Dry direct-seeded rice (Oryza sativa L.), a climate-smart and resource-efficient (labor and water) rice production technology is gaining popularity in many parts of Asian countries; however, weeds are the major constraints for its early establishment and optimum productivity. Chemical weed management is effective, rapid, and also decreases weed management costs in dry direct-seeded rice (DSR) system; however, chemical use for weed management have a negative effect on the environment and also have human health hazards. Therefore, integrated weed management (IWM) is the best option for the sustainability of rice production under the DSR system. Improving competitiveness against weeds, weed-competitive rice cultivars, and high seeding rates were found to be the most promising IWM strategies in DSR. In this context, a field study was conducted to evaluate the weed competitiveness of rice cultivars and seeding rates on the performance of aus rice in dry direct-seeded systems in Bangladesh. Three inbred rice cultivars (CV), namely “BRRI dhan26”, “BRRI dhan48”, and “BRRI dhan55”, and one hybrid cultivar, “Arize” were tested in a seeding rate (SR) of 20, 40, and 80 kg ha⁻¹ under two weeding regimes (WR) of weed-free and partially-weedy. Rice grain yield was strongly affected (p < 0.01) by the interactions of WR, CV, and SR. In weed-free conditions, the yield of all three inbred cultivars was increased up to SR of 40 kg ha⁻¹ and for the hybrid cultivar, up to SR of 20 kg ha⁻¹, and with further increment of SR, there was no yield advantage. Conversely, under partially weedy conditions, the yield of three inbred cultivars increased up to SR of 80 kg ha⁻¹; however, for the hybrid cultivar, this increment was up to SR of 40 kg ha⁻¹ and thereafter, no yield gain. In weedy conditions, the higher SR compensates for the yield losses by increasing the competitiveness of rice with weeds. Across SR, the hybrid cultivar had a significantly (p < 0.01) higher weed competitive index (WCI) than all the inbred cultivars and the highest SR always had a higher WCI.

Cropping systems in the Level Barind Tract (LBT) of Bangladesh are highly diverse, as Transplanted (T.) Aman and Boro (T. Boro) rice are a common practice in the area. Although. T. Aman is generally cultivated in the rainy (monsoon) season, but the T. Boro rice is the intensive irrigation-based winter rice with high establishment costs as a result of exhaustive tillage and high labours for transplanting of seedlings. Furthermore, pumping of a large amount of irrigation during T. Boro cultivation declines the level of groundwater, which is not environmentally friendly nor cost-effective. Therefore, the replacement of the T. Boro rice from the cropping pattern in the LBT area is the major concern of policymakers. In this context, a replicated three to four crop-based cropping systems (CS) field trial was conducted in LBT of Gaibandha, Bangladesh for consecutive three years (2018–2020) to evaluate productivity, profitability and sustainability of the multiple crop-based cropping systems. Among these CS, existing three crops based CS, CS1: T. Aman–Potato–T. Boro (introduction of the local potato in the existing cropping system) were compared with four crops based CS2: T. Aman–Potato–Cucumber–T. Aus (Introduction of high yielding potato, cucumber and T. Aus as an improved cropping system). After two years of observations, significantly higher system productivity (rice equivalent yield; REY) was found in the improved CS2 than that of existing CS1 in both years (two years’ average 49% or 11.1 t ha⁻¹). As a result of the introduction of the high yielding potato, cucumber and T. Aus rice instead of the T. Boro rice. The CS2 was also found profitable as compared to the CS1 in terms of higher gross margin (by 74%), net return (double) and benefit-cost ratio (BCR) (1.69 vs. 1.44) due to higher gross return with slightly higher (by 28%) production cost. It is due to farmers received higher prices for potato, cucumber and two rice crops in the improved CS2 than the existing CS1. On the other hand, protein and energy output was lower (by 17% and 9%, respectively) in the CS2 than the existing CS1, due to the less content of protein and energy value in the vegetable cucumber. The results of the study revealed that crops diversification in the existing T. Boro based CS with high yielding potato, cucumber, and T. Aus rice, improved the system productivity, profitability and sustainability; which lead to improve the food security of the increasing population and also reduce the adverse effect on the environment.

International Potato Center (CIP), -bred potato genotypes produce various yields under heat stress conditions due to being sown late. To explore options for achieving this, a replicated experiment was conducted at the field of Tuber Crops Research Sub-Centre, Bangladesh Agricultural Research Institute, Bogura, Bangladesh to evaluate the performance of fourteen CIP-bred potato genotypes with two controls (Asterix and Granola). The experiment was laid out in a split-plot design with three replications. Several indices were applied to find out the suitable genotypes under heat stress. The plant height increased by 34.61% under heat stress, which was common in all the potato genotypes. Similarly, other yield-participating characters like stem per hill, canopy coverage (%), plant vigor, and tuber number per plant were also increased under heat stress conditions. However, the tuber yield was decreased by 6.30% and 11.41%, respectively when harvested at 70 and 90 days after plantation. Moreover, “CIP-203” yielded the highest (40.66 t ha⁻¹) in non-stressed whereas, “CIP-118” yielded the highest (32.89 t/ha) in stressed conditions. Likewise, the bred “CIP-218” and “CIP-118” performed better under both growing conditions and yielded >35.00 t ha⁻¹. According to a rank-sum test, among the fourteen potato genotypes, “CIP-218”, “LB-7”, “CIP-118”, “CIP-232”, and “CIP-112” were selected as heat-tolerant potatoes and can grow in both growing conditions with higher yield potential.

