ICAR-Indian Agricultural Research Institute Research Articles

Pollen biology and metaxenic studies on early maturing grape (Vitis vinifera) genotypes

The present experiment was conducted during 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to study the impact of open-, self-, and cross-pollination on metaxenic traits (berries) and the incidence of cleistogamy in grapes (Vitis vinifera L.). Seven different cross-combinations were used on the grape variety Pusa Navrang, which were planted at 3 m × 3 m spacing and trained on the Y-trellis training system. The experiment was laid out in a randomized block design (RBD) with four replications. The incidence of cleistogamy, berry set, retention percentage, and the metaxenia effect of pollen grains in different grapevine varieties, namely, Pusa Navrang (PN), Black Muscat (BM), Pusa Swarnika (PS), Beauty Seedless (BS), Perlette (PER), Male Hybrid (MH), were studied. Also, pollen quantity and viability were determined for the different grapevine varieties under study. Depending on the genotypes and whether the fruit set is obtained inside the covered flowers, cleistogamy was confirmed. A significantly higher berry set (40–85%) and retention (32–77%) were recorded in open- and self-pollinated flowers. The total number of pollens/anther in six grape genotypes ranged from 7916.62–23832.02, whereas the maximum active pollen rates were noted in the Male Hybrid (70.01%) and Black Muscat (66.80%). The pollens from the Beauty Seedless genotype exhibited significant enhancement of metaxenic traits such as berry set, retention, and size in Pusa Navrang. Therefore, utilizing Beauty Seedless as a pollen parent in grape breeding programmes holds promise for enhancing berry set and overall berry quality, thus enhancing the hybridization efficiency.

Response of pearl millet (Pennisetum glaucum) to crop residue application and potassium management options under rainfed condition

A field experiment was conducted during rainy (kharif) seasons of 2021 and 2022 at ICAR-Indian Agricultural Research Institute, New Delhi to study the impact of crop residue mulching and potassium management options on growth and yield attributes of pearl millet [Pennisetum glaucum (L.) R. Br]. The experiment was conducted in a split plot design (SPD) with three mains plots, viz. C0, No residue mulching; C1, Crop residue mulching @3 t/ha; and C2, Crop residue mulching @3 t/ha + Pusa decomposer; and five potassium management in sub plot, viz. K0, No potassium application; K1, 40 kg K2O/ha; K2, 40 kg K2O/ha + potassium solubilising bacteria (KSB); K3, 30 kg K2O/ha + KSB; and K4, 20 kg K2O/ha + KSB. Pearl millet variety Pusa Composite 701 was used for the experiment. Significant variation among growth and yield parameters were observed under crop residue as well as potassium management options. Under crop residue mulching these were recorded maximum in treatment C2 (crop residue mulching @3 t/ha + Pusa decomposer). However, under potassium management options plant height (11.8–13.3%), ear head length (9.5 and 9.8%) and yield (26.7 and 24%) of pearl millet was recorded maximum in treatment K2 (40 kg K2O/ha + KSB) during the consecutive year over the control. These finding highlights the synergistic effects of potassium and residue management demonstrating that the presence of KSB enhanced potassium uptake by the plants, resulting in improved outcomes.

Selectivity of new generation herbicide ‘Tembotrione’ under conservation agriculture-based maize (<i>Zea mays</i>) in maize-wheat-mungbean cropping system

