The Dasylirion genus is highly represented in the arid and semi-arid regions of Mexico and USA, playing important ecological and economical roles. Inferring the evolutionary patterns of this group will eventually facilitate understanding biological phenomena and outlining conservation and usage strategies. We performed a molecular phylogenetic analysis based on two chloroplast DNA regions: maturase-K gene (matK) and the large subunit of ribulose-1,5-bisphosphate carboxylase gene (rbcL). We constructed a phylogenetic tree by maximum likelihood with GTR as the sequence substitution model and a relaxed clock, inferred diversification patterns by lineage through time and explored the diversification rates of Dasylirion by the Yule model. The study included 11 species of the genus, which represent 50% of all its known species. We used two calibration points to date the tree, one based on fossil records of Acorus gramineus, and the other on the estimated stem age of the Yucca genus. The combined sequences of the two partial genes comprised 1455 bp and 18 polymorphic sites. We estimated an average substitution rate of 0.0005 nucleotide per million years for the concatenated DNA sequences. The molecular dating analysis estimated that the Dasylirion genus appeared more than 5.46 million years ago, with a rate of diversification of 0.0466 net speciation events per million years. The estimated age represents a lower bound, since not all Dasylirion species are included. These findings are consistent with other origin and diversification hypotheses for arid-land Asparagaceae in the Mexican highlands as a result of geomorphological events in North America.

The plant Camellia fascicularis, belonging to family Theaceae, has high ornamental and medicinal value, and rare gene resources for genetic improvement of Camellia crops, but is currently threatened with extinction because of the unique and extremely small wild populations. Molecular markers have clarified the wild plant species’ genetic diversity structure, new gene resources and relationship with crops. This will be beneficial for conservation of these valuable crop-related wild species and crop improvement. In this study, we identified 95,979 microsatellite loci from 155,011 transcriptome unigenes, and developed 14 polymorphic expressed sequence tag-derived simple sequence repeat (EST-SSR) microsatellite markers for C. fascicularis. The number of alleles (Na) per locus was 2–8 with a mean of 4.86. The genetic diversity of 40 individuals from four natural populations of C. fascicularis was analysed using these polymorphic markers. The number of alleles (Na) for EST-SSR ranged from 2 to 5, with the expected heterozygosities (He) and observed heterozygosities (Ho) in all loci ranging from 0.183 to 0.683, and from 0.201 to 0.700, respectively, implying a rich genetic variation present in wild C. fascicularis populations. Moreover, the phylogenetic analysis among four populations, using the 14 EST-SSR markers developed in this study, grouped 40 individuals into three groups, which coincide with their geographic distribution. These results showed that 14 EST-SSR markers are available for the analysis of genetic variation in C. fascicularis populations and genetic improvement of new Camellias cultivars by interspecific hybridization, and are beneficial for conservation of the endangered species.

Western Himalayan region is a rich repository of common bean genetic resources evolved over generations of farmer selection. The bean variability encompasses various use categories such as dry, snap and shelled beans. The present study aimed to characterize 40 small-seeded red common bean genotypes collected from different districts of Kashmir valley as well as Poonch, Rajouri and Bhaderwah areas of Jammu which are world famous for their beans. Based on 5-year evaluation, there was substantial variability for various qualitative traits as well as quantitative traits. Among variability parameters, higher PCV and GCV values were recorded for plant height, seed yield per plant and number of pods per plant and low for days to maturity, seed length and pod length. High heritability was recorded for all the traits ranging from 78.72 to 94.87%. There was substantial variability in root traits scored in laboratory and greenhouse as well as canopy temperature depression and relative water content. Various genotypes were found resistant to bean common mosaic virus (WB-N-1, WB-N-11, WB-1318, WB-401, WB-451, WB-1634); anthracnose (WB-1634 WB-83, WB-258, WB-1282, WB-1304); angular leaf spot (WB-6, WB-1634, WB-258, WB-451, N-1 and N-10); Fusarium wilt (WB-341, WB-451, WB-N-1 and WB-1587) and Ascochyta blight (WB-6). Similarly WB-92 was highly resistant to shattering. The genotypes WB-341, WB-1634, WB-N-1 performed better under water stress, WB-N-1 and WB-1634 were resistant to multiple diseases and WB-1634 had better cooking quality. The genotypes identified can be used in bean improvement programmes and have also been submitted to NBPGR for long-term storage.

Theobroma cacao L. (cacao) is an important tropical crop used to produce chocolate. Evolutionary relationships between cultivated and wild cacao genotypes and their genetic diversity are poorly understood. Exploring phylogenetic diversity and spatial patterns of both cultivated and crop wild relatives can improve the knowledge of the evolutionary history of a crop, giving insights into its cultivation, breeding programmes and conservation. This study identifies biodiversity priority areas in Colombia by calculating phylogenetic diversity indices using a set of 87 single nucleotide polymorphism markers. These were sourced from 279 genotypes conserved in the Corporación Colombiana de Investigación Agropecuaria (Agrosavia) germplasm collection. The Caribbean and North Andes areas exhibited the highest phylogenetic diversity and significantly high relative phylogenetic diversity. We propose that those regions where wild cacao occurs should be prioritized as conservation areas. Besides, cacao lineages that have recently diverged and are present in Arauca, Huila and Nariño areas, with significantly low relative phylogenetic diversity, should be prioritized for breeding programmes. The Amazonia genotypes were closer to the root of the phylogenetic tree, suggesting an older origin than those found in the Andes region. Our study highlights the importance of using T. cacao germplasm from the Amazonia region as a priority to recover relict diversity in breeding programmes and broaden the gene pool of modern cultivated cacao.

Genetic diversity is essential for the development of more efficient plant types. In the present study, 529 chickpea accessions were evaluated for their agronomic performance, genetic divergence and identification of promising accessions through the use of a simple lattice design. These accessions varied widely in all agronomic traits. The first three principal components (PCs) explained 78.35% variation. The PC1 and PC2 explained 38.05 and 24.30% of total variations. Three traits namely, branches per plant, pods per plant and seed yield per plant contributed to maximum variation. The hierarchical clustering analysis carried out on PCs grouped the accessions into eight clusters. Among 127 selection indices formulated, higher relative efficiency (422.52%) coupled with high genetic advance (34.31%) was exhibited by the combination involving six characters. Based on the index score of greater than 100, 15 genotypes were promising for improving the grain yield. The results of both PC analysis (PCA) and selection indices suggested that branches per plant, pods per plant and 100-seed test weight traits have to be considered for any genetic yield gains. Both the techniques (PCA and selection indices) identified three genotypes (GAG 0733, IC 268988 and IC 269031) as the best performers, suggesting that the two techniques are equally efficient in the identification of superior germplasm that can be used in chickpea hybridization programmes for yield improvement.

A detailed study of rice genetic resources in Bangladesh's coastal areas is necessary. This understanding is a necessary requirement for its utilization in selective breeding. The study reports on the qualitative morphological trait-based assessment of 150 local rice samples collected from Bangladesh's coastal zone, including 50 advanced lines developed from coastal germplasm. Six of the thirteen analysed characters had a substantial gene contribution, whereas the average was 0.694. The most impressive diversity was in leaf blade intensity of green colour (LBIGC: 0.705). The total morpho-qualitative diversity was calculated to be 0.412. The character efficiency content ranged from 0.655 (LBIGC) to 0.136 (Leaf Sheath: Anthocyanin colouration, Leaf Blade: Presence/Absence, and Leaf Blade: Anthocyanin. Colouration). As per the morphological variance study, 93% of morphological changes were detected within individuals, whereas 7% were found in populations. The 150 germplasm samples were divided into four subpopulations using STRUCTURE-based population analysis. A moderate genotypic difference was detected amongst all groups, with an Fst value of 0.111. The G statistic backed up the record as well. The Shannon mutual information index reached a value of 1.252 between populations 2 and 3. In terms of gene exchange, the highest value was found between populations 3 and 4. Our data indicate a high degree of diversity in Bangladesh's coastline rice germplasm. The findings will aid in conferring the farmers' Intellectual Property Rights on the investigated rice germplasm.

