[Shoot type morphology and growth characteristics of winter wheat sown at different dates]

Aiming at the delayed sowing of winter wheat induced by the drought and water logging often occurred in Huanghuai Plains of China, six sowing dates (15 October, normal sowing; 30 October, moderate delay; 15 November, delay; 30 November, seriously delay; 15 February, early spring sowing; and 1 March, spring sowing) were designed to investigate the effects of different sowing dates on the shoot type morphology and growth characteristics of winter wheat. With the delay of sowing date, the winter wheat grew and developed faster, and the growing period of the wheat sown in early spring and spring was 115-130 days shorter than that with normal sowing. As compared with those of the wheat with normal sowing, the shoot height, spike number per unit area, and productive spikelets per unit ear of the wheat sown delayed had a decrease, leaf position and canopy moved down, and leaf area reduced. When the sowing was delayed from the date 15 October (normal sowing) to 1 March (spring sowing), the harvest index increased from 0.46 to 0.53. Delaying sowing date also resulted in the significant reduction of grain yield, with the maximum decrement as high as 43. 6%. The spring-sown winter wheat not going through vernalization could still form yield.