Genotyping of lentil plant genetic resources holds the promise to increase the identification and utilization of useful genetic diversity for crop improvement. The International Center for Agriculture Research in the Dry Areas (ICARDA) lentil reference set plus collection of 176 accessions was genotyped using genotyping-by-sequencing (GBS) and 22,555 SNPs were identified. The population structure was investigated using Bayesian analysis (STRUCTURE, k = 3) and principal component analysis. The two methods are in concordance. Genome-wide association analysis (GWAS) using the filtered SNP set and ICARDA historical phenotypic data discovered putative markers for several agronomic traits including days to first flower, seeds per pod, seed weight and days to maturity. The genetic and genomic resources developed and utilized in this study are available to the research community interested in exploring the ICARDA reference set plus collection using GWAS.

Salt stress is a major abiotic stress affecting the productivity of rice crop worldwide. This study screened a set of 71 rice genotypes collected from coastal parts of Goa and Karnataka states in India for seedling stage salinity tolerance to identify genotypes alternative to standard salt-tolerant donors Pokkali, FL478, etc. Phenotyping for seedling stage tolerance was carried out under micro plots at an induced salinity of 12 dS/m. For haplotyping, 14 Saltol QTL linked simple sequence repeat (SSR) markers on chromosome 1 were utilized. On the basis of the response to salt stress, 10 genotypes were found tolerant, 16 moderately tolerant, 29 sensitive and 15 as highly sensitive. Among the SSR markers, marker RM10871 was the most polymorphic with a polymorphic information content of 0.90, exhibiting 14 different alleles followed by RM10793 (0.84) and RM3412 (0.80) with 8 and 7 alleles, respectively. These markers also exhibited high values for the effective number of alleles (Ne) and gene diversity (I). The haplotype analysis revealed that the allelic constitution of the Saltol region of 10 tolerant genotypes from our study varied in comparison to the reference tolerant check FL478. Further, the haplotype of three tolerant genotypes, namely, Goa Dhan 2, Panvel 1 and Goa wild rice (GWR) 005 appears to be completely different from the FL478 haplotype indicating tolerance in these genotypes is controlled by genomic region other than Saltol. These three genotypes with probable novel regions for seedling stage salt tolerance can be considered for enhancing salinity tolerance of rice cultivars.

Drought is a devastating factor for crop production worldwide. Therefore, an experiment was conducted to study genetics for some agro-physiological traits in cotton under drought stress. The 13 parental cotton genotypes along with their 30 F1 hybrids were planted under normal and drought conditions. The mean performance of the genotypes was assessed through principal component and heat map analyses. The principal component analyses revealed 53.99 and 53.15% in the first two principal components of variability for normal and drought conditions, respectively. Heat map analysis revealed that three cotton genotypes i.e. FH-207 × NS-131, FH-207 × KZ-191 and S-15 × AA-703 attained higher values for all the traits except for canopy temperature under drought conditions. These crosses may proliferate to further filial generations to identify transgressive segregates for drought tolerance. The heritable differences of F̅1 and mid-parent showed dominance and non-additive gene action under drought conditions. Heritable differences between F̅1 and P̅1 showed over dominance and partial dominance under drought conditions. Heritable differences between F̅1 and P̅2 indicated negative over dominance and partial dominance for all traits under drought conditions. Proline contents and the bolls per plant showed high heritability and genetic advance through additive gene action. Therefore, these two traits can be used as a means of selection in future breeding programmes of drought tolerance.

High-molecular-weight glutenin subunit (HMW-GS) is a key factor affecting dough-processing quality. 1Sty13 is a novel HMW-GS found in the tetraploid species, Elymus sibiricus L. 1Sty13 has faster electrophoretic mobility than the 1Dy12 subunit on sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis. The gene encoding the 1Sty13 subunit was composed of 1803 nucleotide base pairs with an open reading frame that was 599 amino acids in length. Analysis of the predicted amino acid sequence of 1Sty13 indicated that the N-terminal domain was similar to the y-type subunit, whereas the C-terminal domains were similar to the x-type subunit. Five cysteine residues were found in 1Sty13, which is one less than the published HMW-GS in the St genome. The 1Sty13 protein was purified at a scale sufficient for incorporation into flour for the SDS sedimentation test, which indicated that incorporating 1Sty13 improved dough quality.

