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.

Determination of the optimum sowing window not only can improve maize yield significantly but also can fit maize in the existing cropping pattern. To get the advantages of sowing maize at the optimum time, a study was designed and carried out at the research field of Bangladesh Agricultural Research Institute, Rangpur, Bangladesh during 2015–2017. Another aim of the study was to forecast the yield of maize for the northern and western regions of Bangladesh using the CERES-Maize model. The study considered 5 November, 20 November, 5 December, 20 December, and 5 January as sowing dates for maize to identify the optimum sowing window. Three hybrid maize varieties, viz., BARI Hybrid Maize-9 (BHM-9), NK-40, and Pioneer30V92 were used. The study was laid out in a split-plot design, assigning the sowing dates in the main plot and the varieties in the sub-plot. To forecast the yield, the daily weather data of 2017 were subjected to run the model along with thirty years (1986–2015) of weather data. The genetic coefficients of the tested maize varieties were obtained through calibration of the model by using the observed field data of 2015–2016 and through validation by using the data of 2016–2017. The seasonal analysis was done using the DSSAT CERES-Maize model to confirm the experimental findings for optimizing the sowing window for maize at the northern region (Rangpur) of the country and subsequently adjusted the model for the western region (Jashore). The model performances were satisfactory for crop phenology, biomass, and grain yield. The NRMSE for anthesis was 0.66% to 1.39%, 0.67% to 0.89% for maturity date, 1.78% to 3.89% for grain yield, and 1.73% to 3.17% for biomass yield. The optimum sowing window for maize at the Rangpur region was 5 November to 5 December and 5 to 20 November for the Jashore region. The CERES-Maize model was promising for yield forecasting of the tested maize varieties. It gave a realistic yield forecast at approximately 45 days prior to the harvest of all the tested varieties. The study results are expected to be useful for both the farmers and the policy planners to meet up the future maize demands.

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.

Rapid climate change may put future food security under threat, which emphasizes the significance of assessing the morpho-physiological and biochemical traits associated with maize tolerance against recurrent water stress at the early vegetative stage. Three maize varieties (V1, SUWAN2301; V2, SUWAN4452; and V3, S7328) and three water levels (I₁, daily watering as the control; I₂, watering every two days as the short stress; and I₃, watering every four days as the prolonged stress) were employed in a factorial design pot experiment. During the experiment, I₁’s soil moisture content (SMC) was maintained at almost 100% of its field capacity (FC), whereas I₂ and I₃’s volumetric SMC dropped to an average of 22.10% and 11.57%, respectively, following a stress phase. Fourteen distinct characteristics of maize were investigated at 5, 9, and 13 days after watering treatment initiation (DAWTI). The findings revealed that water levels significantly influenced all the tested traits (p < 0.05), except for a few traits at 5 or 9 DAWTI only, whereas the maize variety significantly influenced most of the studied attributes (p < 0.05). Except for proline content in leaf (PrL) and root (PrR); total soluble sugar in leaf (TSSL) and root (TSSR); and root length to shoot length ratio (RL:SL), the value of all analyzed characters was higher under I₁ compared to I₂ and I₃. However, during the first recovery period (RP), the recovery rate (RR) of stem perimeter (SP), root length (RL), root dry weight (RDW), leaf water potential (LWP), leaf greenness (LG), and TSSL were higher in I₂, whereas leaf area (LA) and RL:SL was higher in I₃. However, in the second RP, the RR of plant height (PH), SP, RL, LWP, LG, and TSSL were higher in I₃, whereas LA, RDW, RL:SL, PrL, PrR, and TSSR were higher in I₂ compared to each other. Under I₃, the RR of biochemical traits, i.e., PrL (29.45%) and TSSR (20.23%), were higher in the first RP, and PrR (20.74%) and TSSL (15.22%) were higher in the second RP. However, the variety V1 could recover more after a re-watering, and, in the second RP, it performed better in the case of LA (120.14%), PH (18.41%), SP (19.94%), RL (17.74%), Shoot dry weight (SDW) (56.82%), RDW (11.97%), LG (0.05%), PrR (42.55%), TSSL (18.54%), and TSSR (22.87%) than other varieties. The maize varieties performed differently under I₁ and I₃ according to the principal component analysis and stress tolerance index. The variety V1 exhibited superior performance under both water levels. The biplot analysis highlighted the importance of traits, such as PrL, RL, TSSL, TSSR, PrR, and RL:SL, in water-stressed conditions. However, re-watering following a water stress period triggered the recovery rates in most traits, particularly after the second four-day stress period, and variety V1 performed better as well. Nonetheless, more research on a genomic and molecular level is required to gain a deeper understanding of the precise processes of drought tolerance in maize, particularly under recurring water stress circumstances.

