Peeru Saheb et al. Available Ind. J. Pure online App. Biosci.at www.ijpab.com (2020) 8(1), 74 -85 ISSN: 2582 – 2845 DOI: http://dx.doi.org/10.18782/2582-2845.7912 ISSN: 2582 – 2845 Ind. J. Pure App. Biosci. (2020) 8(1), 74-85 Research Article Peer-Reviewed, Refereed, Open Access Journal Mechanisms of Resistance in Groundnut Genotypes against Groundnut Leaf Miner, Aproaerema modicella (Deventer) Y. Peeru Saheb1*, K. V. Hari Prasad 1, K. Swarajya Lakshmi2 and J. Sailaja Rani3 1*&2Department of Entomology, S. V. Agricultural College, Tirupati- 517 502 3Department of Entomology, 4Department of Plant Pathology, Agricultural College, Mahanandi - 518 502, Acharya N. G. Ranga Agricultural University, India *Corresponding Author E-mail: [email protected] Received: 15.11.2019 | Revised: 23.12.2019 | Accepted: 31.12.2019 ABSTRACT Leaf miner, Aproaerema modicella (Deventer) and leaf bud borer, Anarsia ephippias (Meyrick) are the two insect pests belonging to the family Gelechiidae causing considerable yield losses. An experiment was conducted to study the mechanisms of resistance on different groundnut genotypes towards groundnut leafminer. Groundnut genotypes tested for their reaction to leaf miner revealed that the proteins had shown significant negative correlation with incubation period, fourth instar duration, fifth instar duration, and total larval duration and total life span, phenols showed a significant positive correlation with third instar duration, fourth instar duration, total larval duration and total life span and reducing sugars showed positive correlation with incubation period and total life span. Keywords: Groundnut leaf miner, Proteins, Phenols, Reducing sugars. INTRODUCTION the genotypes developed by ICRISAT were Host plant resistance is an important being used as a parent material by many NARI management tool within the framework IPM and SAUs for developing location specific that requires no additional cost inputs to the groundnut varieties. ICRISAT (1986), farmers. Host plant resistance being a seed ICRISAT (1991). Though much work has borne technology gives a promising way of been done on screening of groundnut managing the insect pest which is cost genotypes for plant resistance to gelechiidae effective to the farmers and environmental insect pests, not enough focus has been given friendly. A significant contribution in on studying the mechanism of plant resistance development of resistant or tolerant groundnut involved in groundnut genotypes to genotypes for A. modicella has been made by gelechiidae insect pests’ complex. ICRISAT for the past several years. Some of Cite this article: Peeru Saheb, Y., Hari Prasad, K.V., Lakshmi, K.S., & Sailaja Rani, J. (2020). Mechanisms of Resistance in Groundnut Genotypes against Groundnut Leaf Miner, Aproaerema modicella (Deventer), Ind. J. Pure App. Biosci. 8(1), 74-85. doi: http://dx.doi.org/10.18782/ 2582-2845.7912 Copyright © Jan.-Feb., 2020; IJPAB 74 Peeru Saheb et al. Ind. J. Pure App. Biosci. (2020) 8(1), 74-85 ISSN: 2582 – 2845 MATERIALS AND METHODS Oviposition preference studies (free choice) Studies on biology, larval and ovipositional Seven selected genotypes (two highly preference of groundnut leaf miner on resistant, one moderately resistant and four selected genotypes (under laboratory susceptible genotypes) were tested for adult conditions) ovipositional preference. Fresh tender twigs of Biology of groundnut leaf miner was studied test genotypes with their stalks dipped in water on selected groundnut genotypes (that were in conical flask were placed in Perspex cages grouped into resistant, moderately resistant of 30×30×30 cm. Five pairs of freshly and susceptible based on the per cent emerged moths were released into the infestation data from the field) under oviposition cage for oviposition. Number of laboratory conditions at the Insectray, Dept. of eggs laid on leaves and stems of selected Entomology, S.V. Agricultural College, genotypes were counted and fresh twigs were Tirupati during rabi 2015 at 24±1o C and replaced daily until the moths were dead. The humidity of 85±2 %. experiment was repeated thrice. The data was Stock culture: subjected to statistical analysis using SPSS Groundnut leaf miner larvae were collected software (SPSS, 2014). from the field and were placed in Petri plates Studies on biophysical characters of nine centimeter diameter, and were Trichome density provided daily with tender leaflets. After the The trichome density was measured on the larvae have reached pupal stage, the pupae adaxial surfaces of the leaves of selected were separated and placed in the Perspex groundnut genotypes. The leaf was cut into cages of 30×30×30 cm. The emerging adults 0.25 cm2 area and the number of trichomes were provided with fresh twigs of groundnut present were counted under binocular for oviposition. The twigs along with eggs microscope (MAGNUS Stereoscopic were collected and placed in Petri plates till binocular microscope Model MS 24 Alpha