Addressing the impact of heat stress during flowering and grain filling is critical to sustaining wheat productivity to meet a steadily increasing demand from a rapidly growing world population. Crop wild progenitor species of wheat possess a wealth of genetic diversity for several biotic and abiotic stresses, and morphological traits and can serve as valuable donors. The transfer of useful variation from the diploid progenitor, Aegilops tauschii, to hexaploid wheat can be done through the generation of synthetic hexaploid wheat (SHW). The present study targeted the identification of potential primary SHWs to introduce new genetic variability for heat stress tolerance. Selected SHWs were screened for different yield-associated traits along with three advanced breeding lines and durum parents as checks for assessing terminal heat stress tolerance under timely and late sown conditions for two consecutive seasons. Heat tolerance index based on the number of productive tillers and thousand grain weight indicated that three synthetics, syn9809 (64.32, 78.80), syn14128 (50.30, 78.28) and syn14135 (58.16, 76.03), were able to endure terminal heat stress better than other SHWs as well as checks. One of these synthetics, syn14128, recorded a minimum reduction in thousand kernel weight (21%), chlorophyll content (2.56%), grain width (1.07%) despite minimum grain-filling duration (36.15 d) and has been selected as a potential candidate for introducing the terminal heat stress tolerance in wheat breeding programmes. Breeding efforts using these candidate donors will help develop lines with a higher potential to express the desired heat stress-tolerant phenotype under field conditions.

The bell-type pepper cultivar Golden California Wonder, a source of resistance to southern blight, was crossed with the susceptible cultivar Sweet Banana. The F1, F2 and backcross progenies of this cross and the parental lines were evaluated in an inoculated field study for their reactions to Sclerotium rolfsii Sacc. A categorical rating system was used to rate plants for severity of wilting and severity of stem-lesion development. The plants within all three non-segregating populations (the resistant parent, the susceptible parent and the F1) displayed a range of reactions to S. rolfsii. Variable reactions to S. rolfsii among homogeneous pepper populations were expected because this phenomenon is well documented in the literature and we had observed similar responses in field trials conducted over multiple years. The high level of variation for reactions to S. rolfsii exhibited by the parental and F1 hybrid populations and the categorical system of rating individual plants placed severe limitations on the effective use of any quantitative type of analysis. Accordingly, a weighting procedure was used to correct the F2 and backcross populations based on frequencies of apparent mis-classifications in the parental and F1 populations. Examination of the comparative frequency distributions of the parental and progeny populations and examination of the weighted segregation data suggest that the southern blight resistance in ‘Golden California Wonder’ is conditioned by a single recessive gene. The level of resistance conditioned by this reputed recessive gene appears high enough to recommend it for use in pepper breeding programmes.

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.

The genetic diversity of 39 Iranian black cumin (Nigella sativa L.) landraces was analysed using 14 polymorphic Start Codon Targeted (SCoT) markers. A total of 106 bands ranging from 3 (for SCoT70) to 13 (for SCoT23) were observed. Of them, 33 (31%) bands were polymorphic with a mean of 1.65 bands per primer. Polymorphism information content (PIC) per primer ranged from 0.035 (for SCoT12) to 0.133 (for SCoT70), with an average of 0.078. Besides PIC, Simpson's diversity (D) index was also calculated for each SCoT marker as an indication of discrimination power across population. The D index was used to adjust the PIC of the SCoT markers. As the adjusted PIC (PICD= PIC × D) was calculated based on both the PIC and the rate of band dispersion, this reflected the informativeness of a dominant marker more precisely than PIC. Genetic relationships were estimated using Jaccard's similarity coefficient-generated values between different pairs of genotypes that varied from 80 to 97% with an average of 88%. These coefficients were applied to construct a dendrogram using the UPGMA algorithm. A high genetic similarity was observed that might be due to the fact that N. sativa is a self-pollinated plant not originated from Iran and might have been imported from the Mediterranean regions.

