Correlation and path analysis of interaction between snap beans yield and its components with crop management

PURPOSE: To assess the interaction between the applied some agronomic activities for the production of snap beans Phaseolus vulgaris cv. Starozagorski Cher using Path- correlation coefficient of analysis. METHODS: Using path analysis to illustrate real effect of minimizing doses of vegetative herbicide Basagran-200g/l (Bentazon-3-Isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide) and Fusillade-200g/l (Fluasifop-P-Butil-butyl 2-(4-{[5-(trifluoromethyl)pyridin-2-yl]oxy}phenoxy)propanoate) instead of using Dual 930EK/930g/l-s ( S-metachloras). Collecting data from long years, trials on plants treated with different combinations of foliar suspension fertilizer Lactofol® with pesticides. RESULTS: Growth rate RGR (mg g-1d-1) positively influenced by high statistical significance of the rate of net assimilation NAR– (mg.cm-2d-1). The correlation coefficient between the two indicators is (r = 0.692), followed by the dependence of RGR on the leaf area ratio LAR (cm2 mg-1) with a value of (r = 0.614). High statistical significance ​​of correlation expressing the interaction between the leaf area ratio LAR (cm2 mg-1) and - root weight ratio RWR (g.g-1) (r = 0. 0.837). Leaf area ratio LAR (cm2 mg-1) has a relatively high positive correlation with the rate of net assimilation NAR– (mg.cm-2d-1) (r = 0.508). Results showed that fresh weight of pod/studied variant (+++0.99), fresh weight of one pod (+++0.77), fresh weight of pods/ plant (+++0.67), calcium content in bean pods (++0.57), pods number /plant (++0.51), pollen fertility (++0.44) had positive impact on yield. The partial function of the studied parameters on variability of bean yield is 98.9%. Nitrate content had a major function to the yield (23.3%) followed by Pods/ kg (21.31%).Weeds manifestation caused most negative effect on yield (-0.64). CONCLUSIONS: This study reveals and identifies appropriate changes in applied agricultural techniques in the production of snap beans, which should be paid more attention to decrease water pollution caused by using the soil-applied herbicide without decreasing quantity and quality of yield.

Growth of canola hybrids resistant and sensitive to herbicides

Plant growth analysis is useful for determining adequate management practices and exploring the maximum yield potential of cultivars or hybrids. Canola hybrids with resistance to herbicides have been studied and registered for Brazilian conditions, as they improve weed management in canola crops. This study evaluated the growth of canola hybrids resistant to triazine or imidazolinone herbicides compared to a sensitive hybrid. The experiment was conducted using a completely randomized design, with four replications, in a bifactorial scheme using three hybrids and six sampling times. The canola hybrids used were Hyola 571CL (resistant to imidazolinones), Hyola 555TT (resistant to triazines), and Hyola 61 (sensitive to both herbicides). Height, leaf area, and dry matter of roots, leaves, stems, and shoots of the plants were evaluated at 14, 28, 42, 56, 70, and 119 days after emergence (DAE). The physiological indices absolute growth rate, leaf area ratio, specific leaf area, and net assimilation rate were calculated, and yield indices evaluated. Compared to Hyola 61, the Hyola 555TT hybrid showed lower values of leaf dry matter at 70 DAE, absolute growth rate up to 56 DAE, and net assimilation rate at 14 and 28 DAE, and a higher leaf area ratio at 56 DAE, whereas the hybrid Hyola 571CL presented lower leaf area and lower leaf dry matter at 70 DAE. At flowering, compared to Hyola 61, the hybrid Hyola 571CL presents lower leaf area, and the hybrids Hyola 555TT and Hyola 571CL have lower leaf dry matter accumulation. Differences in the growth of canola hybrids Hyola 555TT, Hyola 571CL and Hyola 61 do not cause differences in their grain yield.

Differential growth response of green and variegated Ficus benjamina to exogenous cytokinin and shade

Benjamin fig (Ficus benjamina) is an important foliage and landscape crop species comprising green and variegated genotypes. The latter develop leaves with yellow and white leaf areas which may impose lower photosynthetic activity, thus resulting in slower growth than green genotypes. In many species, the exogenous supply of cytokinin to pot-grown plants promotes growth, mainly due to enhanced carbon fixation. In this work, we analyze the effect of spraying the cytokinin 6-benzylaminopurine (BAP) on growth and development of green and variegated Ficus benjamina genotypes. Two experiments were carried out in a greenhouse, in which either different number of BAP applications (Experiment 1) or different BAP concentrations (Experiment 2) were tested. In Experiment 2, plants were grown under three different light intensities. BAP sprays promoted rate of leaf appearance, leaf expansion and whole-plant growth, and the effect was stronger in variegated than in green plants. The relative growth rate promotion by BAP was associated with increased net assimilation rate rather than with variation in the leaf area ratio. On the other hand, shading had a more negative impact on growth and development of variegated plants than in green ones. Variegated plants, unlike green ones, developed leaves with high specific leaf area under the lowest light intensity. This led to high leaf area ratio values, which helped to maintain relative growth rates close to those of plants under moderate shading.

