Bijendra Singh

Background/Objectives: Drought stress is a significant environmental challenge that affects plant growth and productivity. Methods: In this study, an underutilized and better drought stress tolerance genotype of Cucumis melo var. melo, i.e., AHK-200, was investigated for drought tolerance potential, with special emphasis on various morphological, physiological, biochemical, and molecular parameters. Results: Our findings show that AHK-200 demonstrates superior drought tolerance with an enhanced root length, better water retention capacity, and stable cell membrane integrity under water deficit conditions. Physiologically, AHK-200 exhibited minimal reduction in relative water content (RWC) and photosynthetic efficiency (PN), along with increased stomatal conductance (gs) and chlorophyll content and reduced photoinhibition under drought stress. Biochemically, AHK-200 showed higher antioxidant enzyme activity (APX, CAT, SOD, GR, POD) and osmolyte accumulation (proline), which are critical for mitigating oxidative stress. At the molecular level, drought-related genes such as DREB2C, DREB2D, and RD22 were upregulated, supporting AHK-200 resilience to drought stress. Additionally, AHK-200 displayed elevated mineral concentrations, including Na, K, Ca, and Fe, which are essential for cellular homeostasis and stress adaptation. Conclusions: Overall, our study provides a comprehensive understanding of the drought tolerance mechanisms in AHK-200, highlighting its potential for use in breeding drought-tolerant genotypes in cucurbits and related crops. This research could guide future efforts in gene manipulation and transgenic development aimed at enhancing drought resistance and yield potential in crop plants. Furthermore, DREB2C, DREB2D, and RD22 transcription factors regulate many pathways related to stress; the overexpression of these genes may open a new avenue in melon improvement against drought stress.

A total of 81 extant cultivars of Brinjal (Solanum melongena L.) were evaluated for 47 botany based morphometric descriptors from various parts of a plant viz., seedling, stem, leaves, flowers and fruits, etc., as well as characterized on the basis of distinctiveness, uniformity and stability (DUS) test guidelines. All the cultivars were analyzed for diversity and stability. In the present study, all the cultivars exhibited distinct and uniform characters. The economic importance of all the botanical traits were also discussed during the study. The cluster analysis grouped the varieties in four major and 10 sub-clusters, indicating a high level of genetic diversity within 81 extant cultivars. The stability analysis indicate a significant interaction between the cultivars and environment for yield contributing charaters. These yield related traits showed stability for most cultivars in different environments. The characterized morphometric characters in this study would be helpful for creating a database for brinjal while the genetically stable cultivars can be cultivated in any climatic region and be utilized for the improvement programme of brinjal.

As a vegetable crop, sponge gourd is widely consumed worldwide due to its health promoting and nutraceutical value. This study describes genetics of an aromatic genotype VRSG-7-17 and deciphers the genetic control and volatile compound composition of sponge gourd. To study the inheritance of this trait, a cross was made between aromatic light-green-fruited VRSG-7-17 and non-aromatic dark-green-fruited VRSG-194 genotypes. The F₁s were found to be non-aromatic and have a green fruit colour. Chi-square (χ²) analysis of backcross and F₂ population segregating for aroma suggested that the inheritance of aroma in VRSG-7-17 is governed by a single recessive gene in a simple Mendelian fashion. The SPME–GC/MS analysis of the volatile compounds suggested that the compounds responsible for Basmati rice-like aroma were mainly hexanal, 1-octen-3-ol, 3-octanone and limonene. The aroma persists in the cooked VRSG-7-17 fruits, that did not lose fragrance traits at high temperatures. The inheritance of fruit colour was found to be controlled by a single gene with incomplete dominance. The segregation analysis showed that the aroma and fruit colour were not linked, and they segregated independently. The findings will lead to understanding the inheritance of the aromatic compounds in the sponge gourd and may be utilised in the breeding programmes for developing improved aromatic varieties.

Grafting on salt tolerant eggplant rootstocks can be a promising approach for enhancing the salinity tolerance of tomato. In this study, the performance of tomato cv. Kashi Aman grafted on two salt tolerant eggplant rootstocks (IC-111056 and IC-354557) was evaluated against non-grafted control under saline (EC_iw 6 and 9 dS m⁻¹) and non-saline (EC_iw ~1 dS m⁻¹) irrigation for 2 years. Grafting improved tomato plant performance under salt stress. Moreover, rootstock IC-111056 outperformed IC-354557. An increase in the average fruit yield of grafted plants compared with non-grafted control at 6 and 9 dS m⁻¹ was 24.41% and 55.84%, respectively with rootstock IC-111056 and 20.25% and 49.08%, respectively with IC-354557. Grafted plants maintained a superior water status under saline irrigation, evidenced with the relative water content and chlorophyll SPAD index, along with higher proline and antioxidant enzyme activities (superoxide dismutase, catalase, and ascorbate peroxidase). Rootstocks mediated the partitioning of toxic saline ions in the scions by promoting higher Na⁺ accumulation (14% of mean accumulation) in the older leaves and lower (24%) in the younger leaves of grafted plants. This resulted in higher K⁺/Na⁺ ratios within the younger (active) leaves of the grafted plants. Our study demonstrates that grafting tomato seedlings on selected salt tolerant eggplant rootstocks is a viable alternative for improving plant physiological status and fruit yield under salt stress, through favorable modulation of salt ion partitioning in the scions.

