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POLLINATOR DIVERSITY, FORAGING ECOLOGY AND ROLE OF HONEY BEES IN SEED PRODUCTION OF SUNFLOWER (Helianthus annuus L.)

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Title POLLINATOR DIVERSITY, FORAGING ECOLOGY AND ROLE OF HONEY BEES IN SEED PRODUCTION OF SUNFLOWER (Helianthus annuus L.)
 
Creator JADHAV AMIT JAYANAND
 
Contributor SREEDEVI, K
 
Subject developmental stages, biological phenomena, sowing, planting, hybrids, productivity, honey, fruits, relative humidity, physical control
 
Description Studies on “Pollinator diversity, foraging ecology and role of honey
bees in seed production of sunflower (Helianthus annuus L.)” were carried out
at S.V. Agricultural College, Tirupati during 2009 and 2010.
Pollinator diversity, relative abundance, foraging activity and its
correlation with plant morphometrics and abiotic factors in sunflower were
studied. The impact of pollinators on seed yield was also assessed. The studies
were carried out on sunflower Hybrid, NDSH-1 and parental lines (CMS 234A
: RHA 859) which were sown separately at fifteen days interval.
Pollinator diversity was high with 24 insect species visiting the
sunflower capitula of both hybrid and parental lines which is inclusive of
diurnal and nocturnal visitors. Bee species belonging to Apidae family were
predominant pollinators and constituted 88.85% and 85.9% on hybrid and
parental lines of sunflower, respectively. Among bees, Apis dorsata and Apis
mellifera were the dominant species on hybrid and parental lines, respectively.
The pollen foragers were active more during the day except Apis cerana
whose activity was more during the late afternoon.
The foraging activity of major pollinators was high during 10.00 and
11.00 h. Co-existence and resource partitioning was observed among different
pollinators without competition exclusion where switch over of the species
existed between A. dorsata and A. cerana.
The higher foraging rate was observed in Xylocopa fenestrata followed
by A. cerana, A. mellifera and Trigona irridipenis. The time spent on
sunflower head foraging for pollen and nectar was maximum in case of A.
dorsata and minimum in case of X. fenestrata.
The pollinator activity showed no significant difference among different
plant traits viz., plant height, disc width and number of rows open in disc
florets except for flower width which had a significant positive correlation with
A. dorsata and A. mellifera activity. Among abiotic factors, pollinator
abundance showed significant positive correlation with maximum temperature,
sunshine hours and significant negative correlation with relative humidity and
rainfall.
The studies on assessment of role of pollinators in sunflower seed set
has revealed that hybrid, NDSH-1 when excluded with pollinator visits yielded
nearly 50% less resulting in chaffy and partially filled grains as compared to
open pollination.
Three modes of pollination viz., bee (A. mellifera) pollination, open and
hand pollination carried out to evaluate the impact on seed yield exhibited that
hand pollination was the best followed by bee pollination.
It is concluded that the insect pollinators play a major role in hybrid
seed production of sunflower. Hence, the conservation of the same is necessary
in lines of biodiversity and sustainability.
 
Date 2016-06-24T13:36:31Z
2016-06-24T13:36:31Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67930
 
Language en
 
Relation D8709;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY