International Journal of Farm Sciences 7(1): 123-126, 2017 Variability studies in Rabi onion (Allium cepa var cepa L) for yield and yield contributing traits ADITIKA, PRIYANKA * , VN DOD ** and MONIKA SHARMA Department of Vegetable Science Dr YS Parmar University of Horticulture and Forestry Nauni, Solan 173230 Himachal Pradesh, India * School of Agricultural Biotechnology, Punjab Agricultural University Ludhiana 141004 Punjab, India ** Department of Horticulture, Dr Panjabrao Deshmukh Krishi Vidyapeeth Akola 444104 Maharashtra, India Email for correspondence: aditikasharma123@gmail.com © Society for Advancement of Human and Nature 2017 Received: 7.8.2015/Accepted: 12.11.2015 ABSTRACT The present study was aimed at investigating the yield and yield contributing traits in onion in order to generate information regarding the extent of genetic variability, heritability and genetic advance. The experiment was laid under randomized block design with three replications at college of Horticulture, Dr Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra during Rabi season 2012-13 to investigate the genetic variability among 21 genotypes. High degree of variation was observed for all the characters studied. The difference between phenotypic (PCV) and genotypic (GCV) coefficient of variation was found to be narrow for most of the traits except bulb weight and neck thickness. The GCV ranged from 4.82 (bulb diameter) to 14.60 per cent (bulb weight) while PCV ranged from 5.72 (number of marketable bulbs per plot) to 17.29 per cent (bulb weight) for the various characters studied. The high estimates of heritability were found for all the characters studied. Expected genetic advance over mean was observed high for the characters viz yield per plot, bulb weight and number of marketable bulb per plot. These characters are therefore governed by additive gene effects. Selection on the basis of these characters will be more useful for the improvement of this crop towards attaining higher yield. Keywords: Variability; heritability; genetic advance; GCV; PCV INTRODUCTION Onion (Allium cepa var cepa L) is a highly cross-pollinated crop, biennial for seed production and annual for bulb production and belongs to family Alliaceae (2n= 16). It is one of the most important vegetables and is grown worldwide under outdoor conditions. It is an indispensible item in every kitchen as vegetable and condiment used to flavour many of the foodstuffs. In addition onion is used as salad and pickle. Nowadays it is used by processing industries for dehydration in the form of onion flakes and powder which are in great demand in the world market. In the world India ranks first in total area (10.51 lakh hectares) and second in production (168.13 lakh tons) for onion after China. The crop accounts for 10.4 per cent share out of total vegetable production in India after tomato (Anon 2012). It has become an important commercial crop because of its area, production and consumption. Yield is a complex character; it depends on a number of agronomic traits and is influenced by many factors which could be genetic or environmental (Uddin et al 1985). To improve the bulb yield, quality and storability through selection the information on the nature and magnitude of variability for yield and yield contributing characters present in the population owing to its genetic and non-genetic causes plays an important role and as such it is a basic prerequisite for any systematic breeding programme. Thus for improving the efficiency of selection in any base population the knowledge of genetic variability present in it is of prime importance to the breeder. The improvement in any crop is proportional to the magnitude of its genetic variability present in the genotypes (Mallor et al 2011).