The study was conducted to investigate genetic variability among 113 aromatic and fine local rice genotypes of which five were exotic in origin. The test genotypes were evaluated for 19 growth traits, yield components, and yield. All the quantitative traits varied significantly among the test genotypes. High heritability along with high genetic advance was observed for flag leaf area, secondary branches per panicle, filled grains per panicle, grain length, grain breadth, grain length breadth ratio, and 1000 grain weight. Such findings suggested preponderance of additive gene action in gene expression for these characters. Grain yield was significantly and positively correlated with days to flowering, days to maturity, panicle length, filled grains per panicle, and 1000 grain weight. According to D 2 cluster analysis, 113 test genotypes formed 10 clusters. Selection of parents from the clusters V and X followed by hybridization would possibly result in desirable heterosis for the development of heterotic rice hybrids. Finally, molecular characterizations of the studied germplasm are required for high resolution QTL mapping and validating the presence of candidate genes responsible for valuable characters.

A total of thirty microsatellite molecular markers were used across 21 rice genotypes for their characterization and discrimination. The number of alleles per locus ranged from three (RM165, RM219, RM248, RM463, RM470 and RM517) to nine (RM223), with an average of 4.53 alleles across the 30 loci obtained in the study. The polymorphism information content (PIC) values ranged from 0.30 (RM219) to 0.84 (RM223) in all 30 loci. RM223 was found the best marker for the identification of 21 genotypes as revealed by PIC values. The frequency of the most common allele at each locus ranged from 24% (RM223 and RM334) to 81% (RM219). A two dimensional principal coordinate analysis (PCoA) with 21 genotypes showed that the genotypes Supper Basmoti,

ABSTRACT:The F2 segregating generations of exotic tomato hybrids were studied to measure variability, character association and path coefficient analysis. Analysis of variance for each trait showed significant differences among the genotypes. Very little differences were observed between phenotypic coefficients of variation (PCV) and genotypic coefficients of variation (GCV) for the traits days to first flowering (pcv=9.21, gcv=7.82), fruit length (pcv=17.14, gcv=14.84) and fruit diameter (pcv=17.10, gcv=14.92). High heritability (>50%) was observed for all the yield contributing characters except flowers per cluster (47.83%). High heritability associated with high genetic advance was observed for fruit clusters per plant (105.11), fruits per plant (103.43), branches per plant (34.49), fruits per cluster (47.43), individual fruit weight (77.73) and fruit yield per plant (108.25). Selection for such traits might be effective for the fruit yield improvement of tomato. Significant positive genotypic and phenotypic correlation was observed between plant height at first flowering, flowers per plant, fruits per cluster, fruit clusters per plant, fruits per plant with fruit yield per plant. Fruits per plant showed the highest positive direct effect (1.096) on fruit yield per plant followed by individual fruits per plant (0.674). 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. @ JASEM

While the pleasant scent of aromatic rice is making it more popular, with demand for aromatic rice expected to rise in future, varieties of this have low yield potential. Genetic diversity and population structure of aromatic germplasm provide valuable information for yield improvement which has potential market value and farm profit. Here, we show diversity and population structure of 113 rice germplasm based on phenotypic and genotypic traits. Phenotypic traits showed that considerable variation existed across the germplasm. Based on Shannon–Weaver index, the most variable phenotypic trait was lemma-palea color. Detecting 140 alleles, 11 were unique and suitable as a germplasm diagnostic tool. Phylogenetic cluster analysis using genotypic traits classified germplasm into three major groups. Moreover, model-based population structure analysis divided all germplasm into three groups, confirmed by principal component and neighbors joining tree analyses. An analysis of molecular variance (AMOVA) and pairwise FST test showed significant differentiation among all population pairs, ranging from 0.023 to 0.068, suggesting that all three groups differed. Significant correlation coefficient was detected between phenotypic and genotypic traits which could be valuable to select further improvement of germplasm. Findings from this study have the potential for future use in aromatic rice molecular breeding programs.

Twenty five advanced lines among them twelve lines obtained from the cross between Edible Podded Pea and IPSA Motorsuty-1, nine obtained from the cross between Local White and IPSA Motorsuty-3 and five parental lines were included to measure genetic diversity. The field experiment was conducted at the research farm, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh. Analysis of variance showed significant differences among the genotypes for all characters. Multivariate analysis based 14 agronomic characters indicated that the 26 genotypes fell into five distant clusters. Fifty percent germination was found to be contributed maximum towards the total divergence. The inter cluster (D 2 values) distance was maximum between cluster I and cluster II and intra-cluster distance was in cluster III. Cluster V comprising five genotypes, namely, G11, G14, G21, G22, G25 and scored first position for 50% germination, pod per plant, 100 green seed weight and seed yield per plant (6.02). Genotypes belonging to the cluster I, II and V having greater inter cluster distance and higher cluster means for various characters could be recommended for inclusion in future breeding program as they are expected to produce good segregates.

Genetic divergence in eighteen eggplant genotypes was studied at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur, Bangladesh during February 2007 to December 2008 using multivariate analysis. Eggplant genotypes were evaluated for different quantitative characters. Among the genotypes wide variations were observed for plant, flower and fruit size, shape and color. Out of 18 genotypes only 8 were found to be suitable for summer and summer rainy season cultivation as heat tolerance. The 18 genotypes were grouped into four distinct clusters. Cluster I comprised of 2 genotypes, cluster II had 3, cluster III had 3 and cluster IV had 10 genotypes. Clustering pattern of the genotypes was not correlated with their geographical distribution. The highest inter cluster distance was between cluster I and IV (764.67) while, it was the lowest between cluster II and III (213.30). The highest and lowest intra cluster distance was displayed in cluster II (94.14) and cluster I (28.79) respectively. Yield per plant, number of fruits per plant, plant canopy, fruit weight, fruit length and number of harvest had the highest contribution towards total divergence. Moderate to high Shannon-Weaver Diversity Indices (SWDI) was found among the genotypes for most of the studied qualitative characters. Quantitative vegetative characters had high diversity among the genotypes, while it was moderate to high diversity for both flower and fruit characters. Eight eggplant genotypes were selected as heat tolerance based on genetic diversity of morphological characters in eggplant.

No abstract

A half diallel set of five parents and their 10 F1’s were studied to determine the combining ability and magnitude of heterosis for eight important characters in snakegourd at the experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University during April to July, 2004. Combining ability analysis revealed that both general and specific combining ability variances were significant for all the characters except fruit diameter and fruit yield per plant. Predominance of additive gene action was noted for all the characters except days to first female flower where non-additive gene action was predominant. Parent P1 was the best general combiner for fruit yield and some yield contributing characters. Among the crosses P2  X P3, P1  X P2 and P1  X P4 were the best specific combiner for fruit yield and some of yield contributing characters. Both positive and negative heterosis was obtained of which few hybrids showed desirable and significant values. P2  X P5 showed the highest significant mid parental heterotic value for earliness and high yield whereas, P1  X P2, P2  X P3, P2  X P5 and P3  X P4 showed the highest significant better parent heterotic effect for earliness and high yield. Key words: Snakegourd (Trichosanthes cucurminata L.); combining ability; heterosis; fruit yieldDOI: http://dx.doi.org/10.3329/bjpbg.v23i2.9318 Bangladesh J. Pl. Breed. Genet., 23(2): 1-6, 2010