Effects of leaf removal on yield components in sunflower.

In a study of the relationship between leaf apparatus and yield in sunflower, the Rumanian hybrid HS 18 and the French hybrid INRA 4701 were subjected to a variety of leaf removal treatments. These treatments differed both in the number and in the position of the leaves removed. The leaves were removed one at a time during the vegetative period in one series and all at once shortly before flowering in another. The effects of the various treatments on final plant ht., size of head, seed setting and different aspects of yield were determined. INRA 4701 was more sensitive to leaf removal in terms of plant ht. and head size, whereas seed and oil yield were affected more in HS 18. Seed setting in the centre of the inflorescence was better in INRA 4701 than in HS 18 for all treatments. Relative to the untreated controls, however, the effect of leaf removal was more injurious to seed setting in INRA 4701. ADDITIONAL ABSTRACT: A study of the varieties HS18 and INRA4701 showed the leaf efficiency of the former to be twice that of the latter. Defoliation had a greater effect on seed yield and oil yield in HS18 and on for plant height, head diameter, grain weight and seed setting in the central area of the head in INRA4701. (Abstract retrieved from CAB Abstracts by CABI’s permission)