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.

Maize, a major food source for the world’s tropical regions, is often impaired by droughts under a changing climate, which creates the importance of making efforts to improve the tolerance characteristics of maize under field conditions. The experiment was conducted during the dry season of the 2020–2021 period to investigate the stimulatory effects of plant growth regulator (PGR) ethephon (2-chloroethylphosphonic acid) on the morpho-physio-biochemical traits of maize and to identify suitable application approaches for efficient production under water stress. The factorial randomized complete block design was followed for the present experiment. Ethephon was applied at the vegetative 6 leaves (V6) and/or 10 leaves (V10) stages. Seven application approaches (doses in g a.i. ha⁻¹) of ethephon, i.e., 281 at the V6 stage (E1), 281 at the V6 stage + 281 at the V10 stage (E2), 281 at the V10 stage (E3), 562 at the V6 stage (E4), 562 at the V6 stage + 562 at the V10 stage (E5), 562 at the V10 stage (E6), and no ethephon (E7), were used for maize production. Another factor was that three water levels were used, i.e., well-watered conditions (watering every week) (W1), short water stress (no watering during 48–69 days after planting) (W2), and prolonged water stress (no watering during 48–83 days after planting) (W3). Water stress negatively affected most of the morpho-physiological traits, and in W2 and W3 conditions, the grain yield was significantly lower, i.e., 4.82 and 4.27 t ha⁻¹, respectively, compared to W1 (5.71 t ha⁻¹). The plant height and leaf area index at the reproductive milk stage of maize (R3) were significantly reduced by all approaches of ethephon application compared to no ethephon. However, across the water levels, E3 performed better and produced a higher grain yield (5.11 t ha⁻¹), which was mostly seen by a higher 100-grain weight (24.52 g) and a slightly higher grain number per plant (356.12). It was also positively supported by most of the physiological and biochemical traits, as they were especially higher in the relative growth rate (25.73 mg plant⁻¹ day⁻¹), net assimilation rate (0.79 mg cm⁻² day⁻¹) at V6-R3, heat use efficiency (3.39 kg ha⁻¹ °C days⁻¹), electrolyte leakage (5.69%), and proline (28.78 µmol g⁻¹ FW). These traits, under prolonged stress, also gave the maximum drought tolerance index by E3, i.e., the relative growth rate (1.00) and net assimilation rate (1.00) at V6 to R3, heat use efficiency (1.06), relative water content (1.00), electrolyte leakage (1.65), proline (1.88), 100-grain weight (1.01), grain yield (1.11), and water productivity (1.53). A path analysis showed that the shoot weight at R3 (1.00), the stem diameter at the R3 stage (1.00), net assimilation rate (0.95), relative water content (0.95), 100-grain weight (0.90), grain number (0.76), proline (0.75), SPAD value (0.71), and total soluble sugar (0.57) were highly positive, and electrolyte leakage (−0.84) was negatively correlated with the grain yield under prolonged water stress. The maximum positive direct effect on the grain yield was found in the shoot weight (1.05), net assimilation rate (0.68), leaf area index at R3 (0.45), SPAD (0.22), and electrolyte leakage (0.21). The ethephon application as the E3 approach was more efficient in both short and prolonged stress, especially under prolonged stress, as it showed a higher energy use efficiency (1.55) and less CO₂-eq emission (3603.69) compared to the other approaches of ethephon. The subsequent efficient ethephon approaches were E1 under short water stress, E6 under prolonged water stress, where E5 performed minimally, and no application of ethephon, which exhibited the worst efficiency under water stress.