An experiment was conducted at the ICAR-Indian Agricultural Research Institute in New Delhi during the rainy (Kharif) seasons of 2021–22 and 2022–23. The study aimed to evaluate the weed control efficiency of low dose new generation herbicide: tembotrione (34.4% SC) as a component of integrated weed management (IWM), on zero-till (ZT) and conventional till (CT) maize (Zea mays L.). The treatments were comprised of conventional tillage maize (M1: CT-M), conventional tillage maize with green manure from preceding green gram (M2: CT-M+GM), zero tillage maize with residue retention at 3 t/ha (M3: ZT-M+R), zero tillage maize with Sesbania co-culture as brown manuring (cover crop) (M4: ZT-M+BM) in the main plot and five weed control treatments, viz S1: Un- weeded check, S2: Pre +1 HW, S3: Pre + Post (tembotrione) @120g/ha, S4: Pre+ Post (Premix of Mesotrione+ Atrazine) @120 g/ha, S5: Weed free check (WFC) in the sub-plots were evaluated in split-plot design. It was ob- served that ZT-M+BM caused a considerable reduction in the population of broad-leaf weed, narrow leaf weed with sedges and total weeds (28.4% reduction at 60 days after sowing) compared to M1. The results also revealed that the sequential application of atrazine @750g/ha+pendimethalin @750g/ha(pre) followed by (fb.) tembotrione (34.4% SC) @120 g/ha (post) among the herbicide options reduced the weeds population (78.5%) and dry weight (81.3%) significantly than the un-weeded control (UWC). Maize yield attributes were higher in ZT with Sesbania co-culture (ZT-M+BM) than conventional-tilled treatments (CT-M). The application of atrazine @750g/ ha+pendimethalin @750g/ha (pre) fb. tembotrione @120 g/ha (post) combined with ZT-M+BM resulting in higher maize yield (6.88 t/ha) which was comparable with that in weed-free check (WFC). The post emergence (PoE) ap- plication of tembotrione (34.4% SC) @120 g/ha recorded highest weed control efficiency (86.2%), weed control in- dex (88.1%) and lowest value of weed index (7.04) when applied in the ZT-maize with sesbania as a cover crop. Therefore, combining zero tillage (ZT) with brown manure (Sesbania), along with atrazine and pendimethalin (@750g/ha each) as pre-emergence herbicides, and tembotrione (@120g/ha) as a post-emergence herbicide is recommended for effective weed control and high maize productivity in the North-Western Indo-Gangetic plains (IGP).

Electrical conductivity based algorithm for precise application of liquid nitrogenous fertilizers

Precise application of nitrogenous fertilizers mainly urea ammonium nitrate (UAN) and granular urea (both pure and neem-coated) in aqueous form, is critically important for basal and foliar applications. The physicochemical properties of aqueous solution of these nitrogenous fertilizers plays important role in design of any liquid fertilizer application system. The study was carried out during 2019–20 at ICAR-Indian Agricultural Research Institute, New Delhi with an aim to develop algorithms for use in sensors-based systems for real time monitoring of available N concentration in the fertilizer solution before its application. The physicochemical properties like pH, electrical conductivity (EC), specific gravity (SG), dynamic viscosity (DV), surface tension (ST) and percentage light absorbance (LA) of urea ammonium nitrate (UAN-28%), pure urea, and neem coated urea in diluted form (pre-selected N-concentrations i.e. 0.78, 0.9, 1.08, 1.33, 1.75, 2.54 and 4.67% corresponding to the dilution ratios of 1:35, 1:30, 1:25, 1:20, 1:15, 1:10 and 1:05) were measured and analyzed for their significance with N-concentration. Electrical conductivity (EC) alone showed a significant relationship with N-concentrations. Prediction models were developed for diluted UAN and granular urea fertilizers based on the EC and N-concentrations. The regression models in terms of EC to predict N-concentration had coefficients of determination (R2) of 0.998, 0.998, and 0.999 for diluted UAN, pure urea, and neem coated urea with water, respectively showed a great potential for their sensor based precise application. The controlled application of diluted liquid fertilizers with water can be achieved through sensing relevant physicochemical property.

Sub-surface drip fertigation of nitrogen coupled with crop residue incorporation enhanced the growth and yield of maize in an alluvial soils

