Introgression of Pi2 and Pi5 Genes for Blast (Magnaporthe oryzae) Resistance in Rice and Field Evaluation of Introgression Lines for Resistance and Yield Traits

Blast caused by Magnaporthe oryzae is the most devastating disease causing significant loss in rice production. The destructive nature of the disease is mainly due to the genetic plasticity of M. oryzae which complicates the breeding strategies. Blast can be effectively managed by the deployment of R genes. In this study, broad‐spectrum blast resistance genes Pi2 and Pi5 were introgressed independently into popular but blast susceptible rice variety, Samba Mahsuri (BPT5204) by applying marker‐assisted backcross breeding approach. Tightly linked markers AP5930 for Pi2 and 40N23r for Pi5 gene were used in foreground selection. Background selection helped to identify the lines with maximum recovery of recurrent parent genome (RPG). The RPG recovery in Pi2 introgression lines was up to 90.17 and 91.46% in Pi5 lines. Homozygous introgression lines in BC₃F₄ generation carrying Pi2 and Pi5 gene were field evaluated for blast resistance, yield per se and yield‐related traits. The lines showed resistance to leaf and neck blast in multilocation field evaluation. Improved BPT5204 lines with improvement for blast resistance were on par with original BPT5204 in terms of grain yield and grain features.     

Activation tagging in indica rice identifies ribosomal proteins as potential targets for manipulation of water‐use efficiency and abiotic stress tolerance in plants

We have generated 3900 enhancer‐based activation‐tagged plants, in addition to 1030 stable Dissociator‐enhancer plants in a widely cultivated indica rice variety, BPT‐5204. Of them, 3000 were screened for water‐use efficiency (WUE) by analysing photosynthetic quantum efficiency and yield‐related attributes under water‐limiting conditions that identified 200 activation‐tagged mutants, which were analysed for flanking sequences at the site of enhancer integration in the genome. We have further selected five plants with low Δ¹³C, high quantum efficiency and increased plant yield compared with wild type for a detailed investigation. Expression studies of 18 genes in these mutants revealed that in four plants one of the three to four tagged genes became activated, while two genes were concurrently up‐regulated in the fifth plant. Two genes coding for proteins involved in 60S ribosomal assembly, RPL6 and RPL23A, were among those that became activated by enhancers. Quantitative expression analysis of these two genes also corroborated the results on activating–tagging. The high up‐regulation of RPL6 and RPL23A in various stress treatments and the presence of significant cis‐regulatory elements in their promoter regions along with the high up‐regulation of several of RPL genes in various stress treatments indicate that they are potential targets for manipulating WUE/abiotic stress tolerance.     

Utilization of Stiff Culm Trait of Rice smos1 Mutant for Increased Lodging Resistance

Although the introduction of semi-dwarf trait into rice has led to improved lodging resistance making it capable of supporting high grain yield, lodging still remains a concern when attempting to further increase the grain yield of rice. However, improving the lodging resistance in rice by depending on the semi-dwarf trait alone is possible only up to a certain limit, beyond which other traits may be needed for reinforcement. To search for alternative traits relating to high lodging resistance, we identified 9 rice mutant lines possessing improved culm strength. To evaluate whether such lines can be useful for breeding lodging resistant rice, small organ size1 (smos1) mutant having increased lodging resistance but low tiller number and low grain yield, was chosen as a representative for a breeding trial. smos1 was crossed with ST-4 (from the Stock rice collection of Nagoya University Togo field #4), a cultivar with high tiller number and high grain yield, and from their progeny, LRC1 (lodging resistance candidate-1) was selected. Although the low tiller number trait of smos1 was not fully reversed in LRC1, this was compensated by an increase in grain weight per panicle, thereby resulting in high grain yield per plant. This important attribute of LRC1 was further enhanced by the improved lodging resistance trait inherited from smos1. Such improved lodging resistance in LRC1 and smos1 was revealed to be mainly due to increased culm diameter and culm thickness, which led to a high section modulus (SM) value, a parameter defining the physical strength of the culm. Since smos1 possesses high breaking-type lodging resistance which is different from semi-dwarf plants with high bending-type lodging resistance, an alternative approach of using thick culm lines for the creation of rice with increased lodging resistance is hereby proposed.     

