DNA Extraction from Half-grain Wheat Seeds without Using Chloroform

In order to overcome the problems that DNA extraction from wheat leaves for PCR is restricted by seasons and chloroform is difficult to be acquired, a method of DNA extraction from wheat seeds without using chloroform was estab- lished in this study. The DNA extracted from wheat leaves and seeds using chloro- form was used as control, the quality of DNA extracted from wheat seeds without using chloroform was examined by muiti-PCR. The results showed that the concen- tration of DNA extracted from wheat seeds by chloroform-free method was lower than those extracted from wheat leaves and seeds using chloroform. The amplifica- tion effect of DNA extracted from wheat seeds by chloroform-free method was also a little worse than those extracted from wheat leaves and seeds using chloroform, but this problem can be addressed though loading higher quantity of DNA sample or adopting polyacrylamide gel electrophoresis method. Therefore, the chloroform-free DNA extraction method can be used when there are no special requirements for DNA quality or chloroform cannot be acquired timely.

Arginine promotes seed energy metabolism,increasing wheat seed germination at low temperature

Low temperatures during germination inhibit seed growth,lead to small and weak seedlings,and significantly reduce the wheat yield.Alleviating the adverse effects of low temperature on wheat seed germination is highly important for achieving high and stable wheat yields.In this study,Tongmai 6(insensitive)and Zhengmai 113(sensitive),which have different low-temperature sensitivities during germination were treated with low temperature during germination.The transcriptome,metabolome and physiological data revealed that low temperature decreased the germination rate,downregulated the expression of a large number of genes involved in regulating glycometabolism,and inhibited carbon,nitrogen(especially amino acids)and energy metabolism in the seeds.Arginine content increased at low temperature,and its increase in the low-temperature-tolerant variety was significantly greater than that in the sensitive variety.Arginine priming experiment showed that treatment with an appropriate concentration of arginine improved the seed germination rate.The conversion of starch to soluble sugar significantly increased under exogenous arginine conditions,the content of key metabolites in energy metabolism increased,and the utilization of ATP in the seeds increased.Taken together,arginine priming increased seed germination at low temperature by relieving inhibition of seed carbon and nitrogen metabolism and improving seed energy metabolism.

Identification of P-type plasma membrane H^(+)-ATPases in common wheat and characterization of TaHA7 associated with seed dormancy and germination

The P-type plasma membrane(PM)H^(+)-ATPases(HAs)are crucial for plant development,growth,and defense.The HAs have been thoroughly characterized in many different plants.However,despite their importance,the functions of HAs in germination and seed dormancy(SD)have not been validated in wheat.Here,we identified 28 TaHA genes(TaHA1-28)in common wheat,which were divided into five subfamilies.An examination of gene expression in strong-and weak-SD wheat varieties led to the discovery of six candidate genes(TaHA7/-12/-14/-16/-18/-20).Based on a single nucleotide polymorphism(SNP)mutation(C/T)in the TaHA7 coding region,a CAPS marker(HA7)was developed and validated in 168 wheat varieties and 171 Chinese mini-core collections that exhibit diverse germination and SD phenotypes.We further verified the roles of the two allelic variations of TaHA7 in germination and SD using wheat mutants mutagenized with ethyl methane sulphonate(EMS)in‘Jimai 22’and‘Jing 411’backgrounds,and in transgenic Arabidopsis lines.TaHA7 appears to regulate germination and SD by mediating gibberellic acid(GA)and abscisic acid(ABA)signaling,metabolism,and biosynthesis.The results presented here will enable future research regarding the TaHAs in wheat.

