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1.
Abstract

The effects of application of zinc fertilizer on dry matter yield, uptake and distribution of zinc and other nutrients by Amazon and Amelonado cocoa cultivars grown in a soil of low zinc content in the greenhouse were investigated.

There was a differential response to zinc fertilization by the two cocoa cultivars. Maximum dry matter yields of Amazon and Amelonado were attained with 10 ppm Zn and 50 ppm Zn, respectively. Under similar experimental conditions Amelonado seedlings expressed zinc deficiency symptoms whereas Amazon did not.

Zinc concentrations in the leaves, stem and roots of both cuitivars did not give a good index of the zinc status of the crops. This was because of the existence of the “Piper‐Steenbjerg”; effect in that nil zinc rates often gave higher leaf concentration of the zinc than next higher rate. In general, the relative content of zinc followed the pattern; leaves > roots > stem with the Amazon cultivar containing more zinc than the Amelonado.

The distribution of absorbed Cu in the leaves, stem and roots did not differ in both varieties. Whereas Fe uptake was mostly concentrated in the roots, Mn absorbed was largely concentrated in the leaves of both varieties and only Mn uptake in the leaves of Amazon consistently increased with Zn application.

The differences in the uptake and distribution of nutrients between the two cocoa cultivars was attributed to differences in their ability to extract nutrients from the soil and in their requirements for metabolic processes.  相似文献   

2.
At Tlaltizapan, Mexico, 26 maize varieties with a wide range of various contrasting traits were grown at three plant densities (25, 000, 50, 000, and 100, 000 plants per ha) to clarify the factors currently limiting grain yield. The following results were obtained.

1. Long-duration varieties compared to short-duration varletles tended to be taller and to produce a larger number of leaves, larger LAl, larger TDW, and higher grain yield. No evidence was obtained to indicate that plant type was important for high-yielding varieties.

2. High grain yield was attributable mainly to the larger number of kernels per unit field area. The sink size is possibly the dominant factor controlllng the grain yield, indicating the importance of studies on the yield components.

For obtaining high-yielding varieties, it would be important to improve a strain so that a single ear became larger and more tolerant to barrenness at a high plant density.  相似文献   

3.
Abstract

The relationship between potassium concentration in the plant at various growth stages and the grain yield of L. angustifolius cv. Unicrop was derived from a rates and times of application of KCl field trial.

Critical levels were defined as those associated with 90% of maximum yield. Critical % K levels in the whole tops were 3.1 at the 4–6 leaves stage, 2.9 at 8–10 leaves, 1.5 at first flowering, 1.2 with flowers on higher order laterals and 0.9 post flowering.

The effect of plant part sampled was examined at early flowering. Critical levels at that stage were 1.2% K for petioles 1–5, 0.6% K for petioles 6–10, 1.3% K for leaves 1–5, 0.5% K for leaves 6–10 and 2.1% K in the growing point of the plant.

Grain K concentrations were very insensitive to changes in supply, and are of little use as a diagnostic tool. The ratio of K concentration in pods to that in seeds increased from 0.5 under extreme deficiency to 1.3 under conditions of adequate supply, and should be a useful diagnostic tool at maturity.  相似文献   

4.
Abstract

Significant varietal differences in plant nutrient content have been reported in the literature which would make extremely difficult the interpretation of plant analysis results for diagnosing plant nutritional problems. This investigation was conducted to analyze a relatively large number of uniformly fertilized commercially grown corn (Zea mays) varieties for possible differences in N, P, K, Ca, and Mg concentrations. Whole young plants 60 to 90 cm tall and ear leaves collected at tassel ling were chemically analyzed.

Varietal differences in the concentrations of N, P, K, and Ca in field corn were statistically significant. Varietal differences in Mg concentrations were significant in three out of the six sets of data.

In spite of statistical significance, plant nutrient concentrations were found to be within expected limits for the morphological parts and growth stages examined except for ear leaf P levels in two varieties. These varieties (P.A.G. SX 29 and Pioneer 3304) apparently were capable of accumulating high levels of P, but only when ear leaf P concentrations were generally high for all varieties indicating excessive soil P levels.

