In the present investigation, 30 different potato genotypes were evaluated for 3 consecutive years. The estimates of different components of variation and coefficient of variability, such as phenotypic, different interaction and error were more or less high for yield, number of leaves/plant, number of tubers/plant and number of eyes/ tuber, which indicates the wide scope of improvement of these traits through selection. The highest of h2b was recorded for tuber yield and lowest in number of tubers/plant.Path coefficient analysis showed that potato genotypes could be grouped into 6 different clusters and for the inprovement of potato, the genotypes should be selected I, II and IV.

The whole work of the present investigation was carried out under two separate parts, such as triple test cross and correlation, path-coefficient and selection index. The additive and dominance components were found to be highly significant in all the crosses for all the characters. The cross 7(Bm1-20kr x L11-30kr) for seed yield and yield components followed by cross 8 (Bm4-30kr x Bm3) and cross 5(Bm1-25kr x L11-30kr) for some of the yield components may be selected for further breeding research, as they showed moderate to high heritability, additive-dominance inheritance and non-significant epistasis. Correlation, path-coefficient and selection index of thirteen parental lines shows that the lines were genetically well differentiated as indicated by the analysis of variance. In the discriminant function analysis, when individual character was judged separately the highest and positive expected genetic gain was found for SWPP followed by PWPP and PHFF. For selection effective major emphasis should be given on PWPP, PHFF and NBPMF. So, during selection NPdPP, PdWPP and NSPP also be considered because they showed significant positive correlation and positive direct effect on yield."

The Sundarbans mangrove is a highly dynamic ecosystem. Gewa (Excoecaria agallocha Linn.) is a codominent species, the merchantable growing stock of which was depleted by 45% during 1959 to 1983. The purpose of this study was to obtain information on phenology, genetic diversity, improvement of selection, and suitable propagation system and hedge development and management as a step towards sustainable management of the species and enhances the productivity of the mangrove forests. Gewa is a commercially important hardwood species. So it is an urgent need to improve this species for maintaining and protecting its genetic erosion. The present situation calls for improvement and management of this species for sustainability of the forest. The seed viability decreases very rapidly within a short time. Natural regeneration of gewa is limited due to several biological factors. Shortage of superior seeds/propagules for plantation forestry may be overcome by using clonal propagation technique. The results suggest that, to increase the timber yields, productivity and sustainability of the forest, enrichment plantation by genetically superior stocks is possible in the mangrove forest.

The present study was conducted to standardize a suitable protocol of in vitro plant regeneration potentiality of seven strawberry varieties viz. AOG, JP-2, JP-3, Camarosa, Sweet Charly, Giant Mountain and Festival. Young leaves, mature leaves and nodes of seven strawberry varieties were used for callus induction and plant regeneration. Among the seven strawberry varieties AOG was found to be the most responsive genotype for primary culture establishment, callus induction, shoot regeneration and rooting. A total of 40- 45 somaclones from each of the tested varieties were established and maintained in the field and were considered as Ro plants. There were no plants found resistance to fungal diseases but somaclones showed better tolerence than the donor plants. Majority of plants were found heat sensitive in donor plants but somaclones of AOG SC 3 showed better performance than other somaclones and donor parents in terms of summer overcoming capacity. These somaclones can be acceptable commercially if the good characters exhibited are transmitted through generations or could be used in future breeding programme for the improvement of strawberry varieties in Bangladesh.

Meristems isolated from shoot tips of field grown mature garlic bulbs of five cultivars were cultured in liquid MS medium with 2ip and NAA for shoot proliferation. In vitro bulblets were produced from meristem derived shoot clumps in MS with high levels of sucrose. Rooted plantlets with bulblets were gradually acclimatized and successfully established in the field. Visual evaluation of the morphological traits of the meristem derived plants showed that all plants were normal and free from virus diseases. Substantial yield increase was observed from meristem derived plants over their source plants. Shoot tip, leaf base, leaf primordia and bulbil from field grown mature garlic bulbs of five cultivars were cultured in MS medium with 2,4-D for callus induction. The calli were transferred to MS medium without any growth regulators for somatic embryogenesis. Plantlet regeneration from somatic embryos was obtained in KIN supplemented MS media. After proper acclimatization rooted callus derived plantlets with bulblets were transplanted in the field and somaclonal variation were found in plant height, number of leaves/plant, bulb diameter/plant, and bulb weight/plant.

