Analysis of genetic variations in plant type of rice : V. Early vs. sustained vigor types in growth and their bearing on yielding potential.

To examine genetic variation in the growth curve parameters and their contribution to factors determining grain yield, 40 randomly chosen F 7 lines of a cross between two contrasting rice varieties were measured for dry matter weight and for other yielding characters during the growing period. From the dry weight data, growth curves were computed using linear and quadratic (Pearl-Reed) logistic equations, and various values derived from them were compared among lines. The results showed that: 1) The growth curves of the lines varied genetically between the "early-vigor" and "sustained-vigor" types.