DIMITRIOS VLACHOSTERGIOS1,ANASTASIOS LITHOURGIDIS2,ATHANASIOS MAVROMATIS3 1Fodder Crops and Pastures Inst., Hellenic Agricultural Organization, 41335 Larissa, Greece, www.nagref.gr,
2
Department of Agronomy, Aristotle University Farm of Thessaloniki, 570 01 Thermi, Greece
3
Lab. of Genetics and Plant Breeding, Aristotle University of Thessaloniki, Greece
Key words: Vicia sativa, weed stress, competition, grain yield
Introduction
Common vetch (Vicia sativa L.) is one of the most widely distributed annual leguminous crops throughout the Mediterranean basin. It is used as a protein crop, for hay or silage production and has interesting traits for organic or low input culture systems. Common vetch forms a strong fibrous root system that develops nodules at an early stage and fixes the atmospheric nitrogen into the soil. It is broadly used in crop rotation systems to manage diseases, weeds, improve soil fertility and contribute to increased yield and protein content in the following crops (Vasilakoglou et al., 2008). Weeds are the main obstacle to common vetch production. Breeding for weed tolerance is the most economic, feasible and environmental friendly method to control weeds (Rubiales et al., 2006). However, the experimental data on diversity for weed tolerance of common vetch are very limited. The objective of this work was to evaluate common vetch genotypes for grain yield under weed stress and identify promising genotypes when grown under low-input farming. Material & Methods
Field experiments were established under a replicated split-plot experimental design at the central farm of Fodder Crops and Pastures Institute (latitude 39o36′N, longitude 22o25′E) and at the University farm (latitude 40o32′N, longitude 22o59′E) of Aristotle University of Thessaloniki (AUTH) during the
growing season 2011-2012. Weed-free and weedy treatments were considered as main plots and subplots were the genotypes. The genotypes evaluated consisted of 8 cultivars and 2 cultivar mixtures (Vlachostergios et al. 2011). The entries were planted at a seed rate of 180 kg ha-1 in the last
week of November, at a depth of 3 cm. Individual plots consisted of six rows spaced 0.25 m apart and 4 m long, occupying an area of 6 m2. All plots in
each replication were separated by 1 m buffer zone and replications were separated by 2.5 m buffer zone. The weeds were not planted; rather, a natural infestation was allowed to emerge and grow. Predominant annual weed species, as determined by systematic visual estimates in all plots, were wild mustard (Sinapis arvensis, >85% of the total weed population) in Fodder Crops and Pastures Institute (FCPI) and common fumitory (Fumaria officinalis, >65% of the total weed population), shepherd's-purse (Capsella bursa-pastoris) and field poppy (Papaver rhoeas) in AUTH. At grain maturity, the experimental plots were hand-harvested and threshed using a stationary Wintersteiger thresher in order to determine grain yield. Combined analysis of variance was performed and differences between means were compared at the 5% level of significance. Weed tolerance (WT) was determined as the ability of a cultivar to achieve high yields despite weed competition (Murphy et al. 2008) and was calculated as a percentage (%) by the formula: WT = 1 - D/Ywf, where D (D=Ywf-Yw) is the difference between the yield of the genotype under weed-free treatment (Ywf) and the yield of the same genotype under weedy treatment (Yw).
Results & Discussion
Partitioning of treatments Sum of Squares (%) across locations indicated that location was the main source of variation, followed by weed-free vs weedy treatment and genotype. Differences between locations could be partially attributed to the different competition ability of the predominant weed species in each location. In AUTH, were the predominant weed species was common fumitory, the mean grain yield under weed competition was 1.65 tn/ha, whereas in FCPI were the predominant weed species was wild mustard the corresponding yield was 0.99 tn/ha. Genotype by location interactions indicated that the grain yield produced depended on the genotypic response in each location and thus resulted in different ranking order of the genotypes in the two locations studied. However, it must be noted that certain genotypes produced high yield in both locations. Significant differences were also detected between treatments (weed-free vs weedy). Common vetch genotypes produced 0.48 tn/ha (on average) less under weed competition. Weed tolerance values ranged from 60 to 91% across locations. Two cultivars illustrated WT values above 80%, while the two cultivar mixtures ranked in the top and gave WT values near 90%. It seems that the functional diversity observed in some culture mixtures could provide a buffering capacity in biotic and/or abiotic stresses (Wolfe 2005).
These preliminary results provide evidence of valuable diversity between common vetch genotypes for weed tolerance. Moreover, cultivar mixtures showed high weed tolerance and may be a useful alternative for cultivation under low-input farming. However, further research is needed to verify these results for more valid conclusions.
Table 1: Yield performance (tn/ha) under weed-free (Ywf) and weedy (Yw) treatment across two locations, difference between treatments and weed tolerance (WT) of ten common vetch genotypes under LI farming
Genotypes Ywf (tn/ha) Yw (tn/ha) Difference (tn/ha)
WT (%) V-65 2.12 1.17 0.94 63 V-233 2.27 1.27 1.01 60 V-209 1.91 1.45 0.46 77 V-216 1.77 1.18 0.59 68 V-89 1.87 1.39 0.48 77 V-64 1.51 1.18 0.33 81 Leonidas 1.68 1.26 0.42 77 M-6900 1.52 1.30 0.22 86 Mix1 (V-65+V-233+V-130) 1.61 1.48 0.14 91 Mix2 (V-233+V-89+M-6900) 1.78 1.53 0.25 88 Mean ± SE 1.80 ± 0.12 1.32 ± 0.12 CV: 13,4% References
Murphy K., J.C. Dawson and S.S. Jones. 2008. Relationship among phenotypic growth traits, yield and weed suppression in spring wheat landraces and modern cultivars. Field Crops Research 105: 107–115.
Rubiales D., Perez-de-Luque A., Fernandez-Aparico M., Sillero J., Roman B., Kharrat M., Khalil S., Joel D. and C. Riches. 2006. Screening techniques and sources of resistance against parasitic weeds in grain legumes. Euphytica 147: 187–199.
Vasilakoglou I, Dhima K, Lithourgidis A and I. Eleftherohorinos. 2008. Competitive ability of winter cereal-common vetch intercrops against sterile oat. Experimental Agriculture 44:509-520.
Vlachostergios D.N., A.S. Lithourgidis, C.A. Dordas and D. Baxevanos. 2011. Advantages of mixing common vetch cultivars developed from conventional breeding programs when grown under low-input farming system. Crop Science 51: 1274-1281.
Session A Poster A16