Fakhrul Islam Monshi

Drought stress is one of the key factors impeding agricultural productivity worldwide. This experiment aimed at investigating the polyethylene glycol (PEG)-induced drought stress effects on seed germination, physiology, and biochemical mechanisms in Tartary buckwheat genotypes. Four PEG-induced stress conditions (0%, 10%, 20%, and 30%) were applied to 14 selected genotypes at the germination stage to evaluate their stress tolerance capacity. Significant differences were obtained in germination percentage, relative water content (RWC), and all growth parameters among the studied 14 genotypes. Based on the stress tolerance index (STI), XiNong 9943, XiNong 9940, and QianKu-5 were found to be tolerant, and QuanKu-4 was susceptible. These cultivars were selected for further physiological and biochemical characterization. The results demonstrated that the activity of enzymes was significantly increased with the increase in PEG dose. SOD (superoxide dismutase), POD (peroxidase), CAT (catalase), and APX (ascorbate peroxidase) levels obtained at 30% PEG in the XiNong 9943 genotype were 2.01, 2.19, 4.92, and 4.46 times higher, respectively, than the normal growth condition (T₀). Moreover, the secondary metabolite content also increased with the increase in PEG dose. At 30% PEG, the genotype XiNong 9943 yielded phenols, flavonoids, polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) levels that were higher by 131%, 95%, 154%, and 164%, respectively, than T₀ condition. From both the findings of the activity of enzymes and the secondary metabolite content, the genotypic response to drought was ranked in the following order: XiNong 9943 > XiNong 9940 > QianKu-5 > QianKu-4, which supported the STI selection system. Assessing the overall performance, the genotype XiNong 9943 shows drought tolerance, which can be useful material for future buckwheat breeding programs.

High temperature during grain filling stage in wheat is greatly affects the wheat production by altering its physiological and biochemical process. Understanding the response of physio-biochemical traits of wheat genotypes under late sowing heat stress condition will facilitate the development of high yielding, stress-tolerant wheat genotypes. Eight diverse wheat cultivars were used to characterize the physiological and biochemical traits for the improvement of heat tolerance by using heat tolerance index (HTI), heat susceptibility index (HIS), multivariate analysis and heatmapping. The flag leaf proline content and water-soluble carbohydrate (WSC) accumulation were increased by 19.0% and 38.9% respectively, while in kernel, the proline was decreased by 23.5% from the optimum to late grown heat condition. The principal component analysis and biplot analysis showed that initial principal components, PC1 and PC2 represented 83% of total cumulative variation. The chlorophyll content, yield and yield contributing characters, proline and WSC showed significant differences between the heat tolerant and heat susceptible variety. Among the studied cultivars, BARI GOM-30 performed better than the others in heat stressed condition. The cluster analysis demonstrated the cultivars were categorized into three groups and Spk and Gr seem to be interesting traits as well as HTI and HIS. It’s concluded that the physio-biochemical traits associated with HTI for grain yield are the major factors which may contribute in improved wheat productivity. If these traits performed appropriately under stress condition the crop will show more productive returns under changing climate.

Rapeseed-mustard is an important oilseed species with high nutritional and economic values; it’s popularity increases due to its diverse uses. Ten genotypes of rapeseed-mustard and two sowing dates were evaluated in a split plot design with three replications. Our study demonstrated that sowing dates and genotypes greatly influenced the growth parameters, yield, and it contributing characters. BARI sarisha-16 had the highest yield (1613 kg.ha^-1) whereas Binasarisha-9 yielded the lowest yield (840 kg.ha^-1). All the yield contributing characters was superior in the earlier (10 November, S₁) sowing date than the 24 November (S₂), demonstrated by the highest grain yield (1120 kg.ha^-1) which was 10 % higher than the seed sown on 24th November (S₂) (1025 kg.ha^-1), and better higher vegetative growth. These results affirmed that the yield contributing traits resulted the higher seed yield. In most of the studied characters, the higher phenotypic variances were observed than that of its genotypic variances. The significant positive correlation with grain yield were found in plant height, number of primary branches/plants, number of siliqua/plants, siliquae length, number of seed per siliquae, days of 50% flowering to maturity and 1000 seed weight. Therefore, based on the yield and the related traits, BARI sarisha-16 can be used for further utilization.