TITLE:
Reproductive Development of Lotus tenuis (Fabaceae) Crop Defoliated at Different Times and Intensities
AUTHORS:
Osvaldo R. Vignolio, Gustavo S. Cambareri, Lucas R. Petigrosso, Natalia Murillo, Néstor O. Maceira
KEYWORDS:
Cutting, Narrowleaf Birdsfoot Trefoil, Vegetative Biomass, Flowering Time, Yield
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.8,
June
7,
2016
ABSTRACT: Lotus tenuis forage yield has been quantified under defoliation conditions in pastures, grasslands
and under dual-purpose production of both livestock forage and seeds. However, little
is known about the effects of defoliation management on L. tenuis flower and pod production
and subsequent seed yield. Two field experiments were conducted to study the response of L. tenuis to defoliation at different flowering stages and intensities. In Experiment 1, crops
were defoliated at the beginning of the flowering (DBF), mid-flowering (DMF) or
full flowering (DFF). In Experiment 2, defoliation was in vegetative
stage at low (LDI) or high (HDI) intensities. Defoliation in Experiment 1 neither
affected plant cover nor the photosynthetically active
radiation intercepted by the crop during pod production. There were less umbels
with dehiscent (shattered) pods in the DFF treatment than in Control, DBF and DMF
treatments. Flower peak occurred first in the Control, DBF and DMF treatments, and
eight days later in DFF plots, however, seed yield was not affected (1324 ± 32.8
kg·ha-1). Defoliation intensity did not affect seed yield (962 ± 25.9
kg·ha-1) because of self-compensation
which increased harvest index in HDI (14.5% ± 0.6%) compared to the Control and
LDI (12.0% ± 0.3%) treatments. Plant survival was not affected by defoliation treatments
in any of the experiments. Flowering can be synchronized
through defoliation. The blooming of large numbers of flowers in a short time was
achieved, reducing the number of shattered pods. Compensatory responses through
plant plasticity conferred L. tenuis the ability to overcome defoliation
without affecting seed yield. Lotus tenuis defoliation as management tool will
be considered in future researches because it is possible to harvest forage and
to increase seed yield through a reduction of shattered pods.