Pigeonpea is an important grain legume. It contributes to the improvement of soil fertility through biological nitrogen (N) fixation. However, the symbiotic efficiency of pigeonpea with native soil rhizobia has not been determined adequately. This study was designed to determine the variation in the N fixation ability of pigeonpea inoculated with the native rhizobia. Forty soil samples were collected from diverse locations across South Africa and used for inoculating pigeonpea seed. Each pigeonpea genotype was inoculated separately with each soil sample and raised in a nitrogen-depleted growth medium in the greenhouse. A split-plot experimental design was used in the study. Several N fixation variables of pigeonpea were measured. There was >40.0% difference in the number of nodules between genotypes ‘Ex-PP-MD-321’ and ‘Mpuma-B-Spot’ but the nodule dry weight between the two genotypes was >80.0%. In contrast, the heaviest dry shoots (0.4513 g), weighed 52.0% heavier than those that were observed for ‘Mpuma-B-Spot’. Pigeonpea showed differential N fixation ability with the nodules, suggesting that there was potential to select for optimum host × rhizobial isolate combinations for the process and to expand the production area of the crop.

Nipa (Nypa fruticans Wurmb.), aside from being part of the mangrove forest ecosystem that has been under assault at an alarming rate, lacks information on its genetic variation at the population level for conservation planning purposes. Microsatellites, or simple sequence repeats (SSRs), are molecular markers employed to detect genetic variations in population studies. Here, the primers for this palm were identified through whole-genome sequencing using the Illumina® Sequencing Technology platform. Over half (52.4%) of SSRs consisted of mononucleotide repeats, whereas the remainder mostly consisted of dinucleotide (22.7%) and trinucleotide (22.4%) repeats. The frequencies of longer repeats (tetranucleotides, pentanucleotides and hexanucleotides) were exceptionally rare (2.5%). At least 18 out of 75 genomic loci were polymorphic, based on 37 randomly selected samples assayed for screening. Polymorphic loci (P) reached a mean of 72% across the Indo-West Pacific region. Estimates of genetic diversity showed a lower mean observed heterozygosity (Ho) (0.195) than expected (He) (0.316), suggesting evolutionary forces were acting across nipa populations. The fixation (F) index (0.388) supported this result, which indicates considerable genetic differentiation among populations in the region. An average of 2.111 alleles (Na) was obtained. In conclusion, these microsatellite markers are promising tools for genetic evaluation of nipa populations to facilitate characterization of this species in its distribution range.

Triticum monococcum L. and T. boeoticum L., diploid wild relatives of bread wheat (T. aestivum L.), possess resistance to leaf rust (also known as brown rust) caused by Puccinia triticina Eriks. Haustorium formation-based resistance mechanisms (i.e. pre-haustorial and post-haustorial resistance) to leaf rust have been studied and reported in various T. monococcum accessions. In the present study, the mechanism of leaf rust resistance in T. monococcum and T. boeoticum accessions was studied using confocal laser scanning microscopy. Components of resistance studied at a histological level against leaf rust pathotypes, a Mexican pathotype (TCB/TD) and a Swiss pathotype (97512-19), indicated different types of resistance mechanism operative in the two accessions. The resistance in T. monococcum ranged from pre-haustorial resistance against 97512-19 to post-haustorial resistance against TCB/TD. The response in T. boeoticum was post-haustorial with necrosis against the two pathotypes. Pre-haustorial resistance observed in T. monococcum could serve as a potential source of durable rust resistance in wheat breeding.

Soil phosphorus (P) deficiency is one of the major challenges for the cultivation of rice worldwide because it limits the growth and productivity of the crop. Therefore, the ability to grow in P-deficit soils is an important trait for rice cultivation. O . rufipogon Griff., a wild relative of rice, is a source of genetic variation for low phosphorus tolerance. The present study was undertaken to identify low P stress-tolerant introgression lines by analysing stress tolerance indices of 40 introgression lines of O. rufipogon. The populations were screened under low soil P and normal soil P plots for two growing seasons. Based on yield under stress and normal conditions, we computed different stress indices, including stress tolerance index (STI), tolerance index, yield reduction ratio (YR), stress susceptibility index, yield stability index (YSI), yield index, per cent yield reduction and geometric mean productivity (GMP). The studies of correlation analysis, principal component analysis and clustering revealed that STI, YSI and GMP were ideal indices for the selection of genotypes that performed well under both stress and normal conditions. Based on these indices, introgression lines (IL-24, IL-29 and IL-32) were identified as promising low P tolerant lines, which exhibited better grain yield under both stress (YS) and normal (YP) conditions. These pre-breeding lines serve as valuable genetic resources for low P tolerance in rice breeding programmes across the world.