The study aimed to select high-yielding, farmers-preferred quality sweet potato varieties that are suitable to grow in various environmental conditions in Bangladesh. In this context, four popular sweet potato varieties (viz., ‘BARI Mistialu-8′, ‘BARI Mistialu-12′, ‘BARI Mistialu-14′, and ‘BARI Mistialu-15′) were used in the study. These varieties were released by Bangladesh Agricultural Research Institute (BARI). In the first season (2018–2019), these varieties were evaluated at nine locations, and in the second season (2019–2020), the same varieties were tested further, but only in three locations. The trial was set up in a randomized complete block design and repeated three times. After two years of observation, it was found that the fresh root yield was varied significantly due to the environment (E), genotypes (G), and their (G × E) interaction (p ≤ 0.01) by using genotype and genotype x environment (GGE) biplot analysis. The E and G × E interaction effects were found to the greater than the genotypes effect solely. In the first year, three varieties, namely ‘BARI Mistialu-8′, ‘BARI Mistialu-12′ and ‘BARI Mistialu-14′, were identified as balanced and comparatively higher in yield in nine locations. These three varieties also showed a similar trend with respect to root yield in tested three locations in the second year. Among the four varieties, ‘BARI Mistialu-12′ was found to be the highest root yielder, followed by ‘BARI Mistialu-8′ and ‘BARI Mistialu-14′. Across the locations, these varieties showed 57.89%, 61.50% and 44.30% higher yield than the local check cultivar. Therefore, these three varieties may be recommended as the best varieties of sweet potato throughout the country.

Orange fleshed sweet potatoes (OFSP) are desirable for high productivity and profitability and their distribution to improve the nutrition of river bank inhabitants of Gaibandha and Rangpur districts of Bangladesh. In this context, a field trial was conducted in two riverbank-based farmers’ fields such as Saghata, Gaibandha, and Pirganj, Rangpur, particularly in the Active Tista Floodplain Agro-ecological Zone of Bangladesh. Four OFSP varieties were evaluated, i.e., G1: BARI SP-8; G2: BARI SP-12; G3: BARI SP-14; G4: BARI SP-15, along with one local cultivar as a control (Red skin with white flesh). Significant variations among the sweet potato genotypes were noted for a number of tuberous roots plant⁻¹, length of root diameter of roots, tuberous root weight plant⁻¹, root yield (fresh), root yield (dry), beta-carotene yield, as well as energy output. Over the locations, BARI SP-12 produced about 73% higher root yield (32.00 t ha⁻¹) and it was like the BARI SP-8 (31.07 t ha⁻¹), which produced about 68% higher yield in comparison with local cultivar (18.51 t ha⁻¹). Across the location, BARI SP-8 performed better in root yield (31.89 t ha⁻¹) in Gaibandha, 69% superior to local cultivar, whereas BARI SP-12 performed better in Rangpur (33.66 t ha⁻¹), which was 86% greater than the local sweet potato cultivar. Considering the root dry yield production, BARI SP-8 produced the highest in the Gaibandha location after that Rangpur location. Further, BARI SP-14 had wider adaptability and stability over the year and location depended on the AMMI model. The beta carotene yield (Vitamin-A precursor) ranged 336–2957 kg ha⁻¹ among the OFSP varieties, whereas the highest (2957 kg ha⁻¹) carotene was recorded in BARI SP-14, similar to BARI SP-15 (2952 kg ha⁻¹) but was much lower in BARI SP-8 and BARI SP-12. Moreover, BARI SP-8 and BARI SP-12 were also economically profitable in terms of gross margin (3233 and 3364 US$ ha⁻¹, respectively), net return (3039 and 3170 US$ ha⁻¹, respectively) and BCR (3.21 and 3.31, respectively, vs. 1.91) due to higher returns with a similar production cost of the local cultivar. The results suggested that BARI SP-8 is economically profitable in the riverbank areas of Gaibandha, and BARI SP-12 is suitable for the riverbank areas of Rangpur.

To estimate energy use efficiency for sweet potato production in Bangladesh under subtropical climatic conditions, a study was conducted with 60 individuals (12 producers for each sweet potato variety) by using a structural questionnaire. The results revealed that the majority of the energy input was consumed by the pre-harvest activities (22,313.55 MJ ha−1 or 90.85%), of which fertilizer application (36.84%) and irrigation (35.24%) consumed the most energy input, with only 9.15% (2,248.42 MJ ha−1) consumed by the post-harvest activity for sweet potato production. The energy input involved in the production system was similar to the direct (12,149.76 MJ ha−1 or 49.47%) and indirect (12,412.21 MJ ha−1 or 50.53%) sources, while it was much higher in non-renewable sources (22,884.21 MJ ha−1 or 93.17%) with a minimum (1,677.76 MJ ha−1 or 6.83%) from renewable sources. The average energy use efficiency, energy productivity, specific energy, net energy, energy profitability and water-energy productivity of orange-fleshed sweet potato (OFSP) varieties 4.36, 1.22 kg MJ−1, 0.83 MJ kg−1, 82,511.73 MJ ha−1, 3.36 and 1.32 g m−3 MJ−1, respectively. The OFSP varieties showed better performance in respect of all the energy and water use indicators.