Role of thiourea in improving productivity of wheat (Triticum aestivum L.)

The role of thiourea (TU), a sulfhydryl compound, was assessed in wheat via soil and foliar treatments. Results showed that at 30 days after flowering, soil-applied TU treatments did not influence dry matter accumulation or its distribution in leaves, stems, and ears, but foliar-applied treatments brought about significant effects varying with the timing of spray. At harvest, however, soil-applied treatment of 10 kg/ha TU increased the number of ears, grains/ear, weight/grain, biological yield (total above ground biomass), grain yield, and harvest index. Grain yield increased by 17.3% over control. Soil-applied 20 kg/ha TU increased the grain yield by 1.6% over control. Foliar applied treatment of 0.5 kg/ha TU at tillering increased the number of ears, grains/ear, weight/grain, biological yield, grain yield, and harvest index. Grain yield increased by 15.2% over control. Foliar spray of 0.5 kg/ha TU at flowering tended to improve only weight/grain, but biological yield and grain yield increased significantly. Grain yield increased by 6.6% over control. TU spray at both tillering and flowering increased the number of ears, grains/ear, weight/grain, biological yield, grain yield, and harvest index. Grain yield increased by 23.9% over control, and when compared with spray at tillering there was a significant increase of 7.5%. Thus, two foliar sprays of thiourea, at tillering and at flowering, at 1 kg/ha can be recommended for improving wheat productivity.Abbreviations TU thiourea - DMA dry matter accumulation - DMD dry matter distribution     

Studies in the Diagnosis of Mineral Deficiency

Material from four fertilizer trials on barley in Hampshire was analysed with the principal purpose of comparing the extent to which the potassium content of different plant organs was diagnostic of potassium deficiency. Samples of older leaf blades and sheaths, young leaves, stems and ears were gathered at the time of ear emergence from each of the 108 plots, and analysed spectrographically for calcium, iron, magnesium, manganese, potassium and sodium.
Differences in composition between plants from the different sites were proportionately greater in the older leaf blades than in the other organs for calcium, the young leaves for manganese and sodium, and the older leaf blades and sheaths for potassium. Differences in sodium and manganese content at the different sites appeared to be related to the differences in potassium status.
Applications of muriate of potash increased the potassium content of all organs except the ears, and decreased the content of magnesium, manganese and sodium, and of iron at one site. The effect of potassium supply on manganese and sodium content was most marked in the young leaves. The proportional increases observed in potassium content as a result of application of muriate of potash were similar at all four sites, in spite of the fact that responses in growth and yield differed greatly.
As between the four sites, the responses to muriate of potash observed in the yields of grain are significantly correlated with the potassium content of the older leaf blades and the stems, and the following tentative limiting values are put forward, above which no increase in grain yield as a result of potassic manuring may be expected:
(a) in the older leaf blades at the time of ear emergence 0.92% potassium in dry matter, (b) in the stems at the time of ear emergence 1–01 % potassium in dry matter.     

Studies in the diagnosis of mineral deficiency; the composition of weed leaves in relation to potassium deficiency in barley

Leaves of five weed species (Brassica sinapis, Cirsium arvense, Polygonum aviculare, P. convolvulus and Potentilla reptans) from fertilizer trials on barley at four sites in Hampshire were analysed with a view to using their composition in forecasting the response of barley to fertilizers. The samples were gathered from as many of the 108 plots as possible, and were analysed spectrographically for calcium, iron, magnesium, manganese, potassium and sodium.
Marked differences in composition between the five species were recorded, the most noteworthy being the high sodium content of Brassica sinapis and Cirsium arvense and the high manganese content of Potentilla reptans. There were also marked differences between the four sites, but these were not uniform as between the different species, and often failed to agree with those observed for barley.
Superphosphate applications decreased the manganese content of the weeds in many cases, and increased their calcium content. Muriate of potash increased their potassium content, but tended to decrease that of magnesium and sodium. The only general effect of sulphate of ammonia on the composition of the weeds was a decrease in iron content.
Except in Cirsium arvense , the potassium content of weed leaves was correlated with that of barley on the same plot if differences within a site only were considered. Differences between sites were not correlated in this way. The correlation between potassium content of weed leaves and the response of barley to muriate of potash application was worthy of note only in Polygonum convolvulus , and even in this case the correlation of site differences did not reach significance. It is tentatively suggested that increases in the grain yield of barley as a result of muriate of potash application are likely to occur only where the leaves of P. convolvulus contain less than 1.83% potassium.     

