Role Of Cultivars Research Articles

Role of cultivars and grass in the stability of soil moisture and temperature in an organic vineyard

Soil water content (SWC) and temperature (ST) are main parameters in agriculture, but are difficult to predict due to the numerous processes involved. To find stability patterns, this study evaluated the soil hydro-thermic response in a rainfed organic vineyard with humid climate, a permanent grass cover and under no-tillage and homogeneous soil and topographic conditions. The differences between the rows (R) and inter-row areas (IR) and two cultivars (Agudelo –Ag– and Blanco Legítimo –BL–) were assessed. SWC and ST were measured with 12 probes every 15 min at 5, 15 and 25 cm depth over the crop cycle (242 days). On average, wetter (+2.2%) and cooler (−1.4%) values appeared in Ag than in BL that may be associated with differences in vine water demand. IR had wetter (+5.9%) and cooler (−0.7%) conditions than R due to higher water consumption by vines. Significant differences appeared when time-series analysis was split into three periods: drying and warming (spring), dry and warm (summer), and wetting and cooling (autumn). SWC and ST correlated well in R, but moderate correlations appeared in IR, showing a more complex pattern in this zone. In general, the most stable conditions appeared at 15 cm depth, with drier and warmer conditions in the deepest layer in spring and autumn. This vertical pattern did not vary over time for ST, but IR had the most stable and moistest conditions in summer at 25 cm. The relative differences among zones and cultivars revealed that Ag had moister, but less representative, conditions than BL at the three soil layers in spring, and this pattern kept in summer at 15 and 25 cm, but only in autumn at 15 cm. Regarding ST, the pattern was very stable, and cooler and representative conditions prevailed in Ag. BL has been rarely cited in the literature, and these results contributed with new insights about the SWC and ST dynamic on this cultivar. Cooler conditions always appeared in IR, compared with R; and R always had more representative values of SWC than IR. The pattern of ST was more variable and R only had more representative values than IR at 15 cm in summer and at 25 cm in spring and summer. This article represents the first study that calculated the index of temporal stability (ITS) for SWC and ST in any type of woody crop. Our findings allowed to identify the most representative areas of the hydro-thermic response of the soil in the vineyard, which is of interest to save time and resources during long-term monitoring tasks in commercial vineyards.

Improving weed control in sustainable agro-ecosystems: Role of cultivar and termination timing of rye cover crop

Alternative strategies to control weeds are required at the field level to reduce herbicides and derived pollution. As cover crop, rye (Secale cereale L.) is adopted mainly because of its allelopathic weed control, which takes place through a strong inhibition of germination and seedling growth in several types of grass and broad-leaved weeds. The present study consisted of: i) a field trial, focused on the evaluation of biomass production and allelochemical concentration in the biomass, and in situ weed control at 30 days after termination (with two termination timings: T1 - heading phase and T2 - 10 days later) of 8 rye varieties; ii) a pot experiment, focused on the inhibition effect of mulches derived by those 8 rye varieties on four summer weeds: velvetleaf (Abutilon theophrasti Med.), lambsquarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), and common purslane (Portulaca oleracea L). Results showed that biomass production was the highest with Protector, closely followed by Primizia, Sito 70, Hellvus, Forestal, and Hymonta. In any case, rye mulching always reduced the weed biomass, especially with Fasto and Forestal. The allelochemical concentration in the biomass was the highest with Fasto and Forestal and decreased on average from T1 to T2 (–38% for total benzoxazinoids and –57% for isovitexin). Conversely, the rye biomass production increased (on average +77%), passing from T1 to T2. We also found that the reduction of weed biomass, compared with the control, is highly correlated with the allelochemical content in rye biomass in the case of T1 termination, while with the biomass production in the case of T2. In pots, a strong inhibitory effect on seedling growth due to rye mulching was observed for C. album (–76%), A. retroflexus (–56%), and P. olearcea (–84%), while not for A. theophrasti. We concluded that, regardless of the variety, adopting rye as a cover crop may be considered as a suitable practice to reduce weed pressure at the field level. Among all the varieties tested, Forestal and Protector showed the most significant weed suppression potential, due to the high amount of allelochemicals production for Forestal and high biomass production for Protector. Highlights - One month after rye termination, the weed biomass under mulching is reduced by 4 times, compared with the control. - When rye is terminated early, the allelochemical content in rye tissues reduces the weed biomass production. - When rye is terminated late, the weed biomass production is reduced by the amount of rye biomass. - Lambsquarters, redroot pigweed and purslane growth is inhibited by rye mulching, while velvetleaf is not affected.

