Modern-day plants are subjected to various biotic and abiotic stresses thereby limiting plant productivity and quality. It has previously been reported that the use of a strong constitutive 35S cauliflower mosaic virus (CaMV) promoter to drive the expression of Arabidopsis CBF1 in tomato improved tolerance to cold, drought and salt loading, at the expense of growth and yield under normal growth conditions. Hence in the present study, the suitability of expressing the Arabidopsis CBF1 driven by three copies of an ABA-responsive complex (ABRC1) from the barley HAV22 gene in order to improve the agronomic performance of the transgenic tomato plants was investigated. Northern blot analysis indicated that CBF1 gene expression was induced by chilling, water-deficit and salt treatment in the transgenic tomato plants. Under these tested stress conditions, transgenic tomato plants exhibited enhanced tolerance to chilling, water-deficit, and salt stress in comparison with untransformed plants. Under normal growing conditions the ABRC1-CBF1 tomato plants maintained normal growth and yield similar to the untransformed plants. The results demonstrate the promise of using ABRC1-CBF1 tomato plants in highly stressed conditions which will in turn benefit agriculture.

In our previous study, we reported the grain weight (GW) QTL, tgw11 in isogenic lines derived from a cross between Oryza sativa ssp. Japonica cv. Hwaseong and O. grandiglumis. The O. grandiglumis allele at tgw11 decreased GW in the Hwaseong background. To fine-map tgw11, one F5 plant homozygous for the O. grandiglumis DNA in the target region on chromosome 11 was selected from F4 line, CR1242 segregating for tgw11 and crossed with Hwaseong to produce secondary F2 and F3 populations. QTL analysis using 760 F2 plants confirmed the existence of tgw11 with an R 2 value of 15.0%. This QTL explained 32.2% of the phenotypic variance for GW in 91 F3 lines. Substitution mapping with 65 F3 lines with informative recombination breakpoints in the target region was carried out to narrow down the position of the tgw11. The result indicated that tgw11 was located in the 900-kb interval between two SSR markers, RM224 and RM27358. QTLs for grain width and grain thickness were also located in the same interval suggesting that a single gene is involved in controlling these three traits. Analysis of F3 lines indicated that the variation in TGW is associated with variation in grain shape, specifically grain thickness and grain width. Genetic analysis indicated that the O. grandiglumis allele for small seed was dominant over the Hwaseong allele. SSR markers tightly linked to the GW QTL would be useful in marker-assisted selection for variation in GW in breeding program.

:The study was conducted to evaluate the genetic similarity among commercial japonica rice varieties in Korea and China and to develop markers to differentiate between japonica cultivars developed in Korea and China. The genetic similarity and cluster of 38 accessions were analyzed using 47 SSR(simple sequence repeat) markers. The number of alleles by 47 SSR markers ranged from 2 to 9 with an average of 3.6. A total of 169 alleles were detected among these tested rice varieties. The PIC value varied from 0.05 to 0.79 with an average of 0.44. The Chinese japonica cultivars could be differentiated from the japonica cultivars in Korea by combining 2 SSR markers, RM223 and RM266. Cluster analysis showed that 38 tested varieties could be distinguished into japonica and indica based on the genetic distance.