Glycolipid and phospholipid composition of wheat and barley chloroplasts

Composition of complex lipid of chloroplasts of two cultivars of wheat and barley was determined at tillering, ear emergence and grain filling stages. The chloroplast lipids, MGDG, DGDG and PG were maximum at grain filling stage in both wheat and barley. PC content showed variations at different stages in both the crops while no significant changes were observed in PI concentrations at grain filling stage.     

The growth, yield and nutrient uptake of winter wheat following root-pruning

The effect of root-pruning on shoot growth was investigated in winter wheat growing in lysimeters. Removal of half of the root axes at the beginning of stem elongation reduced shoot dry matter, determined 1 month after pruning, by 13% and grain yield by 8%. Removal of either the seminal or nodal root system during tillering reduced shoot dry weight, measured during the growing season, by 7% and grain yield by 25%. Root-pruning had negligible, or only transient, effects on the concentration of nitrogen, phosphorus, potassium, magnesium and manganese in the shoots. The harvest index was not affected by root-pruning.     

Time-dependent distribution of sulphur, sulphate and glutathione in wheat tissues and grain as affected by three sulphur fertilization levels and late S fertilization

Sulphur (S) fertilization has beneficial effects on yield and protein composition of mature wheat kernels. However, to understand the impact of S fertilization on storage protein composition, synthesis of S-containing compounds and their distribution during grain development has to be examined. A pot experiment with Triticum aestivum cultivar Türkis under three S fertilization levels (0 g, 0.1 g und 0.2 g S per pot) and a late S fertilization level at ear emergence was carried out. Stalk and leaves, flag leaves, ears and kernels were harvested separately during grain development at ear emergence, milk ripeness and maturity, and analyzed for elemental S, sulphate, glutathione, and protein concentration. Sulphate is the major S compound in stalk, leaf and ears at the start of grain development, whereas glutathione is more important for synthesis of S-containing proteins in the grain. The discrepancy of S concentration comparing low and high S fertilization became obvious after milk ripeness. The N/S ratios in ears at ear emergence and milk ripeness reflected the later N/S ratio in mature grain. Late S fertilization increased sulphate concentrations in the flag leaf within a short period of about two weeks at ear emergence. Late S fertilization prevented S deficiency in late stages of wheat growth and further enabled equal concentrations of S, glutathione and protein in all wheat organs compared to an S application only at sowing.     

Effect of organic and mineral fertilizers on N-use by wheat under different irrigation frequencies

A field trial was established in Errachidia, southern Morocco, to investigate the interaction between wheat residue management and mineral 15N-labelled ammonium sulphate, under different irrigation treatments, applied to wheat (Triticum durum var. Karim). In treatments I1, I2, I3 and I4, plots were irrigated every 10, 15, 21 and 30 days. Each plot contained three sub-plots that received three fertilization treatments: T1 received 42 kg N ha-1 of ammonium sulphate before seedling, 42 kg N ha-1 of ammonium sulphate labelled with 9.764 at % 15N excess at tillering and 84 N kg ha-1 of ammonium sulphate at flowering; T2 received 42 kg N ha-1 of ammonium sulphate labelled with 9.764 at % 15N excess at seedling, 42 kg N ha-1 at tillering and 42 kg N ha-1 at flowering; T3 received 4800 kg ha-1 of wheat residue labelled with 1.504 at % 15N excess and 42 kg N ha-1 of ammonium sulphate before seedling and 42 kg N ha-1 of ammonium sulphate at flowering. Nitrogen fertilization with 168 kg N ha-1 did no significantly increase grain and straw yields in comparison to the 126 kg N ha-1 application. The combination of the organic input and supplementary application of mineral fertilizer N has been found as a more attractive management option. For all irrigation treatments, the % recovery of N in the whole plant was higher in plants that received 15N at tillering (63%, 49% respectively for irrigation intervals between 10 and 30 d) than in plants that received 15N just after seeding (28% for irrigation each 10- and 30-d intervals). For the irrigation treatment each 10 and 15 days, the 15N was mainly recovered by the grain for all fertilization treatments, whereas for irrigation treatment each 30 days, the grain and straw recovered nearly equal amounts of fertilizer. For grain and straw of wheat, nitrogen in the plant derived from the fertilizer was low, while most of the N was derived from the soil for all irrigation and fertilization treatments. The % nitrogen in the plant derived from the fertilizer values showed no significant difference between the different plant parts. The results suggested a dominant influence of moisture availability on the fertilizer N uptake by wheat. Under dry conditions the losses of N can be allotted to denitrification and volatilisation.     

