Interspecific Lines Research Articles

Selection of Cotton Varieties in a Competitive Nursery in the South of Kazakhstan

The Turkestan region is a cotton-growing zone in the south of Kazakhstan, which is the northernmost cotton-growing zone in the world. 115-125 thousand hectares of medium-staple cotton (Gossypium hirsutum L.) are cultivated here annually, of which 80-85 thousand hectares are sown in the Maktaaral and Zhetysay districts. This region is highly susceptible to salinity, drought, invasion of dangerous pests (cotton budworm, beet borer, spider mites, aphids), and diseases (fusarium blight (wilt), gummosis). Considering the high salt content in the arable soil horizon, the aridity of the climate of the Turkestan region are the main limiting factor of the region, and selection and genetic methods is the most effective and economical way to reduce their negative impacts on cultivated vegetation, then research work on the study and creation of new resistant cotton varieties in these soil and climatic conditions are relevant. Considering all the above problems, scientists of the Agricultural Experimental Station of Cotton and Melon Growing LLP have set themselves the goal of creating heat- and drought-resistant, precocious cotton varieties with high productivity, resistance to salinization, diseases, pests, possessing high technological qualities as the yield and quality of fiber of types III-IV, based on previously obtained ones during hybridization of intraspecific and interspecific lines of families. For 30 years, scientist-breeders of Kazakhstan have created 13 varieties of medium-fiber cotton, of which 8 are approved for use in the Turkestan region in the Republic of Kazakhstan. The research method is based on hybridization, multiple selection, and testing of offspring by the half method, according to the full diallel scheme (first Griffing model for F1). The created seven varieties PA-3031, PA-3044, M-4005, M-4007, M-4011, Bereke-07, Myrzashol-80, and M-4017 are zoned for more than 92% of the acreage in cotton-growing farms in the south of Kazakhstan, for the variety M-5027, which is resistant to pests, the patent has been issued 2021 and in 2022 it is planned to enter it into the register of approved varieties.

Novel Alleles from Cicer reticulatum L. for Genetic Improvement of Cultivated Chickpeas Identified through Genome Wide Association Analysis.

The availability of wild chickpea (Cicer reticulatum L.) accessions has the potential to be used for the improvement of important traits in cultivated chickpeas. The main objectives of this study were to evaluate the phenotypic and genetic variations of chickpea progeny derived from interspecific crosses between C. arietinum and C. reticulatum, and to establish the association between single nucleotide polymorphism (SNP) markers and a series of important agronomic traits in chickpea. A total of 486 lines derived from interspecific crosses between C. arietinum (CDC Leader) and 20 accessions of C. reticulatum were evaluated at different locations in Saskatchewan, Canada in 2017 and 2018. Significant variations were observed for seed weight per plant, number of seeds per plant, thousand seed weight, and plant biomass. Path coefficient analysis showed significant positive direct effects of the number of seeds per plant, thousand seed weight, and biomass on the total seed weight. Cluster analysis based on the agronomic traits generated six groups that allowed the identification of potential heterotic groups within the interspecific lines for yield improvement and resistance to ascochyta blight disease. Genotyping of the 381 interspecific lines using a modified genotyping by sequencing (tGBS) generated a total of 14,591 SNPs. Neighbour-joining cluster analysis using the SNP data grouped the lines into 20 clusters. The genome wide association analysis identified 51 SNPs that had significant associations with different traits. Several candidate genes associated with early flowering and yield components were identified. The candidate genes and the significant SNP markers associated with different traits have a potential to aid the trait introgression in the breeding program.

Comparative gene expression in cotton fibres of interspecific lines developed through tri-species (G. hirsutum, G. arboreum &G. anomalum)

Development of superior quality cotton varieties is the only way to meet the demand for the fast-growing textile sector. Fifty interspecific lines were screened to select the diverse lines for expression analysis. Comparative expression and promoter analysis were carried out to comprehend the role of fibre genes (APX1, ATP Synthase, and GhMYB 25-like) in three interspecific lines (SL-19, SL-79 and SL-369) and three Gossypium species (Gossypium hirsutum, Gossypium arboreum &Gossypium anomalum). Among the interspecific lines, the maximum expression was noted in SL-19 for all fibre genes with varying levels at different fibre developmental stages while minimum fibre genes transcripts were present in SL-3.69. Among the species, maximum expression was noted in G. hirsutum while the minimum was noted in G. anomalum. The GhMYB25-like gene was involved in fibre initiation, showing its maximum expression at initial fibre development stages (0 & 5 DPA). APX1 and ATP synthase genes were involved in fibre elongation with more expression at 10 DPA & 15 DPA. Moreover, the identification of various important promoters in APX1, ATP synthase &GhMYB25-like genes was done which makes it an important tool for engineering extra-long fibre traits leading to the development of high-quality cotton varieties.