the eggs hatch. Neonates from this nucleus with objective (2x & 4x) and eyepiece 10x culture were used for further experiments. The (F.N.22) having with in-built Light Stand emerging neonate larvae were provided with (Incident: 6V15W Lamp/ Transmitted: 5W fresh twigs of selected genotypes and Fluorescence Lamp and expressed as number observations were recorded on a number of of trichomes per 0.25 cm2. The data was larval instars, duration of larval instars, pupal recorded on six numbers of leaves in selected duration, adult longevity, duration of total life genotypes. cycle, pre-oviposition, oviposition and post- Leaf area oviposition periods. From each genotype three leaves were taken Larval preference studies (free choice) and leaf area with leaf area meter was taken Tender leaflets of selected seven groundnut and expressed as cm2. genotypes (two highly resistant, one Leaf thickness moderately resistant and four susceptible From each genotype three leaves were taken genotypes) were placed together and radially and were dried in hot air oven for three days arranged along the periphery of a Petri plate of and weights of them were taken and expressed nine centimeter diameter. Fifteen third instar as cm2/g. Roderick13 mentioned Specific Leaf larvae of groundnut leaf miner were released Area (SLA) is a mean area of leaf displayed at the centre of the Petri plate and the number per unit of leaf weight (In a sense a measure of of larvae found inside the tender leaflets of leaf density or relative thickness). each genotype after 24 hours of release, were Measurement of chlorophyll content of counted and the data was used to indicate leaves: index of larval preference. The experiment The chlorophyll content of leaves was was repeated thrice and per cent larval measured using the Chlorophyll meter SPAD preference was calculated. 502. Third opened leaves of each groundnut Copyright © Jan.-Feb., 2020; IJPAB 75 Peeru Saheb et al. Ind. J. Pure App. Biosci. (2020) 8(1), 74-85 ISSN: 2582 – 2845 genotype were used for estimating the The data was subjected to statistical analysis chlorophyll content. Six replications were using SPSS software (SPSS, 2014) used. Studies on biochemical constituents: RESULTS AND DISCUSSION The biochemical constituents such as protein Based on results from the field experiment, the Lowry8 total phenol Malick and Singh9 and genotypes were grouped into resistant, total reducing sugars Somogyi (1952) of the moderately resistant and susceptible for their leaves of selected genotypes were estimated reaction to leaf miner. These genotypes were using the standard protocols. For each again tested in the laboratory for confirming genotype three replications were taken. their resistance rankings. Statistical analysis Table 1: Cumulative data on infestation of groundnut leaf miner based on first and second plantin Character Highly resistant Moderately resistant Highly susceptible Per cent leaf miner ASK-2013-2, ASK- K-1501, K-1559, Dharani, K-4, K- infestation (no. of leaf 2013-5, TCGS-894, ASK-2013-1, TCGS- 1563, Narayani and mines) per plant TCGS-1186 and 1146 and TCGS-1342 TCGS-341 (First and second TCGS-1097 planting) Studies on Biology of groundnut leaf miner observed when larvae were reared on TCGS- on selected genotypes: 1097 (3.50 ± 0.54) followed by ASK-2013-1 Shortest incubation period of eggs of A. (3.00 ± 0.89). The shortest fourth instar larval modicella (2.33 ± 0.51) was observed on duration of A. modicella was observed, when Dharani followed by Narayani (2.50 ± 0.54) larvae were reared on Narayani (2.50 ± 0.54) (on par with each other). Longest incubation followed by Dharani (2.83 ± 0.40) (on par with period was observed on ASK-2013-1 and K- each other). The longest fourth instar larval 1563 (3.33 ± 0.51) (on par with each other). duration of A. modicella (4.17 ± 1.16) was The incubation period on other groundnut observed on TCGS-1097 followed by ASK- genotypes were in between these two groups. 2013-1 (3.83 ± 0.75) (on par with each other). The durations of first instar and second instar Fourth instar larval duration on remaining larvae of leaf miner A. modicella were not genotypes were in between these two groups. significantly different when reared on selected The shortest fifth instar larval duration of A. genotypes of groundnut. The shortest third modicella was observed, when larvae were instar larval duration of A. modicella (2.33 ± reared on Narayani (2.67 ± 0.51), followed by 0.51) was observed, when larvae of was reared Dharani and K-1563 (3.00 ± 0.63) (on par with on Dharani, K-1563, followed by K-4 (2.50 ± each other). The longest fifth instar larval 0.54), Narayani and TCGS – 894 (2.67 ± 0.51) duration of A. modicella was observed, when (on par with each other). The longest third larvae were reared on ASK-2013-1 (3.67 ± instar larval duration of A. modicella was 0.81) followed by TCGS 1097, TCGS 894 and observed when larvae were reared on TCGS- K-4 (3.50 ± 0.54) (on par with each other).