Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology for the evaluation of the drought-tolerant wheat genotypes based on the pheno-physiological traits, a field experiment was executed, entailing four wheat genotypes viz. BARI Gom 26, BAW 1158, BAW 1167, and BAW 1169 and two water conditions viz. control treatment (three times irrigation at 20, 50, and 70 DAS, i.e., 100% field capacity) and stressed treatment (no irrigation during the entire growing season). The results revealed that drought stress drastically reduced the days to booting, heading, anthesis and physiological maturity, relative water content (RWC), chlorophyll content, canopy temperature depression (CTD), and photo-assimilates-spike dry matter (SDM), grains spike−1 and grain yield of all wheat genotypes. In addition, the genotypes BAW 1167 and BARI Gom 26 remained more prone to adverse effects of drought as compared to BAW 1169 and BAW 1158. Furthermore, DS induced biosynthesis of compatible solutes such as proline, especially in BAW 1169, which enabled plants to defend against oxidative stress. It was inferred that BAW 1169 remained superior by exhibiting the best adaptation as indicated by the maximum relative values of RWC, total chlorophyll, CTD, proline content, SDM, grains spike−1, and grain yield of wheat. Thus, based on our findings, BAW 1169 may be recommended for general adoption and utilization in future wheat breeding programs aimed at developing potent drought-tolerant wheat genotypes to ensure food security on a sustainable basis.

Plant non-specific lipid transfer proteins (nsLTPs) are involved in many biological processes. In this study, 51, 47 and 91 nsLTPs were identified in Gossypium arboreum, G. raimondii and their descendant allotetraploid G. hirsutum, respectively. All the nsLTPs were phylogenetically divided into 8 distinct subfamilies. Besides, the recent duplication, which is considered cotton-specific whole genome duplication, may have led to nsLTP expansion in Gossypium. Both tandem and segmental duplication contributed to nsLTP expansion in G. arboreum and G. hirsutum, while tandem duplication was the dominant pattern in G. raimondii. Additionally, the interspecific orthologous gene pairs in Gossypium were identified. Some GaLTPs and GrLTPs lost their orthologs in the At and Dt subgenomes, respectively, of G. hirsutum. The distribution of these GrLTPs and GaLTPs within each subfamily was complementary, suggesting that the loss and retention of nsLTPs in G. hirsutum might not be random. Moreover, the nsLTPs in the At and Dt subgenomes might have evolved symmetrically. Furthermore, both intraspecific and interspecific orthologous genes showed considerable expression variation, suggesting that their functions were strongly differentiated. Our results lay an important foundation for expansion and evolutionary analysis of the nsLTP family in Gossypium, and advance nsLTP studies in other plants, especially polyploid plants.

Three heat tolerant (Aghrani, Kanchan and CBwheat genotypes having the ability to withstand 30) and one heat sensitive (Sonora) wheat genotypes were high temperature stress are known as heat tested under normal and post anthesis heat stress condition tolerant (HT) genotypes and they show greater by seeding them on November 30 and December 30, 2001 at the research farm of Bangabandhu Sheikh Mujibur Rahman heat killing time in MT test. On the other hand, Agricultural University (BSMRAU), Gazipur, Bangladesh to the genotypes which do not have the ability to study their kernel growth physiology in relation to heat stress. Irrespective of growing conditions, both dry matter and starch accumulation in kernel showed a typical sigmoidal pattern in all genotypes. Due to post anthesis heat stress, the quantity of dry matter accumulation a t peak and the duration required to attain peak were higher in heat tolerant (HT) genotypes than the heat sensitive (HS) one. Sonora, a HS genotype, responded to post anthesis heat stress by accumulating larger quantity of soluble sugar during active kernel development period in contrast to HT genotypes indicating poor capacity of kernel of Sonora to utilize sugar for starch synthesis. The heat tolerant genotypes exhibited distinctly higher relative individual kernel dry weight under post anthesis heat stress condition when compared to heat sensitive genotype.

