EFFECT OF NON GENETIC FACTORS ON RELATIVE BODY WEIGHT GAIN IN SHORT TERM SELECTION FOR DIFFERENT AGES IN JAPANESE QUAIL

Meat type Japanese quail were subjected to three different methods of individual phenotypic selection viz., high two week body weight (SWL), four week body weight (FWL) and high four week body weight coupled with low relative body weight gain between 4-6 weeks of age(LWL) and a control (COL) without adopting any selection for threegenerations. The effects of lines,generations, sexes and hatches weresignificant (P< 0.01) on the relative body weight gain (RGW) of birds at all the ages studied. The least square means of RGW during first, second, third, fourth, fifth and sixth week of age in base S0 generation were 370.37±3.85, 124.25 ± 2.20,44.51±1.68, 24.15±0.0.69, 16.94±0.45 and 10.48±0.35 per cent. The corresponding means were 383.81±3.91, 115.03±2.23,42.62±1.70, 31.90±0.70, 18.23±0.46 and11.99±0.35 per cent in first S1 generation,374.04 ±3.76, 92.63 ±2.15, 75.08±1.64,30.18±0.67, 12.25±0.44 and 12.22 ±0.34 per cent in second S2 generation and 381.89±3.42, 103.61±1.96, 62.90±1.49,30.68±0.61, 14.14±0.31 and 10.28±0.31 per cent in third S3 generation. The least squares means of RGW during the above periods were 375.41±3.46, 107.62±1.98,55.20±1.51, 27.93±0.62, 13.04±0.41and8.70±0.31 per cent in males and 379.95±3.39, 110.14± 1.94, 57.35±1.48,30.52±0.61, 17.24±0.40 and 13.77±0.31 per cent in females respectively. The RGW of females was found to be higher thanthat of males at all the ages studied and however the differences were significant after three weeks of age.