the variety with bigger spikes and weightier seeds were 30×10⁴ ears mu^-1,44-47 grains ear^-1 and 45-48g per thousand grain weight; the characters of the variety with more seeds and weightier spikes were 35-40× 10⁴ ears mu^-1, 50-53 grains ear^-1 and 36-37.5g per thousand grain weight; the characters of the variety with more spikes were 50 × 10⁴ stems mu^-1, 33-35 grains ear^-1 and 35g per thousand grain weight.(2) Photosynthetic production indexes:Shoot biomass yield varied from 1200-1500 kg mu^-1 for the varieties whose yield can reach 600Kg mu^-1HI varied from 0.42 to 0.52.Photosynthesis potential varied from 1300-1380m²/mud, net photosynthetic rate varied from 4.1 to 4.4 g /m²d, the amount of dry weight increased everyday from 5.8 to 6.69(kg mu^-1·d).(3) Population component index:As for the stems before winter, the varieties with bigger spikes and weightier spikes and that with more spikes were 80 × 10⁴ stems mu^-1, and which with more seeds and weightier spikes were 70× 10⁴ stems mu^-1. The maximum stem number varied from 100× 10⁴ to 110×10⁴ mu^-1. As for the stem number on mature stage, the varieties with bigger spikes and weightier spikes and that with more seeds and weightier spikes were 30× 10⁴ stems mu^-1 and 35× 10⁴ shoots mu^-1 respectively ,the variety with more spikes was about 50 ×10⁴ stems mu^-1. (4)The LAI index:On priming winter, tittering at upstanding ,at anthesis and at grain filling stage ,LAI was 1,>2.6, 5-5.5 and> 4,respectively.The biggest LAI is 7 or so. (5) The resource-sink-current relation index: Ear-leaf ratio index:For wheat with more spikes, it was 130-140 ears/m ,and for wheat with weightier spikes and seeds it was 90 ears/m ², the other is about 100 ears/m².For variety with more spikes, its best value was 0.45 grain /cm² and for the wheat with weightierseeds and spikes it was 0.4 grains /cm2, the other is 0.51-0.55 grains /cm2.The grain -leaf weightratios 18-19 mg/cm2.The mechanism of yield increase of this way lay in: By increasing seedling number per mum, it enlarged the content of sink; By delaying fertilizing and watering in spring, it reduced the top leaves areas, while the total leaves areas retained stabilization, so it is best for wind and ray. What's more, this way improved the net photosynthetic rate, prolonged the later photosynthetic active duration, increased the photosynthetic product accumulation, and reduced the cost of matter. Therefore, it is well for the balance of resource-sink-current at high level so as to achieve wheat super high yield.The technology is suited for the cultivation of super-high yield about more than 600Kg per mu in north China.