Drought stress significantly limits cotton growth and production due to the necessity of water at every stage of crop growth. Hence, it is essential to identify tolerant genetic resources and understand the mechanisms of drought tolerance in economically and socially important plants such as cotton. In this study, molecular and physio-biochemical investigations were conducted by analyzing different parameters by following standard protocols in three different cotton species, namely TM-1 (Gossypium hirsutum), Zhongmian-16 (Gossypium arboreum), and Pima4-S (Gossypium barbadense). Drought stress significantly decreased plant growth, chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), maximum photochemical efficiency of PSII (Fv/Fm), and relative water content. TM-1 resulted in more tolerance than the other two species. The accumulation of proline, soluble proteins, soluble sugars, hydrogen peroxide (H2O2), and superoxide radicals (O2•−) increased significantly in TM-1. In addition, TM-1 maintained the integrity of the chloroplast structure under drought conditions. The relative expression level of drought-responsive genes including coding for transcription factors and other regulatory proteins or enzymes controlling genes (ERF, ERFB, DREB, WRKY6, ZFP1, FeSOD, CuZnSOD, MAPKKK17, P5CR, and PRP5) were higher in TM-1 under drought, conferring a more tolerant status than in Zhongmian-16 and Pima4-S. The findings of this research could be utilized for predicting a tolerant cotton genotype as well as evaluating prospective cotton species in the variety development program.

Four wheat cultivars e.g., Aghrani, Kanchan, CB-30 and Sonora were tested under normal and post anthesis heat stress condition by seeding them on November 30 and December 30 to evaluate the heat tolerance of wheat in relation to proline content. Time to exceed 50% membrane leakage was about four times longer in Aghrani, and the cultivars were grouped as heat tolerant (HT) than in Sonora (30 min) which considered as heat sensitive (HS). Due to post anthesis heat stress condition the HS cultivar Sonora in comparison to heat tolerant (HT) genotype exhibited larger decrease in kernel proline (47.2%) along with larger increase in flag leaf proline (122%). The heat tolerant cultivars exhibited distinctly higher relative individual kernel dry weight, higher kernel number per spike, higher relative grain yield and low susceptibility index for grain yield under post anthesis heat stress condition compared to heat sensitive cultivar. Strong correlation existed between heat killing time in membrane thermostability test and relative change to normal in proline content (both in flag leaf and kernel) and between heat susceptibility index for grain yield and relative change to normal in proline content.

ABSTRACT

A field experiment was conducted at the research farm of Crop Physiology and Ecology Department, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh during November 2010 to May 2011 to find out the effect of seedlings age and water management on tillering behavior, growth dynamics, yield and yield contributing characters of BRRI dhan28. The experiment was laid out in two factors randomized complete block design with four replications taking two seedlings age i.e. 15 and 30-d-old seedlings at transplanting and two water management practices viz. continuous flooding and intermittent irrigation. Fifteen-d-old seedlings provided greater ability of tiller production, dry matter accumulation and more leaf area than those of 30-d-old seedlings but the ability was influenced more with intermittent irrigation than continuous flooding. Transplanting of younger seedlings provided more effective tillers hill-1, filled grains panicle-1, thousand grain weight and finally grain yield than those of the older one but the younger seedlings interacted with intermittent irrigation significantly to explore all of these parameters. Fifteen-d-old seedlings of took shorter time to be matured than 30-d-old seedlings in both continuous flooded and intermittent irrigated condition. Again the crop matured 2 days earlier in intermittent irrigated plots than continuous flooded plots for both 15 and 30-d-old seedlings. Finally it may be concluded that transplanting of younger seedlings in combination with intermittent irrigation performed the best in tiller production, growth dynamics, yield and yield contributing characters. DOI: http://dx.doi.org/10.3329/agric.v11i2.17484 The Agriculturists 2013; 11(2) 28-37

The experiment was conducted in the Laboratory, Department of Plant Pathology,  HSTU, Dinajpur during April – July 2010 to know the effect of abiotic and biotic  factors, storage periods and storage containers on the seed quality of French  bean. Tin container showed the highest germination, normal seedlings and  vigour index which were followed by polythene bag, where Gunny bag showed  the lowest germination, normal seedlings and vigour index upto 60 days after  storage. The highest 1000-seed weight, moisture content, abnormal seedlings,  seed rot and incidence of the Fusarium oxysporum were recorded in Gunny bag,  where the lowest of these parameters were recorded in Tin container. Seed  colour of Tin container were more or less same as initial colour, but seeds of  Gunny bag were changed into fade or brown colour at 60 days after storage.  Moisture content, 1000-seed weight, abnormal seedlings, seed rot, fungi  association were increased, but germination and normal seedlings were  decreased with the increase of storage periods. Among the three containers, Tin  container was the best and the Gunny bag was the worst storage containers upto  60 days of storage for French bean seed. DOI: http://dx.doi.org/10.3329/bjar.v37i2.11221 Bangladesh J. Agril. Res. 37(2): 195-205, June 2012