Index selection for multiple traits in upland rice progenies.

Abstract

The success of any breeding program depends on the ability of the breeder to select genetically superior progenies formultiple traits simultaneously, and an alternative is the use of selection indexes. In this study, the selection indexesof Smith-Hazel, Base Index, Sum of Ranks, and Index Z were used to select superior upland rice progenies for fourimportant agronomic traits. Five commercial cultivars and 191 progenies F2:4 of upland rice were evaluated for days forflowering, plant height, blast resistance, and grain yield in four environments. The genetic correlation between pairs oftraits, the response of selection in each trait and the correlated response considering the selection for number of days toflowering and the response in grain yield were obtained, using an intensity of selection of 20%. The predicted responseto selection of each trait was expressive, but the indirect selection response was not effective. The most efficient selectionwas obtained by Z Index, which showed the highest response considering all traits simultaneously and was also easyto implement and to interpret graphically interpretation. Therefore, the Z Index can greatly increase the efficiency ofselection for multiple traits in upland rice breeding programs.