Genome-wide analysis of genetic diversity in a germplasm collection including wild relatives and interspecific clones of garden asparagus.

The Asparagus genus includes approximately 240 species, the most important of which is garden asparagus (Asparagus officinalis L.), as this is a vegetable crop cultivated worldwide for its edible spear. Along with garden asparagus, other species are also cultivated (e.g., Asparagus maritimus L.) or have been proposed as untapped sources of variability in breeding programs (e.g., Asparagus acutifolius L.). In the present work, we applied reduced-representation sequencing to examine a panel of 378 diverse asparagus genotypes, including commercial hybrids, interspecific lines, wild relatives of garden asparagus, and doubled haploids currently used in breeding programs, which enabled the identification of more than 200K single-nucleotide polymorphisms (SNPs). These SNPs were used to assess the extent of linkage disequilibrium in the diploid gene pool of asparagus and combined with preliminary phenotypic information to conduct genome-wide association studies for sex and traits tied to spear quality and production. Moreover, using the same phenotypic and genotypic information, we fitted and cross-validated genome-enabled prediction models for the same set of traits. Overall, our analyses demonstrated that, unlike the diversity detected in wild species related to garden asparagus and in interspecific crosses, cultivated and wild genotypes of A. officinalis L. show a narrow genetic basis, which is a contributing factor hampering the genetic improvement of this crop. Estimating the extent of linkage disequilibrium and providing the first example of genome-wide association study and genome-enabled prediction in this species, we concluded that the asparagus panel examined in the present study can lay the foundation for determination of the genetic bases of agronomically important traits and for the implementation of predictive breeding tools to sustain breeding.

Multi-Environment Genome-Wide Association Studies of Yield Traits in Common Bean (Phaseolus vulgaris L.) × Tepary Bean (P. acutifolius A. Gray) Interspecific Advanced Lines in Humid and Dry Colombian Caribbean Subregions

Assessing interspecific adaptive genetic variation across environmental gradients offers insight into the scale of habitat-dependent heritable heterotic effects, which may ultimately enable pre-breeding for abiotic stress tolerance and novel climates. However, environmentally dependent allelic effects are often bypassed by intra-specific single-locality genome-wide associations studies (GWAS). Therefore, in order to bridge this gap, this study aimed at coupling an advanced panel of drought/heat susceptible common bean (Phaseolus vulgaris L.) × tolerant tepary bean (P. acutifolius A. Gray) interspecific lines with last-generation multi-environment GWAS algorithms to identify novel sources of heat and drought tolerance to the humid and dry subregions of the Caribbean coast of Colombia, where the common bean typically exhibits maladaptation to extreme weather. A total of 87 advanced lines with interspecific ancestries were genotyped by sequencing (GBS), leading to the discovery of 15,645 single-nucleotide polymorphism (SNP) markers. Five yield traits were recorded for each genotype and inputted in modern GWAS algorithms (i.e., FarmCPU and BLINK) to identify the putative associated loci across four localities in coastal Colombia. Best-fit models revealed 47 significant quantitative trait nucleotides (QTNs) distributed in all 11 common bean chromosomes. A total of 90 flanking candidate genes were identified using 1-kb genomic windows centered in each associated SNP marker. Pathway-enriched analyses were done using the mapped output of the GWAS for each yield trait. Some genes were directly linked to the drought tolerance response; morphological, physiological, and metabolic regulation; signal transduction; and fatty acid and phospholipid metabolism. We conclude that habitat-dependent interspecific polygenic effects are likely sufficient to boost common bean adaptation to the severe climate in coastal Colombia via introgression breeding. Environmental-dependent polygenic adaptation may be due to contrasting levels of selection and the deleterious load across localities. This work offers putative associated loci for marker-assisted and genomic selection targeting the common bean’s neo-tropical lowland adaptation to drought and heat.