The majority of corn varieties tested contained relatively uniform nutrient levels and were not significantly different from one another. The usual bell‐shaped frequency distribution curves indicated normal distributions of plant nutrient contents. Varietal differences in nutrient concentrations were generally not found to be large enough to interfere with interpretation of plant analysis results (except possibly for P accumulation in the two varieties mentioned above). But, there was no indication that critical phosphorus levels were higher in P accumulating varieties than in other varieties.  相似文献   

5.
Abstract

Mobilization of nitrogen, phosphorus, and potassium from leaf and carpel tissue during seed growth was estimated for 18 diverse, field‐grown soybean lines and cultivars during two years. The objective was to determine whether lines differed in nutrient mobilization and, if so, whether such differences were related to yielding ability.

Lines differed in nutrient concentration and tissue mass and in nutrient content, both at beginning of seed growth and at plant maturity. Mobilization from leaves and carpels potentially supplied up to 47, 23, and 29% of seed N, P, and K. Leaves were three to four times more important than carpels as sources of seed N and K and nearly twice as important as sources of P.

Only mobilized leaf N exhibited a relationship with seed yield (r = 0.73?? in 1978 and 0.43? in 1979). Leaf N mobilization was not heritable (correlation between years for line means was 0.09) in our environment, but might be more so under N‐stress conditions. The major determinant of mobilizable N was leaf mass at beginning of seed growth.  相似文献   

6.
Mineral regulation of two soybean varieties Jackson and Lee was investigated in long term water culture experiments using saline solutions. The effects of extreme K:Na ratios using chloride and sulfate as counterions were studied in the early stages of salinity.

The growth rates of both varieties were not affected by salinization. A K+ stimulated, intensive acropetal Cl translocation was observed in the salt sensitive variety Jackson. The varieties did not differ in Na+ translocation and in the suppression of Ca2+ and Mg2+ in the leaves. But the effect of the nature of salinization indicates already differences in Na uptake and translocation of the cultivars.

The avoidance of Cl, but also of Ha+, in connection with influences of the resulting ionic imbalance on metabolic pathways are probably the most causative factors for the different tolerance to salinity of the two soybean varieties.  相似文献   

7.
Tropical maize varieties were grown at a tropical lowland location in various -seasons and at a highland location in Mexico to study the general growth pattern of tropical maize. The following results were obtained.

1. The tropical maize variety grown at the lowland location in summer was characterized by (a) a high growth rate and a short growth duration, (b) a small leaf area duration during maturing, (c) a sizable loss of dry weight at late maturity, (d) a low harvest index, and (e) a small number of kernels formed per unit field area. Although these characters may be interrelated, the predominant cause of the former two appear to be environmental and that of the latter three, genetic.

2. The grain yield of tropical maize grown at the lowland location in summer was low mostly because of a small number of kernels and maybe also because of short leaf area duration. The senescence of leaves after silking was rapid and the growth duration was short under high temperatures.

3. Although the number of kernels was small, grain yield was higher at the highland than at the lowland location, and also was higher in the winter than in the summer plantings at the lowland location. At the highland location or in winter, the longer growth duration and the longer leaf area duration compensated for the smaller crop growth rate and resulted in a larger dry matter production after silking and a higher grain yield. Larger kernel size also contributed to the higher yield of highland maize.  相似文献   

8.
Abstract

Trials with Moringa oleifera leaf extract (MLE) sprayed on leaves of wheat (Triticum aestivum L.) showed different outcomes in grain yield and the components of yield (biomass at anthesis, number of ears, number of tillers, grain weight, 1000 seed weight). An irrigated field trial testing different MLE concentrations resulted in an increase in grain yield of 19% with a 10% concentration but not significant yield increases for higher concentrations of MLE. Dryland field trials with MLE concentrations at 5% and 10% showed no effects or more moderate (about 5–10%) increases in grain yield, depending on the year and location of study. The differences in grain yield responses are most likely due to changes in phytohormone concentration in MLEs brought on by abiotic stress (moisture deficit and seasonal change) of the moringa tree before the collection of the leaves. Concentrations of gibberellins, auxin, abscisic acid, salicylic acid, and jasmonic acid in MLEs differ markedly due to plants subjected to abiotic stresses. Comparing chemical analysis of MLE with grain yield effects showed that GA4 – most likely in crosstalk with auxin – is the major growth enhancer. It is concluded that the hormonal concentrations of MLEs strongly varies on a yearly basis, which may affect the potential use of this bio-stimulant in agriculture.  相似文献   

