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.

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.

Correlations and path coefficient were studied in 39 exotic tomato (Solanum lycopersicum L.) genotypes for nine yield contributing characters. The correlation coefficients were determined to find out the inter relationship among the characters studied. Yield per plant was found highly significant and positively correlated with flowers per plant, fruits per plant, fruit length, fruit diameter and individual fruit weight which indicated that yield could be increased by improving a traits. In order to obtain a clear picture of the inter relationship between yield per plant and its components, direct and indirect effects were measured using path coefficient analysis. Fruits per plant showed the highest positive direct effect (0.980) on yield per plant followed by individual fruit weight (0.958). On the other hand, the highest negative direct effect on yield per plant showed by days to first flowering (-0.277) followed by fruit length (-0.141). The characters showed high direct effect on yield per plant indicated that direct selection for these traits might be effective and there is a possibility of improving yield per plant through selection based on these characters. Residual effect was considerably low (0.183) which indicated that characters included in this study explained almost all variability towards yield. Keywords: Correlation coefficients; path coefficient analysis; residual effect DOI: http://dx.doi.org/10.3329/bjpbg.v23i1.9313 BJPBG 2010; 23(1): 13-18

This experiment was conducted during September, 2011 to March, 2012 in the experimental field of Department of Horticulture, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur to find out the effect of planting date on the yield of broccoli genotypes. There were five genotypes viz. Early green, Forest green, Green calabrese, Premium crop and Green king and four planting dates viz. 2 October, 27 October, 21 November and 16 December. The treatment effects were statistically analyzed and found significant in most of the characters studied. Genotype Green calabrese was the highest in average plant height (53.70 cm). Green king produced the maximum spread diameter (69.23 cm), stem diameter (30.35 mm) and early initiation of floral head. Genotype Early green performed the best regarding head weight (343.87 g), yield per plant (477.4 g) and yield (19.10 t/ha). Broccoli planted on 21 November initiated early flower head, maximum head diameter (16.99 cm), head weight (314.49 g), yield per plant (453.64 g) and total yield (18.15 t/ha). The genotype Early green planted on 21 November showed the best performance in yield per plant (580.17 g) and yield hectare (23.21 t/ha).Bangladesh J. Agril. Res. 40(3): 465-478, September 2015

The experiment was conducted at the field laboratory of the Department of Genetics and Plant Breeding, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during November 2008 to March 2009 to estimate the genetic diversity of exotic and local onion. Ten genotypes of onion were evaluated for 16 characters in a randomized complete block design to study the genetic divergence through multivariate analysis. Ten genotypes formed three clusters. Cluster III contained maximum number of five genotypes. Cluster I and II contained three and two genotypes, respectively. The inter cluster distance was larger than the intra cluster distances. The inter cluster distance was maximum between the cluster II and III (6.336) and minimum between the cluster I and II (3.876). The intra cluster distance in the entire three clusters was more or less low, indicating that genotypes within the same cluster were closely related. Considering clustered distance and cluster mean, the intra cluster distance revealed that the genotypes Indian big (G1) and Patnai pink (G5) from the cluster II and genotypes Taherpuri, Indian medium (G1), Big single bulb (G7), Big double bulb (G8), Small single bulb (G9) and Small double bulb (G10) from the cluster III may be selected as parents for future breeding program.The Agriculturists 2015; 13(1) 26-34