~ 2003 ~ International Journal of Chemical Studies 2019; 7(1): 2003-2006 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2019; 7(1): 2003-2006 © 2019 IJCS Received: 01-11-2018 Accepted: 05-12-2018 Prakash G Department of Biotechnology and Crop Improvement, College of Horticulture, UHS Campus, GKVK post, Bengaluru, Karnataka, India Muksh L Chavan Professor and Head, Department of Biotechnology and Crop Improvement, College of Horticulture, Yelwala, Mysuru, Karnataka, India Ramachandra RK Department of Biotechnology and Crop Improvement, College of Horticulture, UHS Campus, GKVK post, Bengaluru, Karnataka, India Maheshkumar B Doddamani Department of Biotechnology and Crop Improvement, College of Horticulture, UHS Campus, GKVK post, Bengaluru, Karnataka, India Anurag S Gowda Department of Biotechnology and Crop Improvement, College of Horticulture, UHS Campus, GKVK post, Bengaluru, Karnataka, India Correspondence Prakash G Department of Biotechnology and Crop Improvement, College of Horticulture, UHS Campus, GKVK post, Bengaluru, Karnataka, India Screening of tomato genotypes for various morphological and yield parameters under controlled deficit irrigations in northern dry zone of Karnataka Prakash G, Muksh L Chavan, Ramachandra RK, Anurag S Gowda and Maheshkumar B Doddamani Abstract Tomato is one of the most popular and widely grown vegetable crop in the world which ranks next to potato. Although tomato is generally grown under irrigated conditions, its cultivation as a rainfed crop has gained importance particularly in semi-arid regions. It has been established that, stress due to water deficit is a very important limiting factor at the initial phase of plant growth and establishment. Studies related to identification of suitable drought tolerant genotypes of tomato with the physiological understanding are limiting, hence, the present investigation was carried out to screen the tomato genotypes for various morphological parameters viz plant height, plant spread north to south and plant spread east to west, days to first flowering, days to 50% flowering, stem girth and yield potential by adopting simple field screenings with regulated levels of irrigation at two different stages of plant growth to know the effect of drought on tomato genotypes. The experiment was laid out in a factorial randomized block design with thirteen genotypes and two replications. Water stress was imposed two weeks after the transplanting to all the genotypes in two stress conditions viz the IW/CPE ratio of 0.40, 1.20 and farmers practice as control. Furrow irrigation was given when the pan evaporation reading reached 41.66 mm (1.20 IW/CPE ratio) and 125 mm (0.40 IW/CPE ratio) using V notch. Under moisture stress condition of 1.2 IW/CPE ratio the genotype, Arka Meghali had significantly higher yield (1.65 kg plant -1 and 49.95 t ha -1 ) and under the sever moisture stress of 0.4 IW/CPE ratio higher yield was noticed in the genotype EC 631962 (1.37 kg plant -1 and 39.48 t ha -1 ) and least yield was noticed in the susceptible genotype EC 608269 (0.66 kg plant -1 ) at 0.4 IW/CPE ratio. Irrespective of the irrigation levels, EC 638519 had maximum number of fruits per plant. Genotypes EC 608362, EC 610652, EC 634394, EC 638519, EC 610661, EC 631962, Kashi Anupam and Pusa 120 performed better under drought conditions. Keywords: tomato stress, deficit irrigation, morphological traits, yield, IW/CPE ratio Introduction Although tomato is generally grown under irrigated conditions, its cultivation as a rainfed crop has gained importance particularly in semi-arid regions. Drought affects both elongation and expansion growth, water deficit in the early stages of tomato showed a greater effect on reduction in plant height. There are several physiological, genetical and biochemical traits contributing to the drought tolerance in various agricultural/ horticultural crops. Plants which tolerate moderate stress at low tissue water potential may do so by virtue of several dehydration tolerance mechanisms like maintenance of membrane integrity, osmotic adjustment and chloroplast integrity. The present investigation was carried out to screen the tomato genotypes for various morphological parameters and yield potential by adopting simple field technique of two levels of irrigation water to cumulative pan evaporation ratio (IW/CPE ratio) along with control. Materials and Methods The experiment was conducted at the Biotechnology and Crop Improvement unit of Kittur Rani Channamma College of Horticulture, Arabhavi, is situated in northern dry zone of Karnataka at 16°15’ north latitude, 75°45’ east longitude and at an altitude of 612.03 meters above mean sea level. The experiments were laid out in a factorial randomized block design