Cordia sinensis, locally known as ‘Goondi’ in India, is an underexploited multipurpose fruit species found in hot arid regions that is well adapted to drought, salt and hot conditions. The present study was undertaken to collect fruit samples from different locations in the Kachchh region of Gujarat, India, and to determine their field establishment for characterization, conservation and utilization. The maximum distribution of the species was observed in Bhuj (45%) and Mandvi (25%). Field boundaries (35%) and scrub forests (30%) had greater frequencies, whereas backyards had rarer frequencies (10%). The species most commonly occurred on levelled topography (60%) with a soil pH in the range of 8–8.5 (63%). Morphological data of three-year-old plants in the field gene bank showed a maximum coefficient of variation in the number of leaves per plant (66.6), followed by the number of branches per plant (45.62) and collar diameter (27.69). Wide variations were recorded in plant height (121.67–212 cm), spread (118–223 cm2) and the number of branches per plant (6–24.33). Specific accessions were identified for fodder (CBCG-12, CBCG-13 and CBCG-16), early flowering and fruiting (CBCG-12, CBCG-13 and CBCG-14), easier propagation by seeds (CBCG-12 and CBCG-13) and salt tolerance (CBCG-15 and CBCG-16). Preliminary findings and information provided about this species' utilization and other aspects might be useful for future research on its domestication, sole plantation and conservation aspects, improving the exploitation of this species by present and future generations.

In Chile, two quinoa ecotypes are grown: salares, also present in the highlands of Bolivia, and coastal, in central and southern areas of the country, at sea level. Genotypes from the coastal ecotype have characteristics that differentiate them from the most popular quinoa genotypes grown in the Andean Region of South America. The objectives of this study were: (1) to determine the cardinal temperatures for seed germination in quinoa genotypes from coastal and salares ecotypes cultivated in Chile, and (2) to study the presence of physiological dormancy (PD) in these genotypes. Seed germination from nine quinoa genotypes, two from salares and seven from coastal ecotypes, was evaluated in a gradient of temperatures between 11 and 42°C. Germination was also evaluated at 20°C at 0, 7 and 15 months from harvest. Results showed that seed from the nine genotypes germinated at their maximum percentage between 11 and 35°C. However, their faster germination occurred between 25 and 35°C. There was a significant difference between optimum temperature for germination between genotypes from coastal (28°C) and salares (30°C). An increase in germination rates after 7 months of storage suggested the presence of a non-deep PD in seeds from coastal ecotype, which may be useful to improve pre-harvest sprouting resistance in quinoa breeding programmes.

Plant height in chickpea is a multivariate, dynamic trait, and shows differences in growth rate at different stages of plant development in different genotypes. In the majority of plant-breeding experiments, the phenotypic data on a quantitative trait measured at a fixed time point (generally at maturity) are used for quantitative trait loci (QTL) mapping. However, this method can result in missing important/major QTLs which are expressed at different time points and are not expressed at maturity. In the current study, using a set of 49 desi chickpea genotypes sown at three different durations for two successive years, we observed that heritability for plant height was highest at the 2 month stage in the normal sown trial, and at the 1 month stage in late-sown trials. However, heritability drastically declines at maturity, particularly due to heat stress with an increase in temperatures during the growing period. In the association analysis, it was also observed that almost all the marker–trait associations (MTAs) identified using endpoint phenotypes were identified using data obtained at different intervals. In addition, some novel and stage-specific MTAs were identified using phenotypic data recorded at monthly intervals. The results highlight the importance of multistage phenotyping for dynamic traits like plant height in germplasm characterization programmes.