Buckwheat (Fagopyrum spp.) is an important crop in the high-altitude regions of the Northwest Indian Himalayas. The agro-climatic heterogeneity of this region offers a great deal of diversity in the agro-morphology of buckwheat species. In this study, a total of 61 accessions of Fagopyrum esculentum and Fagopyrum tataricum were characterized for 17 morphological (8 qualitative and 9 quantitative) traits. Significant differences (P < 0.0001) among all the traits were revealed by one-way analysis of variance. Further, significant phenotypic variability in both qualitative as well as quantitative traits was also observed. Both positive and negative correlations were observed between the traits of agronomic relevance. The principal component analysis (PCA) reveals about 69% variability among the first six components. The accessions were divided into two key clusters with numerous subclusters by considering the unweighted pair group method with arithmetic mean dendrogram. A cluster of 19 accessions was formed utilizing a PCA scatter plot indicating accessions with maximum values for important quality traits like plant height, leaf blade width, stem colour (red), primary branches, inflorescence length, flower colour (greenish-yellow), seed anthocyanin colour (green), seed shape (ovate) and seed weight. These accessions can be of vital significance for future buckwheat breeding programmes. The findings from the current study will form a favourable base for genetic resource management, improved cultivation and applications of buckwheat at the commercial level in the northwestern Himalayas of India.

Muskmelon, which is an important cucurbit of the tropical and subtropical region of the world, shows great diversity, with six different botanical or horticultural groups and fifteen varietal groups. In this study, a total of fifty (50) simple sequence repeat (SSR) markers were used to investigate the genetic diversity and population structure of 46 muskmelon accessions of different horticultural or varietal groups. Thirty-eight (38) of the fifty SSR markers were highly polymorphic. A total of 99 alleles were generated by the polymorphic markers, with an average of 2.06 alleles per loci. Heterozygosity among accessions for individual loci varied from 0.00 to 0.21, with the highest (0.21) reported for the CMCTN71 marker. The gene diversity and polymorphism information content (PIC) values varied between 0.08 to 0.72 and 0.07 to 0.67, with an average of 0.47 and 0.38, respectively. The primer that showed the highest gene diversity and PIC values was DM0913. The unweighted pair-group method for arithmetic average (UPGMA)-based dendrogram classified all the 46 accessions into two major clusters. Population structure analysis classified 46 muskmelon accessions into 2 subpopulations. The subpopulation I contained 29 accessions from the cantalupensis group, and subpopulation II contained 17 accessions from momordica, inodorus and conomon groups, respectively. Analysis of variance indicated that 18 and 68% of variance was due to subpopulations and differences among individuals, respectively. The present study supports the existence of sufficient variation among musk melon genetic resources in India, and their classification based on molecular markers will be helpful to accelerate the breeding programme for specific traits.

Rice crop is affected by different types of floods at different stages of the crop cycle. Constant efforts of researchers resulted in the development of rice varieties for anaerobic germination, flash floods and stagnant flooding by both conventional and molecular breeding approaches. Detection of QTLs for different types of floods in new genetic source (AC39416A) is needed to combat adverse effects of climate change. Present investigation was carried out to identify QTLs for flood tolerance using recombinant inbred lines derived from Indra and AC39416A. QTL mapping resulted in identification of QTLs, qAG3.1 on chromosome 3 for anaerobic germination and qSF10.1 on chromosome 10 for plant survival % under stagnant flooding. These QTLs explain 59.08 and 13.21% of phenotypic variance respectively. Two candidate genes were identified in qAG3.1 region, LOC_Os03g42130 gibberellin 20 oxidase2 and LOC_Os03g44170 glutathione S-transferase. The underlying mechanism might be the inhibition of gibberellic acid synthesis and thereby protecting seedlings from oxidative stress under anoxia condition. Genomic region of qSF10.1 revealed LOC_Os10g35020 glycosyltransferase and LOC_Os10g35050 aquaporin protein loci, which might be responsible for adaptive mechanism for plant survival % under stagnant flooding. This indicates that the new genetic resource AC39416A has an ability to adopt to different types of flood tolerance in response to environmental stress. Unveiling physiological and molecular mechanisms for flood tolerance in AC39416A using advanced omics studies would help in precise genomic selections for sustained production in flood-prone areas.

