摘要： 1990~1991年以出苗期为指标。着重研究了单株幼苗活力对向日葵植株籽粒产量的影响。旨在改进Wade等（1988）提出的向日葵苗期估产数学模型。结果表明。向日葵单株葵盘重量与单株籽粒产量之间呈极显著的回归关系（R²=0.97~0.99），由前者预测后者非常可靠。可作为成熟期测产的参考。在苗期根据向日葵苗情预测收获时的籽粒产量。尽管Wade等模型有效。但加入单株幼苗活力这个因素后。整个多元回归模型的可信度大为提高。原模型中的预测因子仅包括单株面积印株距变异系数时。多元回归方程的决定系数R²为0.25；当模型中再加入单株幼苗活力指标后，R²增加到0.44。而且，单株面积与株距变异系数之间和单株面积与单株幼苗活力之间的互作也达到显著水平。改良模型中影响单株籽粒产量的各因素间，以单株面积和单株幼苗活力最为重要。

关键词: 向日葵, 苗期, 数学模型, 估产, 单株幼苗活力

Abstract: Field experiment was conducted to determine the effect of individual plant vigour on the final grain yield in sunflower.Time of emergence and distances to the neighbouring plants within each of the three natural rows were recorded in the field.Head dry weight was measured for each individual plant after harvest.and grain dry weights of individual plants were measured on 50 head subsample for each of the three rows,to draw relationship between head and grain dry weight for prediction of the latter from the former.Results show that it in higii'y reliable to predict grain dry weight from head dry weight of a plant according to the regression between the two (R²=0.97-0.99).For quantifying grain yield loss due to poor plant stand, although the regression technique of Wade et al (1988) has proved valuable, adding individual piant vigour for time of emergence into the equation can greatly improve the accountability of the regression.K R² of the multiple regression increase from 0.25, when only area per plant and coefficient of variation in plant spacing were included, to 0.44, when time of emergence was added.Moreover the interactions between area per plant and variation in plant spacing,area per plant and individual plant vigour are also very important.Among all the factors influencing individual plant yield,area per plant and time of emergence seem the most important.

Key words: Sunflower, Seedling stage, Mathematical model, Computation of yield, Individual plant vigour