9.
The yield of Koshihikari, a Japanese premium rice variety, is relatively lower than that of modern high yielding varieties. IR64 carries several well-known genes such as GS3, an important gene for grain size, sd-1, a semi-dwarf gene, and NARROW LEAF1 (NAL1), a gene for small, narrow flag leaves. In this study, we used two sets of chromosome segment substitution lines (CSSLs), from Koshihikari and IR64, and attempted to evaluate the genetic factors that cause differences between parents by analyzing the function of chromosome regions affecting a trait (CRATs). For 28 traits, we identified 312 CRATs in the Koshihikari background and 275 in the IR64 background. In these, donor alleles had positive effects in 84 and 103 CRATs, respectively. Among these, the CRAT related to GS3 and those for grain number expanded the potential sink size in Koshihikari, although this did not affect final yield. The combination of CRATs that enhances source ability may increase grain yield. Although the sd-1 gene might improve resistance to lodging, the yield of CSSLs with sd-1 decreased by 28.7 %. These results suggest that the smaller biomass conferred by sd-1 might reduce canopy photosynthesis. In the Koshihikari background, the CRAT related to NAL1 and those located on chr. 6 increased SPAD value but had the opposite effect on leaf size. Two CRATs that were detected on chr. 6 and 7 increased leaf area without any effect on the SPAD value. The combination of these CRATs for area and SPAD value might improve source ability.  相似文献   

10.
Abstract

This work was established to study the effects of sources and levels of potassium (K) along with gypsum and the residual effects of K on growth and yield of two potato (Solanum tubrosum L.) cultivars. Two experiments were conducted under field conditions at the experimental station of “Sao Sebastião do Paraíso”; Southeastern Minas Gerais, Brazil. Tuber quality, yield components, and branches and leaves mineral composition were analyzed. In the first year, using the ‘Monallsa’ cultivar, there were significant effects of treatments on plant height, tuber dry matter, and plant mineral composition. In the second year, using the ‘Achat’ cultivar, the K application plus residual gypsum from the first year reduced plant physiological anomaly known as tuber cracking.  相似文献   

11.
《Cereal Chemistry》2017,94(3):451-457
Biodiversity contributes to nutrient production and, together with processing, is a critical factor in product quality. Physicochemical and nutritional properties of toasted tortillas (totopos) were evaluated in 1) maize samples from Oaxaca communities and 2) maize races of different endosperm texture. Texture profiles show that totopos elaborated from Zapalote Chico maize race showed the best performance (low breaking force) and higher crunchability, similar to commercial totopos. Quality of Zapalote Chico totopos was explained by flotation index (FI) and starch viscosity as well as thermal properties. FI was negatively correlated with texture that may related to end use. Zapalote Chico maize gelatinizes at higher (P < 0.05) pasting temperature (72.8–73.3°C) and it had higher (P > 0.05) peak viscosity (3,093–4,723 cP), suggesting a more organized starch structure. In hybrid and Tuxpeño samples, most of the starch granules (90%) were gelatinized and increased the hardness in totopos. The totopo samples increased the peak at 4.45 Å, a characteristic of type‐V diffraction of amylose‐lipid complexes (resistant starch). A small increase in resistant starch (0.6%) was found in totopos, which has important nutritional benefits for consumers. Our results support the preference of Oaxaca people for the totopos made from Zapalote Chico maize.  相似文献   