Badh2 of rice is considered to be the major gene responsible for the fragrance in rice. The wild type badh2 allele encodes betaine aldehyde dehydrogenase 2 (BADH2) enzyme while the mutated version of badh2 gene encodes non-functional BADH2 enzyme that leads to the accumulation of 2-acetyl-1-pyrroline (2AP), the principal fragrant compound in rice. There are many mutated recessive alleles causing fragrance in global rice germplasm, although the badh2.1 allele present in Basmati type rice is the most well-known among breeders. In this study, we attempted to reveal potential fragrance causing mutations, and the respective varieties carrying them, through in silico analysis based on the sequences available in the Rice SNP-Seek-Database of International Rice Research Institute. The sequences of 1878 rice accessions from 22 countries were analysed to identify mutations in each exon of badh2 comparatively with the non-fragrant ‘wildtype’ GenBank sequence in Nanjing11, Oryza sativa indica (EU770319.1). Results revealed that 63 varieties from 12 countries possessed the most prevalent allele, badh2.1 having an 8 bp deletion and three single nucleotide polymorphisms in the 7th exon. The second most prevalent allele in genotypes from Asia was badh2.7 having a ‘G’ insertion in the 14th exon. A novel allele with a T deletion in 9th exon was detected in a Thai rice accession. Rice varieties containing either badh2.1 or badh2.7 alleles could be identified with DNA markers for badh2.1 (frg) and badh2.7 (Bad2.7CAPS). The marker, Bad2.7CAPS, co-segregated with the fragrance phenotype in two crosses, confirming the possibility of employing it in marker assisted breeding.

Andean blackberry (Rubus glaucus Benth.) is an emerging fruit crop with significant commercial potential. Despite its growing popularity, basic research about its genetic resources and breeding remains insufficient. The aim of this study was to assess the genetic diversity of Andean blackberry cultivars and related berries species from the main production areas in Ecuador. We analysed a total of 106 samples and performed DNA screening with different molecular markers: random-amplified polymorphic DNAs (RAPDs), inter-simple sequence repeats (ISSRs) and a set of representative samples with amplified fragment length polymorphisms (AFLPs). The tested RAPD primers did not reveal any differentiation among accessions identified as R. glaucus, however one ISSR primer was useful to find polymorphisms allowing the selection of 29 accessions for the analysis with AFLP markers. AFLP-M13 technology was used for screen genetic variations among these accessions and eight wild Rubus accessions. We scored 203 bands using five primer combinations; out of these 152 were informative in R. glaucus. AFLP markers clearly distinguish R. glaucus from the screened wild Rubus species, also an unexpected genetic structure was revealed among R. glaucus cultivars. This genetic differentiation and detection of admixed genotypes suggest a possible introgression of wild Rubus species in R. glaucus. Our findings are relevant for blackberry genetic breeding and use of these genetic resources.

Rosa x odorata (sect. Chinenses, Rosaceae) is an important species distributed only in Yunnan Province, China. There is an abundance of wild variation within the species. Using 22 germplasm resources collected from the wild, as well as R. chinensis var. spontanea, R. chinensis ‘Old Blush’ and R. lucidissima, this study involved morphological variation analysis, inter-trait correlation analysis, principal component analysis and clustering analysis based on 16 morphological traits. This study identified a high degree of morphological diversity in R. x odorata germplasm resources and the variation coefficients had a distribution range from 18.00 to 184.04%. The flower colour had the highest degree of variation, while leaflet length/width had the lowest degree of variation. Inter-trait correlation analysis revealed that there was an extremely significant positive correlation between leaflet length and leaflet width. There was also a significant positive correlation between the number of petals and duration of blooming, and the L* and a* values of flower colour were significantly negatively correlated. Principal component analysis screened five principal components with the highest cumulative contribution rate (81.679%) to population variance. Among the 16 morphological traits, style length, sepal width, flower diameter, flower colour, leaflet length and leaflet width were important indices that influenced the morphology of R. x odorata. This study offers guidance for the further development and utilization of R. x odorata germplasm resources.

To evaluate the responses of some important agronomic traits of 14 bread wheat cultivars, a split plot experiment was conducted based on a randomized complete block design under non-stress, moderate and severe salinity stress conditions. In this study, Backcross and Roshan were identified as the most salinity-tolerant cultivars, while Mihan and Shirudi were considered as the most salinity-sensitive cultivars. The proline content, as well as Δ1-pyrroline-5-carboxylate synthase (P5CS) and vacuolar-type H+-ATPase subunit E (W36) gene expression levels, were examined in these cultivars under normal, moderate and high salinity stress conditions. The proline content and P5CS gene expression level increased with a rise in NaCl concentration. Further, a direct relationship was observed between the proline content and P5CS gene expression in all samples. Our results showed that W36 gene expression in Backcross and Roshan cultivars, as the most resistant ones, strongly increased with elevation of the NaCl concentrations. On the other hand, in the sensitive cultivars such as Mihan and Shirudi, small changes were observed in the gene expression levels with rising salinity levels. Additionally, Backcross and Roshan cultivars had the highest proline content as well as P5CS and W36 genes expression levels under moderate and high salinity stress levels.