刈割对冬小麦再生积温需求及其籽粒产量和品质的影响

对黄土高原塬区冬小麦‘陇育216’于分蘖期、拔节期及孕穗期进行刈割处理,以不刈割为对照,测定冬小麦再生生长发育的积温需求及籽粒产量及其品质,探究刈割利用时间对冬小麦再生生长积温需求及产量构成的影响。结果表明:(1)分蘖中期(6个分蘖)前刈割利用,小麦再生各阶段的有效积温需求较对照无显著差异,在收获小麦青干草0.9～1.5t/hm2的同时,能保证籽粒、秸秆产量及其品质较对照均无显著下降;分蘖期后期(9个分蘖)及其后刈割利用,拔节至开花及成熟期的有效积温需求显著减少,尽管较分蘖期可多收获60%的青干草,但籽粒、秸秆产量较对照均显著降低。(2)通径分析发现,刈割主要通过降低再生植株高度及减少单位面积穗数而导致冬小麦籽粒减产。研究表明,为维持冬小麦再生生长节律、籽粒产量及品质形成的稳定,冬小麦刈割利用的时期应不迟于分蘖中期(6个分蘖)。     

An investigation into the relations between some growth parameters and yield of barley

Twenty-five field experiments on barley were done at four sites from 1970 to 1975, with an additional site in 1975, comparing five rates of nitrogen application. The crops were sampled at c. 14-day intervals from about the four-leaf stage to maturity to follow changes with time in the dry weights of the constituent plant parts and to measure fertile tiller number, grain number per ear and grain weight. Some data have been selected from this body of information and regression analysis has been used to assess the possible importance of pre- and post-anthesis growth in determining the yield of barley. Ear emergence was taken as an approximate indicator of anthesis. Yield was closely related (r=+0–96) and almost equal to the amount of dry matter accumulated before ear emergence for twenty-one of the experiments, with a regression coefficient of 0–95. In two of the remaining experiments the regression coefficient was greater, 1–14; and smaller in the other two, o-8i. Plant population is also shown to affect the regression coefficient. Despite these anomalies grain yield was more closely related to plant dry weight at ear emergence than to the increase in weight after ear emergence (r =+0–79). The increase in plant dry weight after ear emergence was frequently less than the yield of grain, suggesting that the plant can compensate for inadequate photosynthesis during grain filling. The result of this compensation is a reduction in straw dry weight. This implies that previously assimilated dry matter is transported to the grain, or that respiratory losses from the straw are not replaced by current photosynthesis. These observations suggest that yield may be limited by sink capacity rather than by photosynthesis after ear emergence. The main component of sink capacity, grain number per m² was closely related to yield (r =+0–95) and is known to be determined at or before anthesis. Grain size was shown to be related to grain number per ear (r= 4- 0–99), suggesting that grain size is also, at least partially, determined at ear emergence. Therefore, all the yield components are determined, wholly or partly before ear emergence.     