In order to enhance genetic potential of chickpea materials from the National University of Córdoba Breeding Programme and Germplasm collection (Argentina), a study for a comprehensive understanding of the amount and pattern of genetic variation within and between genotypes was carried out by applying a multivariate analysis form single simple repeats (SSR) and morphological data. Molecular data were also used to determine the discriminating power for genotype identification, and to find the optimal primer combination to ensure unambiguous identification. With the analysis of 15 SSR markers on 53 genotypes, a total of 58 alleles were detected with individual values ranging from one to nine alleles per locus. High values of discriminating power (Dj ⩾ 0.7, PIC ⩾ 0.7), and low values of confusion probability (Cj ⩽ 0.23) were obtained for at least four evaluated markers. The combination of TA113 + TA114 + H1B09 + TA106 primers was effective for discriminating the 53 chickpea genotypes with a cumulative confusion probability value (Ck) of 9.60 × 10−4. Except for some exceptions, individual chickpea genotypes within a cluster in the consensus tree were definitely more closely related with each other by the origin or pedigree. The results confirmed that both multivariate data analysis methods, ordination and clustering, were complementary. In most genotypes, discriminant principal component analysis classification was consistent with the original clusters defined by molecular data. Differences in results from molecular and morphological data indicate that they provide complementary and relevant information for establishing genetic relationships among chickpea materials and a better description and interpretation of the available variability in the germplasm collection.

Fusarium head blight (FHB) and stem rust (SR) threaten the sustainability of wheat production worldwide. Fhb1 and Sr2 confer partial durable resistance to FHB and SR, respectively. Despite resistant alleles of both genes are linked in repulsion, lines with Fhb1-Sr2 in coupling were developed at the University of Minnesota, USA. Marker-assisted backcrossing was used to incorporate the coupled Fhb1-Sr2 into four elite INIA-Uruguay spring wheat varieties lacking both genes and expressing different levels of FHB and SR resistance. In each case, the initial cross between the donor line and recurrent parent was backcrossed three times. Genotypes carrying Fhb1-Sr2 were selected using the molecular marker UMN10. In BC3F3 families, retention of Fhb1-Sr2 was further confirmed with the markers SNP3BS-8 and Sr2-ger9 for Fhb1 and Sr2, respectively. BC3F3 homozygous lines contrasting at UMN10, SNP3BS-8 and Sr2-ger9 were obtained to quantify the effect of Fhb1-Sr2 on the resistance to FHB under controlled conditions and to SR under field conditions. After 26 months period, successful introgression of Fhb1-Sr2 into the four cultivars was achieved, representing novel wheat genetic resources. Lines homozygous for the resistant alleles of Fhb1 were significantly more resistant to FHB as reflected by an 18% reduction of average FHB area under the disease progress curve. A significant effect of Sr2 on SR field resistance was observed in lines derived from the most susceptible cultivar ‘Génesis 2375’. The most resistant lines to both diseases are expected to be valuable genetic resources in breeding for durable resistance to FHB and SR.

Foxtail millet (Setaria spp.) is an ancient cereal crop, having a short cropping cycle. Drought tolerance was assessed in this crop at an early growth stage and the extent of genetic diversity was measured between the foxtail millet genotypes, applying DNA markers. Tolerance of 18 foxtail millet genotypes was studied in vitro under four levels of polyethylene glycol (0, 10, 20 and 30% PEG-6000). PEG-6000 decreased final germination percentage and led to a reduction in shoot and root length with different stress levels. The genotypes ISe 869, ISe 1851 and yellow spike show superiority in stress tolerance for germination and the growth of root and shoot traits. They also clustered together in the biplot diagram and dendrogram of the genotypes based on the morphological traits. Marker polymorphism index (PI) was 80.36% and a total of 132 polymorphic alleles (4.00 alleles/locus) were obtained from 33 polymorphic primers. Polymorphic information content (0.54–0.83) was highly informative with an average value of 0.67. A dendrogram distributed the genotypes into five distinct clusters based on simple-sequence repeat (SSR) data, independent of their geographical distribution. A relationship was established between the SSR markers and the genotypes ability to tolerate drought stress. The SSR markers used could contribute to conducting DNA profiling of foxtail millet, and facilitating their use in future breeding programmes for drought tolerance in this crop. Based on water-stress experiment, three most tolerant genotypes: ISe 869, ISe 1851 and yellow spike are recommended to be cultivated under drought conditions around the world.