Why are tropical conifers disadvantaged in fertile soils? Comparison of Podocarpus guatemalensis with an angiosperm pioneer, Ficus insipida

Conifers are, for the most part, competitively excluded from tropical rainforests by angiosperms. Where they do occur, conifers often occupy sites that are relatively infertile. To gain insight into the physiological mechanisms by which angiosperms outcompete conifers in more productive sites, we grew seedlings of a tropical conifer (Podocarpus guatemalensis Standley) and an angiosperm pioneer (Ficus insipida Willd.) with and without added nutrients, supplied in the form of a slow-release fertilizer. At the conclusion of the experiment, the dry mass of P. guatemalensis seedlings in fertilized soil was approximately twofold larger than that of seedlings in unfertilized soil; on the other hand, the dry mass of F. insipida seedlings in fertilized soil was ~20-fold larger than seedlings in unfertilized soil. The higher relative growth rate of F. insipida was associated with a larger leaf area ratio and a higher photosynthetic rate per unit leaf area. Higher overall photosynthetic rates in F. insipida were associated with an approximately fivefold larger stomatal conductance than in P. guatemalensis. We surmise that a higher whole-plant hydraulic conductance in the vessel bearing angiosperm F. insipida enabled higher leaf area ratio and higher stomatal conductance per unit leaf area than in the tracheid bearing P. guatemalensis, which enabled F. insipida to capitalize on increased photosynthetic capacity driven by higher nitrogen availability in fertilized soil.

Growth and chlorophyll indices in seedlings of Calotropis procera (Aiton) W. T. Aiton submitted to different levels of shading

Several abiotic factors may influence the growth and development of forest species. Among these, luminosity is one of the most important, because it affects plant physiological processes and control their metabolism. The objective of this study was to evaluate the effect of different shading levels under growth and chlorophyll indices on Calotropis procera plants. The experiment was conducted in a greenhouse in a completely randomized design with 5 treatments (0, 30, 50, 70 and 90% of shading), 8 replicates and one plant per plot. Growth characteristics (leaf area, leaf area index, specific leaf area, leaf area ratio and leaf specific weight) and chlorophyll a, b, total index and chlorophyll a/b ratio were evaluated. The data were submitted to analysis of variance by the F test and in the cases of significance a linear and polynomial regression analysis was performed. Shade levels in the 40% range provide higher leaf area and leaf area index in silk flower plants. The specific leaf area and the leaf area ratio are positively influenced by shading. In shaded environments silk flower plants have reduced chlorophyll indices.

Weed Suppression by Cover Plants in the Amazonian

The productivity of citrus plants has not reached its maximum potential due to the action of several factors that directly affect agricultural profitability. Among these factors, weed interference has a great importance since it causes a reduction in crop productivity. The aim of this study was to assess the effect of different cover crops on suppression of weeds in an orange orchard. The research was conducted in a commercial orange production area located in Rio Preto da Eva, AM, Brazil. The experimental design was a randomized block design with six treatments and four replications. Treatments were control, millet, jack bean, forage turnip, brachiaria, millet + jack bean. The evaluated characteristics were weed density, soil cover percentage, total weed dry matter, total cover plant dry matter and growth indices (leaf area index, leaf area ratio, and specific leaf area). Cover plants provided a good dry matter production and had a suppressive effect on weed growth, except for forage turnip. Brachiaria and jack bean presented the highest values of leaf area index and leaf area ratio.

Analysis of cassava growth at different harvest times and planting densities

Vegetative canopy architecture, and plant population density, has a direct influence on the growth and production of crops. The objective of this study was to evaluate the growth of four cassava cultivars of contrasting canopies, in four population densities, during two vegetative cycles. A randomized complete block design was used in a subdivided plot scheme, with two replications, with the population densities in the plots and harvesting times in the subplots. ‘Branca de Santa Catarina’ (BSC), ‘IAC 13’, ‘IAC 14-18’ and ‘Fibra’ were collected every four months, beginning at 120 and ending at 720 days after planting (DAP). Primary data on dry matter and leaf area were calculated. The total dry mass (Wt), leaf area ratio (La), leaf area index (L), relative growth rate (Rw), and net assimilation rate (Ea) were calculated based on the primary data. All cultivars accumulated more total dry mass (Wt) at lower planting densities. The plants reached a higher leaf area ratio (La) 120 days after planting. In the second vegetative cycle, the four cultivars, independently of the population, presented a reduction of assimilate translocation to the leaves. Relative growth rate (Rw) of the cultivars varied strongly with the plant population only in the second cycle. ‘IAC 14-18’ showed greater dependence on spacing, and ‘Fibra’ less dependence. Growth (Rw) and assimilatory (Ea) rates decreased at the end of the first cycle, then increased slowly until the end of the second cycle of vegetation.

Improvement of some growth and yield parameters of faba bean (Vicia faba) by inoculation with Rhizobium laguerreae and arbuscular mycorrhizal fungi

The use of improved biofertilisers such as rhizobia and arbuscular mycorrhizal fungi (AMF) in legume crops is a promising technology that can be an alternative source of nitrogen and phosphorus. A common problem when growing faba bean (Vicia faba L.) and other leguminous plants is the low efficiency of native rhizobial strains. Consequently, there is a need to search for efficient nitrogen-fixing inoculant strains able to increase crop productivity. This study aimed to test the effects of single and dual inoculation with Rhizobium laguerreae and AMF on the growth and yield of faba bean plants. Several parameters were evaluated at flowering stage (number of flowers, stems and leaves, shoot and root biomass, leaf area, leaf mass per area and leaf area ratio, and gas-exchange parameters) and at harvesting stage (number and weight of pods and seeds). Plants receiving single inoculation with Rhizobium laguerreae showed a significant increase in number of leaves, leaf area, leaf mass per area and leaf area ratio, as well as in all yield parameters. Single inoculation with AMF also significantly increased the yield parameters of faba bean plants. Co-inoculation presented significant improvements in leaf area ratio and in all productivity parameters compared with the control, but co-inoculation was not significantly different from the individual inoculations.