Bread wheat (Triticum aestivum) is one of the most important food crops in the world. Its physiological and morphological traits are closely related to yield. Therefore, it is generally important to discover the genomic region associated with these traits. In this research, associations between 21 simple sequence repeat (SSR) markers and 10 inter-simple sequence repeat (ISSR) markers with some traits related to root structure at the embryonic and seedling stages and also some agromorphological traits at the whole plant stage were evaluated on a set of 102 wheat genotypes. A highly significant coefficient of variation among different genotypes was observed in all measured traits. A high level of polymorphism with SSR and ISSR markers was obtained. Genetic structure analysis revealed two distinct subpopulations. Significant correlations were found between genomic markers and evaluated traits. A total of nine markers, including four SSR markers in 1A, 3A, 5A and 2B chromosomal regions and five different ISSR markers were related to the studied traits. Several molecular markers were significantly associated with more than one phenotypic trait, suggesting the possible presence of pleiotropic or indirect effects. The phenotypic variation justified by these alleles ranged from 4 to 15%. Obtained genetic information can be targeted for further validation and genetic analysis in the relevant populations or other breeding sets.

Anthracnose caused by Colletotrichum lentis is an important fungal disease of lentil in western Canada. Two known pathogenic C. lentis races, race 0 and race 1 have been identified and current cultivars of lentil have little or no resistance to the virulent race 0. Seven Lens culinaris subsp. culinaris landrace accessions were previously reported to have resistance to C. lentis race 0. In this study, accession VIR-2633, with reported resistance to both races of C. lentis, and seven accessions were assessed for race 0 resistance relative to LR-59-81, an interspecific line derived from a L. culinaris subsp. culinaris × Lens ervoides cross. The results showed a lack of effective resistance to race 0 among the tested L. culinaris accessions when compared to that of LR-59-81. A few sublines displayed modest improvements in resistance compared to the susceptible check ‘Eston’, but were significantly more susceptible than LR-59-81. Moreover, screening of the sublines of accession VIR-2633 identified 12 sublines with resistance to race 1, but all VIR-2633 sublines were susceptible to race 0. The study underlined the importance of wild lentil germplasm for broadening the genetic base of cultivated lentil and their usefulness in disease screening experiments as positive checks.

A selection of tomato (Solanum lycopersicum L.) genotypes with diverse origin and breeding history including 33 landraces, eight modern varieties and two commercial hybrids has been characterized using a set of 25 qualitative descriptors and six quantitative traits. A wide range of variation was evident for the majority of traits, highlighting their utility for characterizing tomato germplasm collections. A plethora of qualitative traits including type of leaf blade, depression and ribbing at peduncle end, fruit shape at blossom end, number of locules and flowering time, as well as measured traits with economic importance such as fruit fresh weight, firmness and total yield per plant, were found to be highly variable within the collection, with a diversity index greater than 0.8. Strong correlations were detected among several traits related to fruit yield and quality. Two-dimensional principal component analysis as well as the unsupervised hierarchical clustering grouped genotypes according to their phenotypic resemblance and morphological characteristics to a great extent. Landraces from different origins were scattered across the whole variation spectrum of PC1 and PC2. A set of six qualitative traits could efficiently discriminate cultivars in PCA (explaining 75% of total variation), suggesting that it can serve as a valuable breeding tool for the germplasm characterization. The evaluation of the phenotypic diversity in the collection as well as the identification of traits that contribute most to heterogeneity have important implications for establishing core collections with high diversity, as well as designing breeding schemes across the Mediterranean basin.