Effect of Exogenous Gibberellin on Wheat Seed Germination under Salt Stress

[Objectives]In this experiment,wheat seeds were treated with different concentrations of gibberellin and different concentrations of salt solution to study the change of germination index of wheat seeds.[Methods]The germination rate,germination potential and germination index of wheat seeds were measured by routine methods,and the effect of exogenous gibberellin on germination of wheat seeds under salt stress was observed.[Results]The germination rate,germination potential and germination index of wheat seeds under salt stress were significantly increased after exogenous treatment of 0.25 and 0.50 g/L gibberellin within the range of salt concentration gradient.However,when the concentration of gibberellin was too high,it would inhibit the germination of seeds.[Conclusions]Appropriate concentration of gibberellin can effectively alleviate the stress caused by salt on wheat seed germination.In this experiment,the best concentration of gibberellin to alleviate salt stress was 0.25 g/L.

Effects of Nitric Oxide on the Germination of Wheat Seeds and Its Reactive Oxygen Species Metabolisms Under Osmotic Stress

Effects of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on the germination and metabolism of reactive oxygen species were surveyed in wheat (Triticum aestivum L.) seeds. Germination of wheat seeds and even the elongation of radicle and plumule were dramatically promoted by SNP treatments during the germination under osmotic stress. Meanwhile, activities of amylase and EP were enhanced, thus leading to the degradation of storage reserve in seeds. After osmotic stress was removed, higher viability of wheat seeds was also maintained. In addition, the activities of CAT, APX and the content of proline were increased by SNP treatment simultaneously, but activities of LOX were inhibited, and both of which were beneficial for improving the antioxidant capacity during the germination of wheat seeds under osmotic stress. It was also shown that the increase of the activity of amylase induced by SNP in embryoless half-seeds of wheat in the beginning period of germination (6 h) might be indirectly related to GA(3).

Field Experiment for the Effects of Rice Straw Returning and Seeding Pattern on Wheat Seedling Emergence and Grain Yield

In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows： in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was？recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.

Effects of Used Battery on Key Enzyme Activity during the Germination of Wheat Seeds

[Objective] This study aimed to explore the effects of used battery lixivium on wheat germination. [Method] The wheat seeds were treated with used battery lix- ivium at different concentrations to detect the change of activities of amylase, pro- tease, pyruvate dehydrogenase （PDH） and polyphenol oxidase （PPO） during the ger- mination period. [Result] The results showed that the used battery affected enzyme activity. With the increase of concentration of used battery lixivium, trends of the changes of amylase and protease activities were not different. The activities were en- hanced at low concentrations of lixivium, while were inhibited at high concentrations. The tends of changes of pyruvate dehydrogenase （PDH） and polyphenol oxidase （PPO） activities were not consistent with that of either amylase or protease, which showed continuous downward trends with the increasing concentration of used battery lixivium. [Conclusion] This study is of great practical significance for understanding the effects of used battery lixivium on the germination of wheat seeds.

Preliminary Studies on Inheritance of Seed Color in Black Wheat

[Objective]The aim was to study the inheritance property of the color of seed in black wheat.[Method]Segregation for seed coat colors was studied in F1,F2 and F3 population from eight crosses of four black-seed wheat cultivars（Heixiaomai76,Heixiaomai18,96-45 and S-1）with four white-seed wheat cultivars（9-231,Ningchun16,Ningchun17 and Xinchun22）.[Result]The results showed that the color of Heixiaomai 76 maternal genetic traits is controlled by two incompletely dominant genes,the segregation in F3 populations fits 9（dark）∶7（white）ratio.Color of S-1,96-45,and Heixiaomai 18 is controlled by two Independent and complementary genetic genes,the segregation for black kernel color in F2 populations fits 9（dark）∶7（white）ratio.[Conclusion]Different kinds of new species can be breed through the hybrid of black wheat and white wheat varieties.

Optimization of sowing date and seeding rate for high winter wheat yield based on pre-winter plant development and soil water usage in the Loess Plateau,China

Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)) and three seeding rates(SR67.5,SR90,and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.Suitable sowing dates for strong seedlings before winter varied with the seasons,that was SD2 in 2012–2013,SD3 in 2013–2014,and SD2 as well as SD1 in 2014–2015.Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage,and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages,leading to higher grain yield.SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014,it was close to that with SR67.5 or SR112.5.For productive growth from anthesis to maturity stages,SD2 with SR90 had the highest soil water consumption in all three seasons.The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.Ear number largely contributed to the seasonal variation in grain yield,while grain number per ear and 1 000-grain weight also contributed to grain yield,especially when soil water storage was high.Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.By selecting the suitable sowing date(1 October) in combination with the proper seeding rate of 90 kg ha–1,the best yield was achieved.Based on these results,we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.