1-MCP Improved Diverse Sensorial, Biochemical and Physical Apple Traits during Cold Storage Based on Cultivar

Apple cultivars’ storability could be strengthened through known techniques of cold storage, advanced industries of control atmosphere or other routine usages like fruit pre-cooling followed by immersion in CA++ solution, depending on genetic potential of the plant material. At the end of pomology and cold storage assessments of 93 apple cultivars, two high yielding native "Dirras-e Mashhad" and "Wealthy" were treated by single and combined 1-MCP and ethylene nano-absorbent (ENA) to assess eventual improvements in cold storage span, fruit eating quality and role of cultivar. For this purpose, directs effects and interactions between all sources of variance were studied. Ethylene emission and CO2 amounts were measured. The results showed that reduced weight loss and flesh firmness, were registered in the treated samples of both cultivars compared with the control. Using of 1-MCP affected significantly (p 0.05) on these characteristics. The native apple "Dirras-e Mashhad" showed higher pH value than "Wealthy" under the combined treatment (ENA+1-MCP). Genetic source revealed significant difference through lower "Wealthy" storability. Ethylene emission increased to 53.64 ppm/Kg·hr after 5th month, which resulted in significant difference at p > 0.01 level related to the initial value of 3.26 ppm/Kg·hr. The combined treatment (ENA+1-MCP) affected significantly (p < 0.05) most of the fruit characteristics in both of the cultivars. The treatments demonstrated different results by cultivar.

Regionalization of climate scenarios impacts on maize production and the role of cultivar and planting date as an adaptation strategy

Understanding climate change and its impacts on crops is crucial to determine adaptation strategies. Simulations of climate change impacts on agricultural systems are often run for individual sites. Nevertheless, the scaling up of crop model results can bring a more complete picture, providing better inputs for the decision-making process. The objective of this paper was to present a procedure to assess the regional impacts of climate scenarios on maize production, as well as the effect of crop cultivars and planting dates as an adaptation strategy. The focus region is Santa Catarina State, Brazil. The identification of agricultural areas cultivated with annual crops was done for the whole state, followed by the coupling of soil and weather information necessary for the crop modeling procedure (using crop model and regional circulation models). The impact on maize yields, so as the effect of adaptation strategies, was calculated for the 2012–2040 period assuming different maize cultivars and planting dates. Results showed that the exclusion of non-agricultural areas allowed the crop model to correctly simulate local and regional production. Simulations run without adaptation strategies for the 2012–2040 period showed reductions of 11.5–13.5 % in total maize production, depending on the cultivar. By using the best cultivar for each agricultural area, total state production was increased by 6 %; when using both adaptation strategies—cultivar and best planting date—total production increased by 15 %. This analysis showed that cultivar and planting date are feasible adaptation strategies to mitigate deleterious effects of climate scenarios, and crop models can be successfully used for regional assessments.

APPLICATION TIME OF NITROGEN AND PHOSPHORUS FERTILIZATION MITIGATES THE ADVERSE EFFECT OF SUBMERGENCE IN RICE (ORYZA SATIVA L.)

