A three-year field experiment was conducted at the Agricultural Research Station of Mandor, Jodhpur, Rajasthan, under arid climatic conditions in the rabi season of 2016–2019 with the objectives of evaluating the effect of drip irrigation and fertigation levels on cumin plant growth, yield, oil content, water-use efficiency, and water productivity. The pooled data revealed that the drip irrigation at 0.6 cumulative pan evaporation (CPE) recorded significantly higher plant height (31.4 cm), umbels plant⁻¹ (50.4), umbellates umbel⁻¹ (5.07), seeds umbel⁻¹ (5.34), test weight (4.60 g), seed yield (1063 kg ha⁻¹), gross return (₹ 172,600 ha⁻¹), net return (₹ 113,500 ha⁻¹) and benefit, and cost ratio (2.9) over drip fertigation at 0.4 CPE and surface irrigation with 0.8 CPE. The fertigation with 80% recommended dose of fertilizer (RDF) being at par with 100% RDF recorded a significantly higher number of umbels plant⁻¹ (50.0), umbellates umbel⁻¹ (5.03), seeds umbellate⁻¹ (5.24), test weight (4.67 g), seed yield (1052 kg ha⁻¹), gross return (₹ 170,900 ha⁻¹), net return (₹ 111,700 ha⁻¹), and benefit cost ratio (2.9) over fertigation with 60% RDF and control. Maximum water-use efficiency (5.7 kg ha⁻¹ mm⁻¹) and water saving (39.04%) was observed under drip irrigation at 0.4 CPE followed by 0.6 CPE (4.8 kg ha⁻¹ mm⁻¹ and 18.86%, respectively).

Little is known about how Indian farming practices affect German chamomile (Matricaria chamomilla L.). This study examines the effects of the sowing date and spacing of plants on flower productivity, essential oil concentration, and the composition of German chamomile grown in the arid zone of Rajasthan, India. In a factorial randomized block design (FRBD), the treatments consisted of four sowing dates (15 and 25 October, 5 and 15 November) and three spacings of plants (20 × 10 cm, 30 × 10 cm, and 40 × 10 cm). The dried flower yield (Kg ha⁻¹), fresh flower yield (Kg ha⁻¹), and number of flowers per plant of chamomile crop were significantly affected by the varying spacing of plants and the date of sowing. The highest values for dry weight, fresh weight, and number of flowers were obtained from the second date of sowing (25 October) with 40 × 10 cm geometry. Likewise, the highest values for total oil (12.44%) and essential oil (0.94%) contents were also obtained from the D2P3 combination (D2—sowing date 25 October, P3—40 × 10 cm spacing of plants). GC/MS analyses of the samples showed that p-menth-1-en-4-ol, acetate, cis-alpha-farnesene, anethole+estragol, 1,4-cyclohexadiene,1-methyl-4-(1-methylethyl)- and 3,6-dihydro-4-(4-methyl-3-pentenyl)-1,2-dithiin were the main identified compounds in the essential oil of chamomile fresh flowers. The treatments altered the quality profile of the essential oils in general. The principal components of chamomile essential oil were significantly affected by the D2P3 treatment. The findings of this study add to our understanding of how to grow high-quality chamomile flowers in arid regions.