Interspecific common bean population derived from Phaseolus acutifolius using a bridging genotype demonstrate useful adaptation to heat tolerance.

Common bean (Phaseolus vulgaris L.) is an important legume crop worldwide and is a major nutrient source in the tropics. Common bean reproductive development is strongly affected by heat stress, particularly overnight temperatures above 20°C. The desert Tepary bean (Phaseolus acutifolius A. Gray) offers a promising source of adaptative genes due to its natural acclimation to arid conditions. Hybridization between both species is challenging, requiring in vitro embryo rescue and multiple backcrossing cycles to restore fertility. This labor-intensive process constrains developing mapping populations necessary for studying heat tolerance. Here we show the development of an interspecific mapping population using a novel technique based on a bridging genotype derived from P. vulgaris, P. Acutifolius and P. parvifolius named VAP1 and is compatible with both common and tepary bean. The population was based on two wild P. acutifolius accessions, repeatedly crossed with Mesoamerican elite common bush bean breeding lines. The population was genotyped through genotyping-by-sequencing and evaluated for heat tolerance by genome-wide association studies. We found that the population harbored 59.8% introgressions from wild tepary, but also genetic regions from Phaseolus parvifolius, a relative represented in some early bridging crosses. We found 27 significative quantitative trait loci, nine located inside tepary introgressed segments exhibiting allelic effects that reduced seed weight, and increased the number of empty pods, seeds per pod, stem production and yield under high temperature conditions. Our results demonstrate that the bridging genotype VAP1 can intercross common bean with tepary bean and positively influence the physiology of derived interspecific lines, which displayed useful variance for heat tolerance.

Large genomic introgression blocks of Phaseolus parvifolius Freytag bean into the common bean enhance the crossability between tepary and common beans.

The production of the common bean (Phaseolus vulgaris L.), one of the most important sources of protein and minerals and one of the most consumed grain legumes globally, is highly affected by heat and drought constraints. In contrast, the tepary bean (Phaseolus acutifolius A. Gray), a common bean-related species, is adapted to hot and dry climates. Hybridization to introduce complex traits from the tepary bean into the common bean has been challenging, as embryo rescue is required. In this study, we report three novel interspecific lines that were obtained by crossing lines from prior common bean × tepary bean hybridization with Phaseolus parvifolius Freytag in order to increase the male gametic diversity to facilitate interspecific crosses. These interspecific lines enhanced the crossability of the common bean and tepary bean species while avoiding the embryo rescue process. Crossing these three interspecific lines with tepary beans resulted in 12-fold more hybrid plants than crossing traditional common beans with tepary beans. Whole-genome sequencing analysis of these three interspecific lines shows large introgressions of genomic regions corresponding to P. parvifolius on chromosomes that presumably contribute to reproductive barriers between both species. The development of these lines opens up the possibility of increasing the introgression of desirable tepary bean traits into the common bean to address constraints driven by climate change.

Quantitative Trait Analysis Shows the Potential for Alleles from the Wild Species Arachis batizocoi and A. duranensis to Improve Groundnut Disease Resistance and Yield in East Africa

Diseases are the most important factors reducing groundnut yields worldwide. In East Africa, late leaf spot (LLS) and groundnut rosette disease (GRD) are the most destructive diseases of groundnut. Limited resistance is available in pure pedigree cultivated groundnut lines and novel sources of resistance are required to produce resistant new varieties. In this work, 376 interspecific lines from 3 different populations derived from crosses with the wild species A. duranensis, A. ipaënsis, A. batizocoi and A. valida were phenotyped for 2 seasons and across 2 locations, Serere and Nakabango, in Uganda. Several genotypes showed a higher yield, a larger seed, an earlier flowering, and similar resistance to the local cultivar checks. Genotypic data was used to construct a linkage map for the AB-QTL population involving the cross between Fleur11 and [A. batizocoi x A. duranensis]4x. This linkage map, together with the phenotypic data was used to identify quantitative trait loci controlling disease resistance. These lines will be useful in combining good agronomic traits and stacking disease resistance to improve the groundnut crop in sub-Saharan Africa.

