GENOTYPE-ENVIRONMENT INTERACTION ON STABILITY OF GRAIN YIELD AND PHYSIO-BIOCHEMICAL TRAITS IN BREAD WHEAT (TRITICUM AESTIVUM L.)

To assess the stability of genotypes for grain yield and physio-biochemical traits associated with terminal heat tolerance pooled analysis of 8 genotypes of wheat of diverse origin, their 28 F1 progeny and 2 checks were carried out in 4 different environments i.e. early sown (E1), normal sown (E2), late sown (E3) and very late sown (E4) conditions. The pooled analysis of variance due to environment (for proline and chlorophyll content), genotypes and genotype × environment interaction was significant for all the traits under consideration. This indicated the distinct and differential effect of the different sowing conditions (environment) and differential response of all the genotypes chosen for the study. The five stable wheat hybrids viz., HI 1544 × HD 2987, Raj 4037 × HD 2987, PBW 175 × HD 2987, HD 2932 × Raj 4079 and PBW 175 × Lok 1 showed higher mean values, favourable regression coefficient and deviation from regression coefficient for grain yield and other associated characters, thus emerged as stable genotypes as per criteria of stability analysis. Similarly, some genotypes showed specific adaptations for poor or heat stress environment. Introduction Wheat (Triticuma estivum L.) (2n = 6x = 42), a self-pollinated crop of the Poaceae is the world’s largest cereal crop (Sharma et al. 2019). It is the staple food for over 27 per cent of global population in more than 40 countries. It is popularly known as ‘Stuff of life or King of the cereals’ because of the acreage occupied, high productivity and the prominent position it holds in the international food grain trade. The main wheat growing countries include Australia, Canada, China, France, India, Russia, Turkey, Ukrain and USA. It is the second most important grain crop after rice in India and has tremendous yield potential. In India, area and production of wheat during year 2014 2015 was recorded 30.97 million ha and 88.94 million tonnes with an average productivity of 2872 kg/ha (DAC&FW 2015). Wheat grain contains starch (60 68%), protein (6 21%), fat (1.5 2.0%), cellulose (2.0 2.5%), minerals (1.8%) and vitamins. The uniqueness of wheat in contrast to other cereals is that wheat contains gluten protein which enables leavened dough to rise by forming minute gas cells and this property enables bakers to produce light breads. Wheat is a thermo-sensitive crop mostly grown in temperate environment, but on account of its genetic diversity, it has extended its frontiers and has become adapted to nearly all the climates of the world. In subtropical regions it is cultivated in winter season but it exposed to high temperature (> 35oC) stress at the end of the season i.e. during grain filling. Rise in temperature at the time of grain filling is referred to as terminal heat stress which reduces yield and decreases quality of wheat in many wheat environments around the world (Reynolds et al. 2001, Hays et al. 2007). The phenotypic performance of a genotype is not necessarily the same under diverse agroecological conditions (Ali et al. 2003). *Author for correspondence: <107vijaysharma@gmail.com>. Department of Plant Breeding and Genetics, Maharana Pratap University of Agriculture and Technology, Udaipur-313001, India.