A two-year field experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi, to standardize the N-fertigation schedule and crop residue management in sub-surface drip fertigated (SSDF) maize [Pusa HQPM 1’ improved: double bio-fortified]. The experiment was laid-out in a split-plot design with 3 replications. There were 8 main-plot treatments comprising different N sub-surface drip fertigation levels (0, 50, 75, 100% RDN) with one conventional cultivation of maize, where RDN (150 kg/ha) was applied as per recommendation. Under sub-surface fertigation of N, each dose of N was divided into 3-and 4-splits, for fertigation. Sub-plot treatments included greengram residue (3 t/ha) and no greengram residue incorporation. P and K (60 kg P2 O5 /ha and 40 kg K2 O/ha respectively) fertilizers were supplied equally in all the plots by SSDF. Results revealed that plant height at various stages statistically varied with levels and splits of SSDF-N and crop residue incorporation. The highest plant height and leaf area were recorded with 100% RDN-4S which remained at par with 100% RDN-3S and 75% RDN-4S. Conventional maize cultivation was inferior to ‘RDN100’ and 75%, however on par with 50% RDN. The nitrogen uptake was found significantly superior in 100 and 75%RDN over conventional and control treatments. Similarly, the grain yield of maize was highest under 100% ‘RDN-4’ &3 S, and 75% RDN-4S, which were at par with one another. Overall, it could be concluded that sub-surface fertigation of N not only improved the growth and yield of maize but also helped in 25–50% saving of valuable fertilizer.

Effect of tillage and precision nutrient placement on growth and productivity of maize (Zea mays)

The experiment was conducted at ICAR-Indian Agricultural Research Institute, New Delhi during rainy season of 2022 to asses the effect of tillage and precise nutrient placement on maize (Zea mays L.) growth. Employing a split-plot design with 3-tillage methods in main plots, viz. T1 , (conventional tillage); T2 , (once rotavator as minimum tillage) and T3 , (zero tillage) and 4, precision nutrient application options N1 , 50% RDF as point placement; N2 , 75% RDF as band placement; N3, 100% RDF as band placement and N4, 100% RDF as broadcasting were tested in subplots. Results indicated that tillage and precision nutrient placement practices improved the plant height and LAI of maize. Minimum tillage recorded significantly higher crop growth indices, viz. CGR (1.92 g/m2/day), RGR (26.80 g/g/day) and dry matter accumulation (204.58 g/plant) over other tillage practices at 60 to 90 Days after sowing (DAS). Root attributes also improved under minimum tillage. The grain yield was significantly higher with minimum tillage (6.22 t/ha) over other tillage practices. Among the precision nutrient application options, 100% RDF as band placement recorded significantly higher grain yield (6.20 t/ha) over N2 and N4 but remained statistically at par with 50% RDF point placement (6.06 t/ha). The findings suggested that adopting minimum tillage and precise nutrient point placement could significantly enhance maize growth and yield in kharif seasons, offering 50% reduction in fertilizer consumption.

Yield, nutrient uptake and economics of Indian mustard (Brassica juncea) as affected by split and foliar application of potassium

A field experiment was carried out during winter (rabi) season 2021–22 at the ICAR-Indian Agricultural Research Institute located at New Delhi to find out the effect of potassium management on yields, nutrient uptake and economics of Indian mustard. Eight treatments combinations of different doses, methods and time of potassium application i.e. No K = 0 kg K/ha; 100% MOP (muriate of potash) as basal; 2 Foliar sprays of KNO3 at branching and before flowering; 50% MOP as basal + 50% MOP as top dressing at branching; 50% MOP as basal + 2 foliar sprays of KNO3 at branching and before flowering; 75% MOP as basal + 25% MOP as top dressing at branching; 75% MOP as basal + one foliar spray of KNO3 at branching; 75% MOP as basal + one foliar spray of KNO3 before flowering were tested. Grain (1.89 t/ha) and straw yields (6.74 t/ha), harvest index (21.88%) and NPK uptake (93.9, 18.5 and 113.3 kg/ha) were significantly higher under 75% MOP as basal + one foliar spray of 2.5% KNO3 before flowering. However, the treatment i.e. 75% MOP as basal + one foliar spray of KNO3 before flowering remained significantly at par with 75% MOP as basal + one foliar spray of KNO3 at branching and 75% MOP as basal + 25% MOP as top dressing at branching in yield and profitability term. Enhanced net returns amounting to 65,873/ha and a benefit: cost ratio of 1.86 were recorded on the application of 75% MOP as basal fertilizer combined with a single foliar spray of KNO3 before flowering. This remained comparable to most treatments, except the control, 100% MOP applied as basal, the method involving two foliar sprays of KNO3 at branching and before flowering, 50% MOP as basal combined with 50% MOP as top dressing at branching, and the approach combining 50% MOP as basal with 2 foliar sprays of KNO3 at branching and before flowering.