Effect of Cold Plasma Treatment on Seed Germination and Growth of Wheat

This study investigated the effect of cold helium plasma treatment on seed germina- tion, growth and yield of wheat. The effects of different power of cold plasma on the germination of treated wheat seeds were studied. We found that the treatment of 80 W could significantly improve seed germination potential （6.0%） and germination rate （6.7%） compared to the control group. Field experiments were carried out for wheat seeds treated with 80 W cold plasma. Com- pared with the control, plant height （20.3%）, root length （9.0%） and fresh weight （21.8%） were improved significantly at seedling stage. At booting stage, plant height, root length, fresh weight, stem diameter, leaf area and leaf thickness of the treated plant were respectively increased by 21.8%, 11.0%, 7.0%, 9.0%, 13.0% and 25.5%. At the same time, the chlorophyll content （9.8%）, nitrogen （10.0%） and moisture content （10.0%） were higher than those of the control, indicating that cold plasma treatment could promote the growth of wheat. The yield of treated wheat was 7.55 t-ha-1, 5.89% more than that of the control. Therefore, our results show that cold plasma has important application prospects for increasing wheat yield.

Effect of polyamine on seed germination of wheat under drought stress is related to changes in hormones and carbohydrates

Drought is a multifaceted stress condition that inhibits crop growth. Seed germination is one of the critical and sensitive stages of plants, and its process is inhibited or even entirely prevented by drought. Polyamines （PAs） are closely associ- ated with plant resistance to drought stress and seed germination. However, little is known about the effect of PA on the seed germination of wheat under drought stress. This study investigated the involvement of PAs in regulating wheat seed germination under drought stress. Six wheat genotypes differing in drought resistance were used, and endogenous PA levels were measured during seed germination under different water treatments. In addition, external PAwas used for seed soaking and the variation of hormones, total soluble sugar and starch were measured during the seed germination under different water treatments. These results indicated that the free spermidine （Spd） accumulation in seeds during the seed germination period favored wheat seed germination under drought stress; however, the free putrescine （Put） accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress. In addition, seed soaking in Spd and spermine （Spm） significantly relieved the inhibition of seed germination by drought stress; howev- er, soaking seeds in Put had no significant effect on seed germination under drought. External Spd and Spm significantly increased the endogenous indole-3-acetic acid （IAA）, zeatin （Z）＋zeatin riboside （ZR）, abscisic acid （ABA）, and gibberellins （GA） contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination. This may promote wheat seed germination under drought stress. In conclusion, free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.

Preparation of a Novel Highly Effective and Environmental Friendly Wheat Seed Coating Agent

A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it could enhance the yield up to 16% and reduce its input cost to 1/6 as compared with the conventional wheat seed coating agent.It is safe without causing any pollution and would have significant economic and environmental benefits.

Differential Gene Expression Between Cross-Fertilized and Self-Fertilized Kernels During the Early Stages of Seed Development in Wheat

