Field Evaluation of Chilli Genotypes for Resistance to Powdery Mildew Caused By Leveillula taurica

1Department of Plant Pathology, College of Agriculture, University of Agricultural and Horticultural Sciences, Shivamogga 577 225, India. 2Agricultural and Horticultural Resserch Station, University of Agricultural and Horticultural Sciences, Shivamogga Bavikere 577 144, India. 3Horticultural Research and Extension Centre, Devihosur, Haveri, University of Agricultural Sciencees, Dharwad 580 005, India. 4Organic Farming Research Centre, University of Agricultural and Horticultural Sciences, Shivamogga 577 225, India.

Chilli (Capsicum annuum L.) is an important tropical and subtropical spice and vegetable crop.It is an important constituent of food, adding flavour, colour, vitamin C and pungency.It is also used as medicinal herb and ornamental plants in different parts of the world.It is therefore indispensable to the world food and industries.However, the chilli crop is highly susceptible to powdery mildew caused by Leveillula taurica (Lev.)Arn.
The powdery mildew occurs throughout the year under favorable conditions and it is more severe in late sown kharif crop.Powdery mildew has long been known as important disease of plants in all parts of the world.The disease noticed generally on all aerial parts of the plants which cause both qualitative and quantitative loss of dry fruit yield.The reduction in photosynthetic activity and physiological changes are considerable, which lead to potential decrease in yield (24-80%) depending on stage and time at which the disease appears (Mathur et al., 1972;Sharmila et al., 2006).However, disease intensity depends upon the cultivar, growing period and environmental conditions.The disease has world-wide importance, occurring wherever it is grown.The loss caused by chilli powdery mildew is proportional to the disease severity varies remarkably depending on the stage of infection, genotypes and environmental conditions.Many fungicides have been recommended by several workers (Pawar et al., 1985;Sekhar et al., 1988;Mahajan et al.,1991) to control this disease.HAREESH et al.: POWDERY MILDEW CAUSED BY Leveillula taurica However, the use of fungicide is expensive and not eco-friendly.The best approach to control the disease is by using the resistant varieties.Screening for disease resistance is essential to identify resistant variety / source and also cultivation of resistant genotypes is an effective and cheaper method to combat the disease.However, there is need to screen the genotypes against powdery mildew of chilli.Hence, in the study an attempt was made to identify resistant genotypes against chilli powdery mildew.

MATERIALS AND METHODS
For the confirmation of resistance, a field experiment was conducted during kharif and rabi 2015 at College of Agriculture, University of Agricultural and Horticultural Sciences, Shivamogga under natural epiphytotic conditions.Seventy chilli genotype seeds were sown in plastic trays along with Byadagi Kaddi and Bydagi dabbi varieties as susceptible check.Each entry was transplanted in 4.2 m length row and was replicated twice.All the recommended package of practices was applied except protection for control of powdery mildew under natural filed condition.Later, the observations on the intensity of powdery mildew disease was recorded using 0-9 scale given by Mayee and Datar (1986) on five marked plants of each genotype at fruiting stage of the crop.The recorded grade values were converted into Percent Disease Index (PDI) by using following formula proposed by Wheeler (1969).These seventy genotypes were further grouped into six categories based on reaction type as given by Khare and Lakpale (1997).

RESULTS AND DISCUSSION
Field experiments were conducted to identify resistant sources against powdery mildew.Available genotypes were screened under field condition at the department of Plant Pathology, University of Agricultural and Horticultural Sciences, Shivamogga during kharif and rabi 2015.Totally seventy genotypes were screened under natural field condition and the disease severity was recorded using 0-9 scale by randomly selecting five plants.Based on their reaction genotypes were categorised into immune, resistant, moderately resistant, susceptible and highly susceptible, using 0 to 9 scale.
Results of the present study are in agreement with who reported Wankhade and Mohir (2015) differential reactions of different chilli genotypes.These moderately resistant genotypes could be used in further breeding programme for the development of resistant varieties of chilli against powdery mildew.Several workers reported that there is variation in resistance among the genotypes against powdery mildew of chilli (Pawar et al., 1985;Bidari et al., 1985;Anand et al., 1987).Sharmila (2006) reported that, Pant C-1, SIC-10-166 and PMR-21 were resistant to chilli powdery The management of the disease through host plant resistance has been the best and cheapest choice in all the crops.Utilisation of resistant cultivars in farming systems is the most simple, effective and economical method in the management of disease.Besides this, these In the present study, as many as seventy genotypes were screened under field conditions against powdery mildew resistance and none of them were found immune or resistant.However twenty five genotypes were found moderately resistant and forty three found moderately susceptible.

Table 1 .
Screening of chilli genotypes against powdery mildew of chilli caused by Leveillula taurica under field conditions during kharif 2015

Table 2 .
Screening of chilli genotypes against powdery mildew of chilli caused byLeveillula taurica under field conditions during rabi 2015

Table 3 .
Reaction of chilli genotypes against powdery mildew caused by Leveillula taurica