Northeastern states of India are known for unique landraces of Capsicum spp. with geographical indications. However, little information is available about these valuable landraces of chillies. Surveys and collections were carried out in niche areas to find out their ecology and diversity through morphological traits and molecular analysis using microsatellite markers. Our result characterized the ecology of niche areas as cool (11.0°C–20.7°C) and humid (>60% relative humidity) climates for dalle-chilli (Capsicum annuum L.); mild-warm (12.2°C–28.6°C) and humid for king-chilli (C. chinense Jacq.); and cool to warm (11.3°C–33.1°C) and humid for bird’s eye chilli (C. frutescens L.) during the crop period. The canonical correspondence analysis has shown the significant impact of temperature on the agro-morphological traits and distribution of the landraces in their niche areas. A wide variability was observed for different quantitative traits and yield attributing characters (fruit length, diameter, weight, and yield), showing high heritability (97.0%–99.0%), and genetic advance as a percentage of the mean (119.8%–434.0%). A total of 47 SSR markers used for the molecular analysis generated 230 alleles, ranging from 2 (HPMSE-7) to 10 (HPMSE-5), with an average of 4.89 alleles per locus. The average polymorphism information content was also high (0.61) and ranged from 0.20 (HPMSE-7) to 0.85 (CAMS-91). The observed average heterozygosity was lower than the expected value. Analysis of molecular variance has shown significant variation within (69%) and between (31%) of the populations of Capsicum spp. Based on Nei’s genetic distance, bird’s eye chilli and king-chilli were found to be closer to each other, whereas dalle-chilli, a tretraploid species, was closer to hot pepper (C. annuum). However, the flower size of dalle-chilli was large and found closer to king-chilli in color and differs from C. chinense due to the presence of calyx teeth. For quality traits, landraces king-chilli, dalle-chilli, and bird’s eye chilli have shown 2.8, 2.0, and 1.4 times higher average capsaicin and 0.46, 0.25, and 0.22 times higher average oleoresin content over the hot pepper, respectively. The knowledge of ecology and diversity can be used in identifying new areas for production, selection of elite lines, conservation, and crop improvement.

A total of 32 sweet potato genotypes were evaluated to assess the genetic diversity based on quantitative traits and molecular markers, as well as stability for yield and related traits. Wider variability was observed for the traits like vine length (181.2–501.3 cm), number of leaves/plant (103.0–414.0 cm), internodal length (3.20–14.80 cm), petiole length (6.5–21.3 cm), leaf length (8.50–14.5 cm), leaf breadth (8.20–15.30 cm), leaf area (42.50–115.62 cm²), tuber length (7.77–18.07 cm), tuber diameter (2.67–6.90 cm), tuber weight (65.60–192.09 g), tuber yield (7.77–28.87 t ha⁻¹), dry matter (27.34–36.41%), total sugar (4.50–5.70%) and starch (18.50–29.92%) content. Desirable traits such as tuber yield, dry matter and starch content have shown high heritability (>60%) with moderate to high genetic advance. Under molecular analysis, a total of 232 alleles were observed from all 32 microsatellite markers, which ranged from 4 to 14 with an average of 7.77 alleles per locus. In the population, the average observed heterozygosity (0.51) was higher than the expected heterozygosity (0.49). The contribution of genotype, genotype by environment interaction to the total variations was found to be significant. Based on the multi-trait stability index (tuber length, tuber diameter, tuber weight and tuber yield), genotypes X-24, MLSPC-3, MLSPC-5, ARSPC-1 and TSP-12-12 were found to be most stable. Among them, the high-yielding and stable genotypes TSP-12-10 (26.0 t ha⁻¹) and MLSPC-3 (23.9 t ha⁻¹) can be promoted for commercial production or used as parental material in future crop improvement programmes.

Aroids are an important group of indigenous tuber crops, grown widely for their leaves, petioles, stolons, corms, and cormels. A total of 53 genotypes were evaluated for their genetic diversity in northeastern region of India. At household level, a total of 16 landraces of Aroids were recorded having different ethnobotanical uses. Based on the population study underJhum/Shifting farming, landrace Rengama was dominant in area with 47% of the total population followed by Tamachongkham and Tasakrek. However, Pugarkusu and Chigi occupied 33.0 and 24.0% of the population, respectively under backyard farming, and were considered as major landraces. Tamachongkham, high in acridity and total oxalate content (0.82%), was used for cooking with meat, while Tasakrek was used as a baby food due to high total sugar (>3.0%), low in acridity, and total oxalate content (<0.12%). The Simpson’s diversity index of the backyards was higher (0.80) as compared toJhumfield (0.63). The genotypes showed wider variability in growth and yield attributes like; plant height (89.4–206.1 cm), number of side shoots (1.84–5.92), corm weight (38.0–683.3 g), cormel weight (14.0–348.3 g), yield (0.24–1.83 kg plant⁻¹). Similarly, wide variations were also observed for quality traits like total sugar (1.93–4.94%); starch (15.32–32.49%), total oxalate (0.10–0.82%), and dry matter (16.75–27.08%) content. Except for total oxalate, all the growth and yield attributes have shown high heritability and moderate to high genetic advance. Molecular analysis (33 polymorphic SSR markers) detected a total of 136 alleles, ranged 3 to 8 alleles per marker. The observed heterozygosity (0.24) was less than expected heterozygosity (0.69). The group-wise maximum genetic divergence was observed betweenColocasia fallax(cv. Chigi) toC. esculentavar.aquatilis(cv. Tharsing);C. fallax(cv. Chigi) toC. gigantea(cv. Ganima) andC. gigantea(cv. Ganima) toXanthosomaspp., while it was least between eddo and dasheen. The findings indicated, a wider diversity and distinct ethnobotanical uses of Aroid landraces at the house hold levels, which should be conserved and popularized to ensure nutritional security.

Eggplant (Solanum melongena L.) is an important solanaceous vegetable crop grown worldwide over tropics and subtropics. Bacterial wilt (caused by Ralstonia solanacearum) is one of the most serious diseases of the crop, especially in the humid tropics. The present investigation was carried out using 26 accessions of eggplant including wild relatives aiming to identify stable genotypes of eggplant with tolerant to bacterial wilt. The accessions were characterised using 40 simple sequence repeat (SSR) markers. Thirty-four markers were found polymorphic and produced 136 alleles with an average of four alleles per marker. All the markers have shown amplification across accessions of eggplant-related species. Markers EES-050, EES-065, and EES-066 were highly informative. Among the species, scarlet eggplant (Solanum aethiopicum var.gilo) was found to be the closest to S.melongena. Markers, EES-031 and EES-051, were specific to the accessions with tolerance to bacterial wilt. Based on the three-year evaluations, the disease incidence (DI) ranged from 1.27% (S.torvum) to 72.85% (S.melongena var. Kasi Taru). The AMMI and GGE biplot analyses have shown the significant contribution of genotype variation over the environment and interaction. The local eggplant accessions (Bhola Nath, RCMB-10, Singh Nath and RCMBL-1) were found highly stable for yield with lowest wilt incidences when compared to other Indian accessions. The results suggested the incorporation of local accessions/landraces into the eggplant breeding programmes aiming to develop stable cultivars with improved yield and resistant to bacterial wilt. Abbreviation: AMMI, Additive Main-Effects and Multiplicative Interaction; GGE, Genotype Main Effect plus Genotype-by- Environment Interaction; SSRs, Simple Sequence Repeats; QTLs, Quantitative Trait Loci; AMOVA, Analysis of Molecular Variance;