Iron deficiency is the most wide spread nutritional problem in the world. For increasing the iron contents in four potato cultivars, in vitro leaf derived calli were transformed with Agrobacterium tumefaciens strain LBA4404 bearing Ti based binary pCAMBIA2301 plasmid containing selectable marker neomycin phosphotransferase (nptII) and ferritin gene. Maximum kanamycin resistant and ferriitn positive calli with the highest transformation frequency were obtained from Japanese Red by using 50 mg/l kanamycin, 50 mg/l cefotaxime, the bacterial suspension (OD=1.00 at 600 nm), 70 seconds incubation period, 24 h co-cultivation period in the presence of acetosyringone (25 mg/l). Putative transgenic plants were regenerated from the infected calli in medium containing MS + 3.0 mg/l BA + 0.1 mg/l NAA + 50 mg/l kanamycin + 50 mg/l cefotaxime. Kanamycin resistant plants were analysed with PCR and RT-PCR for the detection of ferritin gene and its transcript which reveal that ferritin genes were integrated into the plant genome.

Taxonomic investigation of the Cucurbits (family-Cucurbitaceae) growing throughout the Northern parts of Bangladesh was carried out. Documentation of species distribution, ecology and indigenous uses by local people has been made. Lists of the taxa examined with all synonyms are provided. Taxonomic position, occurrence, cultivation method, food value (mainly cultivated), uses and classification are presented and discussed. All the Cucurbits species studied were collected from the northern parts of Bangladesh. A total of 24 species under 13 genera of the family Cucurbitaceae were collected from the study area. Most of the cultivated species are grown in all districts of Bangladesh. Some of the species which are sometimes cultivated and sometimes wild are grown in particular area. Most of the species are distributed all over the study area, i. e. Benincasa hispida, Citrullus lanatus, Coccinia grandis, Cucumis melo, Cucumis sativus, Cucurbita maxima, C. pepo, C. moschata, Lagenaria siceraria, Luffa acutangula, L. cylindrica, Momordica carantia, M. cochinchinensis, Melothria maderaspatana, Trichosanthes anguina, T. cucumerina, T. bracteata and T. dioica.

Taxonomic investigation of the family solanaceae growing through out the Rajshahi University campus was carried out. A total of 8 (eight) species under 4 (four) genera of the family Solanaceae were collected and identified. A complete taxonomic account of each species is given with current nomenclature, local name, chromosome number, flowering season and uses. All the species are distributed all over the study area and the recorded species are(a) Solanum nigrum, (b) Solanum spirale, (c) Solanum indicum, (d) Solanum xanthocarpum, (e) Solanum torvum, (f) Datura metel, (g) Physalis minima, (h) Nicotiana plumbaginifolia. Datura metel which is sometimes cultivated and sometimes wild is grown in particular a

In vitro propagation of virus free clones through meristem and subsequent field evaluation of microclones were explored. The present study also includes callus induction from leaf explant followed by somatic embryogenesis, plant regeneration from somatic embryos and subsequent field evaluation of embryo derived plants for exploring possible occurrence of somaclonal variations. The meristem culture, somatic embryos and bulblets derived plantlets after proper acclimatization were transplanted to field and were grown to maturity along with conventionally grown clove derived plants as control. The plants were assessed for the occurrence of somaclonal variation using different morphological and yield related characters. The results illustrated in the present study elucidated that meristem culture used for the micropropagation of garlic could be effective in minimizing the incidence of somaclonal variation and could be used for the production of virus free planting materials. In addition, the high incidence of somaclonal variations generated through somatic embryogenesis may be useful as an alternative breeding tool for widening genetic basis for the improvement of new garlic cultivars.

The physiological parameters like PBH, SBH, PH, PAPP and TDM were increased with the advancement of plant age while LWR, CGR and RGR decreased with the increase of plant age. The plants under irrigated conditions produced significantly better performances in all the characters tested than those of the rainfed plants except LWR, CGR and RGR. Most of the yield contributing characters were influenced by irrigation applied at two stages of growth. Primary branch height and relative growth rate were the highest as influenced by irrigation applied at one stage of growth. Some growth attributes like leaf weight ratio and crop growth rate were the highest under rainfed conditions. Correlation and path coefficient analysis revealed that plant area per plant showed the highest positive direct contribution on grain yield and it was followed by pod number per plant and seed number per plant. Stability parameters indicated that Barimasur 6 showed the highest grand mean, regression value nearly one (bi= 1.00) and stability nearly zero at most of the characters. Out of the six genotypes of lentil, Barimasur 6 gave very good grain yield under irrigated and rainfed conditions.

The range of variation was much pronounced in most of the characters and real differences existed among the different varieties. The root number per plant showed the highest phenotypic, genotypic and environmental variance. The highest heritability was found from root length and the lowest was reported from root number. The bulb yield of onion was strongly and positively correlated with most of the characters studied, except with dry matter content of bulb. Pusa Red variety, fertilizer dose at N - 120, P - 130, and K - 160 kg/ha and early planting significantly increased bulb yield.