Genome-wide association analysis of stress tolerance indices in an interspecific population of chickpea.

Chickpea is a cool season crop that is highly vulnerable to abiotic stresses such as heat and drought. High temperature during early flowering and pod development stages significantly reduces the crop yield. The wild relatives of chickpeas can be potential donors for the introgression of heat and drought tolerance into cultivated chickpeas for crop improvement. Initially, 600 interspecific lines were derived from crosses between two elite cultivars, CDC Leader (kabuli chickpea) and CDC Consul (desi chickpea), and 20 accessions of Cicer reticulatum. The F5 interspecific lines were tested for agronomic and seed quality traits including reaction to ascochyta blight disease under field conditions at two locations in 2018. A subset of 195 lines were selected based on resistance to ascochyta blight and acceptable seed quality. These lines were evaluated for their performance under suboptimal conditions at Lucky Lake (2019 and 2020) and Moose Jaw (2019), Saskatchewan, Canada, and Yuma, Arizona, United States (2019–2020). The lines were grown and evaluated at two seeding dates, normal (SD1) and late (SD2) seeding dates, at each location and year. The same lines were genotyped using Cicer60K Axiom® SNP chip. The population structure was determined based on 35,431 informative SNPs using fastStructure, and the interspecific lines were clustered at a k-value of 15. Significant marker-trait associations were identified for seed yield from SD1 and SD2 seeding dates, and stress tolerance indices (ATI, K1STI, MP, SSPI, and TOL) using phenotypic values both from individual locations and combined analyses based on BLUP values. SNP marker Ca2_34600347 was significantly associated with yield from both the seeding dates. This and other SNP markers identified in this study may be useful for marker-assisted introgression of abiotic stress tolerance in chickpea.

In silico analysis and expression profiling of Expansin A4, BURP domain protein RD22-like and E6-like genes associated with fiber quality in cotton.

To supply high-quality cotton fibre for the textile industry, the development of long, strong and fine fibre cotton varieties is imperative. An interlinked approach was used to comprehend the role of fibre genes by analyzing interspecific progenies of cotton species. Wild Gossypium species and races are rich source of genetic polymorphism due to environmental dispersal and continuous natural selection. These genetic resources hold mass of outclass genes that can be used in cotton improvement breeding programs to exploit possible traits such as fibre quality, abiotic stress tolerance, and disease and insect resistance. Therefore, use of new molecular techniques such as genomics, transcriptomics and bioinformatics is very important to utilize the genetic potential of wild species in cotton improvement programs. Interspecific lines and Gossypium species used in the study were grown at Central Cotton Research Institute (CCRI), Multan. After retrieving DNA sequence of the genes from NCBI, the primers for gene expression and full-length gene sequence were designed. Expression profiling of Expansin A4, BURP Domain protein RD22-like and E6-like fibre genes was performed through Real Time PCR. BLAST and DNA sequence alignment was conducted for sequence comparison of interspecific lines and Gossypium species. Different in silico analysis were used for characterization of fibre genes and identification of cis acting promoter elements in promoter region. Variable expression of genes related to fibre development was observed at different stages. BLAST and DNA sequence alignment demonstrated resemblance of interspecific lines with G. hirsutum. In silico analysis on the sequence data also confirmed the role of Expansin A4, BURP Domain protein RD22-like and E6-like fibre genes in fibre development. Genetic engineering is also recommended by transferring E6-like, Expansin A4 and BURP Domain RD22-like genes in local cotton cultivars. Similarly, several stress tolerant and light responsive cis acting elements were identified through promotor analysis, which may contribute for fibre development in the breeding programs. Expansin A4, BURP Domain RD22-like and E6-like have positive role in fibre development with variable expression at fiber length and strength associated stages.