Trait diversity, heritability and genetic advance in selected germplasm lines of tef

The genetic improvement of the Ethiopian cereal, tef, Eragrostis tef (Zucc.) Trotter, depends upon the variability in the indigenous germplasm. A bi-replicated randomized complete block field experiment was, therefore, carried out at Debre Zeit and Alem Tena in Ethiopia during the 1996 main season to study the pheno-morphic and agronomic trait diversity in 320 tef germplasm lines. All of the 17 traits assessed showed substantial (p < or = 0.001) variation among the lines. Genotypes and locations interacted significantly (p < or = 0.05) on 11 of the traits. At about 50% similarity level, the tef lines grouped into six major clusters of nine to 243 lines. Five principal components (PCs) extracted about 71% of the entire variation of the lines. About 28% of the total variance explained by the first PC was due chiefly to variation in main shoot culm length, diameters of the two basal culm internodes, panicle length and grain yield/panicle. About 16% of the whole variance explained by the second PC originated mainly from variation in the length of the first and second basal culm internodes, grain yield/plant, and peduncle length. The third PC accounting for about 12% of the entire variance resulted largely from variation in harvest index and shoot phytomass yield/plant. Across traits, the phenotypic and genotypic coefficients of variation varied in that order from about 2% for grain yield/panicle to 58% for number of fertile tillers/plant, and from less than 1% for diameters of the two basal culm internodes and grain yield/panicle to 35% for panicle length. Estimates of broad sense heritability and genetic advance (as ratio of the mean) were highest for panicle length (71%) and number of fertile tillers/plant (21%), respectively. But both of these were lowest for the second basal culm internode diameter (< 1%). Overall, the study confirmed that tef is a highly versatile crop with broad trait diversity in the germplasm, and this offers ample opportunities for improvement through breeding.     

Molecular mapping of rice blast resistance gene <Emphasis Type="Italic">Pi-1</Emphasis>(<Emphasis Type="Italic">t</Emphasis>) in the elite <Emphasis Type="Italic">indica</Emphasis> variety Samba mahsuri

Samba mahsuri (BPT 5204) is a cultivar of the medium slender grain indica variety of Oryza sativa grown across India for its high yield and quality. However, this cultivar is susceptible to several diseases and pests including rice blast. The analysis of near isogenic lines indicated the presence of a resistance gene, Pi-1(t) in the donor cultivar C101LAC which is highly resistant to the rice blast fungus Magnaporthe grisea (M. grisea). C101LAC was crossed with susceptible indica rice cultivar (BPT 5204) to generate the mapping population. A mendelian segregation ratio of 3:1 for resistant to susceptible F₂ plants using bulk segregation analysis confirmed the presence of a major gene pi-1(t) by simple sequence repeats marker RM224 to the highly virulent blast isolate DRR 001.     

Genetic variation for domestication-related traits revealed in a cultivated rice,Nipponbare (<Emphasis Type="Italic">Oryza sativa ssp. japonica</Emphasis>) × ancestral rice, <Emphasis Type="Italic">O. nivara</Emphasis>, mapping population

Oryza nivara is the ancestral species of cultivated rice (Oryza sativa). It has been the source of novel alleles for resistance to biotic and abiotic stresses, as well as yield improvement, lost during the course of domestication. To determine the molecular changes that occurred during domestication, the O. sativa ssp. japonica variety, Nipponbare, from which a reference sequence (RefSeq) was developed, was crossed with the O. nivara accession (IRGC100897), from which BAC-end sequences (BES) were derived. The mapping population composed of 279 F₂ progeny lines derived from this cross was phenotyped for 19 traits important to domestication and yield improvement, including basal sheath and culm color, culm angle, days to heading, plant height, seed shattering, flag leaf length and width, panicle type and length, awn length and color, pericarp color, and seed color, length, width, length to width ratio, volume and surface area. The population was genotyped using 95 SSR markers and 114 single nucleotide variation (SNV) markers, selected by comparing the Nipponbare RefSeq and O. nivara BES. At least one major QTL was identified for each trait evaluated, and for 28 of the 46 QTL, the trait increase was attributed to the allele contributed by the O. nivara parent. Candidate genes were identified in 37 of the QTL regions. This study validated SNV markers that can be used for mapping in populations with a wild species parent. In the future, SNVs could be used for marker-assisted selection to incorporate desirable, novel alleles for stress resistance and yield improvement, identified in rice wild species like O. nivara into elite, adapted O. sativa varieties.     

