Triazoles and strobilurins group of fungicides have been reported to have dual properties (growth regulator and fungicide) and have been used to prevent the plant lodging. In this study four subsequent field experiments with oat cultivars with and without fungicide application were conducted from 2012 to 2015 aiming to find if fungicide application can improve some yield attributes and quality parameters of oats and find yield attributes that most affect the quality parameters of oats. Multivariate techniques were applied in other to find the most important variables that contribute to sample classification. Fungicide application has a role in reducing the plant stature of oat cultivars with consequent decreasing in lodging index of oat cultivars. Fungicide application reduces the plant stature and lodging index, contributing to best quality parameters of oats. Multivariate techniques (PCA, PLS-DA, OLS-R) were capable in finding the important variables that affect yield attributes and quality parameters and can be applied in a broad range of agricultural systems for predicting important aspects that affect plant growth and development.
The study was conducted in the research field sites of the Institute of Agricultural Research (IRAD), Bambui, North West Region, (IRAD), Ekona South West Region and the International Institute of Tropical Agriculture (IITA) Nkolbisson, Yaoundé, Center Region of Cameroon. Four cultivars of taro (Dark green petiole with small leaves (L1), Red petiole with small leaves (L2), Light green petiole with large leaves (L3) and Light green petiole with small leaves(L4)) were planted in four seasons, for two years, in the months of March and July 2015, March and July 2016 in all the research farms. Ninety corms of the each cultivar were treated before planting with fungiforce at 0.33% concentration while others were not treated. Fungiforce is a contact and systemic fungicide containing high levels of copper oxide (600 grams) and mild levels of metalaxyl (120 grams), various concentrations of 0.4%, 0.33%, 0.27%, at the onset of the first symptom of leaf blight on the leaves using knapsack sprayer of 15 litres at two weeks interval, while the control experiment consisted of unsprayed taro leaves. Data for the disease incidence of taro leaf blight was recorded from the onset of disease in fields and continued at two weeks interval for 6 weeks. The results of planting taro in four seasons in three experimental field sites revealed that there was a decrease in disease incidence in fields sprayed with fungiforce than in the control field. Plots sprayed with fungicide at different concentrations showed no variation on the 4 cultivars in the different field sites. The disease incidence ranged from 10% to 100% in the 4 seasons, at the three experimental field sites. The variation in disease incidence in the three planting sites is an indication of possible genotypes by environment (GXE) interaction that may have significant influence on the taro leaf blight resistance potential.
Aims: This study was conducted to evaluate the effects of water deficits applied at different phenological periods on whole-plant responses of cotton grown under rain-sheltered conditions.
Study Design: A complete randomized design with four replications.
Place and Duration of Study: The study was conducted at the Drought Tolerance Laboratory at the Texas A&M AgriLife Research and Extension Center near Corpus Christi during the 2014 and 2015 cotton growing seasons.
Methodology: Individual plants of the commercial cultivar Phytogen 375 were grown in 13.5-L pots. Daily irrigation of individual pots was controlled with electronic timers and daily whole-plant transpiration was calculated lysimetrically from 10’-interval pot weights measured with electronic load cells. Plant measurements included height, leaf area, total dry biomass and seed-cotton production.
Results: With only few exceptions, the water deficit treatments had significant impact on plant’s production of biomass, leaf area, and seed-cotton, as well as whole-plant transpiration and transpiration per unit leaf area. The responses to these plant variables showed to be different between years as the environmental conditions were more stressful in 2014 than in 2015. Water deficits applied during first bloom (FB) to mid-bloom (MB) had the largest impact on plant growth, plant transpiration, and yield in both years; decreased dry biomass 32% in 2014 but had no effect in 2015, decreased seed-cotton 57% in 2014 and 23% in 2015, completely inhibited plant leaf area growth in both years, decreased cumulative whole-plant transpiration 46% in 2014 and 41% in 2015, decreased transpiration per unit leaf area 41% in 2014 and 37% in 2015.
Conclusion: Seed-cotton production per plant was most affected by water deficits during FB to MB stage (decreased 57% in 2014 and 23% in 2015), less affected during MB to open boll (decreased 49% in 2014 and 0% in 2015), and least affected during match head square to FB (0% in 2014 and 17% in 2015).
Differential pattern of association assessed in sugarcane under two water regimes revealed that cane yield had highly significant positive correlation with stalk length, stalk diameter and single cane weight under both the environments. Physiological traits like relative water content at 60 days after planting had a positive correlation with stalk length under both the environments whereas, it was positively correlated with stalk diameter (0.46) and single cane weight (0.45) under water stressed environment. Path analysis revealed that number of tillers at 240 days had maximum positive direct effect on cane yield followed by relative water content (RWC) at 60 days, stalk length, RWC at 120 days, number of shoots at 120 days and single cane weight. Stalk length, stalk diameter, number of millable cane (NMC), number of tillers at 240 days were found important for cane yield improvement, and low number of stomata, chlorophyll, specific leaf weight (SLW) and RWC at 120 days are associated with stress tolerance.
Rener Luciano de Souza Ferraz, Aldair de Souza Medeiros, Pedro Roberto Almeida Viégas, Alberto Soares de Melo, Patrícia da Silva Costa, Ivomberg Dourado Magalhães, Marcelo de Andrade Barbosa, José Dantas Neto
Potassium silicate optimizes the growth of naturally colored fiber cotton in the semi-arid of Paraíba state, Brazil. The purpose of this research was to evaluate the growth of naturally colored fiber cotton cultivars under silicon foliar application. The experiment was carried out in the experimental area of Embrapa / Algodão, in the Northeast region of Brazil, using a completely randomized design, with 3 ˣ 5 factorial scheme, which was composed by three cotton cultivars ('BRS Topázio', 'BRS Safira', and 'BRS Rubi'), five silicon concentrations (0, 50, 100, 150, and 200 mg L-1), sprayed weekly on leaves, and four replicates. Growth data were submitted to analysis of variance, regression, correlation, and mean test. Treatments had a significant effect on growth variables. When calculating the effects of the factors, it was verified that the cultivars differed among them for the evaluated parameters. For 'BRS Topázio', silicon reduced plant height and increased the stem expansion rate. The application of silicon increased 'BRS Safira' plant height and growth rate. For 'BRS Rubi', silicon increased plant height and stem expansion rate.