An experiment was conducted at the Research farm of Regional Agricultural Research Station, BARI, Hathazari, Chittagong during Rabi season (December to April), 2009-2010 for estimation of genetic variability, genetic parameters and correlation coefficient among different yield components in a randomized block design with three replications. Thirty four groundnut genotypes were tested in the experiment. Highly significant variations were observed among the genotypes for all the characters studied. The highest genetic coefficient of variation was observed for karnel yield per hectare, followed by karnel yield per plant, branches per plant, immature and mature nuts per plant, 100 kernal weight and plant height. The highest heritability was observed in karnel yield per pant (95.08%), followed by karnel yield per hectare (94.38%), 100 kernal weight (87.01%), immature and mature nuts per plant (82.24%, 80.32%), branches per plant (79.54%) and 100 nut weight (78.98%), while high values of genetic advance were obtained in all the characters except days to maturity and days to 50% flowering. The seed yield per plant showed the highly significant and positive association with nut size, number of nuts per plant, karnel size and days to 50% flowering. The number of mature nuts per plant had high positive direct effect on seed yield per hectare followed by nut size, shelling percentage, days to 50% flowering and days to maturity. Therefore, branches per plant, plant height, nuts per plant, nut size, karnel size, days to 50% flowering, shelling percentage and days to maturity were identified to be the important characters which could be used in selection for yield. Keywords: Genetic variability; heritability; genetic advance; groundnut DOI: http://dx.doi.org/10.3329/agric.v9i1-2.9476 The Agriculturists 2011; 9(1&2): 29-36

Twelve exotic cultivars of cucumber (Cucumis sativus) were grown to assess the presence of variability for desired traits and amount of variation for different parameters. Genetic parameters, correlations, partial correlation and regressions were estimated for all the traits. Analysis of variance revealed significant differences among entries for all the characters. The estimates of genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were high for yield per plant, fruits per plant, fruit weight and fruit length. Broad sense heritability estimates for various traits ranged from 42.26 to 89.55%. Fruit yield per plant showed high significant positive correlation with fruits per plant, fruit weight, flesh thickness, fruit diameter and leaves per plant. Partial correlation was significant for fruits per plant and indicated these traits contributed over 70% to total fruit yield. By variability, correlation and regression analysis it was concluded that more fruits per plant and more fruit weight are major yield contributing factors in selecting high yielding cucumber cultivars.

Genetic variability, correlation and path coefficient analysis of yield and yield contributing traits in twenty one varieties of radish were studied. Root length, leaf length and root yield showed high genotypic coefficient of variation and heritability with high genetic advance in percentage of mean. The highest genetic advance was observed in root yield. Root yield had significant and positive correlation with days to harvest, root length and root diameter, and showed only positive correlation with plant height and leaf width. Path coefficient analysis revealed that plant height had the maximum positive direct effect on root yield followed by root diameter, leaf width and days to harvest.

A study on genetic diversity was conducted with 54 Chili (Capsicum annuum L.) genotypes through Mohalanobis's D 2 and principal component analysis for twelve quantitative characters viz. plant height, number of secondary branch/plant, canopy breadth , days to first flowering, days to 50% flowering, fruits/plant, 5 fruits weight, fruit length, fruit diameter, seeds/fruit, 1000 seed weight and yield/plant were taken into consideration. Cluster analysis was used for grouping of 54 chili genotypes and the genotypes were fallen into seven clusters. Cluster II had maximum (13) and cluster III had the minimum number (1) of genotypes. The highest inter-cluster distance was observed between cluster I and III and the lowest between cluster II and VII. The characters yield/plant, canopy breadth, secondary branches/plant, plant height and seeds/fruit contributed most for divergence in the studied genotypes. Considering group distance, mean performance and variability the inter genotypic crosses between cluster I and cluster III, cluster III and cluster VI, cluster II and cluster III and cluster III and cluster VII may be suggested to use for future hybridization program.