Edible coating functionalized with ornamental plant extracts affect the postharvest quality of guava (Psidium guajava) during storage

Present study was carried out during 2021–23 at ICAR-Indian Agricultural Research Institute, New Delhi to investigate the efficacy of active edible coatings, incorporated with extracts from rose leaves and marigold petals in preserving the quality of mature green guava (Psidium guajava L.) cv. Allahabad Safeda during storage at both ambient (25±2°C) and cold (10±1°C) conditions. The coatings, particularly carboxy methyl cellulose combined with rose leaf extract (CMC+RL) demonstrated the highest effectiveness in minimizing per cent firmness reduction (PFR; 77.02% and 84.71%) compared to the control (89.95% and 89.73%) after 4 and 18 days of ambient and cold storage, respectively. Additionally, the coatings significantly influenced total soluble solids (TSS), total sugar content (TSC) and yellowness index (YI) showing potential in slowing down the fruit ripening. Moreover, the coatings demonstrated notable antioxidant activity with CMC+RL coating exhibited the highest activity. Furthermore, the coatings exhibited a substantial inhibitory effect on polygalactouronase (PG) activity, indicating a potential to mitigate cell wall degradation. Overall, the results highlight the promise of these biodegradable coatings as an alternative to synthetic preservatives in preserving postharvest quality and enhancing the shelf-life of guava fruits.

Productivity, nutrient uptake and nitrogen economy of wheat (Triticum aestivum) in a conservation agriculture-based cotton (Gossypium herbaceum)–wheat system

Conservation agriculture (CA) practices like zero-till and residue retention along with nitrogen management is vital for improving degraded soil health and optimizing the yield potential of wheat (Triticum aestivum L.) crop. Present study was carried out during winter (rabi) seasons of 2021–22 and 2022–23 at ICAR-Indian Agricultural Research Institute, New Delhi for optimizing wheat productivity in a conservation agriculture-based cotton (Gossypium herbaceum L.)-wheat system. The experiment was laid out in a randomized complete block design (RCBD) with three replications consisting of combination of 3 different crop establishment methods, viz. permanent broad bed (PBB), permanent narrow bed (PNB) and zero-till flatbed (ZTFB) with residue (R) and without residue along with 2 doses of nitrogen (75N, 100N) and conventional tillage (CT). The CA-based practices showed overall superior response in terms of growth, yield and nutrients uptake of wheat than CT. Among them, the PBBR100N resulted in significantly higher plant height, leaf area index, dry-matter accumulation, crop growth rate, and relative growth rate compared to PNB, PBB, ZTFB and CT. This treatment led to significantly higher grain (16.2–19.4%) and straw (9.6–11.6%) yields than CT. The net returns and benefit cost ratio (23.4% and 27.9%) were also higher than that in CT. Again, in this treatment, N uptake by wheat crop was higher by 85%, P uptake by 53.1%, and K uptake by 40.1%, and available soil N, P and K by 16.1, 25.3 and 43.7%, respectively than CT. Therefore, the study suggests that the adoption of CA-based practices with broad bed in Indo-Gangetic Plains will not only enhance the productivity of wheat but also result in improved soil health by restoring soil fertility.

