PRIKAZ DOMAĆIH I STRANIH KULTIVARA LUKA (Allium cepa L.) ZA POTENCIJAL PROIZVODNJE SJEMENA

An experiment was conducted aiming to find out the seed production potentiality of 19 local and exotic onion cultivars. The analysis of variance showed significant differences among the genotypes for all characters except sprouting percentage, number of flowers per umbel and number of umbel per bulb. Maximum number of days to 50% bolting (52.67) was exhibited by the genotype G2 and minimum by G6 (27.00 days). The larger bulb size after harvest was obtained from G14 and G19 (18.11 g). Genotypes G4 and G11 required the maximum (16.66) and the minimum (9.00) days for 100% sprouting, respectively. The highest stalk length was found in the genotype G1 (67.23 cm) and the lowest in G8 (38.47 cm). Maximum number (5.75) of stalk was produced by the genotype G7 and minimum number (2.09) of stalk by the genotype G11. The genotype G1 produced the highest number of seeds per umbel (1395.92) and seed yield per plant (4.29 g). The lowest (0.45 g) seed yield per plant and maximum bulb weight was obtained by the genotype G8.Istraživanje je provedeno s ciljem utvrđivanja potencijala sjemenske proizvodnje 19 domaćih i stranih kultivara luka. Analiza varijance pokazala je signifikantne razlike između genotipova za sva svojstva, osim postotka naklijavanja, broja cvjetova po štitastom cvatu i broja štitastog cvata po lukovici. Maksimalan broj dana do 50% naklijavanja (52,67) je svojstvo genotipa G2, a minimalan (27,00 dana) je svojstvo genotipa G6. Nakon vađenja utvrđena je veća lukovica kod genotipova 14 i 19 (18,11 g). Genotipovi G4 i G11 trebali su maksimalno 16,66 dana, odnosno minimalno 9,00 dana za 100% naklijavanja, redosljedom. Genotip G1 imao je najdulju (67,23 cm), a G8 najkraću (38,47 cm) stabljiku. Maksimalan broj stabljika (5,75) ustanovljen je kod genotipa G7, a minimalan (2,09) kod genotipa G11. Ustanovljeno je da G1 ima najveći broj sjemena po štitastom cvatu (1395,92) i prinosa sjemena po biljci (4,29 g). Najniži prinos sjemena (0,45 g), kao i najteža lukovica po biljci dobiveni su od genotipa G8

Weed suppressive ability of BRRI released popular monsoon rice varieties

Develoment of weed competitive crop cultivars is an attractive low-cost strategy of integrated weed management program that can reduce the heavy dependence of crop cultivation to chemical herbicides. Hence, to evaluate the weed competitiveness Bangladesh Rice Research Institute (BRRI) released selected monsoon rice varieties, a field experiment was conducted during July to December 2018 at the Agronomy Field Laboratory of Bangladesh Agricultural University. Thirty-three rice varieties were grown under season long weedy and weed-free conditions. Plots without rice plants were also maintained to investigate the natural growth of weed in absence of rice. The experiment was conducted following randomized complete block design with three replicates. The results showed that rice varieties varied widely in yielding ability and weed competitiveness. Among rice varieties, BRRI dhan31 allowed the minimum weed growth (32.5 g m-2) while BRRI dhan51 allowed the maximum weed growth (155.3 g m-2). Grain yield ranged between 3.6 t ha-1 (BRRI dhan49) and 7.5 t ha-1 (BR10) under weed-free condition and between 2.2 t ha-1 (BRRI dhan70) and 3.9 t ha-1 (BRRI dhan34) under weedy condition. Weed imposed relative yield loss ranged from 10.2 to 66.9% among the rice varieties. BRRI dhan34 allowed the least yield penalty (10.2%) while BRRI dhan70 had the maximum yield penalty (66.9%) due to competition with weeds. Although BR10 appear as the most productive variety (7.5 t ha-1) its weed imposed relative yield loss was higher (51.3%) than many other varieties with low yield potential. On the other hand, BRRI dhan34 appeared as the most weed competitive variety (only 10.2% relative yield loss) with productivity of 3.9 t ha-1. Considering the yield, BR10 was the best but for weed suppressive ability BRRI dhan34 performed well

Effectiveness of integrated weed management in five varieties of aromatic rice in Bangladesh

An experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh to evaluate the efficacy, rice selectivity and cost-effectiveness of some integrated weed control methods on the productivity of aromatic rice under randomized complete block design with three replications. The experiment consisted of five aromatic rice varieties; Kalijira, BRRI dhan34, BRRI dhan37, BRRI dhan38 and Binadhan-13, and six different weed management practices comprising no weeding, weed free, mechanical + manual weeding, pre–emergence herbicide + manual weeding, post–emergence herbicide + manual weeding, pre– + post–emergence herbicide. Ten weed species belonging to five families infested the experimental plots. Herbicide treatments provided excellent weed control efficiency and produced much higher net benefit and cost benefit ratio than weedy plot. Among the herbicidal and mechanical treatments, sequential application of Bensulfuran methyl + Acetachlor at early growth stage (pre-emergence herbicide) followed by Pyrazosulfuran ethyl at mid growth stage (post-emergence herbicide) provided the highest weed control efficiency, productivity and net benefit. Single application of Pyrazosulfuran ethyl at mid growth stage followed by one hand weeding performed very close to the pre– + post–emergence herbicide application in terms of productivity and net benefit but in terms of weed control efficiency at 45 days after transplanting application of Bensulfuran methyl + Acetachlor at early growth stage followed by one hand weeding performed very close to pre– + post–emergence herbicide application. Mechanical weeding followed by one hand weeding and application of Bensulfuran methyl + Acetachlor at early growth stage followed by one hand weeding also provided satisfactory results in terms of productivity and economic return. Since manual weeding was less economic, sequential application of pre- and post-emergence herbicides may be recommended for effective weed management in aromatic rice

Weed competitiveness of winter rice (Oryza sativa L.) under modified aerobic system

The study was conducted during winter season (February-June) of 2016 at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh. Fourteen rice varieties namely, BRRI dhan28,  BRRI dhan29, BRRI dhan47, BRRI dhan50, BRRI dhan55, BRRI dhan58, BRRI dhan59, BRRI dhan67, Binadhan-5, Binadhan-6, Binadhan-8, Binadhan-10, BRRI hybriddhan3 and Agrodhan14 were grown under weedy and weed- free conditions. Plots with no rice were also maintained to study the natural growth of weed in absence of rice. Primed rice seeds were dry seeded following 25 cm ×15 cm spacing with 5 seeds hill-1 on non-puddled soil. Plots were surface irrigated as and when necessary to maintain aerobic condition (at around field capacity) up to heading stage followed by wet condition from heading to grain filling stage. The results revealed that rice varieties varied widely in yield performance and weed suppressive ability. Among varieties, BRRI dhan59 allowed the minimum weed growth (20.8 g m-2) while Binadhan-5 allowed the maximum weed growth (65.8 g m-2). Grain yield ranged from 2.2 t ha-1 (BRRI dhan55) to 4.67 t ha-1 (Binadhan-5) under weed-free condition and from 0.62 t ha-1 (BRRI dhan55) to 2.48 t ha-1 (BRRI dhan59) under weedy condition. Weed infected relative yield loss ranged from 40.1% to 78.2% among varieties. BRRI dhan59 incurred the least yield penalty (40.1%) while Binadhan-5 performed the best in terms of grain yield (4.67 t ha-1) but its weed inflicted relative yield loss was higher (76.4%) than any other variety with low yield potential. BRRI dhan59, on the other hand, appeared as the most weed competitive variety (only 40.1% relative yield loss) with yield of 4.19 t ha-1. Present study confirms that the varieties tested under study varied widely in terms of weed suppressive ability and yield performance. Considering both yield and weed competitiveness, BRRI dhan59 can be recommended for cultivation following modified aerobic system

SCREENING OF LOCAL AND EXOTIC ONION (ALLIUM CEPA L.) CULTIVARS FOR SEED PRODUCTION POTENTIALITY

An experiment was conducted aiming to find out the seed production potentiality of 19 local and exotic onion cultivars. The analysis of variance showed significant differences among the genotypes for all characters except sprouting percentage, number of flowers per umbel and number of umbel per bulb. Maximum number of days to 50% bolting (52.67) was exhibited by the genotype G2 and minimum by G6 (27.00 days). The larger bulb size after harvest was obtained from G14 and G19 (18.11 g). Genotypes G4 and G11 required the maximum (16.66) and the minimum (9.00) days for 100% sprouting, respectively. The highest stalk length was found in the genotype G1 (67.23 cm) and the lowest in G8 (38.47 cm). Maximum number (5.75) of stalk was produced by the genotype G7 and minimum number (2.09) of stalk by the genotype G11. The genotype G1 produced the highest number of seeds per umbel (1395.92) and seed yield per plant (4.29 g). The lowest (0.45 g) seed yield per plant and maximum bulb weight was obtained by the genotype G8