Agricultural research communication centre

Symbiotic parameters:
The number and dry weight of root
nodules are index of degree of infection leading to nodule
development (Bhattacharjya 
et al,
2009). The positive effect
of 
Rhizobium
inoculation on number and dry weight of
nodules per plant in chickpea is very well documented by
various researchers (Eusuf Zai 
et al
1999; Bhuiyaan 
et al
,
2008a). 
Rhizobium
inoculation resulted in excellent
nodulation in contrast to poor nodulation in control (Khattak
et al
, 2006). Suryawanshi 
et al
(2007) observed significant
effect of inoculation on nodule number and nodule dry
weight. Inoculation studies have been shown to increase
nodule number and nodule dry and fresh weight per plant in
chickpea (Verma 
et al,
2010; Sahai and Chandra, 2010).
Similarly, Singh 
et al
(2014) observed higher number
(27.6%) and dry weight (22.2%) of nodules per plant as
compared to uninoculated control in chickpea.
Leghaemoglobin, red iron-containing protein,
occurs in the root nodules of leguminous plants where it
facilitates the diffusion of oxygen to the symbiotic bacteriods
in or der to pr omote n itr ogen fixation . Mor eover,
leghaemoglobin is synthesized by the symbiotic partners viz.
the Rhizobia and the host plant. 
Rhizobium
synthesizes the
“haem” portion and plant synthesizes the “globine” portion.
Lakshmanarao 
et al
(1983) evaluated positive relationship
between leghaemoglobin content and nitrogen fixation.
Tagore 
et al
(2013) observed higher leghaemoglobin content
in the nodular tissue of chickpea inoculated treatment.
Further, there was a positive correlation between nitrogenase
activity and both number and dry weight of nodules (Miller
et al,
1986). Seed inoculation showed significant increase
in the nitrogenase activity in contrast to uninoculated control
(Dutta and Bandhyopadhyay, 2009). Malik and Sindhu
(2011) also reported similar findings in chickpea. Such
positive benefits have also been reported by Das 
et al
(2013)
which may be attributed to presence of either low or
ineffective population of native rhizobia nodulating chickpea
in the soil allowing the inoculant strain to form greater portion
of effective nodules on plant roots (Bhattacharjya and
Chandra 2013).