Basis for varietal difference in popping expansion of rice.

Twenty-five varieties of paddy differing widely in their popping expansion were
analysed for their chemical and physical characteristics. Non-starchy polysaccharides
(tested in 10 varieties), amylose and protein; grain length, thickness and weight; huskto-
kernel gap; and thickness of pericarp and aleurone layer (in 10 varieties) were
unrelated to popping expansion. Tightness of husk (lemma-palea) interlocking and
grain hardness were strongly positively correlated with popping and 'white belly'
(grains containing opaque, chalky regions) was negatively correlated. Multiple
correlation analysis showed that these three Cactors could explain 80% of the
variation in popping expansion among the variations; these factors along with the
content and thickness of husk, equilibrium moisture of paddy, and cracked grains
together explained over 95 % of the variation. Grain breadth was positively
correlated to white belly and thus indirectly affected popping inversely.