Drought stress ‘particularly at seedling stage’ causes morpho-physiological differences in wheat which are crucial for its survival and adaptability. In the present study, 209 recombinant inbred lines (RILs) from synthetic wheat (W7984)× ‘Opata’ (also known as SynOpRIL) population were investigated under well-watered and water-limited conditions to identify quantitative trait loci (QTL) for morphological traits at seedling stage. Analysis of variance revealed significant differences (P < 0.01) among RILs, and water treatments for all traits with moderate to high broad sense heritability. Pearson's coefficient of correlation revealed positive correlation among all traits except dry root weight that showed poor correlation with fresh shoot weight (FSW) under water-limited conditions. A high-density linkage map was constructed with 2639 genotyping-by-sequencing markers and covering 5047 cM with an average marker density of 2 markers/cM. Composite interval mapping identified 16 QTL distributed over nine chromosomes, of which six were identified under well-watered and 10 in water-limited conditions. These QTL explained from 4 to 59% of the phenotypic variance. Six QTL were identified on chromosome 7B; three for shoot length under water-limited conditions (QSL.nust-7B) at 64, 104 and 221 cM, two for fresh root weight (QFRW.nust-7B) at 124 and 128 cM, and one for root length (QRL.nust-7B) at 122 cM positions. QFSW.nust-7B appeared to be the most significant QTL explaining 59% of the phenotypic variance and also associated with FSW at well-watered conditions. These QTL could serve as target regions for candidate gene discovery and marker-assisted selection in wheat breeding.

Grasspea (Lathyrus sativus L.) is an annual, herbaceous, drought-resistant legume and staple crop in Asian and African countries. Little is known about the nature and the amount of genetic diversity present in existing grasspea seed collections, yet this information is pivotal for future breeding programmes, such as those striving to reduce high neurotoxin levels present in seeds. Here we report on the level of genetic diversity within a world-wide collection of L. sativus, determined by isozymatic analysis. Although grasspea is generally considered a predominantly self-pollinating species, we found that the population genetic structure of these accessions showed a considerable outcrossing rate of 36%. The identification of a mixed mating system in L. sativus has significant implications for collecting and multiplying genetic resources for conservation and for future breeding purposes. In addition, we determined the genetic closeness of grasspea accessions from different geographical regions around the world. While we noticed an allelic richness in this species that was conserved across the regions, we did not find any evidence of high genetic identity between accessions, even when originating from the same geographical location. Instead, we found that greater genetic variability existed at the intra-regional level than at the inter-regional level.

The Drake Passage arises as a likely route for gene flow into Antarctica, as it is the shortest path between this continent and the rest of the world. Despite this, long-distance dispersion into Antarctica could be particularly complex for terrestrial biota. To compare the levels of genetic diversity between Antarctic and South American populations of the Antarctic pearlwort, Colobanthus quitensis, we conducted the first estimation of genetic diversity in this species using amplified fragment length polymorphism. Four populations across the Drake Passage were selected and their genetic composition was characterized. Differences among the levels of genetic diversity were found between the populations analysed as well as between their allelic identities. However, interestingly, their spatial distribution across the Drake Passage suggests a north-to-south gradient of increasing genetic diversity.

Out-crossing between genetically modified herbicide-tolerant (GMHT) and non-GM rape cultivars was studied using GMHT source field plots of approximately 0.8 ha. Levels of cross-pollination between adjacent fully fertile rape varieties declined rapidly with increasing distance from the interface between plots. A varietal association with low levels of male sterility showed higher levels of out-crossing than other varieties. Out-crossing data were used to compare negative exponential and inverse power-law models for their fit to describe the observed relationship between cross-pollination and distance from source. Results showed that the inverse power-law model provided a better fit of the data.