Investigating genetic structure and diversity is crucial for rice improvement strategies, including mapping quantitative trait loci with the potential for improved productivity and adaptation to the upland ecology. The present study elucidated the population structure and genetic diversity of 176 rice germplasm adapted to the upland ecology using 7063 genome-wide single nucleotide polymorphism (SNP) markers from the Diversity Array Technology (DArT)-based sequencing platform (DArTseq). The SNPs were reasonably distributed across the rice genome, ranging from 432 SNPs on chromosome 9 to 989 SNPs on chromosome 1. The minimum minor allele frequency was 0.05, while the average polymorphism information content and heterozygosity were 0.25 and 0.03, respectively. The model-based (Bayesian) population structure analysis identified two major groups for the studied rice germplasm. Analysis of molecular variance revealed that all (100%) of the genetic variance was attributable to differences within the population, and none was attributable to the population structure. The estimates of genetic differentiation (PhiPT = 0.001; P = 0.197) further showed a negligible difference among the population structures. The results indicated a high genetic exchange or gene flow (number of migrants, Nm = 622.65) and a substantial level of diversity (number of private alleles, Pa = 1.52 number of different alleles, Na = 2.67; Shannon's information index, I = 0.084; and percentage of polymorphic loci, %PPL = 55.9%) within the population, representing a valuable resource for rice improvement. The findings in this study provide a critical analysis of the genetic diversity of upland rice germplasm that would be useful for rice yield improvement. We suggested further breeding and genetic analyses.

Calotropis procera is emerging as a new, yet undomesticated, resource of fibre comparable to cotton and kapok. Screening of efficient genotypes from its wild populations would be a useful pre-domestication process. The desired genotypes can then be improved through conventional breeding programmes to develop a domesticated variety. Molecular markers play a major role in modern breeding systems. Thus, an efficient marker resource for C. procera would prove useful in germplasm selection during breeding programmes. In this study, we undertook an initial step of Simple sequence repeats (SSR) marker development for C. procera, which could be applied for germplasm selection. Furthermore, using the developed markers, we assessed the genetic diversity base within its wild populations which could be useful to identify the hotspot areas of germplasm collection. Out of 94,636 de novo assembled transcripts, 9148 sequences were found to contain 12,884 SSRs at a density of 5.5 SSRs/Mb. Twelve SSRs were found as polymorphic with a mean polymorphic information content of 0.575. We observed a moderate level of genetic diversity (Na = 3.625, Ho = 0.58) in the studied populations. Mantel's test showed significant correlation between the geographic distance and the genetic distance (r = 0.147, P = 0.010). Sirsa was found as a genetically most diverse population followed by Barnala while Gurdaspur was found with the least genetic diversity. These genetically diverse populations can serve as an important resource for effective germplasm collection for breeding programmes.

Cultivated lentil suffers yield loss from stemphylium blight, caused by Stemphylium botryosum Wallr. Identification of sources of stemphylium blight resistance and knowledge of the mode of inheritance of resistance are important for developing resistant cultivars. The interspecific recombinant inbred line (RIL) population developed from a cross between the moderately resistant parent Lens culinaris cv. ‘Eston’ and the resistant parent L. ervoides (Brign.) Grande accession IG 72815 was evaluated for stemphylium blight resistance under controlled conditions at the University of Saskatchewan, Saskatoon, Canada, and under field conditions at the Pulses Research Centre (PRC), Ishurdi, Bangladesh. We hypothesized that resistance from both parents will lead to transgressive segregation indicative of pyramiding of resistance genes from the same. However, no resistant transgressive segregants were observed in the RIL population. A large proportion (50%) of the RILs had disease severity levels similar to the resistant parent IG 72815 in experiments conducted under natural disease pressure in Bangladesh. Under controlled conditions in Saskatoon, 38% of RILs had resistance levels similar to IG 72815. Across all environments, 14 RILs consistently had resistance levels similar to IG 72815. The distribution of disease severity scores for all RILs indicated polygenic inheritance of stemphylium blight resistance in the population. RILs with consistent resistant reactions should prove useful for lentil improvement programmes. This will contribute to increasing the productivity of lentil crops in North America and the Indo-Gangetic region, which account for more than 68% of world lentil production.

