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Nutraceuticals are an important ingredient of functional foods that provide health and medicinal benefits, and are recommended for daily food intake. Seaweeds are highly nutritional and considered a rich source of antioxidants, sugars, fatty acids, essential amino acids, flavonoids, phenolics, and other secondary metabolites. Green seaweeds are distributed worldwide and tropical, green algae including Caulerpa spp. could be potentially explored as a functional food. Seven abundant tropical green seaweeds (four Caulerpa species, two Ulva species, and one native Codium species) were harvested from the Saurashtra Coast (Arabian Sea, Gujarat, India) and their metabolite profiling, total flavonoid and phenolic content, and antioxidant, scavenging, reducing, and anti-proliferative activities were examined. Liquid chromatography-mass spectrometry identified remarkable metabolites, including malvidin, kaempferol, cyanidin, quercetin, apigenin, lutein, and myricetin; ninety-seven metabolites were detected by gas chromatography–mass spectrometry. Approximately forty distinct metabolites were quantified, whereas fifty-seven metabolites were detected in more than one seaweed. Fourteen unique metabolites were detected in C. scalpelliformis, which also contained notable amino acids. Caulerpa spp. (CRM: C. racemosa var. macrophysa, CRC: C. racemosa var. cornyphora, and CS: C. scalpelliformis) showed potential total antioxidant activity (>50%), and the highest potential scavenging activity (>60%) was found in CRM followed by CS and CRC extracts. CRM and CS extracts also showed maximal reducing activity (>78%). A low half maximal effective concentration (EC50) for different biochemical activities was determined for Caulerpa spp., especially CRM (total antioxidant: 150.8 ± 5.7, scavenging: 560 ± 2, and reducing: 86.4 ± 3.1 μg ml−1) compared to other select seaweeds. CRC, CRM, and CS showed significantly high total phenolic contents, 29.2 ± 2.4, 25.0 ± 3.2 and 23.8 ± 3.3 mg gallic acid equivalent (GAE) g−1 extract, respectively. Similarly, a high total flavonoid content was detected in CS (769 ± 33 mg quercetin-equivalent g−1 extract) followed by CRC (562 ± 44), and CRM (523 ± 60). All activities (total antioxidant, scavenging, and reducing) were positively correlated with each other and also with total phenolic and flavonoid contents. Principal component analysis confirmed that CRC is a rich source of phenolic and flavonoid compounds, whereas CS and CRO (C. racemosa var. occidentalis) possessed higher total antioxidant, scavenging, and anti-proliferative activities compared to the other selected seaweeds. The study revealed that Caulerpa spp. are a promising functional food ingredient and could be explored as daily dietary supplements.

Interspecific hybridization is an important tool to elucidate intergenomic relationships, transfer characters across species and develop synthetic amphidiploids, and it has been widely applied for improving brassicas. The objective of the present study was to create genetic variability in Brassica through interspecific hybridization. Crosses between Brassica juncea (AABB, 2n = 36), and Brassica rapa (AA, 2n = 20) vars toria, yellow sarson, and brown sarson were attempted, and the hybrid derivatives were advanced to the F 4 generation. Hybrids were obtained from the crosses B. juncea x toria and B. juncea x yellow sarson. The F 1 plants were vigorous and intermediate to the parents in many morphological traits. The meiotic study of AAB hybrids showed 10 II + 8 I in the majority (71.8%) of cells analysed. A maximum of 12 and a minimum of seven bivalents were also observed in a few cells. The occurrence of multivalent associations (trivalents to pentavalents) at diakinesis/metaphase I and a bridge-fragment configuration at anaphase I were attributed to homoeology between A and B genomes. A high percentage of plants resembling B. juncea was observed in the F 2 generation. Transgressive segregation in both directions was found for plant height, primary branches, main raceme length, siliquae on main raceme, siliqua intensity, seeds per siliqua and seed yield. There were significant differences for the 14 characters in the F 4 derivatives. Moderate to high estimates of phenotypic and genotypic coefficients of variation, broad-sense heritability, and expected genetic advance were found for seed yield, 1000-seed weight, siliquae per plant, seeds per siliqua and days to flowering. Intergenomic recombination, reflected as wide variation in the hybrid progenies, permitted the selection of some useful derivatives.

The crossability between Brassica tournefortii (TT, 2n = 20) and Brassica rapa (AA, 2n = 20) and the cytomorphology of their F1 hybrids were studied. Hybrids between these two species were obtained only when B. tournefortii was involved as a female parent. The hybrid plants were intermediate for most of the morphological attributes and were found to be free from white rust under field conditions. The F1 plants showed poor pollen fertility, although occasional seed set was achieved from open pollination. Self-pollination or backcrosses did not yield any seeds in these plants. The occurrence of chromosome association ranging from bivalents (0–7), trivalents (0–2) to a rare quadrivalent (0–1) in the dihaploid hybrids indicates pairing between the T and A genomes. The homoeologous pairing coupled with seed set in the F1 plants offer an opportunity for interspecific gene transfers from B. tournefortii to B. rapa and vice-versa through interspecific hybridization.