Inheritance of the light intensity response in spring cultivars of common wheat

The effects of low/high light intensities and day length on ear emergence time in climatic chambers were studied in 12 common wheat (Triticum aestivum L.) cultivars of different ecogeographical origin. Low light intensity (LI) affected the time to ear emergence in all the wheat cultivars of both the photoperiod sensitive and insensitive genotypes, increasing the number of days to ear emergence (DEE). Based on the increase in DEE, we chose samples with different light intensity responses among the cultivars and analyzed their F2 hybrids to see if they were segregating. Taken together, the data for the F2 plants and test cross showed that the strong response to light intensity is a recessive trait and that the parental cultivars differ by the two genes controlling the LI response in common wheat. Besides heading time, low LI increased the number of days to tillering in all the cultivars except Pitic 62, but short day affected the period to tillering less than low LI. The symbol Rli (the response to light intensity) is suggested to designate the genetic control of the response to LI in wheat. Thus, the response to LI may influence the adaptability to changing environmental conditions and yield of wheat cultivars.     

小麦磷素利用效率的品种差异

通过土培盆栽试验,研究了小麦不同品种在低磷水平下生物量、磷浓度、磷素干物质生产效率及磷素籽粒生产效率的差异,以筛选磷高效利用小麦品种.结果表明：分蘖期、拔节期、扬花期和成熟期,供试小麦品种单株生物量的变幅分别为0.46～1.09、0.85～2.10、3.00～7.00和3.85～12.88 g,磷浓度变幅分别为2.21～4.26、2.38～4.42、2.44～4.96和1.30～5.09 mg·g^-1.随生育时期的推进,小麦磷素累积量、磷素干物质生产效率对生物量形成的影响程度呈减小趋势.分蘖期（CV=16.3%）、拔节期（CV=15.0%）、扬花期磷素干物质生产效率（CV=13.3%）和成熟期磷素籽粒生产效率（CV=20.5%）的品种差异较大.CD1158-7和省A3宜03-4具有较高的磷素干物质生产效率和磷素籽粒生产效率,而渝02321较低;不同生育时期高效品种磷浓度极显著低于低效品种,而高效品种CD1158-7和省A3宜03-4的籽粒产量分别是低效品种渝02321的1.98和1.78倍.     

Dry Matter Partitioning between Plant Organs in Wheat Cultivars Differing in Productivity and Drought Resistance

In microplot field experiments conducted over the course of 12 years, the accumulation of dry matter was recorded in the leaves, stems, and ears of the primary shoots of plants of four cultivars of spring wheat (Triticum aestivumL.) differing in productivity and drought resistance. The contribution of organs to the accumulation of dry matter by the shoot from emergence to anthesis was calculated, and relative changes in the weight of the ear after anthesis were assessed. In all the cultivars, the contribution of the leaves was the same; however, the share of the ear was greater in short-stem cultivars of the intensive type in which the leaves were more active during the time of grain filling. Furthermore, this load increased, and the relative increment in the ear weight after flowering decreased in the years of drought, because the contribution of the leaves did not depend on water supply during the growing season. During these years, the contribution of the ear increased in the plants of all the cultivars. The authors conclude that, in arid regions, in addition to drought resistance, the cultivar should display such a ratio between the ear weight and the weight of leaves that would still ensure satisfactory grain filling     

The effect of varying nitrogen supplies on the content of amino acids in wheat grain

Summary The effect of nitrogen applications on the amino acid composition of wheat grain was studied in a pot experiment, in which spring wheat was supplied with increasing amounts of ammonium sulphate. The ensuing yield curve extended from very small N-applications to applications resulting in a toxic effect on the yield.The contents of dry matter, total N, 15 amino acids and ammonia were determined in samples taken from 9 representative treatments. The relationship between the yield of dry matter and the concentration in the dry matte rof the individual amino acids showed the same characteristic variations as those previously found for total N and for a number of plant nutrients.In accordance with the results cited in the literature, increasing applications of N caused an increase of glumatic acid and proline on a nitrogen basis, whereas lysine and arginine decreased.     