SUMMARYLarge areas of rainfed lowlands of Asia annually experienced flash flooding during the rice-growing season, which is an important abiotic stress that adversely affect grain yield of rice (Oryza sativa L.) crop. Submergence stress is a common environmental challenge for agriculture sustainability in these areas because lack of high-yielding, flood-tolerant cultivars. In this study, IR64-Sub1 and IR64 were compared for their tolerance to submergence at active tillering (AT), panicle initiation (PI) and heading (H) stages with nitrogen and phosphorus application time. We evaluated the role of cultivars, stage of submergence and N and P application on phenology, leaf senescence (LS), photosynthetic (Pn) rate, yield attributes and yield. Under non-submerged conditions, no difference was observed in phenology, Pn rate and yield of both cultivars. Submergence substantially reduced biomass, Pn rate, yields attributes and yield across cultivars with more drastic reduction in IR64. Submergence at H stage proves to be most detrimental. Nitrogen application after desubmergence with basal P improved the Pn rate resulting in significantly higher yield and yield components. Nitrogen application before submergence resulted in increased LS and ethylene accumulation in shoots leading to drastic reduction in growth, Pn rate and yield. Crop establishment and productivity could therefore be enhanced in areas where untimely flooding is anticipated by avoiding N application before submergence and applying N after desubmergence with basal P (phosphorus).

The Role of Cultivars and Sowing Date in Control of Broad Bean Weevil (Bruchus Rufimanus Boh.) in Organic Cultivation

Summary During 2010-2011 the studies were conducted on the cultivation of three broad bean cultivars Windsor Biały, Makler and Bartom with organic and conventional method. The aim of research was to determine the influence of cultivar and sowing date on the seed damage caused by broad bean weevil and on the total seed yield. Seeds were sown on April 10 and 20th. At the harvest the yield was divided into following grades: marketable, small seeds, damaged by Bruchus rufimanus Boh. and diseased. Plants selected on each plot were examined towards the relation between plant architecture and seed damage. The effect of applied treatments on seed yield and damage was found. The lowest percentage of injured seeds presented cv. Makler irrespectively on sowing date and growing method. The differences were proved statistically. Delay of sowing restricted the percent of damaged seeds but also decreased the yield in both growing methods. Cluster located at upper parts of a plant contained lower amount of damaged seeds.

Influence of within-tree and environmental factors on fruit quality of cactus pear (Opuntia ficus-indica) in Italy

Introduction . Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits·tree–1 ], and no more than six fruits were left on each of the fruiting cladodes. At commercial harvest time, indicated by the peel colour breakage, 75 fruits in each orchard and 750 fruits for each site were picked, analysed and evaluated by a consumer panel. A second experiment was carried out in 2006 on 8-year-old O. ficus-indica trees, cv. Gialla, grown in a commercial orchard. Within-tree factors, such as fruit position within the canopy, number of fruits per tree and per cladode, and cladode dry weight were studied. Results and discussion. Fruit weight, shape and total soluble solid content significantly changed with the environmental conditions, i.e., site and altitude, while flesh percent, pH and total titratable acidity did not. Cultivars had a significant influence only on fruit weight and seed content. Fruit weight changed greatly within the tree, while total soluble solid content and flesh percent variability was much reduced. Fruit weight decreased with fruit number per tree and both fruit weight and total soluble solid content decreased with more than six fruits per cladode. Light interception and cladode dry weight were the main sources of fruit dry weight variability and sugar content, while cladode surface area was poorly related to fruit quality. The role of cultivars in determining fruit quality did not change with site and, moreover, the sensory analysis was unable to discriminate for cultivar and environment.

Role of cultivars, physical, chemical and organic treatments in the management of bacterial blight of cotton

As a part of a broader program for management of bacterial blight of cotton, the cultivars, the application of bactericides, chemicals and organics were evaluated. Among cultivars JK (42 – 44) was found to be resistant and the cultivar LRA-5166 remained highly pathogenic. Seeds of cotton cv. LRA 5166 and JK (42 – 44) inoculated with Xanthomonas campestris pv. malvacearum were subjected to different treatments in the greenhouse and field experiments to evaluate seed germination and their resistance to blight and in improving seed germination in cotton, respectively. Hot water treatment inhibited the incidence of bacterial blight to a lesser extent and the germination was also poor. Organic treatments exhibited better performance in increasing germination and in reduction of blight disease, which was significantly superior over all other treatments by 72, 67, 66 and 68%, respectively. Whereas in the case of chemical treatment, the incidence of blight was reduced to a greater extent and germination was affected.