Characteristics of genetic variation in the progenies of protoplast-derived plants of rice, Oryza sativa cv Nipponbare

Genetic variation in protoplast-derived rice (Oryza sativa L.) plants was characterized using first and second generation selfed progenies. A total of 133 regenerated plants were obtained from ten protoplasts of the japonica rice cultivar Nipponbare. Sixty two regenerated plants which set enough seeds for the subsequent field tests at the next generation and were derived from five protoplasts were selected, and their selfed seeds were used as the first selfed-seed progeny generation). Fifteen plants were selected from each of the 15 lines, and their selfed seeds were used for tests at the generation. Thirty seven lines (60%) segregated plants with detrimental mutant characters of yellow-green phenotype, dwarf stature, dense and short panicle, or low seed fertility. According to the segregation patterns in the lines having mutated plants among those originated from the same protoplasts, the stages of mutation induction were estimated. Additionally, five quantitative traits were changed in almost all and lines. Varied quantitative traits of heading date, number of spikelets per panicle, and seed fertility, were in a heterozygous state. However, culm and panicle lengths showed high uniformity, whereas reduced culm and panicle lengths were caused by mutational changes in polygenes and/or multiple genes. Received: 20 March 1996 / Accepted: 21 June 1996     

Genome‐wide expression quantitative trait locus studies facilitate isolation of causal genes controlling panicle structure

The morphology of rice (Oryza sativa L.) panicles is an important determinant of grain yield, and elucidation of the genetic control of panicle structure is very important for fulfilling the demand for high yield in breeding programs. In a quantitative trait locus (QTL) study using 82 backcross inbred lines (BILs) derived from Koshihikari and Habataki, 68 QTLs for 25 panicle morphological traits were identified. Gene expression profiling from inflorescence meristems of BILs was obtained. A combination of phenotypic QTL (pQTL) and expression QTL (eQTL) analysis revealed co‐localization between pQTLs and eQTLs, consistent with significant correlations between phenotypic traits and gene expression levels. By combining pQTL and eQTL data, two genes were identified as controlling panicle structure: OsMADS18 modulates the average length of the primary rachis and OsFTL1 has pleiotropic effects on the total number of secondary rachides, number of grains per panicle, plant height and the length of flag leaves. Phenotypes were confirmed in RNA interference knocked‐down plants and overexpressor lines. The combination of pQTL and eQTL analysis could facilitate identification of genes involved in rice panicle formation.     

Effect of Introducing a Lactone Group into Typhasterol and Teasterone to Promote Rice Lamina Inclination

Protein phosphorylation may be required for plant cell response to phytohormones and other extracellular signals. Protein phosphorylation and protein kinase activity in the culm of heading time of rice (Oryza sativa L.) were studied. Before heading, protein kinase activity was increased by Ca²⁺ in the membrane fraction of the panicle and culm. The protein kinases with M_r of 51,900, 49,200, and 45,500 isolated from the membrane fraction of culm increased the protein phosphorylation of M_r and pI of 40,000/7.5 and 40,000/7.6 in the culm extract. The activation of protein kinases, associated with membrane and subsequent protein phosphorylation, thus appears to be involved in the regulation of heading time in rice.     

Epigenetic responses to drought stress in rice (Oryza sativa L.)

Cytosine methylation polymorphism plays a key role in gene regulation, mainly in expression of genes in crop plants. The differential expression of cytosine methylation over drought stress response was analyzed in rice using drought susceptible but agronomically superior lines IR 20 and CO 43, and drought tolerant genotypes PL and PMK 3 and their F₁ hybrids. The parents and hybrids were subjected to two moisture regimes viz., one under drought condition and another under control condition. The cytosine methylation polymorphism in genomic DNA was quantified under both the conditions at the reproductive stage of the plant using the Methylation Sensitive Amplified Polymorphism (MSAP) technique devised by Xiong et al. (261:439–446, 1999). The results depicted that under drought condition, hyper-methylation was predominant in the drought susceptible genotypes while drought tolerant genotypes presented hypo-methylation behavior. While imposing drought, spikelet sterility per cent was positively correlated to percentage of methylation whereas, panicle length, number of seed per panicle, panicle weight, 100 seed weight, and yield/plant were negatively correlated indicating the role of epigenetic regulation in yield attributing traits in response to drought. Thus, methylation can be considered as an important epigenetic regulatory mechanism in rice plants to adapt drought situation. From this study, we speculate that the hyper- methylation may be an indicator of drought susceptibility and the hypo-methylation for drought tolerance and this methylation polymorphism can be effectively used in drought screening program.     