Asian palmyrah palm (Borassus flabellifer L.) is a multipurpose, economically important tree widely distributed in the Indian subcontinent and Southeast Asia. The multifaceted uses (~800 uses) of the tree as food, wood and medicine make it a viable industrial crop. However, the dioecious nature of the tree coupled with long juvenile phase (12–20 years to initiate flowering), long stature and considerable variations in the productivity of male and female trees necessitates the application of new biotechnological tools for crop improvement. This review provides comprehensive information on the extent of genetic diversity of the crop, problems associated with palmyrah cultivation along with its multifaceted application and research gaps to be addressed for the effective utilization and conservation of palmyrah palm genetic resources.

Knowledge of the genetic diversity and relationships among maize inbred lines can facilitate germplasm management and plant breeding programmes. The study investigated the level of genetic diversity among S6 lines developed from a tropical-adapted shrunken-2 (sh-2) maize population and their relationship with normal endosperm tropical inbred lines of known heterotic groups. Ninety-one sh-2 maize inbred lines (UI1-UI91) developed in the University of Ibadan super-sweet Maize Breeding Programme were genotyped at 30 simple sequence repeat (SSR) loci, alongside five normal endosperm maize inbred lines viz. TZi3, TZi4, TZi10, TZi12 and TZi15, four of which belong to two heterotic groups. Twenty-three SSR markers were polymorphic and detected a total of 61 alleles, with a range of 2–7 and an average of 2.65 alleles per locus. The polymorphic information content ranged from 0.12 in bnlg1937 to 0.77 in phi126, with an average of 0.36. The gene diversity (He) averaged 0.43. Cluster analysis resulted in five groups consisting of 16, 36, 17, 23 and 3 inbred lines, with one sh-2 line ungrouped. TZi 12 and TZi 15, both of which are of the same heterotic group, clustered with TZi 3 of another heterotic group. Considerable genetic diversity exists among the 96 inbred lines. Only two of the five normal endosperm lines shared clusters with the sh-2 lines. The clustering of the normal endosperm inbred lines is not related to their established heterotic patterns. Inbred lines in two clusters offer the possibility of guiding the exploitation of heterosis among the sh-2 lines.

Genetic improvement along with widened crop base necessitates for the detailed understanding of the genetic diversity and population structure in wheat. The present investigation reports the discovery of a total of 182 alleles by assaying 52 simple sequence repeats (SSRs) on 40 genotypes of bread wheat. Unweighted neighbour-joining method grouped these genotypes into two main clusters. Highly heat tolerant and intermediate tolerant cultivars were grouped in the same cluster, whereas remaining genotypes, particularly sensitive ones, were assigned different cluster. Similarly, the entire population was structured into two sub-populations (K = 2), closely corresponding with the other distance-based clustering patterns. The marker-trait association was discovered for four important physiological parameters, viz. canopy temperature depression, membrane thermostability index (MSI), normalized difference vegetation index and heat susceptibility index, indicating for heat stress (HS) tolerance in wheat. Both general and mixed linear models of association studies during 2017 and 2018, revealed the association of SSR markers, wmc222 (17.60%, PV) and gwm34 (20.70%, PV) with the mean phenotypic value of MSI. Likewise, SSR markers barc183, gwm75, gwm11 and cfd7 revealed a unique relationship with four selected physiological traits. Candidate genes discovered using in silico tools had nine SSR markers within the genic regions reported to play a role in heat and drought stress responses in plants. The information generated about these genic regions may be explored further in expression studies in-vivo to impart HS tolerance in bread wheat.

Cotton is one of the most important crops among natural fibres. Fibre quality determines the spinning ability, which is negatively correlated with yield and yield-contributing traits. Limited efforts have been made to improve fibre quality and yield in diploid cotton. Therefore, screening a large panel of germplasm lines can help identify genotypes with better fibre quality and yield. We evaluated 712 desi cotton genotypes for fibre quality traits. The genotypes showed a significant difference for all the traits, suggesting considerable variability for fibre quality improvement. Fibre length and strength showed high phenotypic and genotypic coefficients of variation. Heritability was high for fibre strength, length, and elongation. Fibre length and strength were positively correlated; however, micronaire was negatively correlated with these two traits. Superior accessions were identified for fibre length (11), strength (20), uniformity (7), and elongation (25) among genotypes. Most of the desi lines (71%) had medium micronaire values. Twenty accessions identified were ideal for spinning, showing the fibre strength-to-length ratio of one. Cluster analysis based on Euclidean distance grouped all 712 accessions into four major clusters. Principal component analysis biplot revealed that accessions AC3418, 360-SP1, AC3522B, Kanpur A, Gao16CB-9, and AC3370 were genetically diverse. The superior accessions for fibre quality identified in this study are potential lines for the diploid cotton improvement programme.