Whitefly (Bemisia tabaci)-transmitted begomoviruses cause severe diseases in numerous economically important dicotyledonous plants. Okra enation leaf curl disease (OELCuD) has emerged as a serious threat to okra (Abelmoschus esculentus L. Moench) cultivation in the Indian subcontinent. This study reports the association of a monopartite begomovirus (bhendi yellow vein mosaic virus; BYVMV) and betasatellite (bhendi yellow vein mosaic betasatellite; BYVB) with OELCuD in the Mau region of Uttar Pradesh, India. The BYVMV alone inoculated Nicotiana benthamiana and A. esculentus cv. Pusa Sawani plants developed mild symptoms. Co-inoculation of BYVMV and BYVB resulted in a reduced incubation period, an increased symptom severity, and an enhanced BYVMV accumulation by Southern hybridization and quantitative real-time PCR. This is the first study that satisfies Koch’s postulates for OELCuD in its natural host. Activities of various antioxidative enzymes were significantly increased in the virus-inoculated okra plants. Differential responses in various biochemical components (such as photosynthetic pigments, phenol, proline, and sugar) in diseased okra plants were observed. This change in phytochemical responses is significant in understanding its impact on virus pathogenesis and disease development.

An elite cultivar of eggplant, Ramnagar Giant (Solanum melongenaL.) and W-4 (S. incanumL.) with contrasting horticultural traits were used as parental lines to develop a mapping population of RILs. To accelerate breeding programs and to develop large scale SSR markers to be used in QTL mapping, RNASeqlibraries from different tissues of both the parental plants were deep sequenced and assembled into representation of a high qualityde novotranscriptome using Illumina-based Next Generation Sequencing technology. 99.99% of high quality bases were obtained from all the tissues and deposited in TSA database at the NCBI link. Total 3, 156 and 3, 196 SNVs were detected inS. melongenaandS. incanum, respectively. InS. melongena, 11, 262 SSR while inS. incanum11, 829 SSR containing regions were identified. Based on functional annotation, 21, 914 unique genes could be identified forS. melongena, 21,706 unique genes forS. incanumand overall, 60 different transcription factors were identified in both the lines. Further, a total of 536 SSR markers were designed and screened for polymorphism of which, 157 markers produced polymorphism between the parental lines. The polymorphic SSRs shall be used for genotyping of RILs to map QTLs for various horticultural traits in eggplant and identification of candidate genes in response to biotic and abiotic stress.

Malabar spinach (Basella alba L.) belongs to the family Basellaceae which is native to Southeast Asia. It is widely cultivated as a perennial leafy vegetable in India. The leaves are rich sources of vitamin A, vitamin C, iron, calcium, soluble fiber and protein per calorie. It possesses immense potential in androgenic and nephroprotective activity, antioxidant and antibacterial activity, anti-inflammatory activity and central nervous system (CNS) depressant activity (Kumar et al. 2013). During the period of August to October2016, plants were observed with charcoal rot symptoms at Research Farm of ICAR- IIVR and in six farmers’ fields ranging in size from 200 to1000 m2 in Varanasi district of Uttar Pradesh, India. The symptoms, observed on 30 to 40% of the plants, consisted of brownish to black discoloration at the collar region of the stem and branches that progressed into wilting and drying of entire plant. Infected plant stems appeared shredded and contained black microsclerotia. Symptomatic plants were...

Bitter gourd (Momordica charantia L, family Cucurbitaceae) is a major vegetable crop widely cultivated throughout India. Bitter gourd pods are consumed for their nutritional and medicinal value. In 2016, nearly 15% of plants showed virus-like symptoms in a 0.6 ha bitter gourd farm at the Indian Institute of Vegetable Research, Varanasi, Uttar Pradesh, India. Symptomatic plants were stunted with necrosis of growing tips and yellowing and downward cupping of leaves that became thick and leathery in appearance. Since these symptoms were like those produced by orthotospoviruses in vegetable crops (Kunkalikar et al., 2011), leaves from five symptomatic and five non-symptomatic plants were initially tested by indirect ELISA using polyclonal antibodies raised against Peanut bud necrosis virus (PBNV; Genus: Orthotospovirus; Family: Tospoviridae). These antibodies were obtained from the International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India. Only samples from symptomatic plants gave pos...