Local cultivars of pearl millet in Saudi Arabia are known to tolerate extreme heat and drought stress. In the current study, the sequences of internal-transcribed spacers (ITSs) of six pearl millet cultivars were sequenced and analysed to investigate the genetic diversity among the local cultivars. The nucleotide polymorphism, secondary structures and phylogenetics were analysed for ITS sequences of the six local cultivars. The obtained sequences were 772–774 base pairs (bp) in length, including complete sequences of the ITS1–5.8S–ITS2 region and partial sequences of 18S and 26S rRNA. The nucleotide diversity among cultivars was higher in ITS2 sequences than ITS1 sequences. The ITS2 had four variable nucleotide sites in three native cultivars, whereas the ITS1 contained one base insertion. The secondary structures of the ITS1 and 5.8S region were highly conserved among the six cultivars and contained some motifs that are conserved across Viridiplantae. However, the ITS2 secondary structure for the two native cultivars, Sayah and Jazan, was distinct from the other cultivars, which confirms the applicability of the ITS2 sequence in distinguishing between genetically close taxa. Additionally, the phylogenetic analysis of the six investigated cultivars and 31 pearl millet accessions from the NCBI database showed close relationships between the local accessions and NCBI accessions from India and France. However, the local cultivar Sayah appeared to be distinct from the other cultivars in the phylogenetic trees. This study provides insights into the polymorphism within local pearl millet cultivars which is important for the identification and conservation of these cultivars.

The Sikkim-Himalaya represents one of the unique reservoirs of rice genetic resources in India owing to the presence of a large number of landraces adapted to extreme climatic and edaphic conditions. This valuable gene pool is now under threat due to the introduction of high-yielding varieties, wanting suitable genetic intervention for enhancing their productivity, and thus economic viability. Development of lodging resistant, high-yielding varieties tolerant to soil acidity through association mapping aided marker-assisted breeding programmes can help achieve this in a fast and efficient manner. But this requires information on genetic diversity, population structure, etc., of the germplasm collection, which is strikingly lacking. We, therefore, characterized a set of 53 rice landraces from Sikkim to address the above issues. The results revealed moderate diversity, poor divergence and high gene flow in our germplasm collection attesting its utility as an association mapping panel. Further, a total of 115 putative marker-trait associations (P < 0.05, R2 ≥ 10%) were obtained using the general linear model and mixed linear models of which 25 were identical in both. Some of the associated markers were positioned in those regions where Qualitative Trait Loci have been previously identified in rice, providing credence to our results. The resources generated from this study will benefit the rice breeders from this region and elsewhere for targeting the yield and related traits, in addition to conservation efforts by the interested researchers.

Okra (Abelmoschus esculentus L. Moench) is considered as a treasure house of nutrients and it is one of the major vegetables widely spread all over tropical, subtropical and warm temperate regions of the world. Yellow vein mosaic virus (YVMV) and enation leaf curl virus are the most destructive diseases of okra as they affect both crop growth and yield. Due to the frequent breakdown of resistance and lack of a stable source of resistance in the cultivated species, interspecific hybridization is considered as a reliable approach for durable resistance. Cultivated species from The United States Department of Agriculture and wild accessions from The National Bureau of Plant Genetic Resources were screened at YVMV hotspot (Guntur, Andhra Pradesh) to identify the potential donors for disease resistance. Accessions IC141032 and IC141012 were found to be free from both viruses and categorized as resistant lines. Interspecific hybridization between A. tetraphyllus and A. esculentus revealed a high crossability index of around 80% when A. esculentus was utilized as a female parent. The bottleneck of hybrid sterility was partially overcome by the colchicine treatment of interspecific F1 hybrids. Good seed set was observed when raw colchiploids were backcrossed to the recurrent parent.

Emmer wheat (Triticum turgidum ssp. dicoccum) is one of the most promising gene sources for drought tolerance improvement of durum wheat (Triticum turgidum ssp. durum). Achieving desired results requires a conscious choice of crossing parents based on general and specific combining ability (GCA and SCA) and also understanding the genes action involved in controlling the desired traits. In this study a 12 × 12 full diallel cross was performed using four emmer and eight durum wheats. The 132 hybrid progenies along with their parental lines were field evaluated under water-stressed and non-stressed conditions. Based on the Griffing diallel analysis both GCA and SCA effects were highly significant for all measured traits under both water treatments indicating possibility of improvement for drought tolerance. In this respect, the amount of additive effect was higher than the non-additive suggesting the chance for genetic advancement through selection. Based on Hayman's graphical analyses under the two water conditions it was revealed that several grain yield component traits were under the control of partial dominance. In contrary, grain yield and most morphological traits showed either dominance or over-dominance gene action. Grain yield had a significant positive correlation with the number of kernels per spike, kernel diameter, grain weight per spike and harvest index. These traits also had greater share of additive effects, relatively high narrow-sense heritability and high Baker ratio suggesting effective indirect selection for grain yield. Most durum × emmer hybrids had grain yield and drought tolerance indices better than the parents indicating that Iranian emmer wheats have a great genetic potential for drought tolerance improvement of durum wheat.