Capitulum Diameter Research Articles

Breeding sunflower for semi-arid regions

SUMMARYA breeding programme was initiated to develop populations of sunflower (Helianthus annuus L.), suitable for the semi-arid regions of Iran. Crosses were made between Chernianka 66 (having low yield, low oil content, short stem, and early maturity), as the female parent and VNIMK 8931 and Record (having high yield, high oil content, long stem, and late maturity) as the male parents. Selection, together with selfing and sib-crossing, resulted in six populations with high yields, high oil content, short stems, and early maturity.Correlation coefficients of oil yield and its components, i.e. seed yield and oil content, were highly significant and significant respectively. Capitulum diameter had highly significant correlations with seed yield and oil yield. Earlier maturity was associated with shorter stems and lower oil content.

Factors affecting the production of filled seeds in sunflower

The capitulum and stem diameter have been found to be negatively correlated with the percentage of the filled seed. The correlation is significant. The partial correlation between the above is also negative but the values are not significant which shows that it is the joint interaction of stem and capitulum diameter which markedly influences seed set. It has been concluded that increased stem thickness adversely affects seed set because of greater increase in leaf area which in turn restricts nutrient supply to the developing seeds. Both stem and capitulum diameter are important from yield point of view as they lead to increased seed producing area. It is essential for a good variety to have large capitula with well filled seeds. It has been pointed out that in a breeding program it should be possible to get desired combinations of above characters without much difficulty.