12.
Abstract

Manganese (Mn) is an essential micronutrient in all organisms, but may become toxic when present in excess. Four maize (Zea mays L.) varieties, Kneja 605, Kneja 434, Kneja 509 and Kneja 537, were studied with respect to their responses to excess Mn in hydroponic solution. In the varieties Kneja 605, Kneja 509 and Kneja 537, increasing Mn concentrations in the nutrient solution negatively affected biomass accumulation, photosynthetic rate, transpiration, stomatal conductance and chlorophyll content. In addition, these varieties showed increased electrolyte leakage and lipid peroxidation (malondialdehyde [MDA] content). Increased Mn leaf concentrations, higher contents of chlorophyll a and chlorophyll b, higher photosynthetic rate and transpiration, lower concentrations of MDA and insignificant changes in the electrolyte leakage in the leaves were found in var. Kneja 434 compared with the other maize varieties studied. This variety appeared to possess a stronger ability to cope with Mn phytotoxicity, suggesting high potential for Mn detoxification and var. Kneja 434 could be a good candidate for improving maize productivity on acid soils under non-tropical conditions.  相似文献   

13.
Abstract

Field studies were made to determine the yield and quality of wheat at different landscape positions managed with uniform vs. variable rates of nitrogen (N). A moderately‐eroded wheat farm near Thana (Swat) was divided into four parallel transects which were further divided into two strips each. On one strip, fertilizer was applied at a uniform rate of 120 kg N ha‐1, and along the other strip, three different rates of N (80, 110, and 125 kg N ha‐1) were applied to match the crop productivity patterns. A basal dose of 90 kg P2O5 and 60 kg K2O ha‐1 was applied to the whole field. Soil profiles were described for the three different zones, i.e., low, medium, and high productivity zones. Soil in Zone I was Pirsabak, moderately deep variant, and in Zones II and III, Badwan soil series. Although uniformly fertilized strip (120 kg N ha‐1) received 40 and 10 kg N ha1 more than Zone I and Zone II (variable management strategy), there were no significant differences in yield. The differences in three fertilizer management zones were due to differences in moisture content at sowing, infiltration rate, lime content, steepness, and soil depth. Test weight of wheat grains was not significantly affected. Protein content of wheat was significantly higher in variably fertilized strips than in uniformly treated strips. Based on these results, it is suggested that farms with spatially‐variable soils should be fertilized according to the crop productivity and soil fertility patterns.  相似文献   

14.
Abstract

A water culture pot experiment was conducted to analyze the effects of N application during the ripening period (RP) on photosynthesis, dry matter production, and its impact on grain ripening and yield in two semidwarf indica type varieties viz. Gui Zhao 2 (GZ) and BR3 (BR) compared with a japonica type variety Koganemasari (KO) under four N rates viz. 0 (N0), 10 (N10), 20 (N20), and 40 (N40) mg L?1. Results showed that N application enabled to maintain a higher leaf area and delay leaf senescence in both indica and japonica type varieties but the decrease in the rate, of leaf area was higher in the former than in the latter and the rate was reduced with increasing N rates. Flag leaf photosynthesis and SPAD values of N treated plants were higher throughout the RP, showing the presence of a significant correlation either for each variety or all the varieties together. Higher photosynthetic rate was supported by higher leaf chlorophyll (SPAD value basis) content, stomatai conductance, and N concentration in leaf blades. Top dry matter content increased with increasing N rates mainly due to mean leaf area rather than NAR except for BR during RP but it was higher in KO than in GZ and BR. Reduction of shoot weight due to translocation of dry matter to panicles during RP was suppressed by N rates both in GZ and BR while shoot weight increased in the N-treated plants in KO. The dependency of KO on current photosynthates for panicle weight was found to be almost hundred percent while the contribution of stored carbohydrates in shoot before heading to panicle weight in GZ and BR was in the range of 4-27 and 33-54%, respectively and the rest was contributed by current photosynthates. The percentage increased with increasing N rates. Percentage of ripened grains (PRG) increased with increasing N rates in GZ and BR due to the increase in dry matter production and in the photosynthetic rates of apex leaves, despite the larger spikelet number and larger hull size. However, KO showed almost no variation although it had the highest PRG among the varieties. Brown rice yield followed the same pattern as that of PRG in GZ and BR and the highest yield was produced by BR followed by GZ and KO. These results suggest that N application during RP was more effective in increasing yield in the semidwarf indica type varieties than in the japonica type variety.  相似文献   

15.
Abstract

Six soybean cultivars (maturity group V) were sown in a Typic Argiudoll. Experimental plots were arranged in a randomized block design with three replications. Sampling dates were at different stages: V, R2, R4, and R55. All the varieties showed that the greatest sulfur (S) concentrations were in stage V and the lowest in stage R55. No significant differences were found between the means of the S concentrations during the V, R4, and R55 stages. In the R2 stage, there was a poor correlation with the weight of 1,000 seeds.  相似文献   

16.
Abstract

Corn (Zea mays L.) was grown in the greenhouse in a Laughlin (Ultic Haploxeroll) loam soil, with various amounts of N and S added in order to determine possible interactions of these nutrients with the relationship between plant composition and grain yields. Previous field experience and preliminary experiments had shown that this soil gave yield responses to N and S additions.

