Experiments were carried out at the University of Agricultural Sciences, Bangalore, during L993, to screen the germplasm lines with high dry matter production to achieve higher seed yields since total dry matter prôduction (fDM) was shown to have a positive effect on seed yield in sunflower. Significant genotypic variations for leaf area index (I-AI) at flowering, assimilation rates (DMÂ-AD or DM/I-A), TDM, and seed yield and harvest index were observed both in summer and rainy season. Certain genotypes (Acc 1630, Acc 1.603, Acc 421, etc.), which possess high TDM, also had higher seed yields and higher l-AI or assimilation rates. A correlation study again confirmed that the TDM had a direct and significant effect on seed yield. The TDM or seed yield, which is indirectly influenced by l-AI or assimilation rate, was also found to be positively correlated. Therefore, selection of genotypes such as ACC 1630, ACC 1603, ACC 421, etc., which have high assimilation rates with high LAlmay, further increase the yield when used in breeding programmes.