Reduced leaf senescence (stay-green) has been demonstrated to improve tolerance of post-Xowering moisture stress in grain sorghum. A number of quantitative trait loci (QTLs) associated with staygreen have been identiWed in sorghum, to facilitate transfer of this trait into adapted genetic backgrounds. This study reports initial evaluations, in both well watered and post-Xowering stress environments, following partial introgression (BC 2 F 3 /BC 1 F 4 generations) of four stable stay-green QTLs (StgB, Stg1, Stg3 and Stg4) from donor parent B35 to senescent variety R 16. The majority of the introgression lines had higher leaf chlorophyll levels at Xowering (a distinctive trait of the donor parent) and a greater percentage green leaf area during the latter part of grain Wlling, than did R 16, indicating that the stay-green QTLs were expressed phenotypically in the R 16 background. None of the QTL introgression lines achieved the same level of stay-green as B35, however.Maintenance of a greater relative green leaf area during the latter half of grain Wlling was related to a greater relative grain yield in two of three post-Xowering moisture deWcit environments in which the materials were evaluated (r 2 = 0.34 in 2004-2005 and r 2 = 0.76 in [2005][2006], as was a direct measure of leaf chlorophyll in one of the post-Xowering stress environments in which this was measured (r 2 = 0.42, P < 0.05). Thus the study provided useful evidence that the marker-assisted backcross transfer of staygreen QTLs from B35 into an adapted, but senescent background has the potential to enhance tolerance of post-Xowering drought stress in sorghum.

The sequencing and detailed comparative functional analysis of genomes of a number of select botanical models open new doors into comparative genomics among the angiosperms, with potential benefits for improvement of many orphan crops that feed large populations. In this study, a set of simple sequence repeat (SSR) markers was developed by mining the expressed sequence tag (EST) database of sorghum. Among the SSR-containing sequences, only those sharing considerable homology with rice genomic sequences across the lengths of the 12 rice chromosomes were selected. Thus, 600 SSR-containing sorghum EST sequences (50 homologous sequences on each of the 12 rice chromosomes) were selected, with the intention of providing coverage for corresponding homologous regions of the sorghum genome. Primer pairs were designed and polymorphism detection ability was assessed using parental pairs of two existing sorghum mapping populations. About 28% of these new markers detected polymorphism in this 4-entry panel. A subset of 55 polymorphic EST-derived SSR markers were mapped onto the existing skeleton map of a recombinant inbred population derived from cross N13 x E 36-1, which is segregating for Striga resistance and the stay-green component of terminal drought tolerance. These new EST-derived SSR markers mapped across all 10 sorghum linkage groups, mostly to regions expected based on prior knowledge of rice-sorghum synteny. The ESTs from which these markers were derived were then mapped in silico onto the aligned sorghum genome sequence, and 88% of the best hits corresponded to linkage-based positions. This study demonstrates the utility of comparative genomic information in targeted development of markers to fill gaps in linkage maps of related crop species for which sufficient genomic tools are not available.

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B.M. Kassahun et al. / International journal of Advanced Biological and Biomedical Research (2015) 3(4) 351-360 352 AbstractThis experiment was conducted with the objective of evaluating the performance sage (Salvia officinalis L.) in different agroecology of Ethiopia for morpho-agronomic and chemical traits at Wondo genet, Hawassa, Qoqa and Holleta for two years from 2011/2012 to 2012/2013 cropping seasons. Data on plant height, branch number/plant, fresh leaf weight/plant, fresh stem weight/plant, above ground biomass/plant, fresh leaf weight/ha, essential oil (EO) content and EO yield/ha were collected from four locations arranged in randomized complete block design with four replications. Growing location demonstrated a significant influence (P<0.05) on the performance of all the parameters considered. With increasing year, the performance of Sage was significantly affected (P<0.05) only on three of the nine traits. The interaction between location and yea was significant for seven of the nine traits. The overall average value of plant height, branch number/plant, leaf number/plant, fresh leaf weight/plant, fresh stem weight/plant, above ground biomass/plant, fresh leaf weight/ha EO content and EO yield/ha of sage across the tested location and years ranged from 47.7-66.9 cm, 70. 13-262.07, 619.7-4046.2, 159.13-506.31 g, 63.77-279.93 g, 221.6-743.8 g, 2772-14064 kg, 1.11-1.70% and 30.67-240.03 kg, respectively. The maximum for all the characters were recorded at Hawassa and Wondo Genet except for branch number which was found tall at Holleta. Most of the characters are statistically the same over the testing years; however, plant height, branch number and leaf number/plant demonstrated a respective percent increase value of 21.3%, 50.19% and 71.98% during the first testing year.