Regression equations were used to describe the relationship between composition of various plant parts and grain yields. The best correlation (R2 = 0.943) was obtained using the total N concentration in leaf samples taken at the silking stage, but excluding data from plants which, based on their amide N concentrations (greater than 500 ppm), were considered S deficient. Calculations using the first derivative of the cubic polynomial indicated that a concentration of 2.5% N in the lower leaves was necessary in order to obtain maximum grain yields. The concentrations of total N in the upper leaves and the stalks at the silking stage also correlated well with the grain yields. The relationship of NO3‐N in the stalks at silking to grain yields could be better described mathematically with an exponential function, but the correlation coefficient was low (R2 = 0.58). The responses of two genotypes, one containing the opaque ‐ 2 gene, the other its normal counterpart, were similar.

The total N concentration in the leaves collected at the tassel stage did not correlate quite as well with grain yield as those collected later, but using the exponential model NO3‐N concentrations in the stalks at the earlier stage showed a closer relationship to grain yield than for samples collected at silking. Excluding data for the plants showing S deficiency, a correlation coefficient of 0.90 was obtained. At both tasseling and silking stages, the S deficient plants were characterized by high N:S ratios, with values of 18 to 50 for the stalks, compared to values of less than 10 for the S adequate plants. The marked effect of inadequate S on grain formation was not evident in the amounts of leaves and stalks produced.

Field studies will be necessary to evaluate further the merit of the diagnostic procedure indicated by these experiments.  相似文献   

17.
Moringa leaf extracts (MLE) from two varieties of Moringa oleifera Lam. were applied to leaves of wheat (Triticum aestivum L.) in two glasshouse experiments. MLE was extracted from the leaves of using three different solvents (hexane, butanol; ethyl-acetate). The extracts were applied as foliar sprays at different growth stages of wheat (T. aestivum L.) grown on two soil types with either adequate or low phosphorus (P) nutrient additions at Albany, Western Australia. Sprays were applied at the 4–5 leaf (tillering) and the 7-leaf (Boot) stage either as a single spray or a combination of sprays at tillering and boot stage. The application of MLE either at tillering or boot stage increased the dry weight of shoots (biomass) and grain yield of wheat. A foliar spray of MLE applied at tillering increased biomass at the boot stage by ~37% and grain yield increased by ~34% compared to nil MLE spray. A single spray of MLE increased grain yield by ~30% when applied at boot stage. A single application at tillering gave a better yield response than a single spray at the 7-leaf or boot or than a double spray applied at tillering and boot stage. A 50% dilution of the extractant concentration gave the same grain yield response as the original concentration applied at tillering stage. The hexane extracts gave the significantly higher grain yield responses. Plant tissue and grain analysis showed no significant difference in protein and nutrient concentration of wheat grain from plants sprayed with and without MLE. A MLE spray at boot also increased grain yield by 44% on the red sandy-loam soil where P application was at sub-optimum levels, ~80% of P requirement for maximum yield. The partial factor productivity (PFP) index indicated that the P and potassium (K) use improved where MLE was applied as a foliar spray. For example, the PFP of P and K for grain yield increased by about 30%, where MLE was sprayed to foliage. The results of this study indicate that MLE extracted can potentially be a viable option to increase wheat grain yield and fertilizer efficiency use, particularly P and K, in Mediterranean wheat production system.  相似文献   

18.
Purpose: Sorghum [Sorghum bicolor (L.) Moench] has been cultivated for centuries as a staple food crop for millions of people in sub-Saharan Africa and Asia. In Ethiopia a total of 4.34 million tons of sorghum is being produced per annum, predominantly in the arid and semi-arid areas. However, the yield and quality of sorghum is affected by a wide array of production constraints, notably severe and recurrent drought stress. The aim of this study were to determine the impact of drought on sorghum production and productivity over time and space, and to identify farmers’ trait preferences, production constraints and coping strategies when dealing with drought in north eastern Ethiopia.

