中文摘要：

在1998—2002年预备试验的基础上，于2003—2004年期间研究了不同播期对沙芥生长发育及种子产量的影响。试验采用直播法，每隔15d播种1次，共12个播种期。结果表明：沙芥从播种至出苗需7～18d，种子发芽出土的活动起始温度为12．56％，有效积温为69．07℃；各播种期株高、总叶片数、株展、茎粗、一级分枝数、返青率、种子产量均随播种期推后而降低，且播种过晚，翌年才出苗；一年生植株安全越冬且翌年能抽薹开花的日历苗龄为59d以上，植株形态指标为株高9．6cm，株展为15．5cm，平均叶片数为5．8片，茎粗为0．8cm以上；二年生植株生长势、种子产量与一年生苗生长势呈正相关，返青后二年生植株的生育进程基本相同，其全生育期分为营养生长期、休眠期、生殖生长期。沙芥在内蒙古呼和浩特地区的栽培或采种的春季适宜播期是5月中旬，寄子栽培可以在10月上旬播种。研究确定了人工栽培条件的适宜播种期，掌握了越冬的最小苗龄，为沙芥人工栽培及繁育技术的研究奠定了基础。

英文摘要：

Effects of different sowing dates on growth, development and the formation of seed yield of P. cornutum were studied from 2003 to 2004, the study were based on the experiment during 1998 to 2002 . Used direct-seeding method, the seed was sowed every fifteen days, there were twelve sowing dates in all. The results showed that the initial temperature and effective accumulated temperature were 12.56 ℃ and 69.07 ℃, respectively. With sowing dates delayed, plant height, number of total leaves, plant extending diameter, stem thick, number of primaries per-panicle, the regreening rate and seed yield were decreased, and if sowing dates were too late, seedling emergence stage was postponed to next year . The seedling age that could be over-winter and be bolting in next year were exceed 59 days, at the same time morphological index of seedling were 9.6 cm plant height, 15.5 cm extending diameter, 5.8 pieces of leaves, over 0.8 cm stalk thick . The growth potential and seed yield of biennial seedlings were positively correlated with the growth potential of annual seedlings . The course of growth and development of biennial plant was accord with annual plant, the period of growth development of P. cornutum was divided into vegetative growth stage, dormant period and reproductive stage . The optimum sowing date of P. cornutum for cultivation or harvesting seed were in the mid May in spring, sowing date of over-winter cultivation using germinated seed was in the early October in Inner Mongolia . The study clarified the optimum sowing date of artificial cultivation and the youngest seedling age over-winter cultivation of P. cornutum, it will be useful for artificial cultivation and breeding of P. cornutum .