Response and correlated response of yield parameters to selection for salt tolerance in rice

Abstract

Lack of reliable selection criteria is one of the major reasons for the limited success in salt tolerance. This study was designed to determine the responses of yield parameters in rice plants to the selection for salt tolerance. F2 populations were developed from crosses between ‘M-202’ (salt-sensitive) and ‘Agami’ (moderately salt-tolerant) and grown in the greenhouse under salt stress (NaCl and CaCh, 5: 1 molar concentration). Selections were made among the F2 plants for the highest values of grain weight per plant, tillers per plant, and panicle weight under salt stress. The F3 populations of the selected F2 plants and unselected F2 plants, and their parental plants were evaluated for salt tolerance. Broad-sense heritability and realized heritability of grain weight per plant were determined to be 0.40-0.45 and 0.25, respectively. Higher broad-sense heritability (0.45 to 0.65) and realized heritability (0.42) of tillers per plant suggest this trait is genetically controlled. Moderately high realized heritability indicates the effectiveness of early selection for salt tolerance if tiller number is used as selection criterion. Low genetic correlation between tiller number and panicle weight was identified in F3 populations derived from the selected F2 plants. The low genetic correlation indicates the low compensatory relationship between these two yield parameters in equal spaced rice plants under salt stress.