Physicochemical and proximate composition of mungbean × urdbean and mungbean × ricebean interspecific lines

The present investigation reports physicochemical parameters and proximate composition of twenty mungbean interspecific lines and 5 released (check) varieties. The interspecific lines exhibited 100-seed weight, seed volume, seed density, water absorption capacity, volume expansion, swelling capacity, swelling index, hydration capacity and hydration index in the range of 2.92–4.64 g, 0.032–0.063 ml, 0.774–1.39 g/ml, 120–174, 200–528%, 0.101–0.161 ml/seed, 0.660–0.840, 0.050–0.079 g/seed and 1.21–1.74, respectively. Interspecific lines exhibited lower mean seed volume and swelling index but higher mean values for seed density, volume expansion and swelling capacity per seed as compared to check varieties. Interspecific lines contained 7.86–12.1% moisture content, 18.4–50.8% neutral detergent fiber, 7.00–11.4% acid detergent fiber and 0.55–2.25% acid detergent lignin. P, K, Mg, Ca, Fe, Mn, Zn and Cu content among the interspecific lines ranged from 280 to 335, 488 to 1401, 86.0 to 204, 68.6 to 202, 2.59 to 5.51, 0.501 to 0.823, 2.13 to 3.32 and 0.715 to 3.02 mg/100 g, respectively. Overall, SML 2033 was found to be a promising line as it exhibited the highest 100-seed weight and hydration capacity with high amounts of Fe, Mn and P. In addition, SML (summer mung Ludhiana) 1827, SML 1933, SML 2011, SML 2016, SML 2031 and SML 2032 are other promising lines with better processing attributes.

Root Plate Growth in Sunflower and Its Relevance to Sclerotinia Basal Stalk Rot

Sclerotinia basal stalk rot (BSR) of sunflower (Helianthus annuus L.) is a fungal disease of the roots that causes symptoms of wilt and a basal stem lesion. Evaluating root plate growth could improve our understanding of BSR. Separate studies were conducted to determine the effect of sunflower growth stage or genotype on root plate diameter in North American environments. Root plate diameter of cultivated hybrids at reproductive growth stages was 3 to 4 times larger than vegetative stages. Cultivated hybrids had larger root plate diameter than interspecific lines. These results have implications for artificial inoculation methods that evaluate genotypes for BSR resistance in the field or greenhouse. Disease escapes can occur if field-grown plants are inoculated too far from the root plate and/or too early at vegetative growth stages. Side-dressing mycelium-infested cereal grain closer (i.e., 10 cm) to plants at reproductive growth stages (i.e., R1 - R4) can increase disease pressure and reduce disease escapes. These guidelines for the field can be used to validate results from artificial inoculations in the greenhouse.

Assessment of yield components and fibre quality traits in an introgressed population derived from Gossypium hirsutum and G. barbadense

The introgressed populations developed from crosse between Gossypium hirsutum and G. barbadense were used to assess genetic variation for yield components and fibre quality traits. A difference among introgressed lines and parental lines was significant for all traits except sympodial branches, node number, uniformity index and fibre elongation. The lines with high ginning outturn showed higher values for plant height, seed index and lint index than the lines with cluster boll bearing, round boll lines and fibre length-strength lines. However, the majority of introgressed lines had lower values for boll number and seed cotton yield as compared to the parental lines Suraj and NH 615. For fibre strength and ginning outturn, the lines viz., CNH 31-90 and CNH 29-90 had higher fibre strength of 30.5 and 30.1 g/tex, respectively. CNH 19-5 (35.8 mm) and CNH 19-4 (33.9 mm) showed higher values for fibre length which was significantly higher than the variety Suraj (31.6 mm). Similarly, CNH 29-90 (30.1 g/tex), CNH 31-90 (30.5 g/tex) as well as CNH 19-4 and CNH 42-6 (29.9 g/tex) displayed higher values for fibre strength. Lines viz., CNH 44-31, CNH 47-31, CNH 19-4, CNH 19-5 and CNH 42-6 were identified for a desirable combination of yield and fibre quality and ginning percentage. CNH 31-90, CNH 33-94 and CNH 48-4 had a combination of fibre quality and high ginning percentage. In the majority of lines, the mean values for fibre length and strength were the most biased towards the G. hirsutum variety Suraj and NH 615. Fibre quality traits viz., length and strength, were highly and positively correlated (0.41) suggesting that selections can be made for simultaneous improvement of fibre length and strength. Fibre length (-0.04) and fibre strength (-0.06) had a lesser negative association with seed cotton yield indicating breaking of strong negative correlation between yield and quality (either length or strength) in interspecific lines between G. hirsutum and G. barbadense. Key words: Correlations, Fibre quality, G. barbadense, Introgression lines, Yield components, Upland cotton

Adaptation of Interspecific Mesoamerican Common Bean Lines to Acid Soils and High Temperature in the Amazon Region of Colombia.

