The objective of this study was to determine the effect of 24-epibrassinolide (24-EBL) applications on growth, chlorophyll, and mineral content of lettuce (Lactuca sativa L. var. Crispa) grown under salt stress. The study was conducted in pot experiments under greenhouse conditions. Lettuce seedlings were treated with seed and foliar 24-EBL applications at different concentrations (0, 1, 2, and 3 μM). Salinity treatments were established by adding 0, 50, and 100 mm of sodium chloride (NaCl) to a base complete nutrient solution. Results showed that salt stress negatively affected the growth and mineral content of lettuce plants. However, seed and foliar applications of 24-EBL resulted in greater shoot fresh weight, shoot dry weight, root fresh weight, and root dry weight as well as higher stem diameter than the control under salt stress. Salinity treatments induced significant increases in electrolyte leakage of plant, but foliar 24-EBL application reduced leaf electrolyte leakage and has determined lower values of leaf electrolyte leakage than non-treated ones. In regard to nutrient content, it can be inferred that 24-EBL applications increased almost all nutrient content in leaves and roots of lettuce plants under salt stress. Generally, the greatest values were obtained from 3 μM 24-EBL application. Treatments of 24-EBL alleviated the negative effect of salinity on the growth of lettuce.
Melek Ekinci, Ertan Yildirim, Atilla Dursun, and Metin Turan
Soon O. Park, Dermot P. Coyne, Atilla Dursun, and Geunhwa Jung
Common bacterial blight (CBB), incited by Xanthomonas campestris pv. phaseoli (Xcp), is an important seed-transmitted disease of common bean (Phaseolus vulgaris L.). Tepary bean (Phaseolus acutifolius A. Gray) has high resistance to Xcp. The objective of this study was to identify RAPD markers linked to genes controlling resistance to three isolates of Xcp using bulked segregant analysis in an F2 population from the tepary bean cross CIAT-G40005 (resistant to Xcp) × Nebr.#4B (susceptible to Xcp). Twelve RAPD markers were mapped in a coupling-phase linkage with three genes for resistance to Xcp. The linkage group spanned a distance of 19.2 cM. A marker L7750 was linked to the genes for resistance to Xcp strains EK-11 and LB-2 at 8.4 cM and 2.4 cM, respectively. Markers U10400 and Y14600 were detected as flanking markers for the resistance gene to Xcp strain SC-4A at 2.4 cM and 7.2 cM, respectively. The symbols Xcp-1, Xcp-2, and Xcp-3 were assigned for the genes for resistance to Xcp strains EK-11, LB-2, and SC-4A, respectively. RAPD markers linked to the genes for resistance to Xcp could be used for transferring all of the resistance genes from P. acutifolius to a susceptible P. vulgaris cultivar.
Ertan Yildirim, Huseyin Karlidag, Metin Turan, Atilla Dursun, and Fahrettin Goktepe
This study was conducted to investigate the effects of root inoculations with Bacillus cereus (N2-fixing), Brevibacillus reuszeri (P-solubilizing), and Rhizobium rubi (both N2-fixing and P-solubilizing) on plant growth, nutrient uptake, and yield of broccoli in comparison with manure (control) and mineral fertilizer application under field conditions in 2009 and 2010. Bacterial inoculations with manure compared with control significantly increased yield, plant weight, head diameter, chlorophyll content, nitrogen (N), potassium (K), calcium (Ca), sulfur (S), phosphorus (P), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) content of broccoli. The lowest yield per plant, plant weight, steam diameter, and chlorophyll content were recorded in the control, but the manure with Bacillus cereus (BC), Rhizobium rubi (RR), and Brevibacillus reuszeri (BR) inoculations increased yield 17.0%, 20.2%, and 24.3% and chlorophyll content by 14.7%, 14.0%, and 13.7% over control, respectively. Bacterial inoculations with manure significantly increased uptake of macronutrients and micronutrients by broccoli. In conclusion, seedling inoculation with BR and especially RR may partially substitute costly synthetic fertilizers in broccoli.
Metin Turan, Nizamettin Ataoglu, Adem Gunes, Taskin Oztas, Atilla Dursun, Melek Ekinci, Quirine M. Ketterings, and Yuh Ming Huang
Boron (B) deficiency is widespread in the Anatolia region of Turkey. This could impact production and quality of Brussels sprout (Brassica oleracea L. gemmifera). A 2-year field experiment was conducted to study yield and quality response of four cultivars (Star, Brilliant, Oliver, and Maximus) to B addition (0, 1, 3, and 9 kg·ha−1 B). The optimum economic B rate (OEBR) ranged from 5.5 to 6.3 kg·ha−1 B resulting in soil B levels of 0.94 to 1.13 mg·kg−1. Independent of cultivar, B application decreased tissue nitrogen, calcium, and magnesium but increased tissue phosphorus, potassium, iron, manganese, zinc, and copper content. We conclude a B addition of 6 kg·ha−1 is sufficient to elevate soil B levels to nondeficient levels. Similar studies with different soils and initial soil test B levels are needed to conclude if these critical soil test values and OEBR can be applied across the region.