Pure Appl. Biol. http://dx.doi.org/10.19045/bspab.2018.700174 Published by Bolan Society for Pure and Applied Biology Research Article Assessment of genetic variability, heterosis and heritability for morphological parameters in rice Muhammad Ismaeel 1,2* , Syed Mehar Ali Shah 1 , Syed Suliman 1 , Ahmad Raza 1 and Muhammad Anwar 2 1. Department of Plant Breeding and Genetics, The University of Agriculture, Peshawar-Pakistan 2. Agricultural Research Station Swabi, Department of Agriculture Research Khyber Pakhtunkhwa Peshawar- Pakistan *Corresponding author’s email: ismaeelpbg@gmail.com Citation Muhammad Ismaeel, Syed Mehar Ali Shah, Syed Suliman, Ahmad Raza and Muhammad Anwar. Assessment of genetic variability, heterosis and heritability for morphological parameters in rice. Pure and Applied Biology. http://dx.doi.org/10.19045/bspab.2018.700174 Received: 09/08/2018 Revised: 08/10/2018 Accepted: 20/10/2018 Online First: 25/10/2018 Abstract This study was performed to estimate genetic variability and heterosis in rice genotypes using fourteen parents and their ten F1 hybrids in a randomized complete block design (RCBD) using two replications at The University of Agriculture, Peshawar-Pakistan. Significant differences among the parents and F1 hybrids were observed for all the studied traits. The parental genotypes Sadahayat, Dokri-Bas and Khushboo-95 exhibited maximum mean values for panicle length (36.6 cm), spikelets panicle -1 (264.0) and grains panicle - 1 (202.3), respectively while IR-8 displayed maximum mean values for 1000-grain weight (28.7 g) and grain yield plant -1 (50.8 g). Among F1 cross combinations, DR-83/Sugdesi displayed the maximum spikelets panicle -1 (249.1), grains panicle -1 (201.7) and grain yield plant -1 (41.8 g) while Pakhal/Kashmir-Bas displayed maximum 1000-grain weight (27.5 g). Among the F1 hybrids, Pakhal/Kashmir-Bas manifested maximum significantly positive mid and high parent heterosis for spikelets panicle -1 (40.8 and 25.4 %), 1000-grain weight (22.7 and 14.9 %) while DR-83/Sugdesi exhibited significant positive mid and high parent heterosis for grains panicle -1 (66.7 and 18.9 %) and grain yield plant -1 (73.8 and 50.4 %). High phenotypic and genotypic coefficient of variation (PCV and GCV) values were observed for grains panicle - 1 and grain yield plant -1 . High heritability values were recorded for all the studied traits. The genetic potential of Sadahayat, Khushboo-95, IR-8 and Dokri-Bas for yield and yield associated traits can be exploited in future rice breeding program. The F1 hybrids viz. DR-83/Sugdesi and Pakhal/Kashmir-Bas on account of their better performance for yield and yield associated traits could be further studied in segregating generations for development of new rice cultivars. Keywords: Genotype; GCV; Heritability; Phenotype; PCV; Rice Introduction Rice (Oryza sativa L.) is the main staple food for about half of the human population and occupies the pivotal place in global food and livelihood security systems. It provides 55% of the protein and 75% of the calories in the average daily diet of the people. It is globally planted on 164.1 million hectares with total production of 722.5 million tones. China (202.7 million tons), India (155.7 million tons), Indonesia (65.7 million tons), Bangladesh (50.6 million tons) and Vietnam (42.3 million tons) are the chief producing countries of rice [1]. The world’s population