Genetic analysis in green gram (Vigna radiata (L.) Wilczek)

Abstract

The study entitled “Genetic analysis in green gram (Vigna radiata (L.) Wilczek)” was conducted at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2018-2020. The study was carried out to assess the existing genetic variability and performance of different genotypes of green gram under open and partially shaded conditions and to identify the best genotype in terms of yield and protein content. Two simultaneous field experiments under open and partially shaded conditions were conducted during 2019-2020. Intercropping is done in coconut garden with an average of 57 per cent shade in order to provide required partial shade. Thirty green gram genotypes procured from NBPGR, New Delhi and nearby State Agricultural Universities were assessed in a randomized block design, replicated thrice. The seeds were dibbled on raised beds in the field at a spacing of 30 cm x 15cm and each genotype was considered as individual treatment. Very few pests and pathogen attack was observed in the field for which control measures were taken up. The thirty genotypes were evaluated for eighteen characters and their mean values were recorded. Analysis of variance, estimation of genetic parameters such as genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability and genetic advance, correlation analysis and path coefficient analysis were carried out. A pooled analysis was also conducted to compare the performance of genotypes for each character in open and partially shaded conditions. Variability analysis revealed the existence of a considerable amount of variability for yield per plant, plant height, number of pods per plant, harvest index and days to maturity under both open and partially shaded conditions, whereas number of secondary branches and chlorophyll content showed narrow range of variation. Emergence percentage was more under partial shade than open condition. Likewise, plant height, specific leaf area and chlorophyll content exhibited an increase under partial shade compared to those under open condition. Estimates of phenotypic coefficient of variation were higher than corresponding genotypic coefficient of variation for all the characters studied. The highest GCV was recorded for yield per plant under both open and partially shaded conditions, respectively followed by number of primary branches per plant and number of pods per plant. High heritability was recorded for most of the characters studied under both growing conditions. High heritability coupled with high genetic advance as per cent of mean was recorded for yield per plant, number of primary branches, number of pods per plant and 100 seed weight under both conditions, whereas under open condition, two more characters such as number of secondary branches per plant and chlorophyll content also showed high heritability with high genetic gain. The character yield per plant was found to be highly significant and positively correlated with harvest index, number of pods per plant, number of secondary branches per plant and pod length both at genotypic and phenotypic levels under open and partially shaded conditions indicating their importance in yield enhancement. Path analysis was carried out using yield per plant as the dependent variable and other characters as independent variables. The study revealed that, harvest index and number of pods per plant had high positive direct effect on seed yield per plant, followed by days to maturity, pod length and number of primary branches per plant. High indirect effect was recorded for number of pods per plant on yield per plant through harvest index. The results of the present study revealed the presence of ample variability among the thirty green gram genotypes under open and partially shaded conditions. The genotype BGS 9 was found to be superior in yield performance under open condition which was on par with the genotype IC 282124. Under partially shaded condition, the genotype K7 recorded the highest yield and was on par with the genotypes BGS 9 and IC 282124. When protein content was assessed, maximum value was recorded for genotype K10 under open condition and genotype K13 under partially shaded condition. The superior genotypes identified in the present study can be utilized as such after further trials or as parents for crop improvement programmes to develop superior varieties.