In order to understand molecular basis of cross-fertilized kernel advantage and heterosis, improved differential display of mRNA was used in this study to analyze alterations in gene expression between cross-fertilized and self-fertilized kernels at 2, 4, 6, 8, 10 and 12 days after pollination (DAP) by using 3 wheat hybrids with different level of heterosis. Four patterns of differential expression were observed: (i) bands observed in cross-fertilized kernels but not in self-fertilized kernels (BCnS); (ii) bands occurring in only self-fertilized kernels but not in cross-fertilized kernels (BSnC); (iii) cDNA over-expressed in cross-fertilized kernels compared to self-fertilized kernels (OEC); (iv) cDNA under-expressed in cross-fertilized kernels compared to self-fertilized kernels (UEC). Further analysis showed that BCnS is positively correlated with heterosis, but BSnC is negatively correlated with heterosis. Four differentially expressed cDNA fragments were verified by reverse-northern blot and sequence homology search in GenBank showed that one of them was new sequences; the other exhibited higher similarity to NBS-LRR type resistance protein, 1,6-bisphosphatase and photosystem Ⅱ chlorophyll a-binding protein psbB, respectively, which indicated diverse pathways may be involved in heterosis formation.

Proteomic Analysis of Wheat Seed in Response to Drought Stress

Drought stress is one of the major factors affecting in wheat yield and grain quality. In order to investigate how drought stress might influence wheat quality during grain filling, three wheat cultivars Gaocheng 8901, Jagger and Nongda 3406 were subjected to drought stress during the grain filling stage. Neither globulin and glutenin, nor the relative percentage ofamylose significantly changed following drought treatments, whereas albumin and gliadin concentrations did. The SDS-sedimentation, which has a strong linear correlation with wheat baking quality was markedly decreased following drought stress. These results indicated that drought had an adverse effect on wheat qualit3,. In order to investigate the protein complexes in the wheat flour, the data from native PAGE and SDS-PAGE were combined and a total of 14 spots were successfully identified, and of these eight protein types were determined to be potential complex forming proteins.

Seed Yield Potential of Five Wheat Species/Cultivars without and with Phosphorus Fertilizer Application on a P-Deficient Soil in Northeastern Saskatchewan

In the Canadian Prairies, many soils on organic farms are low in available phosphorus (P). Previous research has shown that wheat species/cultivars vary in their sensitivity to P deficiency, yield response to applied P fertilizer, P uptake and P use efficiency on P-deficient soils. A 3-year field experiment was conducted from 2012 to 2014 on a P-deficient soil at Kelvington, Saskatchewan, Canada, to determine the potential of five wheat species/cultivars (Spelt and Kamut representing “ancient”, Red Fife representing “old”, and Unity and Goodeve representing “modern” wheat species/cultivars) for seed yield, protein concentration (PC) in seed, partial factor of productivity (PFP, kg seed kg-1 of N applied), total N and P uptake, P use efficiency (PUE, kg seed kg-1 of P applied) and % recovery of applied P in seed under zero-P and with P fertilizer (triple superphosphate) applied at 20 kg P ha-1. Seed yield, PFP and PUE were determined in all 3 years, but PC, total N and P uptake, and % recovery of applied P in seed were determined only in 2012. There was a marked and significant response of seed yield and PFP of all wheat species/cultivars to P fertilizer in all 3 years, but the actual seed yield and PFP, without and with applied P fertilizer, as well as PUE, varied with species/cultivar in different years. On the average of 3 years, seed yield and PFP were greatest for Unity in both without and with applied P fertilizer treatments. Seed yield increases from applied P were 1111, 773, 890, 1810 and 2028 kg·ha-1, respectively, for Spelt, Kamut, Red Fife, Unity and Goodeve. Total N and P uptake were lowest for Kamut and greatest for Unity or Goodeve, in both without and with applied P fertilizer treatments. Percent recovery of applied P in seed was greatest for Goodeve or Unity and lowest for Spelt or Kamut. Protein concentration in seed usually decreased with P fertilizer, and wheat species/cultivars with higher PC in seed usually showed greater reduction in PC with P application. In conclusion, the findings suggest that the “modern” wheat species/cultivars Unity or Goodeve might be more suitable for high sustainable seed yield and total P or N uptake than the “ancient” wheat species Spelt and Kamut or the “old” wheat cultivar Red Fife, especially when adequate amount of P fertilizer is applied to optimize crop production on a P-deficient soil.