Castor is a prime industrial crop belonging to a monotypic genus and its genetic improvement depends on creating desired variability in the primary gene pool. This study reports the development of tetraploid castor plants through colchicine treatment. Seeds of three castor genotypes were soaked in aqueous solutions of colchicine with variable concentrations, and the LD50 value was determined. Of 1010 treated field-raised plants, three were identified as potential polyploids based on increases in a guard cell size and reductions in the number of stomata. The putative polyploid plants were selfed and the progeny were subjected to meiotic analysis. All the progeny were found to be tetraploid. The pairing of chromosomes was abnormal with univalent to octavalent configurations during meiosis-I, but the later parts of meiosis were normal. Seasonal variations in pollen fertility indicated the possible role of temperature-sensitive male sterility in causing the sterility in tetraploid plants. The tetraploid plants were phenotypically comparable with their diploid counterparts, but produced substantially bigger seeds. Thus, these tetraploid plants are valuable resources for basic and applied research in castor.

Phoebe cooperiana U.N Kanjilal ex A. Das is an indigenous forest tree species yielding fruits consumed widely across the state of Arunachal Pradesh, India. As part of an initiative to domesticate the species, phenotypic variation in fruit and seed morphology as well as the biochemical properties of the pulp were assessed for 14 populations within the state. Nine fruit and seed characters were measured and 12 biochemical parameters of the fruits were analysed. Five trees were selected from each population and a minimum of 30 fruits were collected from each tree. Analysis of variance indicated significant variation in all fruit and seed morphological parameters. The coefficient of variation for fruit weight was reported to be 5.02%, seed weight 5.60%, pulp weight 5.36% and pulp fruit ratio 4.14%. Among biochemical parameters which are of nutritive value, crude protein, vitamin E and A were higher than that found in most common fruits and vegetables. These traits also showed significant variation among the 14 selected populations with crude protein values ranging between 5.99 and 10.76%, vitamin E between 4.80 and 7.33 mg/100 g and vitamin A between 1.88 and 3.13 mg/100 g. The fruits are also high in phenol with a mean value of 22.19 mg/g and displayed promising 2,2-diphenyl-1-picrylhydrazyl radical scavenging properties averaging 56.94% antioxidant activity. However, cyanogen content in the fruits was higher than the permissible amount for human consumption, for which processing is recommended before use. The opportunities for domestication are discussed and some promising traits and populations that can be utilized in the domestication programme are identified.

The development of crop varieties with enhanced economic value requires considerable resources, time and intellectual input. The individual/agencies/institutions other than the originator/developers can easily multiply and commercialize pure-line varieties which are the only cultivar option in predominantly self-pollinated crops like dolichos bean and derive economic benefits from them. Seeking legal rights on crop varieties is the best and the only way to protect them from unlawful claim of their origin/development and deriving economic benefits from them. Seeking legal protection from unauthorized commercialization of crop varieties under Indian PPV & FR Act requires establishment of their distinctness (D), uniformity (U) and stability (S). DUS of crop varieties are established predominantly using morphological descriptors. Five genotypes which include two released varieties (HA 3 and HA 4) (referred to as reference varieties) and one advanced breeding line, HA 11–3 and two elite germplasm accessions, Kadalavare and GL 66 (referred to as candidate varieties) were characterized for 25 morphological descriptors to establish their DUS. All the candidate varieties differed from reference varieties for at least one characterization descriptors, indicating their distinctness. The absence of off-types indicated the uniformity of reference and candidate varieties and hence was deemed stable. Thus, the study demonstrated the utility of morphological descriptors for establishing DUS dolichos bean genotypes.