Relationships between photosynthetic area and other growth attributes with grain yield in 6- and 2-row barley genotypes

Six-row and 2-row barley genotypes were grown as individually spaced plants in the field, and estimates of area of green tissue and other characters were obtained at ear emergence and maturity. Positive correlations (P<0.01) were found within both 6- and 2-row types between grain dry wt per main culm and grain number, mean date of ear emergence, area of green tissue above the flag-leaf node, and dry wt of the third leaf below the ear (F-2 leaf). This supports the hypothesis that the magnitude of assimilate supply prior to anthesis is a very important determinant of grain yield in barley, and the possible use of the F-2 leaf as a criterion for selection of genotypes with a large photosynthetic capacity and grain yield is discussed.     

不同生育时期增铵营养对小麦生长及氮素利用的影响

通过两年的田间试验,研究了不同生育时期增铵营养(EAN)对小麦生长和氮素利用的影响．结果表明,田间增铵营养促进了小麦植株的生长和氮素吸收．其中基肥、分蘖期、拔节期EAN提高了小麦的干物质积累量、地上部氮积累量、有效穗数、叶面积指数、叶片叶绿素含量以及小麦的籽粒产量;孕穗期EAN效果不明显;全生育期EAN在促进生长方面的效果并无明显优势,但可有效降低土壤NO3^--N的淋溶损失．与对照相比,EAN提高了氮流效率和吸收效率,但以拔节前处理最为明显．拔节期EAN主要在于改善后期的叶片光合性能,并促进同化物向籽粒的再分配,而基肥和分蘖期EAN主要在于提高有效分蘖数．     

Physiological Causes of Differences in Grain Yield between Varieties of Barley

In a field experiment on barley at Rothamsted with the highmean yield of 49 cwt. of grain per acre, the varieties Proctorand Herta produced 10—15 per cent, more grain than Plumage-Archeron plots that received no nitrogenous fertilizer. When nitrogenwas applied the difference was increased to about 30 per cent.,because the higher nitrogen supply caused the Plumage-Archercrop to lodge and did not increase its yield, while Proctorand Herta remained standing. The three varieties did not differ in leaf-area index nor innet assimilation rate before ear emergence, so that all hadthe same total dry weight. After ear emergence, the leaf-areaindices of Proctor and Plumage-Archer were nearly equal, butthat of Herta was smaller. Assuming that the photosyntheticefficiency of the leaves continued to be the same in all varieties,the higher grain yields of Proctor and Herta cannot be attributedto greater production of dry matter by the leaves, either beforeor after ear emergence. A pot experiment on plants with shadedears confirmed that the dry matter contributed to grain yieldby unit leaf area was nearly equal in all the varieties. The higher grain yield of Proctor and Herta than of Plumage-Archermust therefore have come from additional photosynthesis in partsof the plant other than the leaves, i.e. in the ears themselves.An attempt to demonstrate this directly in a pot experiment,by comparing the grain yields of plants with shaded or withunshaded ears, was unsuccessful because the varieties behaveddifferently in pots; Proctor and Herta produced only about 6per cent, more grain yield than Plumage-Archer, and though thedecrease in grain yield by shading the ears was slightly greaterfor Proctor and Herta, the differences were not significant. The sum of ear sizes (estimated from length and breadth measurements)per m.1 in the field experiment was greater for Proctor andHerta than for Plumage-Archer. Also the distribution of drymatter between developing ears and shoots apparently differedwith variety, so that at ear emergence the dry weight of earsper m.² was greater in the two higher yielding varieties. Theincreased amount of photosynthetic tissue in the ears of Proctorand Herta, as measured by size or weight, may not wholly explaintheir greater dry-matter production; ears of Herta may alsohave a higher photosynthetic efficiency. No differences in nutrient uptake that could account for thevarietal differences in grain yield were found. Plumage-Archerabsorbed more potassium, and Herta less phosphorus than theother varieties. About a quarter of the final content of nitrogen,and a third of the phosphorus, was absorbed after ear emergence,but the potassium content was nearly maximal at ear emergenceand later decreased. The pot experiment showed that, on the average of all varieties,26 per cent. of the dry matter in the grain at harvest originatedfrom photosynthesis in the ears, including 10 per cent, fromthe awns; 59 per cent, came from photosynthesis in the flag-leaflamina and sheath and peduncle, and 15 per cent, from partsof the shoot below the flag leaf.     