Substantial variation in phenotypic traits and ISSR fingerprinting was observed among twenty populations of Achillea fragrantissima (Forssk.) Sch. Bip. in Egypt. Such variation was reflected in the clustering of the examined populations into two major groups: one representing populations in the mountainous area of South Sinai and the other comprising populations growing at low elevations in the middle of Sinai and the desert west of the Suez Canal from Suez in the east to Cairo in the west. Five populations in the eastern part of Sinai near Nuwieba and Taba on the Gulf of Aqaba were loosely assigned to the first group. The populations growing at high elevations in South Sinai, under lower temperature and higher humidity, were characterized by a higher number of total and polymorphic ISSR markers compared with other populations. Unique ISSR markers were more often observed in the fingerprinting of seven populations including five populations growing in the high mountains of Saint Catherine in South Sinai and two populations growing at low elevations but at Wadi Hof south-east of Cairo. Interestingly, unique bands were found in the populations that possessed traits associated with larger plant size and seed yield as well as better vigour. These are important criteria for the selection of A. fragrantissima populations for conservation and sustainable commercial use.

Castor is an industrially important oilseed crop. Vascular wilt caused by the soil borne fungus Fusarium oxysporum f. sp. ricini is a serious disease of castor. Use of resistant cultivars is the only viable option for management of wilt disease problem in castor production. Excellent sources of resistance to wilt have been found in castor germplasm. In this study, a set of four castor inbred lines (48–1, CI-1, AP42 and AP48) was characterized for inheritance of resistance to wilt by studying segregating populations generated by crossing these inbred lines with eight different susceptible genotypes. An artificial screening method (sick pot) with a new scoring system (days to wilt) was used for evaluation of plant progenies for reaction to the pathogen infection. The reaction of F1s indicated that the nature of resistance in 48–1, CI-1 and AP48 is recessive whereas it was dominant in AP42. Inheritance results from eight F2 populations showed that resistance to wilt is conferred by a single locus in one population and at least two loci, which interact in complementary way, in other seven populations. Different modes of inheritance were also observed when the same resistant source was crossed with different susceptible parents, indicating the possible role of genetic backgrounds in determining resistance. Overall, the results suggested that Mendelian resistance to wilt is predominant in the castor genotypes, which can be exploited for breeding cultivars. Particularly, AP42 with dominant nature of resistance will be of great interest to hybrid breeding.

This study was conducted to characterize new plant type (NPT) traits among 650 genetically diverse rice genotypes of tropical japonica and indica and to establish an initial core set for NPT traits. Analysis of variance revealed highly significant differences among the genotypes for all the traits assessed except flag length and width and leaf angles. Dendrogram categorized the genotypes into five distinct duration groups. Genotypes viz., Pumphamah, IRGC5097, IRGC37015, IRGC43741, IRGC50448, IRGC53089, IRGC39111, IRGC18021, Haorei Machang, IRGC44069, IRGC8269, Thangmoi, IRGC33130 and IRGC29772 were identified as possessing strong culm. Long panicles with a length of more than 35 cm were found in IRGC8269, IRGC9147, IRGC14694, IRGC19642, IRGC27435, IRGC39111, IRGC31051, IRGC26011and IRGC25892. Ideal leaf angle of NPT genotypes of 5°, 10° and 20° of flag leaf, 1st and 2nd leaves was not found in any genotype but with a combination of 5°, 10° and 10° was observed in IRGC63102 and IRGC66644. NPT flag leaf length and width of 50 and 2 cm, respectively, was seen in ‘Kemenya Kepeu’ and ‘IRGC29772’. High grain number of more than 350 was observed in IRGC53089, IRGC31063 and Azhoghi. A total of 72 genotypes were found with a combination of one or more ideal plant type traits of which, hierarchical cluster analysis based on genetic distances selected 32 as NPT core set. This core set will serve as an ideal genetic resource for breeding programs aimed at NPT development.