Planting Date, Seeding Rate, and Cultivar Impact Agronomic Traits and Semolina of Durum Wheat

Durum wheat (Triticum durum Desf.) is a market class of wheat subject to price discounts in the marketplace if quality standards are not met. This study was conducted in order to determine how certain agronomic practices might impact durum wheat quality. The effects of planting date (PD), cultivar, and seeding rate on agronomic and semolina quality traits were investigated in field trials conducted near Hettinger and Minot, ND in 2014 and 2015. The interaction of PD and cultivar was significant for many of the traits evaluated. There was a significant PD X cultivar interaction or PD and cultivar effect for yield in all environments. Planting date X cultivar interacted for test weight at all environments. In general, a delay in PD resulted in a significant decrease in yield and test weight for all cultivars. However, Carpio yielded more than other cultivars in high yielding environments while the yield and test weight of Joppa was more adversely affected by delays in PD. Seeding rate did not have a consistent effect on any agronomic or quality trait. Protein content, kernel yellow pigment content, falling number (FN), and vitreous kernels were more dependent on cultivar, regardless of PD and environment. Semolina extraction, gluten index (GI), and wet gluten (WG) values tended to decrease with a delay in PD. These data continue to support cultivar selection as a critical component for obtaining high-yielding, high-quality durum wheat. However, PD and environment can impact certain agronomic and end-use traits, regardless of cultivar grown.

Negative Association between Seed Dormancy and Seed Longevity in Bread Wheat

Many organisms have dormant stages with an extension of their life span to increase longevity, and deeper dormancy is usually related to greater longevity. In cereal crops, seed dormancy is significantly associated with pre-harvest sprouting tolerance during seed development, as seed longevity is a valuable trait for seed banks and providing reliable crop seeds to farmers. In this study, we evaluated both seed dormancy and longevity in bread wheat based on germination and artificial aging tests. According to phenotypic clustering analysis, relative germination rate/potential and relative seedling vigor index were more effective to indicate seed longevity than relative electrical conductivity in wheat, while all the four investigated phenotypes of relative germination potential, relative germination rate, germination index and degree of seed dormancy fit well as a reflex of wheat seed dormancy. In the correlation analysis, the germination level of newly harvested grain negatively reflected its degree of seed dormancy, while the germination ability of grain after artificial aging reflected its seed longevity. However, in contrast to the current opinion in plant, seed dormancy was significantly negatively correlated to seed longevity in our study, and it was not an accidental phenomenon, for that the majority of accessions with high degree of seed dormancy had short seed longevity. To our knowledge, this is the first to report the negative association between seed dormancy and longevity in cereal crops. It would lead to further concerns about how to breed wheat with both prolonged seed longevity and deep dormancy to avoid pre-harvest sprouting.

Effects of Different Row Ratios of Male and Female Parents and Application Amount of Nitrogen Fertilizer on Hybrid Wheat Seed Production and Its Component Factors

In order to screen suitable high hybrid wheat seed production technology,the split-plot experiment design was adopted and study was carried out about the effects of the different row ratios of male and female parents and application amount of nitrogen fertilizer on hybrid wheat seed production and its component factors. The results showed that the seed production increased with the increase in the number of female parent row. When the row ratio of male and female parents was 2 ∶ 6,the seed production was 3 683. 8 kg/ha; when the application amount of nitrogen fertilization was 50 kg/ha,the seed production was 3 649. 4 kg/ha; the interaction between the row ratio of male and female parents and the application amount of nitrogen fertilizer indicated that when the row ratio of male and female parents was 2∶ 6 and the application amount of nitrogen fertilizer was 300 kg/ha,the seed production reached the highest( 4160. 6 kg/ha). The row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the component factors of seed production,including the number of grains per spike,spike weight and setting percentage. When the row ratio of male and female parents was 2∶ 5,the number of grains per spike,spike weight and setting percentage were the highest at 26. 7 grains,1. 12 g,and 62. 6% respectively; when application amount of nitrogen fertilizer was 450 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 26. 0 grains,1. 08 g,and59. 2% respectively; the interaction of row ratio of male and female parents and application amount of nitrogen fertilizer had significant effect on the number of grains per spike,spike weight and setting percentage; when the row ratio of male and female parents was 2∶ 5 and the application amount of nitrogen fertilizer was 300 kg/ha,the number of grains per spike,spike weight and setting percentage were the highest at 29. 6grains,1. 24 g,and 71. 6% respectively. The number of grains per spike is the largest component factor for seed production. Increasing the number of grains per spike can increase the seed production. According to the effects of row ratio of male and female parents and application amount of nitrogen fertilizer on the component factors of seed production,the optimal condition was 2∶ 5-2∶ 6 for row ratio of male and female parents and 300-450 kg/ha for application amount of nitrogen fertilizer.

