| Davood Eradatmand Asli*, I.S. Dua and Hamid Mehrpanah
Department of Agronomy and Plant Breeding, Islamic University of Saveh,
Saveh, Iran
Department of Botany, Panjab University, Chandigarh - 160 014
*Corresponding author : eradatmand_d@yahoo.co.in
Abstract
A field experiment was conducted to investigate the hypothesis that yield
of some cultivars of rice (Oryza sativa L.) may be limited by potential
seed size. In this investigation, the source – sink ratio was manipulated
to examine the performance of source-sink interactions after anthesis and
the factor(s) limiting grain filling. Plants of three rice cultivars were
artificially modified to give different source – sink ratios. The
treatments were; I. control, II. cutting flag leaf blade, III. thinning
half of the plants, IV. cutting flag leaf blade and thinning. The distribution
of dry matter between kernels was analyzed at harvest in all the three cultivars.
For determining potential grain weight in each plot, 50 per cent of grains
at anthesis in mean shoot was reduced. Modification of source – sink
ratio led to different patterns of allocation of dry matter between cultivars.
The pattern of partitioning of dry matter observed in plants suggests both
source and sink limitation in different rice cultivars. Also, in one of
the cultivars there was a relative balance between source and sink and none
of the two factors were limited.
Key words:Thinning, Flag Leaf, Source, Sink, Manipulation, Rice.
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