An experiment was conducted under pot culture to investigate physiological responses as well as antioxidative enzymes activities that may lead to select sesame genotype (s) which were more waterlogging tolerant at vegetative stage. Four sesame genotypes viz. BD-6980, BD-6985, BD-6992 and BD-7012 were grown under waterlogged (at vegetative stage) and control (no waterlogged) conditions. Plant height, root length, root volume, root dry weight and leaf area per plant in all the four sesame genotypes significantly decreased due to waterlogging at vegetative stage in comparison to controlled condition. Higher SPAD value (Soil and Plant Analyzer Development) and specific leaf mass were recorded in waterlogged plant than controlled plant during waterlogging period but reverse was the case during recovery period. All the genotypes showed positive indices of waterlogging tolerance in terms of better performance of root, stem, leaf and petiole. Among the genotypes, BD 6980 showed higher waterlogging tolerance in all the components followed by BD 6985. Malondialdehyde (MDA) content was found higher in waterlogged plant of all the four sesame genotypes in both waterlogging period and recovery period than the controlled plant. Antioxidant enzyme activities like Peroxidase (POD), Catalase (CAT), Ascorbate peroxidase (APX), Glutathione peroxidase (GPX) and Superoxide dismutase(SOD) were inconsistent in the present study but most of the antioxidant enzyme activities showed an increasing trend in waterlogged plant than that of control plant in all the genotypes. Comparatively low amount of MDA content and high antioxidant activities of sesame genotype BD 6980 is considered as highly tolerant to waterlogging and other three genotypes are moderately tolerant under water logging condition.

A pot experiment was conducted with five selected rapeseed/mustard genotypes (BJDH-11, BJDH-12, BJDH-20, BARI Sarisha-14, and BARI Sarisha-16) under two sowing dates (November 20 and December 20) for evaluating their responses to sowing date induced high temperature stress during rabi season of 2017-18. Sowing dates induced temperature variability showed remarkable changes in pheonlogy, leaf area, leaf chlorophyll content, dry matter production and seed yield. Although December 20 sown crop received lower temperatures (minimum 9.8 to 13.2 and maximum 22.6 to 27oC) than November 20 sown crop (minimum 14.8 to 16.4 and maximum 21 to 27.2oC) at flowering but reverse was found at grain development stage. Grain development stage of November 20sown crop received lower temperatures (minimum 8.2 to 13.2 and maximum 24.1 to 27 oC) while December 20 sown crop received higher temperatures at grain development stage (minimum 8.2 to 18 and maximum 22.6 to 32.5oC).As a result December 20 sown crop matured earlier (6 to 9 days) than November 20 sown crop. Leaf area/plant was higher in December 20 sown crops compared to November 20 sown but total dry matter production was more or less same in both the sowing dates. Leaf chlorophyll content did not show any remarkable variation due to variation in sowing dates. However, antioxidant activity like Catalyse (CAT), Peroxidase (POD) Ascorbate peroxidase (APX) and Malondial dehyde (MDA) were found higher in December 20 sown crops than that of November 20sown. Higher activity of APX, POD and CAT with lower activity of MDA indicates comparatively high temperature tolerant genotype. Among the genotypes APX, POD and CAT activity were found higher with lower activity of MDA in BJDH-11 and BJDH-20 and these genotypes also gave higher yield than others. On the basis of growth parameters, antioxidant activity and seed yield of genotype BJDH-11 and BJDH-20 could be select as terminal high temperature tolerance genotypes. Bangladesh Agron. J. 2019, 22(1): 47-56

The presence of water or the degree of soil saturation has a direct impact on the root development and function in rice. In this regard, a pot investigation was performed to test the response of root traits and yield components of boro (irrigated) rice. Three boro rice varieties named Binadhan-10, Hira-2 and BRRI dhan 29 were grown at four irrigation regimes, viz. continuous flooding (CF), saturation (S), 75% S and 50% S at Bangladesh Agricultural University, Mymensingh, Bangladesh, throughout the boro period of 2020–2021. The study was replicated three times by employing a completely randomized design (CRD) method. The study revealed a drastic decline in root attributes at 75% and 50% S. A significant increase in root number (RN), root length (RL), root volume (RV), total dry matter (TDM) and grain yield (GY) under S condition followed by CF was observed. Binadhan-10 exhibited the largest scores of RN (359.00), RL (1577.83 cm) and RV (8.34 cm3 hill−1) at 80 DAT under S condition. Root attributes and GY were found to be substantially and positively associated in all observations. Binadhan-10 performed best with regard to seed output (26.13 g pot−1) under S condition. S condition increased the yield of Binadhan-10 in CF, 75% S and 50% S by 4.06%, 23.72% and 46.00%, respectively.

Nitrogen (N) is a highly essential macronutrient for plant root growth and grain yield (GY). To assess the relationship among N, root traits, and the yield of boro (dry season irrigated) rice, a pot experiment was performed in the Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh, during the boro rice season of 2020–2021. Three boro rice varieties, namely BRRI dhan29, Hira-2, and Binadhan-10, were planted at four N doses: 0 kg ha−1 (N0), 70 kg ha−1 (N70), 140 kg ha−1 (N140), and 210 kg ha−1 (N210). The experiment was conducted following a completely randomized design with three replicates. The varieties were evaluated for root number (RN), root length (RL), root volume (RV), root porosity (RP), leaf area index (LAI), total dry matter (TDM), and yield. The results indicated that the Binadhan-10, Hira-2, and BRRI dhan29 varieties produced better root characteristics under at the N140 and N210 levels. A substantial positive association was noticed between the grain yield and the root traits, except for root porosity. Based on the root traits and growth dynamics, Binadhan-10 performed the best at the N140 level and produced the highest grain yield (26.96 g pot−1), followed by Hira-2 (26.35 g pot−1) and BRRI dhan29 (25.90 g pot−1).