Biochemical Basis of Resistance in Brinjal Genotypes Against Shoot and Fruit Borer (Leucinodes Orbonalis, Guenee)

Brinjal (Solanum melongena L.) is an important solanaceous vegetable, which holds a coveted position among different vegetables. Due to its low calorific value (24 kcal 100 g-1) and high potassium content (200 mg 100 g-1), it is suitable for diabetes, hypertensive and obese patients. It holds an important place in China, India, Japan and Europe. It is believed to be native of tropics of the old world [1]. India seems to be original habitat as this plant still exists here in wild state [2]. India is the second largest producer of brinjal crop after China, and in India it is popular vegetable grown [3]. In India it is cultivated in an area of 0.612 million hacters with production of 105.63 million tons and average productivity is 17.2 metric tons per hectare [4]; making it one of the main sources of cash for many farmers [5]. While among the states, area under this crop in Jammu and Kashmir is 850 hacters with the production of 17000 metric tons and productivity of 20 metric tons per hector [6]. Among the biotic stress factors that hamper the production of brinjal, brinjal shoot and fruit borer (BSFB) (Leucinodes orbonalis Guen.) is the most destructive [6,7], and economically harmful insect pests of brinjal [8,9,10]. L. orbonalis is practically monophagous, feeding principally on eggplant [11]. The loss caused by this deleterious pest was reported to be around 54 to 60% [12], 12.59 to 38.65 [13], 60-70% [14], 40.96% [15] and 70 to 80% [16] and has become a major threat for brinjal cultivation. Besides it inflicts sizeable damage up to80 % to vitamin C [10]. Dar et al. [17] conducted an evaluation of combined options for the management of L. orbonalis, but the chemical control of shoot and fruit borer may reduce the pest attack to a greater extent; however, it causes adverse effects on the environment and human health, besides the indiscriminate use makes it expedient to seek for safe and eco-friendly measures [18]. Before initiating any breeding programme, one must have enough information about the ways and means by which the resistance can be exploited. Besides, the various morphological characteristic of the brinjal varieties/ genotypes responsible for resistance to L. orbonalis [19], biochemical defense mechanism would certainly be helpful in the selection of plants as a source of host plant resistance [20,21]. Exploiting host plant resistance through breeding approaches will be highly beneficial to develop superior high yielding genotypes with resistance to the shoot and fruit borer in brinjal. Among the major constraints in economic cultivation of brinjal, pest infestation causes heavy losses. Chemical control is widely used means of managing insect pests in brinjal. Repeated uses of broad spectrum synthetic chemicals also result in Abstract The biochemical basis of host plant resistance for shoot and fruit borer of brinjal was investigated, using two brinjal hybrids and ten cultivated varieties reflected different levels of infestation. The different levels of biochemical constituents namely total phenol and total sugar were observed that exhibited a clear correlation with the pest incidence. A higher level of total phenol activity was observed in resistant Brinjal-85 and Local long. Shalimar Brinjal Hybrid-1 and 2, showed maximum shoot infestation of 9.10, 8.69 and fruit infestation of 23.07 and 22.0 per cent, respectively, recorded higher content of total sugars and lower content of total phenols, respectively. Brinjal Oblong and Brinjal Purple Long exhibited shoot and fruit infestation of 7.50, 18.18 and 7.50, 16.63 per cent recorded the total phenol content of 1.16, 1.31 and 0.78, 0.83 mg/g in shoots and fruits, respectively. Varieties, Brinjal -85 and Local Long were found least attacked by the pest recorded the shoot and fruit damage of 2.34, 4.60 and 3.30,5.15 per cent, respectively with total phenol of 2.30, 2.09 and 1.51,1.45mg/g in shoots and fruits, respectively. The Correlation coefficients of shoot and fruit infestation were strong and negative with total phenols and positive and significant with respect to total sugars.