The first experiment involving different explants and concentrations of 2,4-D and kinetin showed highly significant differences for length and weight of callus formed except interaction of callus weight. Leaf explant appeared to be best of all for callus length and weight when 1.0 mg/L 2,4-D + 0.25 mg/L kinetin concentration was used. Similarly, different explants versus different concentrations of BAP/GA 3 /IAA showed significant differences for shoot length and leaf number per plantlet and also for root length. However, interaction term confirmed node and node/internode explants produced better results in shoot length and number of leaves per plantlet when concentrations 1 .0 mg/L BAP + 0.1 mg/L GA 3 and 1.0 mg/L BAP + 0.2 mg/L GA 3 , 1.0 mg/L BAP + 0.4 mg/L GA 3 , respectively, were used. Similarly, internode explants produced better results for root length after 21 days plantlet -1 when concentration of 1.0 mg/L IAA + 0.25 mg/L GA 3 was used. Shoot tip explants also produced better results in root length after 28 days plantlet -1 when concentrations 1.0 mg/L IAA + 0.25 mg/L GA 3 were used.

An experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh to assess the effect of weeding on growth, yield and yield contributing characters of mungbean (Vigna radiata L.) cv. BINA mung- 4 during October 2011 to February 2012. The experiment was laid out in a randomized complete block design with four replications. The trial comprised seven treatments namely, T1 = no weeding, T2 = one-stage weeding (Emergence-Flowering), T3 = one-stage weeding (Flowering-Pod setting), T4 = one-stage weeding (Pod setting- Maturity), T5 = two-stage weeding (Emergence-Flowering and Flowering-Pod setting), T6 = two-stage weeding (Flowering-Pod setting and Pod setting-Maturity) and T7 = three-stage weeding (Emergence-Flowering and Flowering-Pod setting and Pod setting-Maturity). The growth parameters such as relative growth rate (0.075 g g-1 day- 1) and net assimilation rate (0.075 g m-2day-1) showed the best performance with T2 at one-stage weeding condition (Emergence-Flowering). Three-stage weeding ensured the highest plant height (58.62 cm) as well as the highest number of branches (4.45) and leaves (10.34) plant-1. Dry weight plant-1 (12.38g) was highest from three stage weeding and the lowest from no weeding treatment. The highest number of pods (22.03) plant-1, the longest pod (5.95 cm), the highest number of seeds (17.07) pod-1 and the highest seed yield (1.38 t ha-1) were obtained from three-stage weeding (Emergence-Flowering and Flowering-Pod setting and Pod setting-Maturity) in mungbean. On the other hand, the lowest seed yield was obtained under no weeding condition. The highest seed yield resulted in higher biological yield (4.70 t ha-1) and the highest harvest index (37.15%) in three-stage weeding and the lowest from no weeding. Number of pods plant-1, length of pod, number of seeds pod-1 and 1000-seed weight showed highly significant positive correlations with seed yield. These parameters strongly influenced the growth, yield and yield contributing characters of mungbean (Vigna radiata L.) DOI: http://dx.doi.org/10.3329/jbau.v11i1.18209 J. Bangladesh Agril. Univ. 11(1): 53-60, 2013

Growth rate of mungbean was very slow during the vegetative phase in all the four genotypes. A relatively smaller portion of total dry matter (TDM) was produced before flower initiation and the bulk of it after anthesis. The maximum crop growth rate (CGR) was observed due to maximum leaf area (LA) development during the pod filling stage in all the genotypes. LA and CGR contributed to the superior TDM production. It appeared that a high yielding mungbean genotype should possess larger LA, high TDM production ability, superior CGR at all the growth stages, high relative growth rate and net assimilation rate at the vegetative stage as superior yield components. Key words: Seed yield; Mungbean; Growth; Dry matter DOI: http://dx.doi.org/10.3329/bjb.v40i2.9768   Bangladesh J. Bot. 40(2): 133-138, 2011 (December)

The effect of BAP and IBA on in vitro regeneration of four banana cultivars viz. 'Amritsagar', 'Seeded banana', 'Sabri' and 'Anajee' was studied. The response of single shoot regeneration from shoot tips of four banana cultivars at different concentrations of BAP was found to be different. The cultivar 'Amritsagar' produced the highest percentage (60 %) of single shoot at 4.0 mg/l BAP within 10-15 days. The cultivar 'Sabri' and 'Anajee' produced lower percentage of single shoots. Rates of shoot multiplication of 'Amritsagar', 'Sabri', and 'Anajee' were 6-7 plantlets/explant, 2-4 plantlets/explant, and 2 plantlets/explant, respectively on medium containing 4.0 mg/l BAP after 30 days of culture. But in subsequent subculture, on the same medium, 'Amritsagar' produced the highest number of plantlets (9 plantlets/explant) within the same period of time. The best root formation in multiplied shoots of 'Amritsagar' was found on MS medium containing 2.0 mg/l IBA after 15 days of culture. All the in vitro cultured banana plantlets of 'Amritsagar' survived when weaned to ex vitro conditions on soil.

The experiment was conducted with mature embryos of an aromatic rice variety (Basmati 370) to investigate the appropriate growth condition for callus induction as well as plant regeneration. Different concentrations of 2,4-D (0.0, 1.5, 2.5, 3.5, 4.5 mgL -1 ) in MS medium were used for callus induction. Among the concentrations of 2,4-D, 2.5 mgL -1 was the best concentration for callus induction (95.83%). Different concentrations of Kinetin (0.0, 8.0, 10.0, 12.0, 14.0 mgL -1 ) with a constant concentration of NAA (0.5 mgL -1 ) were used for plant regeneration from callus. The combination of 10.0 mgL -1 Kinetin and 0.5 mgL -1 NAA was found to be the best for shoot regeneration (77.50%). Different concentrations of MET (1.5, 2.5, 3.5 mgL -1 ) in MS medium with a constant concentration of NAA (0.5 mgL -1 ) were used for root induction. A combination of 2.5 mgL -1 MET and 0.5 mgL -1 NAA was found most efficient for root induction (85.00%) with higher number of roots per plant (19.50) and better root elongation (1.88 cm). The plantlet was survived well in the plastic pot as well in the earthen pot or in the field.