Knowledge of the physiological basis for improved genetic adaptation of common bean (Phaseolus vulgaris L.) lines to acid soils and high temperature conditions in the Amazon region of Colombia is limited. In this study, we evaluated the differences among 41 common bean lines in energy use, leaf cooling, photosynthate partitioning to pod formation and grain filling, and grain yield over two seasons under acid soil and high temperature stress in the Amazon region of Colombia. Common bean lines evaluated included medium and large seeded interspecific lines of Mesoamerican and Andean gene pools with different levels of adaptation to abiotic stress conditions and some lines are improved for iron and zinc (biofortified) concentration in seeds. We found three bean lines (GGR 147, SMG 21 and SMG 12) that were superior in their photosynthetic response, leaf cooling, photosynthate partitioning ability to pod formation and grain filling, resulting in grain yields exceeding 1900 kg ha−1 under acid soil and high temperature stress conditions. The superior photosynthetic performance was attributed to the efficient use of absorbed energy on the electron level in thylakoids, which is mainly oriented to a higher quantum yield of PSII (ΦII), lower energy dissipation in the form of heat (ΦNPQ), high linear electron flow (LEF) and high fraction of PSI centers in open state (PSIopen). We speculate that these photosynthetic and photosynthate partitioning responses of superior bean lines are part of the genetic adaptation to acidic soils and high temperature stress conditions. Among the evaluated bean lines, three lines (GGR 147, SMG 21 and SMG 12) combined the desirable attributes for genetic improvement of stress tolerance and biofortification. These lines can serve as parents to further improve traits (energy use efficiency and multiple stress resistance) that are important for bean production in the Amazon region.

Multi-Environment Yield Components in Advanced Common Bean (Phaseolus vulgaris L.) × Tepary Bean (P. acutifolius A. Gray) Interspecific Lines for Heat and Drought Tolerance

Heat and drought are major stresses that significantly reduce seed yield of the common bean (Phaseolus vulgaris L.). In turn, this affects the profitability of the crop in climatic-vulnerable tropical arid regions, which happen to be the poorest and in most need of legume proteins. Therefore, it is imperative to broaden the sources of heat and drought resistance in the common bean by examining closely related species from warmer and drier environments (i.e., Tepary bean, P. acutifolius A. Gray), while harnessing such variation, typically polygenic, throughout advanced interspecific crossing schemes. As part of this study, interspecific congruity backcrosses for high temperature and drought tolerance conditions were characterized across four localities in coastal Colombia. Genotypes with high values of CO2 assimilation (>24 µmol CO2 m−2 s−1), promising yield scores (>19 g/plant), and high seed mineral content (Fe > 100 mg/kg) were identified at the warmest locality, Motilonia. At the driest locality, Caribia, one intercrossed genotype (i.e., 85) and the P. acutifolius G40001 control exhibited sufficient yield for commercial production (17.76 g/plant and 12.76 g/plant, respectively). Meanwhile, at southernmost Turipaná and Carmen de Bolívar localities, two clusters of genotypes exhibited high mean yield scores with 33.31 g/plant and 17.89 g/plant, respectively, and one genotype had an increased Fe content (109.7 mg/kg). Overall, a multi-environment AMMI analysis revealed that genotypes 13, 27, 82, and 84 were environmentally stable with higher yield scores compared to the Tepary control G40001. Ultimately, this study allows us to conclude that advanced common bean × Tepary bean interspecific congruity backcrosses are capable of pyramiding sufficient polygenic tolerance responses for the extreme weather conditions of coastal Colombia, which are likely to worsen due to climate change. Furthermore, some particular recombination events (i.e., genotype 68) show that there may be potential to couple breeding for heat and drought tolerance with Fe mineral biofortification, despite a prevalent trade-off, as a way to fight malnutrition of marginalized communities in tropical regions.