The effect of semi-dwarf genes on root system size in field-grown barley

Root system size (RSS) was measured in 12 diverse barley genotypes and 157 double-haploid lines (DHs), using electric capacitance. The parents of the DHs, Derkado and B83-12/21/5, carry different semi-dwarfing genes, sdw1 and ari-e.GP, respectively. Estimates of RSS were taken in the field thrice during plant development: stem elongation (RSS1), heading (RSS2) and grain filling (RSS3). The 12 barley genotypes were assessed over 3 years and at two or three locations each year; the DH mapping population was assessed at two locations in 2002. Among the 12 barley genotypes, those with the semi-dwarf genes had greater RSS values in all 3 years (28.9, 24.6 and 15.0% in years 1, 2 and 3, respectively) compared to non-semi-dwarf controls. The DH population showed transgressive segregation on both sides of the parent means, indicating polygenic control of RSS. Quantitative trait loci (QTLs) for RSS were found on five of the seven chromosomes: 1H, 3H, 4H, 5H and 7H and these were compared with previously mapped agronomic traits. The TotalRSS QTL on 3H was associated with sdw1 and QTLs for height, plant yield and plant weight. The RSS3 QTL on 5H was associated with ari-e.GP and QTLs for height, plant yield, plant weight, harvest index and tiller number. The RSS3 QTL on 7H was also associated with a TotalRSS QTL and QTLs for plant weight and harvest index. Other RSS QTLs were not associated with any other trait studied. RSS is considered to be a polygenic trait linked to important traits, in particular to yield. The study highlights the effects of semi-dwarfing genes and discusses the potential for breeding for root traits.     

Local plant density,pollination and trait–fitness relationships in a perennial herb

Both differences in local plant density and phenotypic traits may affect pollination and plant reproduction, but little is known about how density affects trait–fitness relationships via changes in pollinator activity. In this study we examined how plant density and traits interact to determine pollinator behaviour and female reproductive success in the self‐incompatible, perennial herb Phyteuma spicatum. Specifically, we hypothesised that limited pollination service in more isolated plants would lead to increased selection for traits that attract pollinators. We conducted pollinator observations and assessed trait–fitness relationships in a natural population, whose individuals were surrounded by a variable number of inflorescences. Both local plant density and plant phenotypic traits affected pollinator foraging behaviour. At low densities, pollinator visitation rates were low, but increased with increasing inflorescence size, while this relationship disappeared at high densities, where visitation rates were higher. Plant fitness, in terms of seed production per plant and per capsule, was related to both floral display size and flowering time. Seed production increased with increasing inflorescence size and was highest at peak flowering. However, trait–fitness relationships were not density‐dependent, and differences in seed production did not appear to be related to differences in pollination. The reasons for this remain unclear, and additional studies are needed to fully understand and explain the observed patterns.     

Identification and characterization of a major QTL responsible for erect panicle trait in <Emphasis Type="Italic">japonica</Emphasis> rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Panicle erectness (PE) is one of the most important traits for high-yielding japonica cultivars. Although several cultivars with PE trait have been developed and released for commercial production in China, there is little information on the inheritance of PE traits in rice. In the present study, 69 widely cultivated japonica cultivars and a double haploid (DH) population derived from a cross between a PE cultivar (Wuyunjing 8) and a drooping panicle cultivar (Nongken 57) were utilized to elucidate the mechanisms of PE formation and to map PE associated genes. Our data suggested that panicle length (PL) and plant height (PH) significantly affected panicle curvature (PC), with shorter PL and PH resulting in smaller PC and consequently more erect. A putative major gene was identified on chromosome 9 by molecular markers and bulk segregant analysis in DH population. In order to finely map the major gene, all simple sequence repeats (SSR) markers on chromosome 9 as well as 100 newly developed sequence-tagged site (STS) markers were used to construct a linkage group for quantitative trait locus (QTL) mapping. A major QTL, qPE9-1, between STS marker H90 and SSR marker RM5652, was detected, and accounted for 41.72% of PC variation with pleiotropic effect on PH and PL. another QTL, qPE9-2, was also found to be adjacent to qPE9-1. In addition, we found that H90, the nearest marker to qPE9-1, used for genotyping 38 cultivars with extremely erect and drooping panicles, segregated in agreement with PC, suggesting the H90 product was possibly part of the qPE9-1 gene or closely related to it. These data demonstrated that H90 could be used for marker-aided selection for the PE trait in breeding and in the cloning of qPE9-1.     