Testing of Seedborne Fungi in Wheat Germplasm Conserved in the National Crop Genebank of China

There is a primary understanding of the dominant fungi in wheat seeds conserved in the National Crop Genebank of China （NCGB） and an evaluation of the healthy status of wheat germplasm propagated in different regions. A total of 1 465 wheat accessions were detected for seedbone fungi by blotter, agar plate, and wash tests. By blotter test, 17 genera of fungi, including more than 30 species, were detected in 712 wheat accessions from Shaanxi, Hebei, and Qinghai provinces, China. Alternaria was the most frequently detected in wheat seeds from Shaanxi Province, followed by Rhizopus, Penicillium, Aspergillus, Bipolaris, Cladosporium, Gonatobotrys, Chaetomium, and others. Seedborne fungi in wheat seeds from Hebei Province, with relatively high incidence were Alternaria, Rhizopus, Penicillium, Aspergillus, Bipolaris, Cladosporium, and Fusarium. In the seeds from Qinghai Province, Alternaria, Rhizopus, Bipolaris, Cladosporium, and Trichothecium are important seed-borne fungi. The seed germination was reduced substantially when seeds were infected by Fusarium verticillioides （syn. F. moniliforme）, Bipolaris nodulosa, and Cladosporium herbarum. Eighteen genera and 25 species of fungi were identified in 353 accessions from Shaanxi Province using the agar plate test. The dominant fungi were Alternaria, Aspergillus, Bipolaris, Gonatobotrys, Penicillium, and Fusarium. The smut fungi, Ustilago tritici, was detected by the wash test in 400 accessions, but it was low in incidence in 300 seed samples from Shaanxi Province （1.3%）, and in 100 samples from Hebei Province （2.0%）. Totally 19 genera of fungi were detected in wheat seed samples, and some seedborne fungi were saprophytic and others were biotrophic which could cause seedborne diseases in the field.

Physiological Mechanism of Thermotolerance in Wheat (<i>Triticum aestivum</i>Lin.) Seedlings

A research work was performed under sub-tropical condition (24&deg;8'N, 90&deg;0'E) at Bangabandhu Sheikh Mujibur Rahman Agricultural University with three wheat genotypes (BARI Gom 25, BARI Gom 26 and Pavon 76) to observe the mobilization of seed reserve and seedling growth under normal (15&deg;C/25&deg;C) and elevated (25&deg;C/35&deg;C) temperature in growth chamber. The effect of high temperature on wheat seedling was observed in terms of mobilized seed reserve, respiration and transpiration efficiency and seedling growth. At 35&deg;C temperature, maximum mobilization of seed reserve was observed in BARI Gom varieties (BARI Gom 25 and 26) but the respiration efficiency was higher in Pavon 76 in comparison to other genotypes. Maximum loss of respiration and transpiration at 35&deg;C temperature was found to produce low seedling growth in Pavon 76. It appeared from the result that at high temperature the maximum mobilized seed reserve and subsequently minimum loss of respiration and transpiration collectively contributed a positive role for better seedling growth in BARI Gom 25 and BARI Gom 26. Therefore the better mobilized seed reserve and subsequently minimum loss of respiration and transpiration during seedling development are indicators of the thermo tolerance in growing wheat seedling.