Chenopodium quinoa W. is a species of South America with an exceptional nutritional content and wide agroclimatological adaptation. It has great genetic and phenotypic variability, however in Colombia there are few genetic improvement programmes that take advantage of its great genetic and productive potential. In Cundinamarca there are some adapted genotypes which have been selected by farmers. We evaluated 36 genotypes of Blanca de Jericó, Blanca Subachoque, Aurora, Púrpura and Tunkahuan from Cundinamarca, using eight ISSR markers. The analysis by the coefficient of Nei-Li at the level of similarity of 0.40 divided the population into three groups according their background genetic and the colour of oxalates. The percentage of polymorphic loci was higher than 90%. The average value of heterozygosity was 0.32, which is low given the selection processes that the evaluated germplasm has undergone. We found moderate genetic differentiation (Fst = 0.23). The analysis of molecular variance (AMOVA) showed higher variation (77%) groups than among groups (23%). The results revealed intra-population diversity, which suggests that farmers within their farms should undergo a more rigorous seed selection process. Our results demonstrate that ISSR markers are useful and powerful to assess the genetic relationships, polymorphism and genetic diversity of quinoa cultivars. The genetic characterization results reported in the present study will be promising for guiding the breeding of quinoa seed quality in Colombia.

To explore trait variation, assess relative performance and establish association among yield and its associated traits in maize under organic system, 373 maize genotypes that consisted of landraces, open-pollinated varieties and single-cross hybrids were tested under organic management in Sikkim midhills. Data of 8 years (2009–2015 and 2019) for 12 agronomic traits viz., plant height, days to 50% tasselling, days to 50% silking, days to 75% dry husk, grain yield per ha, anthesis–silking interval, cob length, cob diameter, kernel rows per cob, kernels per row, number of cobs per plot and test weight were taken for analysis. Conventionally bred maize hybrids yielded 95.36% higher than the landraces and 58.60% higher than the open-pollinated varieties. Landraces displayed highest mean anthesis–silking interval of 7.18 days. In open-pollinated varieties, test weight showed a positive association with grain yield (0.37) while plant height (0.33) and kernels per row (0.34) were positively correlated to grain yield in case of landraces. Number of cobs per plot showed a very strong association with grain yield in hybrids (1.0). Kernels per cob and test weight contributed 24% to the variation in grain yield in open-pollinated varieties while anthesis–silking interval, days to maturity, number of cobs/plot, test weight and kernel per row accounted for 97% of the variation in grain yield in landraces. Grain yield in single-cross hybrids is contributed maximum (97%) by days to tasselling, silking, anthesis–silking interval, plant height and number of cobs per plot. The study indicates attaining high number of cobs per unit area along with emphasis on traits such as kernels per row, cob length and diameter for achieving higher yields in single-cross hybrids, selection of high test weight genotypes for open-pollinated varieties and emphasis on cob length, kernels per row and plant height for yield improvement in landraces.

