Development of SSR-based sorghum (Sorghum bicolor (L.) Moench) diversity research set of germplasm and its evaluation by morphological traits

Assessment and utilization of diversity in plant genetic resources is vital for the improvement of plant species. A sorghum diversity research set (SDRS) was developed by using SSR markers. A total of 320 sorghum accessions were selected based on geographic distribution from more than 3,500 germplasm accessions comprising Asia (East, Southeast, South and Southwest Asia) and Africa, conserved at NIAS Genebank, Japan. We selected 38 simple sequence repeats (SSR) markers which generated 146 alleles, covering ten chromosomes of sorghum from a three different published SSR linkage map of sorghum. The average percentage of polymorphic loci (P) and gene diversity (He) observed in this study were 82.8 and 0.217 respectively. Analysis showed a positive correlation with geographic pattern of differentiation. Based on SSR assessment, 107 sorghum accessions were selected as diversity research set. There was no significant difference in pattern of genetic spectrum between SDRS and base population. Similarly no greater change was observed for variability parameters (Dice, %P, He) and almost all of the SSR alleles were retained in selected sorghum accessions except for the loss of a single allele at locus Xtxp287. SDRS was sown during sorghum sowing season in two replications. Data were recorded on 26 important morphological traits according to the standard sorghum descriptors at Genebank. Analysis of variance showed a highly significant difference among all accessions for all of the traits. Morpho-agronomic traits could not effectively classify the accessions according to geographic origin by using cluster analysis

The Impact of Salinity on the Productivity and Quality of Durum and bread Wheat

Salinity poses a significant challenge to the quality and productivity of crops. In the primary wheat cultivation areas worldwide, salinity negatively affects wheat growth, yield, and quality. To address this issue, the development of tolerant wheat varieties through selective breeding techniques is essential. The aim of this study was to assess the effects of salinity on grain yield, protein content, and thousand-kernel weight (TKW) among 55 different varieties and accessions of bread and durum wheat. The findings revealed that the application of salt treatment (100 mM NaCl solution) resulted in reduced growth and yield production in 45 bread and durum wheat varieties. However, 6 durum wheat varieties, 3 durum wheat accessions, and 1 common wheat accession showed insignificant susceptibility to salinity. These included Chryssodur from Greece, Saragolla, Silur, and Dakter from Italy, Sculptur from France, Karim from Tunisia, Algeria 70-2 from Algeria, Ethiopia 201 and Ethiopia 229 from Ethiopia, and the Morocco 85 accession of bread wheat from Morocco. The decline in grain yield could be attributed to salinity, which led to a decrease in photosynthetic capacity, resulting in reduced starch synthesis and accumulation in the grain. Furthermore, the study demonstrated that winter wheat exhibited greater tolerance to salt stress compared to spring wheat, and durum wheat displayed higher tolerance than common wheat. Additionally, salt accumulation was found to increase protein content in five varieties and one accession of durum wheat. This variation may be linked to the relatively stable nitrogen metabolism under salt stress, contributing to higher protein concentrations. TKW also decreased in all 10 varieties and accessions, irrespective of the species

Genetic analysis of QTLs controlling allelopathic characteristics in sorghum.

Mature sorghum herbage is known to contain several water-soluble secondary metabolites (allelochemicals). In this study, we investigated quantitative trait loci (QTLs) associated with allelochemical characteristics in sorghum using linkage mapping and linkage disequilibrium (LD)-based association mapping. A sorghum diversity research set (SDRS) of 107 accessions was used in LD mapping whereas, F2:3 lines derived from a cross between Japanese and African landraces were used in linkage mapping. The QTLs were further confirmed by positional (targeted) association mapping with Q+K model. The inhibitory effect of water-soluble extracts (WSE) was tested on germination and root length of lettuce seedlings in four concentrations (25%, 50%, 75% and 100%). A Significant range of variations was observed among genotypes in both types of mapping populations (P < 0.05). A total of 181 simple sequence repeats (SSRs) derived from antecedently reported map have been used for genotyping of SDRS. A genetic linkage map of 151 sorghum SSR markers was also developed on 134 F2 individuals. The total map length was 1359.3 cM, with an average distance of 8.2 cM between adjacent markers. LD mapping identified three QTLs for inhibition effect on germination and seven QTLs for root length of lettuce seedlings. Whereas, a total of six QTLs for inhibition of germination and ten QTLs for root length were detected in linkage mapping approach. The percent phenotypic variation explained by individual QTL ranged from 6.9% to 27.3% in SDRS and 9.9% to 35.6% in F2:3 lines. Regional association analysis identified four QTLs, three of them are common in other methods too. No QTL was identified in the region where major gene for sorgoleone (SOR1) has been cloned previously on chromosome 5