GENETIC IMPROVEMENT OF SALT TOLERANCE IN RICE

Authors: Zeng, Linghe; Wilson, Clyde; Grieve, Catherine

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2004
Publication Date: 10/10/2004
Citation: Zeng, L., Wilson, C., Grieve, C.M. 2004. Genetic improvement of salt tolerance in rice. ASA-CSSA-SSSA Annual Meeting Abstracts, CD-ROM, Seattle, WA.

Interpretive Summary:

Technical Abstract: The success in genetic improvement of salt tolerance in crops using traditional approaches has been limited in the past decades. One of the major reasons for the limited success is the lack of reliable selection criteria in screening for salt tolerance. Screening for growth vigor at early vegetative growth stages in rice may be more convenient than that for yield related parameters, but the selections have only developed low yielding and non-dwarf lines. Direct selection for grain yield in cereal crops grown under saline conditions is a common practice of plant breeders in salt tolerance breeding programs. However, the improvement of yield is low in salt-sensitive crops such as rice because of the low selection efficiency when final grain yield is the selection criterion. Improvement of yield potential, i.e., the selection of yield components, under salt stress may be a good strategy in salt tolerance breeding. This study was designed to determine the response of grain yield and yield components in rice plants to selection for salt tolerance. F2 populations were developed from crosses between M-202 (salt-sensitive) and Agami (moderate salt-tolerant) and grown in greenhouse under salt stress. Selections were made in the F2 plants for the highest values of grain weight per plant (grain yield), panicles per plant, and panicle weight under salt stress. The progenies of the selected F2 plants, unselected F2 plants, and their parental plants were evaluated for salt tolerance in F3 generation. The moderately low realized heritability of salt tolerance in grain yield was identified. The realized heritability of salt tolerance in yield components was higher than that of grain yield. The high genetic correlations between grain yield and panicle number and between grain yield and panicle weight were identified based on the double selections on respective parameters. These results suggest the effectiveness of selection on panicle number and panicle weight to improve the final grain yield under salt stress. The interrelationships among the yield related parameters are also discussed.