Crop planning using innovative trend analysis of 62-years rainfall data

The success of climate-smart agriculture in high rainfall zone lies in understanding the rainfall trend and planning or modifying the cropping system for maximum yield. Moisture stress in critical crop growth stages is detrimental to the crop and drastically reduces the yield. Udhagamandalam region in Western Ghats is a high rainfall area and is largely cultivated by vegetable crops. Rainfall trend based crop planning would enhance the crop yield without water stress. A study was carried out at ICAR-Indian Agricultural Research Institute, Dhemaji, Assam focused on assessing the long-term seasonal and monthly rainfall trends of Udhagamandalam region, Tamil Nadu using non-parametric tests and Innovative Trend Analysis (ITA). Daily rainfall of 62 years from 1960–2021 was analyzed with non-parametric tests, viz. Mann-Kendall and modified Mann-Kendall and ITA to find the seasonal rainfall characteristics. Mann- Kendall (3.055) and modified Mann-Kendall (3.055) tests showed a significantly increasing trend in the annual and seasonal monsoonal rainfall. ITA revealed either a significant positive or a negative trend in all the months except February, with the highest trend in June (2.625). In contrast to standard non-parametric tests, ITA detected a significant positive trend in all seasons and annual rainfall, except in cold winters where the trend is negative. The long-term trend analysis results suggest that the ITA is more precise for rainfall trend analysis than standard non-parametric tests and can be used to evaluate hidden variations of rainfall trends. Hence, ITA is recommended for analyzing rainfall trends for crop planning in high-rainfall regions. IT analysis of 62 years of rainfall data of Udhagamandalam suggested that vegetable crop planning can be done by farmers from August–November months as the rainfall trend during this period is assured as an increasing trend of rainfall pattern was observed.

Interactive effect of ambient and elevated levels of tropospheric ozone, nutrition and PGPR on growth and yield of chickpea (Cicer arietinum)

An experiment was conducted during 2020 and 2021 at ICAR-Indian Agricultural Research Institute, New Delhi, to study the interactive effect of nutrient and PGPR (Plant growth promoting rhizobacteria) on growth and yield of chickpea (Cicer aeritinum L.) cv. Pusa 3043 under ambient and elevated levels of ozone in FAOE (Free air ozone enrichment). A loss of 15–16% in dry matter production was observed under elevated ozone (EO3) when compared to ambient ozone (AO3) conditions. Seed treatment with PGPR was found to compensate for this loss as an increase in seed yield 18–19% was observed over untreated seeds. In terms of seed yield, the PGPR treatments with 75% nitrogen showed significant improvement compared to the recommended dose of fertilizer (RDF) application. A yield increase of 12% and 14% was observed with PGPR like RPAN8 (Anabena laxa) and An-Rh (Anabena torulosa with Mesorhizobium ciceri) (chickpea rhizobium) respectively, suggesting an advantage of an–Rh over RPAN8 under EO3. A combination of both PGPRs outperformed the individual PGPR, showing a 19% yield increase over RDF. This proves the potential of seed treatment with PGPR (RPAN8 and An-Rh) in ameliorating tropospheric ozone-induced stress in chickpea plants.

Assessing genetic diversity of tomato (Solanum lycopersicum) genotypes cultivated under protected condition

Present study was carried out during 2018–19 and 2019–20 at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate 16 quantitative and qualitative traits of 36 genotypes of Tomato (Solanum lycopersicum L.) and to examine the genetic variability and character association between yield and its component traits. This investigation involved correlation and genetic divergence analyses to gain insights into the relationships among the various traits. The variance analysis revealed notable variations among genotypes, indicating a substantial level of genetic diversity among them. Among the genotypes, 178 and 115 were found promising for both yield and quality traits. Genotype no. 178 was found superior for fruit weight and yield. The principal component analysis indicated that the first 3 components i.e. component 1 (equatorial diameter, average fruit weight and fruit weight uniformity); component 2 (number of locule and equatorial/polar index); and component 3 (number of fruit and number of fruit/cluster) collectively accounted for 81.48% of the variability. The yield exhibited significant positive correlation with average fruit weight (g), pericarp thickness (cm), polar diameter of fruit (cm), equatorial diameter of fruits (cm) and average fruit weight after each harvest (kg).