Mucuna pruriens (L.) DC is a tropical legume cover crop with promising nutritional and agronomic potentials. It is also a key source of 3,4 dihydroxy-L-phenylalanine (L-Dopa) – a precursor of dopamine used in the treatment of Parkinson's disease. However, lack of well-characterized germplasm plus poor accessibility to genomic resources has hindered its breeding programs. Furthermore, the cause and effect of various biotic and abiotic stresses impacting yield is also little studied. Systematic collection and evaluation of Indian germplasm by our group revealed presence of a diverse gene pool in India that can support a variety of breeding needs. The stability of L-Dopa trait across environments examined through Genotype and environment (G × E) interaction studies, as well as feasibility check on barcoding and phylogenetic analyses based on karyotype and conserved nuclear and chloroplast genes showed promising outcome. Germplasm screening for select biotic abiotic stresses identified resilient genotypes. Advances in use of DNA markers for diversity analysis, linkage map development, tagging of genes/quantitative trait loci for qualitative and quantitative traits, and progress in genomics are presented.

This study reviews the various conservation strategies applied to the four redwood species, namely coast redwood (Sequoia sempervirens), Sierra redwood or giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides) and South American redwood or alerce (Fitzroya cupressoides), which are endemic in the USA, China and South America, respectively. All four redwood genera belong to the family Cupressaceae; they are monospecific, share a number of common phenotypic traits, including red wood, and are threatened in their native ranges due to human activity and a changing climate. Therefore, the management objective should be to conserve representative populations of the native species with as much genetic diversity as possible for their future survival. Those representative populations exhibiting relatively high levels of genetic diversity should be selected for germplasm preservation and monitored during the conservation phase by using molecular markers. In situ and ex situ strategies for the preservation of germplasm of the redwoods are discussed in this study. A holistic in situ gene conservation strategy calls for the regeneration of a large number of diverse redwood genotypes that exhibit adequate levels of neutral and adaptive genetic variability, by generative and vegetative methods for their preservation and maintenance in their endemic locations. At the same time, it would be desirable to conserve the redwoods in new ex situ reserves, away from their endemic locations with similar as well as different environmental conditions for testing their growth and survival capacities. In addition, other ex situ strategies involving biotechnological approaches for preservation of seeds, tissues, pollen and DNA in genebanks should also be fully exploited in the face of global climate change.

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.

The endangered alpine plant Aconitum heterophyllum was conserved under ex situ conditions (greenhouse and open) of Palampur by overcoming seed dormancy and plant establishment through hot water treatment (40–60 °C for 30–120 s) of seeds. High seed germination (88 and 76%) was obtained when seeds were treated with hot water at 45 and 50 °C for 90 s. Correlation studies also revealed that treatment enhanced vegetative growth and reproductive yield of the plants. The total alkaloid content of the roots and rhizomes of the plants growing under ex situ conditions was lower than the ones collected from the natural habitat in the 1-year-old plants. However, in the 2-year-old plants, it was almost at par with the ones collected from nature. The life cycle of the plants growing under ex situ conditions also did not vary largely from the plants growing under in situ conditions. Therefore, the present study indicates the successful adaptation of A. heterophyllum plants in conditions other than their natural habitat and hence its potential for sustainable commercialization.

African yam bean (AYB) is an affordable protein source capable of diversifying the food base in sub-Saharan Africa. However, research efforts made towards the crop's improvement and in expanding production are limited. This study characterized 169 AYB accessions at Jimma, Ethiopia, using 31 phenotypic characters. The analysis of variance revealed highly significant (P < 0.01) differences for days to 50% flowering, days to first flowering, leaf area, number of seeds per pod, pod length, seed thickness, total seed weight, petiole length and significant (P < 0.05) difference for terminal leaf length. Accession TSs62B produced the highest number of seeds per pod (17.65) and recorded the highest 100 seed weight (25.30 g), while 3A was the earliest to flower at an average of 84.50 d. Principal component analysis (PCA) of qualitative traits attributed 77.6% of observed variations to the first five principal components, of which the first two PC axes accounted for 53.6% of total variations. Cluster analysis and PCA biplot distinctly grouped the accessions into two major groups, cluster I had the highest number of accessions (108). The analytical approaches used confirmed considerable diversity across the germplasm with a distance matrix ranging from 0.37 to 0.85. The extent of diversity reflected in the current study provides breeders the baseline information to design breeding strategies, which might help identify materials for release as variety or parental lines for hybridization programmes.

