The development of root system was slow during first 40 days after sowing
and then it was almost linear until physiological maturity. The slow
increase in root dry weight in the beginning of plant age may be associated
low translocation of photosynthetic materials due to low leaf area (Fageria,
2007). When there is low amount of photosynthetic product major part go
the shoot and a very small part is translocated to root (Fageria, 1992). The variability in root dry weight was 91% and shoot dry weight 97% due to plant
age factor. Root dry weight was having highly significant correlation (r =
0.95∗∗) with shoot dry weight plus grain yield (Table 2). This means that
increasing root dry weight can increase rice dry weight (shoot plus grain).