Unraveling the mystery of non extraction of honey from modern sunflower hybrids

Abstract

Sunflower (Helianthus annuus L.) has largely failed as a source of extractable honey from present day cultivated hybrids in India since 1999. So, the amount and rhythms of nectar secretion measured as dry nectar sugars (DNS) of 6 hybrids and 2 old populations were evaluated. Three day old florets (DOF) produced maximum DNS (0.891 mg/floret) at 1000 h and in the outermost ring of the capitulum (0.917 mg). Per floret production of DNS in populations was 17.7% higher (0.974 mg) than hybrids (0.803 mg). Population HS-1 and Morden produced maximum DNS per floret (1.004 and 0.943 mg) and DK-3849 was the only comparable hybrid (0.993 mg). Noticeable reduction (14.2–37.5%) was recorded in the rest of hybrids, maximum being in HSFH-1183 (37.5%) followed by Pioneer 64A57 (33.1%). Per hectare, DNS production too was higher (10.2%) in populations (174.3 kg) than hybrids (145.8 kg) although hybrid HSFH-848 was most copious (200.0 kg/ha) followed by populations Morden (188.1) and HS-1 (160.6 kg), other 5 hybrids yielding a low DNS of 116.3–142.5 kg/ha. Populations outperformed hybrids in all DNS production factors viz. per floret (0.974 mg), by florets in their life cycle of 3 days (2.921 mg), per capitulum (3137.5 mg) and per hectare basis (174.3 kg). High DNS producing old populations Morden and HS-1 recorded lowest honey bee abundance (0.33 and 0.47 bees/capitulum/minutes⁻²) than hybrids (0.51–0.69 bees) except Pioneer 64A57 which despite the lowest DNS (116.3 kg/ha) recorded maximum abundance (0.69 bees), indicating their preference for pollen. Studies attribute non extraction of honey to lower nectar production by a majority (83.3%) of new hybrids than old populations.

Keywords:

• sunflower
• honey bees
• dry nectar sugars
• floral visitors
• populations
• hybrids
• honey production

Acknowledgements

Authors gratefully acknowledge the help of Dr. R.K. Sheoran, Principal Scientist, Oilseed Section, Department of Genetics and Plant Breeding for providing seeds material and field facilities for the research and suggestions during the course of investigations. Authors are grateful to Dr. H.D. Kaushik, Principal Scientist (Entomology) for his valuable suggestions and help in providing laboratory facilities for conducting nectar sample analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.