Agronomic performance of F₂ populations of aus rice (Oryza sativa L.)

Aus is a traditional rice grown under rainfed condition from March to August. Agronomic performance of 15 F₂ populations along with 10 parents were studied for grain yield and related characters. A wide range of variation was observed in 15 F₂ families for each of the characters studied. Variation occurs within and between families of F₂ population and that was due to segregation of alleles responsible for the traits. The lowest days to panicle exertion was found from the crosses P2 x P1 and the maximum value was found from the cross P3 x P7 for day to maturity. Variation was found among the parents and their 15 F₂ families for plant height and it ranged from 73.00 to 129.66 cm. The lowest mean values were found from the F₂ families of P7 x P11 (88.75cm) and the highest in P3 x P4 (122.96 cm). The highest mean value was found for total number of tillers and effective tillers per plant from the parental genotypes P7 (21.92 and 18.15) and F₂ progenies of P7 x P11 (22.70 and 18.7), respectively. The longest panicle was found from the parental genotypes P7 (27.30) and the F₂ progenies of P7 x P3 (26.70cm). Maximum number of filled grains per panicle was found from P3 (143.38; empty grain 24.68) and F₂ progenies of P7 x P6 (116.57; empty grain 21.74). F₂ progenies of P7 x P6 showed extreme performance for number of filled grains per panicle (17.2 to 237.6). The lowest mean values for plant residue weight were found in the parent P10 (16.33g) and the F₂ progenies of P2 x P5 (18.62g). The highest mean value for grain yield per plant was found fromthe parent P4 (30.83;maximum 40.12). On the otherhand, the highest mean values for grain yield per plant was found in the F₂ progenies of P3 x P6 (30.80; maximum 62) followed by P3 x P4 (30.53; maximum 86). The F₂ progenies of several crosses showed extreme performance for grain yield per plant (4.78 to 86.00g) which indicates the transgressive segregation of the traits. The progenies with high grain yield were found to possess high values for their performance in panicle number, panicle length and filled grain number, thus suggesting the presence of high correlation of grain yield with the studied component traits.