Correlated evolution between climate and suites of traits along a fast–slow continuum in the radiation of Protea

Evolutionary radiations are responsible for much of Earth's diversity, yet the causes of these radiations are often elusive. Determining the relative roles of adaptation and geographic isolation in diversification is vital to understanding the causes of any radiation, and whether a radiation may be labeled as “adaptive” or not. Across many groups of plants, trait–climate relationships suggest that traits are an important indicator of how plants adapt to different climates. In particular, analyses of plant functional traits in global databases suggest that there is an “economics spectrum” along which combinations of functional traits covary along a fast–slow continuum. We examine evolutionary associations among traits and between trait and climate variables on a strongly supported phylogeny in the iconic plant genus Protea to identify correlated evolution of functional traits and the climatic‐niches that species occupy. Results indicate that trait diversification in Protea has climate associations along two axes of variation: correlated evolution of plant size with temperature and leaf investment with rainfall. Evidence suggests that traits and climatic‐niches evolve in similar ways, although some of these associations are inconsistent with global patterns on a broader phylogenetic scale. When combined with previous experimental work suggesting that trait–climate associations are adaptive in Protea, the results presented here suggest that trait diversification in this radiation is adaptive.     

Genetic analysis of panicle and physiological traits in hill rice grown in mid altitudes of northeastern India

This paper aims to discover the genetic parameters underlying the physiological efficiency and panicle characters of hill rice plants. In order to improve these characters, it is crucial to learn the nature and magnitude of gene action involved in inheritance of panicle and physiological traits. With this purpose, we combined a line × tester analysis of crosses involving local cultivars and indigenous and exotic germplasm grown at the northeastern hill region of India. From the study it follows that number of tillers per hill, number of ear bearing tillers per hill, panicle length, panicle weight, number of grains per panicle, number of filled grains per panicle, pollen fertility, spikelet fertility, leaf area index, total chlorophyll content and harvest index were mainly under the control of non-additive gene action, while total dry matter accumulation and grain yield per plant were under the control of additive gene action. The genotypes DR 92, Ngoba, IET 16451 and UPR 1425-1-1-4 were identified as superior parents with high performance and significant general combining ability effects. For heterosis breeding six cross combinations, viz., DR 92/IET 16471, DR 92/UPR 1425-1-1-4, DR 92/IET 15482, Ngoba/IET 16469, Ngoba/H274-27-24, Manipuri/IET 16451, and for recombination breeding two cross combinations, viz., DR 92/IET 16470 and Ngoba/UPR 1425- 1-1-4, were found suitable to ameliorate the panicle and physiological traits of hill rice grown in northeastern India.     

Dissecting spatiotemporal biomass accumulation in barley under different water regimes using high‐throughput image analysis

Phenotyping large numbers of genotypes still represents the rate‐limiting step in many plant genetic experiments and in breeding. To address this issue, novel automated phenotyping technologies have been developed. We investigated for a core set of barley cultivars if high‐throughput image analysis can help to dissect vegetative biomass accumulation in response to two different watering regimes under semi‐controlled greenhouse conditions. We found that experiments, treatments, genotypes and genotype by environment interaction (G × E) can be characterized at any time point by certain digital traits. Biomass accumulation under control and stress conditions was highly heritable. Growth model‐derived maximum vegetative biomass (K_max), inflection point (I) and regrowth rate (k) were identified as promising candidate traits for genome‐wide association studies. Drought stress symptoms can be visualized, dissected and modelled. Especially the highly heritable regrowth rate, which had the biggest influence on biomass accumulation in stress treatment, seems promising for future studies to improve drought tolerance in different crop species. A proof of concept study revealed potential correlations between digital traits obtained from pot experiments under greenhouse conditions and agronomic traits from field experiments. Overall, non‐invasive, imaging‐based phenotyping platforms under greenhouse conditions offer excellent possibilities for trait discovery, trait development and industrial applications.     

