Heritability and genetic advance in segregating populations of wheat J. Agric. Res., 2013, 51(4) 349 ESTIMATES OF HERITABILITY AND GENETIC ADVANCE FOR GRAIN YIELD AND ITS COMPONENTS IN DIFFERENT SEGREGATING POPULATIONS OF WHEAT Fida Hussain, Muhammad Rafiq, Zafar Iqbal, Javed Iqbal* and Muhammad Aslam Chowdhry** ABSTRACT A study was conducted in the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, Pakistan during the year 2011. The objective was to select some heritable characters of existing wheat genotypes for their inclusion in future breeding programme to improve genetic potential. The results depicted that mean standard deviation, variance, coefficient of heritability and genetic advance for various plant characters like plant height, flag leaf area, tillers per plant, peduncle length, spike length, spikelets per spike, grains per spike and 1000-grain weight as well as grain yield per plant of different wheat cultivars were affected significantly in F2 through various cross combinations. Maximum heritability estimates (92.39%) for 1000-grain weight were recorded in cross MH-97×Iqbal-2000. The heritability estimates were maximum (86.76%) for number of grains per spike in cross MH-97×Uqab-2000. The highest values for genetic advance regarding 1000-grain weight (12.29), number of grains per spike (11.39), spike length (2.70) and flag leaf area (6.69) were recorded in crosses MH-97×Iqbal-2000, MH-97×Uqab-2000, MH- 97×Punjab-96 and MH-97×Punjab-96, respectively. Similarly heritability percentage was higher for 1000-grain weight (92.39), number of grains per spike (86.76), spike length (78.55), flag leaf area (92.52) and grain yield per plant (93.93) recorded in crosses MH-97×Iqbal-2000, MH-97×Uqab-2000, MH- 97×Punjab-96, Iqbal-2000 × Uqab-2000 and MH-97×Punjab-96, respectively. The study clearly indicated that varieties Iqbal-2000 and MH-97 may be used for transmission of desirable genetic characteristics to any high yielding wheat genotype for maximization of grain yield in wheat. KEYWORDS: Triticum aestivum; genotypes; cross breeding; F2 population; heritability; agronomic characters; Pakistan. INTRODUCTION Wheat (Triticum aestivum L.), a major food grain crop of Pakistan, is grown on an area of 8.67 million hectares with annual production of 23.52 million *Oilseeds Research Institute, AARI, Faisalabad, **Department of Plant Breeding & Genetics, University of Agriculture, Faisalabad, Pakistan.