Materials and methods: Participatory rural appraisal (PRA) was employed in three administrative zones of north eastern Ethiopia. One Woreda from each Zone and two Kebeles from each Woreda were selected on the basis of sorghum area coverage, production, consumption and prior information on the intensity, duration and spatial coverage of drought. In each kebele, 30 respondents were selected for interview and 12 key informants were selected for group discussions and transect walk personal observations. Data collected from 180 respondents was subjected to statistical analysis and the information gathered from 72 key informants through focus group discussions and transect walk observations were used in discussing the results.

Results and discussion: The present study found that productivity of sorghum was challenged by recurrent droughts, Striga infestation, insects, birds, diseases, a lack of varieties with farmers-preferred traits and high yield potential, limited policy support, a lack of improved seed system, poor sorghum production practices and application of crop input and poor soil fertility, in a decreasing order of importance. Among the listed sorghum production constraints, severe drought in the post-flowering stage was identified by most interviewed farmers as the leading constraint across the three study zones. Focus group discussions and transect walk observations held in each Kebele revealed that farmers’ had lost numerous valuable local landrace varieties due to extreme drought conditions over the years. A significant number of interviewed farmers preferred to grow high grain and biomass yielder medium-maturing sorghum varieties which can be sown at the normal planting time but which would escape post-flowering drought.

Conclusion: Overall, sorghum breeding programme should be directed at developing farmers’ ideal sorghum varieties with high grain and biomass yield, adequate level of drought and Striga tolerance. In addition, development of farmer preferred medium-maturing sorghum varieties suitable for April planting should be strengthen to boost its productivity and to increase varietal adoption rate in the area.  相似文献   

19.
The main objective of this study was to investigate the performance of faba bean landraces originating from different regions of Greece under both organic and conventional farming systems focusing mainly on yield, biological nitrogen fixation (BNF), and competitiveness to weeds. Faba bean exhibited a high ability to fix nitrogen from the atmosphere, as indicated by the percentage of N2 derived from the atmosphere which exceeded 75% in all evaluated varieties, and the total amount of biologically fixed N up to full anthesis, which fluctuated from 118.5 to 193.9?kg?ha?1 in the various cropping systems and cultivars. The weed density was appreciably higher in the organic plots, without significant differences among the faba bean cultivars, while wild mustard and corn poppy were the most competitive weeds. The application of inorganic starter fertiliser in the conventionally-treated plots had no negative effect on biologically-fixed nitrogen by faba bean plants, while the herbicide pendimethalin had no negative impact on the nodulation process. Protein concentrations in faba bean cultivars fluctuated from 27.3% to 31.4%. The evaluated landraces could be utilised in breeding programmes due to their earliness, and their high performance in terms of protein content, BNF ability, and productivity.  相似文献   

20.

Mulberry (Morus spp.) is a cross-pollinating and highly hybridized plant of which productivity are greatly varied in different varieties. Accurate distinction among mulberry varieties and understanding of phylogenetic relationship among them would be crucial for the development of sericulture. We have analysed molecular distinction among four mulberry species and varieties cultivated in DPR Korea by using nuclear ribosomal internal transcribed spacer (ITS) sequences and inter simple sequence repeat (ISSR) markers. ITS sequences doesn’t represent a remarkable interspecific distinction among four mulberry species used in our study, suggesting that it could not be employed to identify them. ISSR analysis using 16 random primers generated 158 different markers ranging from 100 to 4000 bp in size. The results showed the inter-specific genetic variation (55.34%) was slightly higher than intra-specific genetic variation (44.66%), with comparatively low average number of migrants per generation (Nm) among populations (0.3886). Using ISSR primers selected in this study, in the future, the suitable breeding strategy might be established in raising of elite mulberry varieties on the basis of interspecific hybridization.

  相似文献   

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