A field experiment was conducted to investigate the effectiveness of different herbicides for controlling wild onion (Asphodelus tenuifolius) in cumin (Cuminum cyminum L.) during the rabi seasons (2018–2019 and 2019–2020) at Agricultural Research Station, Agriculture University, Jodhpur, Rajasthan. The experiment comprised eight herbicidal weed management treatments for wild onion applied to cumin in a three-replication randomized block design. Among the herbicidal weed management treatments, early post-emergence (8 DAS) application of oxyfluorfen 200 g/ha resulted in the lowest weed density and dry matter of Asphodilus tenuifolius, with maximum weed (Asphodilus tenuifolius) control efficiency at 40 days after sowing (DAS) during both experimental years. Likewise, the highest total efficiency of weed control was recorded with the application of oxyfluorfen 200 g/ha at 8 DAS. Oxyflourfen 200 g/ha used early post emergence (8 DAS) reduced the weed index more effectively than the other herbicides. It also recorded the highest number of branches/plant, plant height, umbels/plant, umbellates/umbel, seeds/umbellates, and seed yield. However, application of oxyflourfen @ 200 g/ha 8 DAS–early POE and pendimethalin 38.7 CS 500 g/ha + oxyfluorfen @ 150 g/ha 8 DAS–early POE were statistically similar in terms of plant growth, yield, and yield attributes. The net returns (366.49 USD/ha in 2018–2019 and 175.72 USD/ha in 2019–2020) and B:C ratio (1.70 and 1.33 in 2018–2019 and 2019–2020, respectively) were also superior, with oxyfluorfen 200 g/ha applied early post emergence.

A comprehensive study spanning three kharif and rabi seasons (2018–2019, 2020–2021, and 2021–2022) was conducted to investigate the intricate interactions among different cropping sequences and their impacts on cumin yield, financial outcomes, and soil microbial dynamics. The experiment was designed using a randomized block design, comprising eight distinct treatment combinations, each replicated three times. The results revealed compelling insights into the potential of specific cropping sequences to enhance multiple aspects of agricultural sustainability. The results revealed that the highest cumin yield (averaging 592 kg ha⁻¹ over the three years) was achieved when cumin was cultivated subsequent to pearl millet, showcasing significant increases of 14.28% and 23.07% over the cumin–fallow and cumin–cotton cropping systems, respectively. When it came to cumin equivalent yield, the cumin–cotton cropping sequence (985 kg ha⁻¹) emerged as the most favorable, closely followed by cumin–groundnut (968 kg ha⁻¹). Furthermore, analyzing net realizations and benefit–cost ratios demonstrated that the cumin–pearl millet cropping sequence stood out with the maximum values (₹88,235 ha⁻¹ and 2.7, respectively), followed by the cumin–mung bean cropping system (₹84,164 ha⁻¹ and 2.47, respectively). Among the various cropping sequences studied, cumin–mung bean, cumin–cluster bean, cumin–pearl millet and cumin–groundnut were recorded as statistically similar in terms of soil microbial enzymatic activities viz. fluorescein diacetate (FDA), alkaline phosphatase (ALP), dehydrogenase activity (DHA), and microbial biomass carbon and were at par over the cumin–sorghum, cumin–sesame, cumin–cotton and cumin–fallow cropping systems. These findings emphasize the significance of strategic crop sequencing for sustainable agriculture practices that simultaneously optimize productivity and maintain soil health.