Zinc uptake in rice (Oryza sativa)-wheat (Triticum aestivum) cropping system under the influence of microbial consortia (Pusa decomposer) mediatedin situ rice straw management options

A field experiment was conducted during the rainy (kharif) and winter (rabi) seasons of 2019–20 and 2020–21 at research farm of ICAR-Indian Agricultural Research Institute, New Delhi to study the effect of various crop establishment methods and microbial consortia (Pusa decomposer) mediated in situ rice straw management options on zinc (Zn) concentration and uptake in rice (Oryza sativa L.) (cv. Pusa Basmati 1509) and wheat (Triticum aestivum L.) (cv. HD 2967). The experiment was laid out in split-plot design (SPD) with 3 replications having 2 main plot (main factor) treatments, viz. aerobic rice (AR); and conventional transplanted (CT) rice in wet season; and 7 sub- plot (sub-factor) treatments, viz. Clean cultivation (removal of paddy straw); Paddy straw incorporation (PSI); Paddy straw mulching (PSM); PSI + Pusa decomposer (PD); PSM + PD; PSI + urea @20 kg/ha; and PSI + PD + urea @10 kg/ha in dry season. Findings showed that, in rice the zinc concentration (18.51 and 20.30 mg/kg in grain; 57.02 and 57.81 mg/kg in straw) and uptake (78.38 and 89.81 g/ha in grain; 427.1 and 434.6 g/ha in straw) were significantly superior in CT rice than AR in main plots during both the years of experiments. However, sub-plot treatments were non-significant in the zinc concentration and uptake. In wheat, among in situ rice straw management options (sub- plots), paddy straw incorporation + Pusa decomposer + Urea @10 kg/ha treatment significantly resulted in higher Zn concentration (38.08 and 39.03 mg/kg in grain; 28.24 and 29.01 mg/kg in straw) and uptake (185.0 and 191.9 g/ha in grain; 234.2 and 242.6 g/ha in straw) compared to other treatments and control (clean cultivation). The principal component analysis revealed that Zn uptake positively correlated with straw and grain yields in rice and wheat. Thus, the same treatment was found to be a better option for higher Zn concentration and uptake in the rice-wheat cropping system.

Unraveling the effect of drought and heat stresses on grain quality of wheat (Triticum aestivum)

Drought stress (DS) and heat stress (HS) have adverse effects on wheat (Triticum aestivum L.) growth, serving as the primary constraints that significantly limit grain yield. Present study was carried out during 2020–21 and 2021–22 at the research farm of ICAR-Indian Agricultural Research Institute, New Delhi to evaluate the effects of drought and heat stress on grain quality parameters of 4 contrasting wheat genotypes. Several physiological and biochemical parameters were analyzed in wheat cv. C306 (thermotolerant), HD3271 (thermosusceptible), H11500 (drought tolerant) and HD3226 (drought susceptible) under DS and HS. Our study found that disintegration of chlorophyll pigments was higher in wheat cv. HD3226 (43%) under combined stress. Grain weight per spike was reduced by 30% in C306 and 47.3% in HD 3271 under combined drought and heat stress treatment. All cultivars showed reduction in starch, amylose, amylopectin, AGPase and Soluble starch synthase activity under DS and HS. Additionally, a significant increase in total soluble protein and free amino acid content were observed in all genotypes under combined stress. Chlorophyll content and grain weight per spike were positively correlated with the starch, amylose, amylopectin, soluble starch synthase and AGPase activity, while negatively related to the total soluble protein and free amino acid content. The tolerant genotypes maintained higher chlorophyll content, grain weight per spike, starch, amylose, amylopectin, soluble starch synthase and AGPase activity could be used for breeding, for the adaptation to drought and heat under climate change.

New records of family Chalcididae (Hymenoptera: Chalcidoidea) on vegetables ecosystem from New Delhi, India

ABSTRACT Chalcidids are important primary parasitoids for controlling several economic insect pests, and some are secondary parasitoids. These specimens were collected by using different traps during the period extending from November 2021 to October 2022, from various vegetable crops grown in different localities at ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi. The larvae and pupa of the pests were brought to the lab and reared for the emergence of parasitoids at 25 ± 0.5°C and relative humidity of 65 ± 5%. Eleven species belonging to four genera in three subfamilies were identified: Brachymeria bengalensis (Cameron, 1897); B. hime (Habu, 1960); B. kassalensis (Kirby, 1886); B. lasus (Walker, 1841); B. minuta (Linnaeus, 1767); B. podagrica (Fabricius, 1787) (Brachymeriinae); Dirhinus anthracia (Walker, 1846); D. auratus Ashmead, 1905 (Dirhininae) and Antrocephalus sepyra (Walker, 1846); Kriechbaumerella kraussi (Narendran, 1989); K. rufimanus (Walker, 1860) (Haltichellinae). Among them six species are newly recorded from New Delhi. On the other hand, B. hime was recorded for the first time as a parasite on Leucinodes orbonalis Guenée (Lepidoptera, Crambidae).