Mungbean x ricebean and mungbean x urdbean interspecific lines are nutritionally comparable to mungbean cultivars

The present investigation reports the contents of nutrients and antinutrients of 7 Mungbean x Ricebean (MR) interspecific lines, 13 Mungbean x Urdbean (MU) interspecific lines and 5 check varieties. SML 1808 exhibited the highest content of total soluble sugars (328.44 mg g−1) while SML 2011 exhibited the lowest (30.65 mg g−1). Mean values of reducing sugars, non-reducing sugars, sucrose, starch, amylose and amylopectin in interspecific lines were 3.62, 111.21, 26.34, 329.50, 163.24 and 166.23 mg g−1, respectively. Interspecific lines exhibited 1.96–2.54 mg g-1 phytate, 0.66–2.18 mg g-1 tannins, 120–2560 HU g-1 lectins, 7.50–23.46 TIU mg-1 trypsin inhibitor and 48.87–61.47 AIU g-1 amylase inhibitor activities. SML 1809 was rich in carbohydrates and tannins. SML 1820, SML 1827 and SML 2034 lines exhibited low phytic acid and trypsin inhibitor activity and higher sugar content. SML 2031 and SML 2032 (MR lines) and SML 1817, SML 2033 and SML 2034 (MU lines) were better in terms of their nutritional composition. Overall, SML 1809 and SML 2034 were found to be nutritionally promising lines as they exhibited the high carbohydrate content with low phytate and lectins concentration.

Heat stress-induced changes in shoot and root characteristics of genotypes of tepary bean (Phaseolus acutifolius A. Gray), common bean (Phaseolus vulgaris L.) and their interspecific lines

Heat stress is a major limitation to grain yield in common bean (Phaseolus vulgaris L.). Tepary bean (Phaseolus acutifolius A. Gray) is better adapted to heat stress than common bean. Ten tepary bean accessions, four common bean genotypes and four interspecific lines involving P. vulgaris and P. acutufolius, P. coccineus and P. dumosus were evaluated for tolerance to heat stress conditions induced under greenhouse conditions and these were compared to plants grown under ambient temperatures. The high temperature treatment was 29 ±5 °C during the day and was >24 °C (up to 27 °C) during the night, while the ambient temperature (AT) treatment was 25 ±5 °C during the day and 19± 2 °C at night. The genotypic differences were evaluated for morpho-physiological characteristics of shoot and root and also yield components. The Genotype and Genotype × Temperature interactions were significant for all shoot and root morpho-physiological characteristics evaluated. Higher temperature (HT) significantly affected leaf photosynthetic efficiency, total chlorophyll content, and stomatal conductance. The effect was positive or negative, depending on the genotypes. Tepary accessions showed reduced total chlorophyll content, while common bean genotypes and the interspecific lines were less affected. Tepary accessions also showed reduced stomatal conductance, but increased leaf photosynthetic efficiency under HT. Common bean genotypes increased stomatal conductance and decreased leaf photosynthetic efficiency. High temperature decreased total root length, specific root length and pod biomass compared to ambient conditions, but there was no marked effect on pollen viability of the tested genotypes. The superior adaptation of tepary germplasm accessions to high temperature is attributed to their ability to regulate stomatal opening and photosynthetic efficiency, together with a superior ability to remobilize photosynthates from older leaves to pods during physiological maturity

Genetic analysis and population structure of wild and cultivated wishbone flower (Torenia fournieri Lind.) lines related to specific floral color.