Cumin (Cuminum cyminum L.), is an important export-oriented seed spice crop for India. Cumin is popularly used for flavouring food, including soups, pickles and vegetables, and for herbal medicine. India is the largest producer, consumer and exporter of cumin seed with an annual production of 0.795 million tones over an area of 1.09 million hectares. During 2020-21, India exported about 0.299 million tons of cumin worth of Rs 33280 million (Anonymous, 2021). Recently, phytoplasma suspected symptoms were observed in cumin at Agricultural Research Station, Mandor, Jodhpur, Rajasthan, India from 2019. The symptoms related to phytoplasma infection were first recorded after 70-75 days of sowing in the month of January of the years 2019 to 2022. The major symptoms recorded were yellowing, phyllody, witches-broom, yellowing and deformed elongated seeds. Disease incidence was recorded as 0.25-1.0%, 0.5-1.5%, 0.5-2.5 % and 0.5-10.6% during the years 2019, 2020, 2021 and 2022, respectively using quadrate method. In 2022, among different genotypes assessed GC 4, MCU 73, MCU 105, and MCU 32 exhibited lower disease incidences ranging from 0.5% to 1.5%, while MCU 78 recorded the highest disease incidence at 10.6%. To detect the association of phytoplasma with symptomatic cumin samples, genomic DNA was extracted from four representative cumin genotypes (CuPP-MND-01 to CuPP-MND-04) and one asymptomatic cumin plant using the Qiagen DNeasy plant mini kit (Germany). The extracted DNA was amplified using nested PCR assays with universal phytoplasma detection primers for 16S rRNA gene (P1/P7 and R16F2n/R16R2) (Schneider et al., 1995; Gundersen and Lee, 1996) and secA gene specific primers (SecAfor1/SecArev3 followed by nested PCR primers SecAfor5/ SecArev2) (Hodgetts et al. 2008; Bekele et al. 2011). The amplicons of ∼1.25 kb with 16S rRNA gene and ∼600 bp with secA gene specific primers were amplified in all symptomatic cumin plant samples and positive control of brinjal little leaf. PCR amplified products from the four selected positive samples (CuPP-MND-01 to CuPP-MND-04) of 16S rRNA gene and secA gene, were sequenced from both ends. The 1,245 bp sequences were deposited in GenBank (OQ299007-10), which showed 100% sequence identity with each other and 99.4% identity with 'Candidatus Phytoplasma citri' reference strain (GenBank accession: U15442) (Rodrigues Jardim et al. 2023). The phylogenetic analysis and virtual RFLP analysis using 17 restriction enzymes of 16S rRNA gene sequences through iPhyclassifier allowed affiliating the cumin phytoplasma strains with 16SrII-C subgroup strain with a similarity coefficient of 1 to the reference pattern of 16Sr group II, subgroup C (GenBank accession: AJ293216) (Zhao et al. 2009). In addition, the phylogenetic analysis of the secA gene-based sequences (OQ305073-76) further confirmed the close association of 16SrII-C group phytoplasmas with phyllody and witches' broom disease of cumin. Earlier 16SrII-C subgroup phytoplasma has been reported from various crops and weeds in India (Rao et al. 2021). However, no phytoplasma association has been reported earlier with cumin in India and abroad. To the best of our knowledge, this is the first report on the association of 16SrII-C group phytoplasma causing phyllody, witches' broom in cumin genotypes. This report has economic and epidemiological implications and needs immediate attention to reduce export losses due to phytoplasma disease in cumin and to prevent the potential spread to other crops.

An experiment was conducted at Agricultural Research Station, Mandor during two consecutive rainy (Kharif) seasons of 2021 and 2022 and subsequent Rabi season of 2021-22 and 2022-23 to optimize groundnut (Arachis hypogaea L.) production through diclosulam-based weed management and its residual effect on consecutive wheat crop. The findings disclosed that all the weed management treatment significantly reduced weed density and weed dry matter at 50 days after sowing (DAS) and increased yield attributes and pod yield of groundnut over weedy check. The highest weed control efficiency (WCE) was observed in thrice manual weeding at 25, 50 and 80 DAS/weed free (84.0%) followed by (fb) application of diclosulam 25 g/ha pre-emergence (PE) fb hand weeding at 30 and 60 DAS (79.2%). The maximum pod yield (2.03 t/ha) was recorded due to thrice hand weeding at 25, 50 and 80 DAS/weed free, which was at par with diclosulam 25 g/ha PE fb quizalofop-ethyl 50 g/ha PoE at 30 and 60 DAS, pendimethalin 1.0 kg/ha PE fb quizalofop-ethyl 50 g/ha PoE at 30 and 60 DAS, diclosulam 25 g/ha PE fb hand weeding at 30 and 60 DAS and diclosulam 20 g/ha fb hand weeding at 30 and 60 DAS. Results further indicate that highest net returns and B: C ratio were recorded in pendimethalin1.0 kg/ha PE + quizalofop-ethyl 50 g/ha PoE at 30 and 60 DAS followed by diclosulam 25 g/ha PE + quizalofop-ethyl 50 g/ha PoE at 30 and 60 DAS.