**3.1 Morphological and biochemical characterisation of biomass traits**

In simple term, it refers to the study of various morphological, physiological, biochemical traits, associated with grain and biomass yield. Rigorous phenotyping is essential for the success of any crop improvement programme. In breeding for biofuel, although some noticeable work has been done in case of bioenergy crops like sorghum, maize and sugarcane, very limited information is available with respect to rice, which is considered as a hinderance in effective phenotyping in this regard.

It is reported that culm length, stem girth, tiller length and diameter, leaf characteristics such as leaf length, width and angle as well as leaf, stem, tiller dry weight are few key biomass traits that can be used for indirect selection [40, 41]. These traits recorded at different developmental stages will help to decipher the genetic basis of biomass partitioning and accumulation in vegetative parts.

Biochemical characterisation of rice straw cell wall polymers (cellulose, lignin and hemicellulose) is an integral part of biomass phenotyping. Many methods like use of ultrasonicator, HPLC, microarrays, Infrared absorption spectroscopy, X- ray diffraction (XRD), transmission electron microscopy (TEM) and carbon-13 nuclear magnetic resonance (C-NMR) spectroscopy can be used for quantitative estimation of cell wall polymers [42, 43].
