International Journal of Agriculture Sciences ISSN: 0975-3710&E-ISSN: 0975-9107, Volume 9, Issue 7, 2017 || Bioinfo Publications || 3843 Research Article GENETIC VARIABILITY FOR YIELD PARAMETERS AND SPOT BLOTCH RESISTANCE IN F2 POPULATION OF DURUM WHEAT (Triticum turgidum var durum) CHETHANA C.K.* AND RUDRANAIK V. Department of Genetics and Plant Breeding, University of Agriculture Sciences, Dharwad, 580 005, Karnataka *Corresponding Author: Email-ckcnanda608@gmail.com Received: November 26, 2016; Revised: January 24, 2017; Accepted: January 25, 2017; Published: February 12, 2017 Citation: Chethana C. K. and Rudranaik V. (2017) Genetic Variability for Yield Parameters and Spot Blotch Resistance in F2 Population of Durum Wheat (Triticum turgidum var durum). International Journal of Agriculture Sciences, ISSN: 0975-3710 & E-ISSN: 0975-9107, Volume 9, Issue 7, pp.-3843-3845. Copyright: Copyright©2017 Chethana C. K. and Rudranaik V. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are cred ited. Academic Editor / Reviewer: Dr. S. A. Desai Introduction Wheat (Triticum aestivum L.) is one of the world’s major cereal crops and staple food of many regions grown under both irrigated and rain-fed conditions. India is the world’s second largest wheat producer, behind China and ahead of USA. It is a remarkable achievement but India continues to face formidable problem of ever increasing population and future wheat demand will be 110 mt to feed 1.5 billion people of India by 2020 [1]. The wheat production and productivity is affected by various fungal, bacterial, viral diseases etc. Among these, Spot blotch caused by fungi Bipolaris sorokiniana, also known as leaf blight is a devastating disease of wheat particularly in warm and humid regions such as NEPZ of India, South East Asia, Latin America, the tarai of Nepal, China and Africa [2]. Due to continuous rise in temperature during the wheat growing season and high humidity coupled with winter rains, spot blotch is getting favourable conditions to develop aggressively and causes damage to wheat crop at larger scale by causing significant yield loss up to 18-50 per cent loss in favourable conditions [3]. The spot blotch disease is gaining much importance in Karnataka state of India because of the occurrence of severe outbreak every year [4] where majority of area under tetraploid wheat cultivation characterized by dry and irrigated weather conditions favours spot blotch disease incidence in our area. Generally, tetraploid wheat is endowed with natural resistance rusts but is highly susceptible to spot blotch. The genetic understanding of spot blotch resistance is limited and not well documented so far. Information on genetic variability, heritability and other genetic parameters of spot blotch resistance with other agro-morphological attributes is pre-requisite for genetic improvement through systemic breeding programmes targeted at improving spot blotch disease resistance. It is generally believed that the level of resistance to spot blotch in high-yielding wheat genotypes is still unsatisfactory and needs to be improved significantly in warmer and humid regions of South Asia. The genetic variability study in segregating population of wheat is also reported by several researchers on yield and its attributing traits. Although, studies on genetics of spot blotch resistance are limited and there is little effort has been made to study the genetic variability for spot blotch resistance in segregating populations of durum wheat. Hence, the present investigation was conducted to study the extent of variability, heritability and possible amount of genetic gain expected to occur during the selection for yield parameters and spot blotch resistance in the F2 population of cross Bijaga yellow x NIDW 295. Genetic studies presented in this study will enable breeder to make predictions about the possible progress that can be achieved by making the selection more effective for genetic improvement of spot blotch disease resistance. Materials and Methods The experimental material for the present study comprised of the F2 population of cross involving spot blotch susceptible (Bijaga yellow) and resistant (NIDW-295) genotypes. The present study was conducted in the experimental area of Agricultural Research Station (ARS), Arabhavi, University of Agricultural Sciences, Dharwad considered as hotspot for spot blotch screening located between 15 o 26’ N latitude and 75 o 07’ E longitude. The F2 seeds of cross Bijaya yellow x NIDW 295 were space planted along with parents Bijaga yellow and NIDW-295. The susceptible checks viz., Kiran, Bijaga Yellow and Amruth were also sown as an infector row to increase and uniform spread of disease in an experimental field. The F2 seeds and checks were sown in a row length of one meter length with the help of a dibble, keeping plant to plant distance of 20cm and row to row distance of 23 cm during Rabi 2014-15. The recommended agronomic practices were followed during the crop growth period. Each individual F2 plants were tagged to International Journal of Agriculture Sciences ISSN: 0975-3710&E-ISSN: 0975-9107, Volume 9, Issue 7, 2017, pp.-3843-3845. Available online at http://www.bioinfopublication.org/jouarchive.php?opt=&jouid=BPJ0000217 Abstract- The experiment was conducted to study the extent of genetic variability for grain yield, its component traits and spot blotch in F2 population of the cross Bijaga yellowx NIDW-295. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for all the characters except for days to fifty percent flowering, spike length and number of spikelet’s per spike. High herita bility and genetic advance were recorded for all the characters except days to fifty percent flowering, awn length, spike length, number of spikelet’s per spike, thousand grain weight and seed yield per p lant. These results suggested that better scope for selecting superior transgressive segregants in this population. For spot blotch incidence, high genetic coefficients of variation along with high heritability and genetic advance were recorded indicating the greater effectiveness of selection and improvement can be expected for spot blotch resistance. Present investigation suggests that selection in F2 population of Bijaga yellowx NIDW-295 will be effective in selecting superior plants for yield parameters and spot blotch resistance in evolving high yielding disease resistant genotype in wheat. Keywords- Area Under Disease Progress Curve (AUDPC), Genetic variability, Wheat, Spot blotch.