Horseradish is a crop grown for its edible underground parts. The development of new cultivars is hindered by the species' predominant vegetative reproduction, making it essential to evaluate locally cultivated accessions to identify new types suitable for cultivation. To this end, 11 horseradish accessions from family vegetable gardens in Trentino-Alto Adige, Italy were examined using 26 qualitative and six quantitative morphological descriptors and characterized by the five major glucosinolates (GSLs) present in the rhizome compared to a reference cultivar. A wide range of variability was observed for the considered qualitative morphological traits. The rhizome's top and basal diameters were 9.9 and 6.2 cm, respectively, with an average fresh weight of 521 g. Total GSL content ranged between 79.5 and 133.5 μmol/g dry weight (DW), with sinigrin (SIN) being the primary component at an average content of 110.0 μmol/g DW. Differences among the investigated accessions were noted for quantitative traits describing their productive features and for GSL content. A positive correlation was discovered between the biometric traits of the plant's underground parts and the SIN and total GSL content, suggesting a link between the quality and yield of the edible product. According to the multivariate analysis, accessions were grouped into three main clusters: the largest of the reference cultivar and the majority of accessions with similar productive and qualitative traits; another featuring two with good qualitative and productive characteristics. The investigated accessions proved to be a valuable germplasm source for cultivating the species.

Grapevine (Vitis vinifera L.) is a major worldwide crop of high economic importance, tightly interwoven with the traditions and the culture of many civilizations. The Greek vineyard is one of the oldest in the world composed of an ample number of highly diverse indigenous landraces. However, over the last decades the local cultivated grapevine germplasm has undergone a drastic reduction of diversity, due to the established market preferences for international varieties. In the current work a combined approach involving both, ampelographic traits and microsatellite markers has been undertaken, to study the genetic diversity within and among 96 grapevine genotypes belonging to 36 V. vinifera subsp. vinifera cultivars, predominantly representing autochthonous Greek landraces. Results revealed high genetic diversity for the Greek cultivars yielding a mean number of alleles per locus 14.69 and mean polymorphic information content 0.848. Hierarchical cluster analysis, employing both, ampelographic and microsatellite data, showed a clear distinction based on the origin of the germplasm; Anatolian versus Mediterranean. Principal component analysis, based on the most informative ampelographic traits, coupled to the results from genetic structure analysis further corroborated the proposal of germplasm differentiation on the basis of geographic origin. This information can be further utilized for the reconstitution of the Greek vineyard and can significantly contribute towards a rational conservation and utilization strategy for breeding or for direct cultivation of the Greek indigenous grapevine germplasm.

As a country of origin of coffee, Ethiopia is endowed with an immense diversity of the crop in its diverse coffee-growing agro-ecologies. Amaro Kelo is one of the major coffee production agro-ecologies in Ethiopia, where the genetic diversity of its landrace coffee germplasm was not properly characterized previously. The study aimed to characterize 64 Amaro Kelo local coffee accessions to understand the potential of the accessions for utilization in future coffee genetic improvement efforts. The experiment was laid out in an 8 × 8 simple lattice design with two replications at Awada Agricultural Research Sub-Center. Data were collected on 19 quantitative and 10 qualitative traits, and subjected to multivariate analyses, i.e. cluster and principal component analyses. The cluster analysis identified five clusters based on the quantitative characters, and the distances between most of the clusters were highly significant at P < 0.01. Principal component analysis revealed the first six principal components with Eigenvalues greater than one accounted for 77.7% of the total variation. The first two principal components with respective contributions of 23.32 and 18.85% cumulatively accounted for 42.2% of the total variation in the accessions. In addition, high values of Shannon-diversity index were found for the qualitative traits: branching habit, growth habit, fruit shape, overall appearance and stem habit. In general, the multivariate analyses confirmed the presence of high variation among the studied Amaro-Kelo coffee accessions that might serve as an important genetic resource for future coffee genetic improvement or conservation efforts.