Brown manuring in maize (Zea mays): Effects on weed interference and crop productivity

A field experiment was undertaken during rainy (kharif) season 2017 at ICAR-Indian Agricultural Research Institute, New Delhi to study the effects of brown manuring on weeds and maize (Zea mays L.) productivity. Season-long weed infestation (~unweeded control) resulted in the highest reduction (~41%) in grain yield of maize. Among the brown manuring (BM) treatments, growing of 1:1 mixture of Sesbania bispinosa (12.5 kg seed/ha) + Crotalaria juncea L. (12.5 kg seed/ha) supplemented with 2,4-D 0.5 kg/ha applied at 35 DAS, resulted in the highest reduction in weed density (~93%) and dry matter (~94.4%). This BM, in these regards, was comparable with the atrazine + hand weeding (HW) at 35 days after sowing (DAS) and weed-free control treatments. All BM treatments suppressed noxious weed Cyperus rotundus, which was poorly or not controlled by the recommended tank-mixture of atrazine and pendimethalin. Weed-free control resulted in the highest values of maize plant dry-matter (~210.6 g/plant), cob weight (~155.9 g/cob), and grain yield (~6.0 t/ha). The atrazine + HW, Sesbania + Crotalaria (12.5 + 12.5 kg/ha) mixture applied with 2,4-D 0.5 kg/ha at 25 DAS, Sesbania 25 kg/ha with 2,4-D 0.5 kg/ha at 25 DAS, and pendimethalin 0.75 kg/ha + atrazine 0.75 kg/ha treatments were comparable with weed-free control on maize grain yield.

Impact of diverse tillage and nitrogen management on growth and yield of conservation agriculture-based wheat (Triticum aestivum)

A study was carried out during the winter (rabi) seasons of 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to assess the effects of diverse tillage and nitrogen management scenarios on growth, development, and yield of a conservation agriculture (CA)-based wheat (Triticum aestivum L.) crop grown in sequence with maize (Zea mays L.). Experiment was conducted in split plot design (SPD) comprised of 3 different tillage practices in main plots [Conventional tillage + residue (CT); Zero tillage + residue (ZT); and Permanent beds + residue (PB)] and 5 nitrogen (N) options in sub plots [Control (zero nitrogen); Recommended dose of N-RDN @150 kg N/ha (50 kg N/ha Basal + 2-equal splits at 37 days after sowing (DAS) and 84 DAS); Green Seeker (GS) based application of N @148 kg N/ha (GS); Urea super granules applied as basal @75 kg N/ha + GS based N application (USG); and Slow release fertilizer as 100% basal application @150 kg N/ha (SRF)] with 3-replications. The findings revealed that in both the seasons, both tillage and nitrogen management approaches significantly affected wheat growth, yield characteristics, and overall yield, whereas the time to anthesis and physiological maturity, and test weight remained unaffected. Within the spectrum of tillage practices, leaf area index (LAI) and yield attributes exhibited the trend PB>ZT>CT. PB recorded the highest grain yield (5159 kg/ha), followed by ZT (4916 kg/ha) and the lowest grain yield was observed with CT (4578 kg/ha). The wheat grain yields were 12.7% and 7.4% higher in PB and ZT, respectively, over to CT. Among nitrogen management options, the grain yield exhibited the pattern USG>N150>SRF>GS>N0. This study emphasizes that adopting conservation agriculture (CA) practices, particularly CA-based permanent beds using urea super granules (USG) for nitrogen management can improve wheat growth and yield.