Amphidiploid Raphanofortii was synthesized by colchicinization of the F1 hybrid Brassica tournefortii (TT, 2n = 20)×Raphanus caudatus (RR, 2n = 18). The crossability between these two species, and the cytomorphology of the F1 plants and the amphidiploids were investigated. Intergeneric hybrids between the species were obtained only when B. tournefortii was involved as female parent. The hybrid plants were intermediate for most of the morphological attributes and showed very low pollen fertility compared to the parents. Although a majority of the pollen mother cells of the dihaploid hybrid (TR, 2n = 19) harboured univalents, a maximum of six bivalents were also observed. Of the 37 colchicine-treated F1 plants analyzed cytologically, 21 were found to be true amphidiploids (2n = 38), whereas seven were mixoploids. Meiosis in the amphidiploids was characterized by the occurrence of 19 bivalents, though multivalents and univalents were also observed in a few cells. Most of the amphidiploid plants exhibited a fairly high pollen and seed fertility, which was further enhanced with the advancement of generations. Out of 69 plants investigated in the A2 generation, 64 were euploids while the remaining five were aneuploids (2n = 36, 37, 39, 40 and 42). The newly synthesized Raphanofortii has great potential as a new commercial crop, as well as a bridge species for the transfer of economically important attributes of both the species to other Brassicas.

The crossability between Brassica carinata (BBCC, 2n=34) and Brassica rapa (AA, 2n=20), and the cytomorphology of their F1 hybrids were studied. Hybrids between these two species were only obtained when B. carinata was used as the female parent. The hybrid plants exhibited intermediate leaf and flower morphology, and were found to be free from white rust and Alternaria blight diseases. One of the four F1 plants was completely male sterile, while the remaining plants had 4.8, 8.6, and 10.9% stainable pollen, respectively. No seed was produced on hybrid plants under self pollination or in backcrosses; but seed was obtained from open pollination. The occurrence of the maximum of 11 bivalents as well as up to 44.8%) of cells with multivalent associations in the form of trivalents (0-2) and a quadrivalent (0-1) in the trigenomic triploid hybrid (ABC, 2n = 27) revealed intergenomic homoeology among the A, B and C genomes. Meiotic analysis of F1 hybrids indicated that traits of economic importance, such as disease resistance, could be transferred from B. carinata to B. rapa through interspecific crosses.

The inheritance of siliqua orientation and seed coat colour in Brassica tournefortii was investigated using four genotypes varying in these two characters. The F 1 , F 2 and backcross generations of two crosses were used for studying the segregation pattern of the traits. The plants were classified for seed colour as having brown or yellow seeds and for siliqua orientation as having upright, semi-spread or spread siliqua. Seed colour was found to be under monogenic control with brown being dominant over yellow. Siliqua orientation was under digenic polymeric gene action: upright siliqua was produced by the presence of two dominant genes and spread siliqua by two recessive genes. The absence of even a single dominant gene resulted in a third type of siliqua orientation, semi-spread siliqua.

The inheritance of siliqua locule number and seed coat colour in Brassica juncea was investigated, using three lines each of tetralocular brown seeded and bilocular yellow seeded. Three crosses of tetralocular brown seeded x bilocular yellow seeded lines were attempted and their F 1 , F 2 and backcross generations were examined for segregation of these two traits. Brown seed colour and bilocular siliqua characters were found to be dominant over yellow seed and tetralocular siliqua, respectively. Chi-square tests indicated that each trait is controlled by different sets of duplicate pairs of genes. Bilocular siliquae or brown seeds can result from the presence of either of two dominant alleles, whereas tetralocular siliquae or yellow seeds are produced when alleles at both loci are recessive. A joint segregation analysis of F 2 data indicated that the genes governing siliqua locule number and seed colour were inherited independently.

Host plant resistance is an important component for management of the melon fruit fly, Bactrocera cucurbitae (Coquillett) owing to difficulties associated with its chemical and biological control. A total of 27 watermelon varieties/genotypes were evaluated for their susceptiblity to the fruit fly in hot arid region of Rajasthan. The results showed that the varieties/genotypes viz. percentage of fruit infestation and larval population per fruit varied significantly. Pooled data showed that the varieties/genotypes viz., AHW/BR-60, BSM-1, IC 582909, AHW/BR-9, AHW/BR-137, Durgapura Kesar, AHW/BR-10, AHW/BR-18, AHW/BR-8, AHW/BR-21, AHW/BR-20 and YF-4 can be categorized as susceptible with considerable fruit infestation (55.72%, 59.28%, 53.05%, 67.20%, 60.43%, 61.83%, 63.87%, 63.62%, 59.45%, 59.62%, 62.52% and 55.68%, respectively) and with larval population per fruit viz. 17.12, 17.85, 16.45, 19.23, 17.90, 18.48, 18.38, 18.32, 18.40, 17.57, 17.93 and 17.70, respectively. The varieties/genotypes Asahi Yamato, AHW/BR-16 and Thar Manak had 12–18% fruit infestation (12.75%, 15.05% and 18.18%, respectively) with 1–1 lawal per fruit (10.13, 10.82 and 11.08, respectively) and declared which can be considered resistant. Lower values of host plant susceptibility indices based on fruit infestation (HPSI) were recorded on resistance varieties/genotypes, viz., Asahi Yamato, AHW/BR-16 and Thar Manak (28.85%, 34.05% and 41.14%, respectively). These could be used as a source of resistance for developing watermelon varieties/genotypes resistant to fruit fly.