Theobroma cacao L., or cacao, is the source of cocoa products used in the making of chocolate. These tropical trees are conserved in living genebanks. The International Cocoa Genebank, Trinidad is one of the largest ex situ collections in the public domain. Mislabelling is a critical problem and the correction of this problem is vital to improve the accuracy and efficiency of genebank management. Using microsatellite DNA markers, we assessed the level of mislabelling in a group of Refractario cacao that originated from Ecuador and determined their population memberships through Bayesian clustering analysis. The microsatellite data revealed a synonymous rate of 7.5% and an error rate of 39.4% in this germplasm subset. The analysis of the population structure grouped the Refractario accessions into four subclusters, indicating intra-population heterogeneity in this germplasm group. Based on the results, we recommend that when the assignment test is used for cacao genotype identification, it should (a) use duplicated samples as internal checks, (b) choose suitable reference accessions, including a known homogeneous group and (c) employ subclustering checks to obtain reliable results. The information framework generated is discussed in relation to the management of the collection, population enhancement and future research of the collection.

Natural hybridization between wild/weedy and crop species often results in rare hybrids, which can be more weedy and difficult to control. Moreover, the advent of transgenic crop plants raises questions of biosafety risk assessment on the consequences of rare hybrids with possible fitness enhancing genes on the environment. This study aimed at measuring the fitness components of wild–crop sorghum hybrids for various juvenile survival and adult morphological and fertility characters as part of the risk assessment of transgenic sorghum in Africa where the crop was believed to have first domesticated and serves as the major staple. Out of a pool of hybrids made in 2010 from 23 wild sorghum accessions and two released cultivated sorghum varieties using hand emasculation techniques, seven were selected for the field study of their fitness components in 2011. The study confirmed that crop–wild hybrids of sorghum are fertile. Two approaches were followed (relative fitness and mid-parent heterosis) which showed that most of the hybrids were as fit as their wild parents, and in some cases they showed mid-parent heterosis for the measured traits. The results of this study highlighted a potential risk that hybrids carrying crop genes (including herbicide resistance transgenes) could pose because they could be more weedy than their wild/weedy parents if transgenic sorghum is deployed in regions where the wild and cultivated sorghum populations coexist, such as in Ethiopia and in other parts of Africa.

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.

Soybean is a leading oilseed crop in India, which contains about 40% of protein and 20% of oil. Core collection will accelerate the management and utilization of soybean genetic resources in breeding programmes. In the present study, eight agromorphological traits of 3443 soybean germplasm were analysed for the development of core collection using the principal component score (PCS) strategy and the power core method. The PCS strategy yielded core collection (CC1) of 576 accessions, which accounted for 16.72% of the entire collection (EC). The analysis based on the power core programme resulted in CC2 of 402 accessions, which accounted for 11.67% of the EC. Statistical analysis showed similar trends for the mean and range estimated in both core collections and EC. In addition, the variance, standard deviation and coefficient of variance were in general higher in core collections than in the EC. The correlations observed in the EC in general were preserved in core collections. A total of 311 and 137 unique accessions were found in CC1 and CC2 in addition to 265 accessions that were found to be common in both core collections. These 265 common accessions were the most diverse core sets, which accounted for 7.64% of the EC. We proposed to constitute an integrated core collection (ICC) by integrating both common and unique accessions. The ICC comprised 713 accessions, which accounted for about 20.62% of the EC. Statistical analysis indicated that the ICC captured maximum variation than CC1 and CC2. Therefore, the ICC can be extensively evaluated for a large number of economically important traits for the identification of desirable genotypes and for the development of mini core collection in soybean.