Pre-storage melatonin treatment maintains cell membrane integrity, reduces fruit browning and decay incidence in guava (Psidium guajava)

An experiments were conducted during 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi to study the impact of melatonin (MT) on key characteristics of guava (Psidium guajava L. cv. Barafkhana). Guava fruits were treated with different MT concentrations (200, 400, 600 and 800 μM) and stored at 10±1°C with 85–90% RH. The research revealed that treating with 600 μM MT notably decreased polyphenoloxidase activity by 57%, leading to delayed peel browning and also suppressed polygalacturonase (PG) activity by approximately 45% and pectine methylesterase activity by about 73%, resulting in higher firmness (5.33 N). Following a 20-days period of cold storage, significant reductions in electrolyte leakage, hydrogen peroxide accumulation and lipoxygenase activity were observed, thereby preserving cell membrane integrity. Additionally, MT stimulated the antioxidant defense system, boosted proline content accumulation, and enhanced phenylalanine ammonia-lyase activity. Together, these effects contributed to enhanced resistance against postharvest fungal decay (8.75%). In conclusion, MT at a concentration of 600 μM proves to be an effective postharvest treatment for maintaining texture, reducing fruit decay and extending the shelf-life of guava during cold storage.

Determination of insecticide resistance in cotton whitefly in north India

The whitefly, Bemisia tabaci (Gennadius) considered as most destructive pest, poses a significant threat to various crop species globally has developed resistance due to the indiscriminate use of synthetic chemicals. A study was carried out in 2018 at ICAR-Indian Agricultural Research Institute, New Delhi to determine insecticide resistance, in five Asia II 1 populations of B. tabaci from different cotton (Gossypium hirsutum L.) growing regions of north India. The susceptibility of the populations to different insecticide classes, viz. synthetic pyrethroid (cypermethrin); neonicotinoids (imidacloprid and thiamethoxam); thiourea (diafenthiuron) and diamide (cyantraniliprole) were assessed. Results revealed substantial heterogeneity in the responses of these populations to the insecticides. Sriganganagar and Bathinda populations exhibited moderate resistance to cypermethrin, imidacloprid, and thiamethoxam. Low level of resistance was observed in Bathinda and Sriganganagar populations against diafenthiuron. All populations were highly susceptible to cyantraniliprole. No cross-resistance was observed between cyantraniliprole and other insecticides, suggesting its potential as an alternative for managing insecticide resistance. High levels of detoxification enzymes (esterase, cytochrome P450 monooxygenase, and glutathione-S-transferase) in Sriganganagar and Bathinda populations indicated a positive correlation between insecticide resistance and detoxifying enzymes. These findings offer valuable insight for implementing insecticide rotation strategies to combat B. tabaci resistance in India.

Interactions of Microbial Inoculations with Fertilization Options and Crop Establishment Methods on Modulation of Soil Microbial Properties and Productivity of Rice

A field investigation was undertaken to assess the interactive effects of different crop establishment methods (CEMs) and microbial formulations in field conditions. The two year experiment was carried out in kharif season (June to October) of both 2013–14 and 2014–15 at Research Farm of ICAR-Indian Agricultural Research Institute, New Delhi India. The CEMs studied consist of puddled transplanted rice (PTR), system of rice intensification (SRI) and aerobic rice system (ARS); while microbial formulations consist of Anabaena sp. (CR1)+Providencia sp. (PR3) consortium (MC1) and Anabaena–Pseudomonas biofilm formulation (MC2). The microbial inoculation was applied with 75% recommended dose of nutrients (RDN) (90 kg nitrogen ha-1 and 19.35 kg phosphorus ha-1) and compared with 100% RDN. Soil microbiological properties showed significantly higher values in SRI in the first year; while in the second year, SRI and PTR remained on par and superior to ARS. Among the combinations of nutrient supplements, application of Anabaena–Pseudomonas biofilm formulation (MC2) with 75% RDN was superior in terms of all microbiological attributes studied [acetylene reduction activity (ARA), soil chlorophyll, soil dehydrogenase activity, microbial biomass carbon and alkaline phosphatase activity]. Application of microbial inoculation led to an increase in milled rice yield from 230 to 240 kg ha-1. Among the different combinations of CEMs and inputs investigated the application of 75% RDN+MC2+zinc (Zn) (soil applied 5 kg Zn ha-1 through zinc sulphate heptahydrate) in SRI can be a judicious option to maximize rice yield and soil health.