Characterizing the Saltol quantitative trait locus for salinity tolerance in rice

This study characterized Pokkali-derived quantitative trait loci (QTLs) for seedling stage salinity tolerance in preparation for use in marker-assisted breeding. An analysis of 100 SSR markers on 140 IR29/Pokkali recombinant inbred lines (RILs) confirmed the location of the Saltol QTL on chromosome 1 and identified additional QTLs associated with tolerance. Analysis of a series of backcross lines and near-isogenic lines (NILs) developed to better characterize the effect of the Saltol locus revealed that Saltol mainly acted to control shoot Na +/K + homeostasis. Multiple QTLs were required to acquire a high level of tolerance. Unexpectedly, multiple Pokkali alleles at Saltol were detected within the RIL population and between backcross lines, and representative lines were compared with seven Pokkali accessions to better characterize this allelic variation. Thus, while the Saltol locus presents a complex scenario, it provides an opportunity for markerassisted backcrossing to improve salt tolerance of popular varieties followed by targeting multiple loci through QTL pyramiding for areas with higher salt stress

Recent Developments in Wild Rice Conservation, Research, and Use

In this chapter, we assess the current status of wild Oryza gene bank collections and in situ protection sites. We have identified O. neocaledonica and O. schlechteri as priority species, and Africa and South America as priority regions for ex situ and in situ conservation. We review recent genetic diversity studies and explained how information on population genetic structure, ecogeographic differentiation within species, and intra- and interspecific gene flow can be used in enhancing the effectivity and efficiency of conservation methods. We emphasize the need for further studies on species-specific dormancy-breaking treatments and on seed longevity of wild rice species under storage conditions. We discuss the potentials of molecular taxonomic markers, tissue culture, and plant-dwelling symbionts in improving gene bank practices. Finally, we present the significant contributions of wild Oryza species to rice improvement

Maintaining elevated Fe2+ concentration in solution culture for the development of a rapid and repeatable screening technique for iron toxicity tolerance in rice (Oryza sativa L.)

Iron toxicity decreases rice (Oryza sativa) grain yield especially in acid soils after flooding. Our aim was to establish a high-throughput screening technique using nutrient solution culture for identifying Fe-toxicity-tolerant genotypes