Soil application of silicon reduces yellow stem borer,Scirpophaga incertulas (Walker) damage in rice

The effect of soil application of rice husk ash (RHA), a cheap renewable source of silicon, and imidazole (a silicon solubilizer and carrier) on yellow stem borer (YSB), Scirpophaga incertulas (Walker), and its damage to rice plants were investigated. Treatments included soil application of RHA (T1), imidazole (T2), RHA + imidazole (applied once at vegetative stage, T3) and RHA + imidazole (applied twice at both vegetative and booting stages of crop growth, T4) with an untreated control (T5). The effect was tested in five varieties, viz., BPT 5204, KRH2, Pusa Basmati 1, MTU1010 and Vandana. All the soil treatments reduced damage by YSB at vegetative and reproductive phases across five varieties as compared to untreated control. Scanning electron micrograph and electron‐dispersive X‐ray spectrum analysis of stem tissue of rice variety BPT 5204 treated with silicon revealed the enhanced deposition of silicon in cell walls and 2.1‐ to 5.3‐fold increase in silicon content across treatments. Larvae collected from the silicon‐treated plants had worn mandibles, and the histological studies showed rupture of the peritrophic membrane, increased vacuolation, disintegration of columnar cells and discharge of cellular contents into the gut lumen due to abrasion of midgut epithelium, as compared to untreated control where the columnar cells and midgut lining were intact. Although all the treatments were effective, T4‐imidazole applied twice along with RHA was more effective in reducing YSB damage followed by T3‐imidazole applied once with RHA at tillering stage, T2‐imidazole alone and T1‐RHA in the descending order of efficacy.     

ASSOCIATION BETWEEN QUANTITATIVE TRAITS AND ALLOZYME HETEROZYGOSITY IN A TETRASOMIC SPECIES: DACTYLIS GLOMERATA

Tetraploid individuals of orchardgrass (Dactylis glomerata L. subsp. hispanica Roth.) sampled from a natural population were used to evaluate the correlation between both single and multilocus heterozygosity at 7 enzyme loci, and several quantitative traits (plant size at time of collection, leaf weight, and panicle number in experimental trials). Four hundred and forty-eight plants were studied at the 7 loci and 288 of these individuals were scored for an additional eighth locus. Five genotype classes (monogenic, simplex, and duplex digenic, trigenic, and tetragenic) were distinguished according to their heterozygosity level. Multilocus heterozygosity showed a significant positive correlation with both leaf and panicle yield in experimental conditions, but not with original plant size, which was found to be markedly influenced by environmental microheterogeneity. Multilocus heterozygosity, estimated from both the number of heterozygous loci and the number of distinct alleles per locus, had a significant influence on plant performance. Individual locus effects were positive and significant at two loci (GOT1 and PX1). Panicle number increased regularly with heterozygosity level (from monogenics to tetragenics) at the GOT1 locus, as did leaf weight and panicle number at the PX1 locus. Such variation would be predicted by overdominance at these loci or at linked loci. Significant relationships between leaf yield and heterozygosity level at the GOT1 locus distinguished the homozygotes from the heterozygotes (of any class) and was thus more consistent with inbreeding effects. No significant differences were observed among the five genotype classes for any quantitative trait at the six remaining loci. At both the GOT1 and PX1 loci, heterozygosity had a significant independent effect on leaf weight and panicle number even when the correlation between these traits was removed by analysis of covariance.     

Study of genetic variation in sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) using agro-morphological traits and <Emphasis Type="Italic">ISSR</Emphasis> markers

This research was conducted to study the genetic variation among eighteen genotypes of sesame (Sesamum indicum L.) collected from various agro-climatic regions of Iran along with six exotic genotypes from the Asian countries using both agro-morphological and ISSR marker traits. The results showed significant differences among genotypes for all agro-morphological traits and a relatively high genetic coefficient of variation observed for number of fruiting branches per plant, capsules per plant, plant height and seed yield per plant. Cluster analysis based on these traits grouped the genotypes into five separate clusters. Larger interthan intra cluster distances implies the presence of higher genetic variability between the genotypes of different groups. Genotypes of two clusters with a good amount of genetic divergence and desirable agronomic traits were detected as promising genotypes for hybridization programs. The 13 ISSR primers chosen for molecular analysis revealed 170 bands, of which 130 (76.47%) were polymorphic. The generated dendrogram based on ISSR profiles divided the genotypes into seven groups. A principal coordinate analysis confirmed the results of clustering. The agro-morphological traits and ISSR markers reflected different aspects of genetic variation among the genotypes as revealed by a non significant cophenetic correlation in the Mantel test. Therefore the complementary application of both types of information is recommended to maximize the efficiency of sesame breeding programs. The discordance among diversity patterns and geographical distribution of genotypes found in this investigation implies that the parental lines for hybridization should be selected based on genetic diversity rather than the geographical distribution.