Characterization and genetic variability analysis in Capsicum annuum L. germplasm

SAARC J. Agri., 11(1): 91-103 (2013) CHARACTERIZATION AND GENETIC VARIABILITY ANALYSIS IN Capsicum annuum L. GERMPLASM S. Datta1 and L. Das Department of Vegetable and Spice Crops, Uttar Banga Krishi Viswavidyalaya Cooch Behar - 736165,West Bengal, India, ABSTRACT Fifty three genotypes of Capsicum annuum L. collected from different parts of the West Bengal, India were characterized for 23 characters namely, stem colour, plant growth habit, branching habit, leaf size, leaf shape, leaf margin, leaf colour, leaf pubescence, pigment at node, flower per axil, corolla colour, anther colour, calyx margin, mature fruit colour at intermediate stage, fruit shape, fruit position, fruit adherence to the calyx, fruit shape at pedicel attachment, blossom end fruit shape, ascorbic acid content of the fruit, capsaicin in red fruit and colour value of the ripe fruit. These genotypes upon cataloguing showed distinct variations with respect to vegetative, inflorescence, fruit and quality characters. A wide range of variation was also observed among the genotypes for several morphological, fruit and quality characters. Among the different characters, white corolla colour showed 100 % frequency and higher frequency was also recorded in single flower per axil (86.79 %), number pigmentation at node (83.02 %) and green fruit colour (69.81%) at intermediate stage. Predominance of single descriptor state was found in more than 50 % genotypes for 15 characters. Based on the D2 value 53 genotypes were grouped into 17 clusters and results indicated that Cluster I and Cluster VII comprised with 29 and 9 genotypes respectively. Rest of clusters consisted of one genotype in each case. Variability studies revealed that there was a wide range of variability for all the characters studied. High heritability along with higher genetic advance (as a %age of mean) was found in capsaicin content in fruit, number of fruits per plant, yield per plant and primary branches per plant. These characters may be considered as reliable selection indices as they are possibly governed by additive gene effect. Key Words: Chilli, characterization, cluster, utilization, variability 1 Corresponding author email: Received: 17.02.2013 92 S. Datta and L. Das INTRODUCTION Chilli (Capsicum annuum L.) is one of the important commercially grown vegetable cum spice crops in the terai zone of West Bengal, India. Chilli is mainly used for its pungency and pleasant flavor. Consumption of small amount of chilli enriches diet and considered as of minerals, vitamins and other food components (Farhad et al., 2010). The genus Capsicum originated in the American tropics. Five species of capsicum were cultivated in different parts of the World (Pickergill, 1997). It is probably introduced by Portuguese into Southern parts of India and cultivation spread out throughout India by the end of 19th century. Due to long history of cultivation, selection and popularity of crops sufficient genetic variability has been generated. Rich variability in morphological traits in hot pepper occurs through out India particularly in south peninsular region, North Eastern foot hills of Himalayas and Gangetic plains (Pradheep and Veeraragavathatham, 2006). Collection and maintenance of the genetic diversity in capsicum are important to avoid genetic erosion. Besides the identification of species, the characterization and evaluation of genotypes maintained in gene banks are of fundamental importance (Sudre et al., 2006). Genetic cataloguing based on standard descriptors helps to easily describe the morphological features of a genotype and thus helps exchange of information about new genotypes. Characterization and evaluation of germplasm are prerequisite for the utilization of the available diversity in the chilli improvement programme. Desirable parental combinations provide the basis for selection in the follow up hybrid breeding process for exploitation of heterosis (Thul et al., 2009). Desirable parental combination can be identified on the basis of cluster analysis. To initiate any breeding work, it is necessary to assess the genetic variability present in the indigenous genotypes for yield and its components. Parameter of genotypic and phenotypic coefficient of variations is useful in detecting the amount of variability present in the germplasm. Heritability and genetic advance helps in determining the influence of environment in expression of the characters and the extent to which improvement is possible after selection. Hence, the genotypes were characterized to assess the variability and identification of promising genotypes which can be used in further breeding programme. MATERIALS AND METHODS The present experiment was carried out at the experimental field of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, India. Geographically the experimental field is situated at 26019'86" N latitude and 89023'53" E longitude, at an elevation of 43 meter above mean sea level with an objective of characterization of collected germplasm of chilli. Fifty three genotypes (Table 1) were evaluated in Randomized Complete Block Design with three replications during the rabi (winter) season of 2006-07 and 2007-08. The climatic condition of terai zone is sub-tropical humid in nature characterized by high rainfall, high relative humidity, moderate temperature, prolonged winter with high residual soil moisture. The experimental soil CHARACTERIZATION AND GENETIC VARIABILITY ANALYSIS 93 was sandy clay loam having pH 5.6. The soil contains 0.91% organic carbon, 133.78 kg ha-1 available nitrogen, 45.72 kg ha-1 available phosphorus and 59.35 kg ha-1 available potash. Healthy and uniform seedlings were transplanted in plots of 3.60 m x 3.0 m size with a spacing of 30 cm x 45 cm during middle of November. Organic manure @ 15 t ha-1was applied as basal. Inorganic fertilizers were applied @100: 50: 50 kg ha-1 N: P2O5 : K2O. Full dose of P2O5, half dose of K2O and one third of nitrogen was given as basal dose at the time of land preparation. After 45 days of transplanting top dressing was done with one third of nitrogen and rest half K2O. Second top dressing was done with rest one third of nitrogen at 75 days after transplanting. Observation on different morphological and yield attributing characters were recorded from ten randomly selected plants from each replications. Plant height was measured by meter scale from the base of the plant to the tip of the top leaf at full bearing stage. Number of primary branches per plant were counted at the time of full bearing stage. Harvesting of chilli was done at the mature green stage when a few number of fruits change colour from green to red considering consumer preference. Harvesting of the mature fruit was done at 15 days interval. The fruit yield of chilli per plant was recorded as average of cumulative yield of all pickings at mature green fruit stage of 10 plants and measured in gram. Total quantity of (...truncated)