Genotypic response of rice under contrasting production systems : organic vs conventional
2015
Palanog, A.D. | Seville, C.U. | Dogenio, I.G. | Ciocon, I.M.G. | Sta. Ines, I.T.
The breeding goals and objectives of conventional and organic rice systems are much alike. Basically, the breeding is directed to achieve desired traits such as high green yield, resistance to biotic and abiotic stresses, and grain qualities acceptable to consumers. The main differences are the selection environments and the expression of these traits on these environments. Thirty rice genotypes were evaluated under three different production systems: conventional (high input), organic (low-input), and zero input. A 90-30-30 NPK kg/ha was applied for high input system, 10 t/ha of vermicompost organic fertilizer for low-input system while no fertilizer application was made on zero input system. A wide genotypic variation was observed on the traits measured in within and between systems. However, it is interesting to note the positive phenotypic correlation of major traits such as grain yield and biomass was observed among the production systems suggesting that responses of the genotypes did not differ in production system per se. Heritability of grain yield and biomass is moderately high (0.47-0.67) in all systems thus, direct phenotypic selection for these traits is possible. Effectiveness of indirect selection was computed using the ratio of correlated response to determine the need for a separate breeding program for organic rice. Results showed that direct response to selection is effective than indirect response since the value generated was 1 it can be concluded based on the result that selection of organic rice varieties should be done under organic rice production system not on conventional system. The result of the study will help in developing organic rice breeding program.
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