BackgroundThe wishbone flower or Torenia fournieri Lind., an annual from tropical Indochina and southern China, is a popular ornamental plant, and many interspecific (T. fournieri × T. concolor) hybrid lines have been bred for the international market. The cultivated lines show a pattern of genetic similarity that correlates with floral color which informs on future breeding strategies. This study aimed to perform genetic analysis and population structure of cultivated hybrid lines comparing with closely related T. concolor wild populations.MethodsWe applied the retrotransposon based iPBS marker system for genotyping of a total of 136 accessions from 17 lines/populations of Torenia. These included 15 cultivated lines of three series: Duchess (A, B, C); Kauai (D, E, F, G, H, I, J); Little Kiss (K, L, M, N, P) and two wild T. concolor populations (Q and R). PCR products from each individual were applied to estimate the genetic diversity and differentiation between lines/populations.ResultsGenotyping results showed a pattern of genetic variation differentiating the 17 lines/populations characterized by their specific floral colors. The final PCoA analysis, phylogenetic tree construction, and Bayesian population structural bar plot all showed a clear subdivision of lines/populations analysed. The 15 cultivated hybrid lines and the wild population Q that collected from a small area showed the lowest genetic variability while the other wild population R which sampled from a larger area had the highest genetic variability.DiscussionThe extremely low genetic variability of 15 cultivated lines indicated that individual line has similar reduction in diversity/heterozygosity from a bottleneck event, and each retained a similar (but different from each other) content of the wild genetic diversity. The genetic variance for the two wild T. concolor populations could be due to our varied sampling methods. The two wild populations (Q, R) and the cultivated hybrid lines (I, K, M, N, P) are genetically more closely related, but strong positive correlations presented in cultivated lines A, C, E, M, and N. These results could be used to guide future Torenia breeding.ConclusionsThe genetic variation and population structure found in our study showed that cultivated hybrid lines had similar reduction in diversity/heterozygosity from a bottleneck event and each line retained a similar (but different from each other) content of the wild genetic diversity, especially when strong phenotypic selection of floral color overlaps. Generally, environmental factors could induce transposon activation and generate genetic variability which enabled the acceleration of the evolutionary process of wild Torenia species. Our study revealed that wild Torenia populations sampled from broad geographic region represent stronger species strength with outstanding genetic diversity, but selective breeding targeting a specific floral color decreased such genetic variability.

Identifying interspecific lines of coffee resistant to Hemileia vastatrix Berk. et Br. and evaluating their adaptability to the coffee growing region of Puerto Rico

Thirteen lines from the coffee germplasm collection of the Adjuntas Agricultural Experiment Substation, lines T-5175 and T-8667 from Costa Rica, and four advanced multilines from the Portugal Research Center for Coffee Rust (CIFC; ‘Centro de Investigación de la Roya del Café de Portugal’) were evaluated for resistance to Hemileia vastatrix and their performance under coffee production conditions in Puerto Rico. The evaluations were conducted in the laboratory and on selected coffee farms. Lines of “Catimor” and “Sarchimor” types were selected based on their reaction to the rust pathogen and excellent agronomic characteristics and named ‘Frontón’ and ‘Limaní’, respectively. Incidence of black beans was examined in red, medium and green beans and was significantly higher in line T-5175, in plantings <300 meters above sea level, and in medium ripe and green fruits. Catimor lines from the CIFC were superior to the check ‘Caturra’ in fruit production and yield of green coffee.

Evaluation and Selection of Interspecific Lines of Groundnut (Arachis hypogaea L.) for Resistance to Leaf Spot Disease and for Yield Improvement.

Early and late leaf spot are two devastating diseases of peanut (Arachis hypogaea L.) worldwide. The development of a fertile, cross-compatible synthetic amphidiploid, TxAG-6 ([A. batizocoi × (A. cardenasii × A. diogoi)]4x), opened novel opportunities for the introgression of wild alleles for disease and pest resistance into commercial cultivars. Twenty-seven interspecific lines selected from prior evaluation of an advanced backcross population were evaluated for resistance to early and late leaf spot, and for yield in two locations in Ghana in 2006 and 2007. Several interspecific lines had early leaf spot scores significantly lower than the susceptible parent, indicating that resistance to leaf spot had been successfully introgressed and retained after three cycles of backcrossing. Time to appearance of early leaf spot symptoms was less in the introgression lines than in susceptible check cultivars, but the opposite was true for late leaf spot. Selected lines from families 43-08, 43-09, 50-04, and 60-02 had significantly reduced leaf spot scores, while lines from families 43-09, 44-10, and 63-06 had high pod yields. One line combined both resistance to leaf spot and high pod yield, and several other useful lines were also identified. Results suggest that it is possible to break linkage drag for low yield that accompanies resistance. However, results also suggest that resistance was diluted in many of the breeding lines, likely a result of the multigenic nature of resistance. Future QTL analysis may be useful to identify alleles for resistance and allow recombination and pyramiding of resistance alleles while reducing linkage drag.