Manganese deficiency in sugar beet and the incorporation of manganese in the coating of pelleted seed

Summary A laboratory study, three glasshouse tests and eight field experiments on commercial farms in East Anglia during 1972 to 1974 tested the effect of incorporating manganese in the coating of pelleted seed on the manganese nutrition and yield of sugar beet. The pelleting material readily absorbed manganese from solution but most of the manganese was held in plant-available forms. Tests in the glasshouse showed that manganese sulphate or manganous oxide were likely to be the most effective seed-pellet additives, but manganese sulphate was harmful to sugar beet in slightly acid potting compost.Incorporating manganous oxide in the pellet prevented early symptoms of deficiency on sugar beet in field experiments and replaced an early foliar spray but the plants developed manganese deficiency later. The treatment was an economic and effective method of supplying manganese to sugar-beet seedlings too small to spray but, should manganese deficiency be prolonged, the plants will need spraying when large enough.     

Sulphur accumulation and redistribution in wheat (Triticum aestivum): a study using stable sulphur isotope ratios as a tracer system

Wheat plants were grown hydroponically and fed with two sulphate sources differing in stable isotope composition, one having a δ ³⁴S of 13·7‰ and the other 4·1‰. Plant sulphur (S) isotope ratios were determined using an on-line continuous flow-isotope ratio mass spectrometer. This method greatly simplified the procedure for the measurement of S isotope ratios, and was found to be precise for samples containing > 1 mg S g^–1 dry weight. The δ ³⁴S values of plant shoots, which had been grown on a single sulphate source, were very close to the source values, suggesting little isotope fractionation during sulphate uptake and transport from roots to shoots. By changing the sulphate sources at different growth stages, it was possible to estimate S accumulation and redistribution within different plant parts. At maturity, wheat grain derived 14, 30, 6 and 50% of its S from the accumulation during the following successive growth stages: between emergence and early stem extension, between stem extension and flag leaf emergence, between flag leaf emergence and anthesis, and after anthesis, respectively. It was estimated that 39, 32 and 52% of the S present in the flag leaves, older leaves and stems, respectively, at anthesis, was exported during the postanthesis period. These results demonstrate considerable cycling of S within wheat plants, and highlight the importance of S uptake after anthesis to the accumulation of S in grain under the experimental conditions employed.     

Phosphorus uptake from different sources of phosphatic fertilizers by maize and wheat at two stages of growth

The results of pot experiments on wheat and maize with³²P labelled phosphatic fertilizers showed that P uptake after one month of sowing and at ear emergence in case of wheat has significant positive correlations with dry matter yield where as P uptake after one month of sowing has only significant positive correlation with dry matter yield and P uptake at tasseling has no correlation with dry matter yield in case of maize. P uptake and P concentration have significant correlation at both the stages of growth in case of wheat but P uptake from fertilizer and its respective concentration has only significant correlation at both the stages in case of maize.     

不同生育时期增铵营养对小麦生长及氮素利用的影响

通过两年的田间试验,研究了不同生育时期增铵营养(EAN)对小麦生长和氮素利用的影响.结果表明,田间增铵营养促进了小麦植株的生长和氮素吸收.其中基肥、分蘖期、拔节期EAN提高了小麦的干物质积累量、地上部氮积累量、有效穗数、叶面积指数、叶片叶绿素含量以及小麦的籽粒产量;孕穗期EAN效果不明显;全生育期EAN在促进生长方面的效果并无明显优势,但可有效降低土壤N₃^--N的淋溶损失.与对照相比,EAN提高了氮流效率和吸收效率,但以拔节前处理最为明显.拔节期EAN主要在于改善后期的叶片光合性能,并促进同化物向籽粒的再分配,而基肥和分蘖期EAN主要在于提高有效分蘖数.