High-molecular-weight glutenin subunits (HMW-GS) contribute to dough elasticity and bread baking quality in wheat. In this study, wheat varieties were classified based on their HMW-GS composition into three groups: 1Dx5 (5 + 10, Gaoyou 8901, Xinmai 28, Xinmai 19, Xinmai 26 and Jinbaoyin), 1Dx2 (2 + 12, Zhoumai 24, Xinmai 9 and Yumai) and 1Dx4 (4 + 12, Aikang 58). Sequence analysis showed that 1Dx-GY8901, 1Dx-XM28, 1Dx-XM19 and 1Dx-XM26 were similar to the 1Dx5 gene and clustered on the same branch, while 1Dx-AK58, 1Dx-ZM24, 1Dx-JBY, 1Dx-YM, 1Dx-XM9 and 1Dx-JBY were more similar to the 1Dx2 gene and clustered on the same branch with 1Dx.2.2. There was a mutation of Ser to Cys at position S2, for an extra Cys in the repeat regions of 1Dx-XM19, 1Dx-XM26, 1Dx-XM28 and 1Dx-GY8901. The wheat HMW-GS genes exhibited similar percentages of α-helix, extended strand, β-turn and random coil structure, with ranges of 13.33–13.59, 4.77–5.78, 7.08–9.18 and 72.3–73.94%, respectively. Sequence conservation and the composition of HMW-GS subunits were also analysed for a series of strong gluten wheat varieties, Xinmai 9 (1, 7 + 8, 2 + 12), Xinmai 19 (1, 7 + 9, 5 + 10), Xinmai 26 (1, 7 + 8, 5 + 10) and Xinmai 28 (1, 7 + 9, 5 + 10). The results of this work should facilitate future breeding efforts and provide the theoretical basis for wheat quality improvement.

Knowledge on genetic architecture and inheritance of tomato shelf life contributing traits in different genetic backgrounds is a key issue for shelf life improvement. An investigation was undertaken to estimate the nature and magnitude of variability, traits inter-relationships, third and fourth degree statistics to unravel the genetics of 18 fruit quality and yield traits governing shelflife in F2 population of ‘Arka Vikas’ × ‘Red ball’ cross. The wider standardized range and higher estimates of phenotypic coefficient of variation indicated prevalence of adequate variability for fruit quality and yield traits. Fruit firmness and pericarp thickness ranged from 1.20–3.44 kg/cm2 and 2.44–5.31 mm respectively. Pulp content and shelflife ranged from 58.59–94.70% and 10.60–26.40 days respectively. Significant positive correlation with direct effect on fruit shelf life was exhibited by fruit firmness, pericarp thickness, TSS, titratable acidity, pulp content, fruit length and locule number. Positive skewness with platykurtic distribution recorded for TSS, lycopene, ascorbic acid, titratable acidity, fruit length, weight, pericarp thickness, plant height and number of branches. Negatively skewed with platykurtic distribution observed for pH, fruit diameter, firmness, pulp content, locule number, shelf life and number of clusters which signified duplicate epistasis of dominant genes in traits inheritance. The transgressive segregants for fruit quality traits indicated complementary effects of dispersed allele combinations between parents. Additive and dominance components could be exploited in the advanced segregating population by evaluating large number of families. In addition to additive effects, predominance of dominance effects of genes are important in inheritance of fruit quality traits governing shelflife.

Cashew (Anacardium occidentale L.) is cultivated in more than 30 countries because of its economic and nutritional importance. Despite having a significant agronomic role, little is known about the genetic and phenotypic diversity of cashew populations in Brazil. Thus, we aimed to characterize and estimate the diversity among cashew genotypes based on agro-morphological and physicochemical traits, with an objective of selection of varieties for breeding programmes. Forty-three cashew trees were evaluated based on 13 morphological traits and three physicochemical traits. A wide range of variations was recorded for the phenotypic characteristics, including total weight, fruit weight, pseudofruit length, kernel weight and total acidity, suggesting the existence of considerable variations for potential use in breeding programmes. Principal component analysis explained 79.74% of the total variation in the first two principal axes. The dendrogram based on the UPGMA method classified the 43 genotypes into six groups. Groups IV and VI were the most dissimilar, with emphasis on the genotypes 28 and 43, which were observed to be most divergent based on the Euclidean distance matrix (3.054). This makes it possible to select genotypes for hybridization with F1 generation gains. Based on cluster analysis and comparison of means among the six groups, promising genotypes were identified with superior traits, such as fruit weight, pseudofruit length, kernel weight and total acidity. This suggests the importance of phenotypic characterization for cashew breeding programmes. In addition, the observed vast diversity is an important genetic basis for improving cashew yield in northeastern Brazil.