Twenty parental genotypes of tomato were planted and observed of yield and yield attributing traits to measure genetic variability, character association and path coefficient analysis. Parent TM 371 ranked first with respect to yield (4.73 kg fruit yield per plant) followed by TM 390. In terms of average fruit weight TM 390 also was better performer. Analysis of variance for each trait showed significant differences among the genotypes. High genotypic and phenotypic coefficients of variation were recorded for fruits per plant, locule number per fruit and fruit yield per plant. Heritability was observed high for flowers per cluster, fruits per plant, fruit weight and fruit length. fruit per plant (52.30), followed by fruit weight (46.32).High heritability associated with high genetic advance was observed for fruits per plant (52.30) and fruit weight (46.32) and flower per cluster (33.50). Selection for such traits might be effective for the fruit yield improvement of tomato. Significant positive genotypic and phenotypic correlation was observed of fruits per plant, fruit weight, fruit diameter and locule number per fruit with fruit yield per plant indicated that selection strategies must be focus on these traits. Fruit diameter showed the highest positive direct effect (3.25) on fruit yield per plant followed by fruits per plant (1.54). Direct selection may be executed considering these traits as the main selection criteria to reduce indirect effect of the other characters during the development of high yielding tomato variety.

A field experiment was conducted comprising eighteen advanced lines of mustard in a randomized block design with three replication at Regional Agricultural Research Station, BARI, Hathazari, Chittagong during Rabi season (December 2009 to April 2010) for estimation of divergence among advanced lines of mustard. The genotypes were grouped into four clusters. Cluster I contained the highest number of genotypes (6) and the cluster III contained the lowest (3). The inter-cluster distances in all cases were larger than the intracluster distance which indicated that wider diversity was present among the genotypes of distant grouped. The highest intra cluster distance was observed in cluster II and the lowest in I. The highest inter cluster distance was observed between the cluster III and II followed by III and I and the lowest between cluster IV and III. Days to 50% flowering (81.94%), days to maturity (8.24%), plant height (5.82%), branches per plant (1.91%) and siliquae per plant (1.17%) contributed maximum towards the total divergence which suggested that these characters were highly responsible for genetic divergence in the present materials. But the highest cluster means for primary branches per plant and maximum seeds per siliquae with minimum seed yield per plant were obtained from the cluster II. The genotypes from cluster I had dwarf plant along with earliness in days to 50% flowering, days to maturity and maximum number of primary branches per plant. Therefore, the genotypes from cluster I and III could be utilized in the hybridization programme for getting desirable transgressive segregants and high heterotic response due to getting maximum yield along with short duration.

Twenty genotypes of tomato were assessed for their genetic divergence using Mahalanobis D 2 statistics. Based on D2 values of eleven yield related characters, genotypes were grouped in to five clusters. Maximum genotypes were grouped in cluster II (6) followed by cluster IV (5) the remaining 9 genotypes were distributed in three clusters, four in cluster III, three in cluster I and two genotypes in cluster V. Clustering pattern indicated that there was no association between geographical distribution of genotypes and genetic divergence. The mean intra and inter cluster distance (D) revealed that cluster I had highest intra cluster distance (0.979), while the inter cluster distance was maximum between cluster III and I (13.546) followed by III and V (11.218). The characters like plant height, fruit weight, fruits per plant contributed maximum to genetic divergence.

Phenotypic divergence was quantified by multivariate analysis among the 70 genotypes collected from different agro-climatic regions and was available in the gene bank of Energypac Agro Ltd., Gazipur, Bangladesh. Based on the phenotypic value of 11 characters, 70 genotypes were grouped into five clusters. The genotypes of tomato were distributed in different clusters suggesting that no association was found between geographical and phenotypic diversity. Cluster II consisted of maximum twenty three genotypes (32.86%) followed by cluster III of sixteen genotypes (22.85%). Cluster IV and Cluster V comprised of thirteen (18.57%) and ten genotypes (14.29%), respectively. Cluster I consisted of eight genotypes (11.43%). The highest intra-cluster divergence (0.061) for cluster I was invariably smaller than the lowest inter-cluster divergence between cluster IV and cluster V (2.83), thus authenticating the clustering pattern formed in this study. The intra-cluster divergence ranged from 0.007 to 0.061, whereas the inter-cluster divergence ranged from 2.83 to 8.34 between clusters IV and V and clusters III and V, respectively. The four characters that played the greatest role in differentiation were locule number per fruit, pericarp thickness, fruits per plant and days to 50% flowering. Twenty homozygous parents (15 female and five male) were selected from five clusters using range test among genotypes within cluster. From cluster I parents TM409, TM386 and TM528 and from cluster III parents TM403 and TM349 were selected as male. Parents TM356, TM361, TM368, TM371, TM377, TM384, TM422 and TM423 from cluster II; parents TM388, TM390, TM392 and TM410 from cluster IV and parents TM382, TM419 and TM360 from cluster V were selected as female. SAARC J. Agri., 17(2): 185-195 (2019)