Effect of Different Herbicides on Seed Yield and Physiological Aspects in Soybean ( Glycine max L.).

The Soybean contains many medicinal virtues. It helps to maintain the intestinal health, prevent diseases (a lower risk of breast and prostate cancer) arising from defective digestion and retard the ageing process. In order to study advantages and disadvantages of herbicides on soya bean harvesting, 13 different concentrations of pre and post emergent herbicides were assessed in comparison with control (without any operation). The data were collected for increase percentage of the seed yield, 1000-grain weight, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia. *Corresponding Author: Sadegh Mohajer; Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia. E-mail: s.mohajer@siswa.um.edu.my Effect of Different Herbicides on Seed Yield and ... 61 Recent Advances in Medicinal Plants and Their Cultivation 60 arabica,Rottboellia exaltata, Cyperus rotandus, Commelina benghalensis, Commelina communis,Euphorbia geniculata, Acalyphaindica, Leucasaspera, Physalis minima, Phyllanthus speciesand Digitaria sanguinalis in soybean crop. Gaikwad and Pawar (2002) found, Brachiaria ramosa, Cyanodon dactylon, Echinochlo acrus galli, Convolvulus arvensis and Acalyphain dica in soybean crop. Balyan and Malik (2003) noticed Trianthema monogyna, Echinochloa colona, Celosia argentea, Digera arvensis, Cyperus rotandus, Physalis minima and Dactyloctenium aegyptiumin soybean crop. Rohitashav et al. (2003) observed Trianthema monogyna, Echinochloa colona, Celosia argentea, Dactyloctenium aegyptium, Eleusine indica, Cleome viscosa, Cucumis trigonus and Commelina benghalensis in soybean field. Marload and Krausse (1987) reported that during crop growth and development, weed competition caused decline in photosynthetic leaf area. Stoimenova (1989) reported that soybean yield was inversely related to total weed dry matter and directly correlated when weeding was done during critical period. Chhokar et al. (1995), Joshi and Billore (1997) and Dubey (1998), reported that weed competition increased the plant height of soybean. On the other hand, Pholan (1986), Pandey et al. (1996) and Kuruchania et al. (1996) observed continuous decrease in plant height with the increasing of weeds competition which was attributed to growth habit of a variety. Generally, an increase in one kilogram of weed growth corresponds to a reduction in one kilogram of crop growth as weeds remove plant nutrients more efficiently than crop plants. However, yields from un-weeded soybean plots from different studies were compared and the reduction was approximately 50-60 percent (Jadhav, 2007). Although more reductions are encountered when certain highly competitive species predominate such as Cyperus rotundus, Commelina benghalensis, Echinochloa crus galli, Euphorbia geniculata, Merimia emerginata, Phyllanthus niruri, Rotalla species in soybean field (not reported). Soybean cultivar HIL is the most popular variety of the transitional tract of Iran and it has an average yield potential ranging between 2.5-3.5 ton h -1, if it is properly managed. In this respect, it is felt necessary to find out the avenues The addition of adequate iodine to the diet reverses any goiter-causing effects of soy. Population studies suggest that soy protects against thyroid cancer (Hom-Ross et al., 2002). Soy isoflavone enhances the immune response and provides a possible explanation for lower incidence of certain cancers in soy-eating parts of the world (Watanabe et al., 2002; Jenkins et al., 2002). The pain of arthritis has been helped by soy through modulating the immune system (Arjmandi et al., 2004). Weeds represent the most economically important pest complex to global food production and it has significantly impact on mankind at all levels, from health perspectives to the pursuit of recreation (Basu et al., 2004; Bridges, 1994). Interestingly, the better weed management becomes, the more difficult it becomes to manage weeds. This conundrum reflects the diversity of weed genomes facilitating their continued adaptation to all forms of selective practices (control) necessary for effective crop production (Barrett, 1983; De Wett and Harlan, 1975; Gould, 1991). Recent efforts to manage weeds have taken a slightly different path and focus on the use of herbicides that are selective to crops due to genetic-engineering (Duke and Powles, 2008). Researchers have demonstrated, in general, that the likelihood of soybean yield Loss increases: 1) when exposure to the plant growth regulator (PGR) herbicide occurs closer to the time of soybean reproductive development (flowering or later), and 2) as the dose of the PGR herbicide increases (Kelley, 2005). In general, certain weeds species are predominately observed in specific crops. Similarly, in soybean also four predominant weeds were observed by several workers in different parts. Arya and Singh (1998) observed weed species viz., Oxalis ratifolia in soybean crop. Kuruchania et al. (1999) reported the presence of weeds like Echinochlo acrus galli, Phyllanthus fraternus, Commelina communis, Rotala axillaris, Eclipta alba, Cyanotis axillaris,Corchorus olitorius, Euphorbia geniculata, Chichorium intybus and Merremia emarginata among the broad leaf weeds, and Cyperusrotandus and Cyperusiriaas sedges in soybean field. Sharma and Raguwanshi (1999) found Echinochlo acrusgalli, Dinebra Effect of Different Herbicides on Seed Yield and ... 63 Recent Advances in Medicinal Plants and Their Cultivation 62 subsequently the land was harrowed twice, followed by planking to level and to bring the soil to a fine tilth suitable for sowing. The plots were laid out according to the plan. Fertil izer doses were applied according to the recommendation for soybean in the transition tract of Lavasanat were applied at the rate of 20 kg nitrogen per hectare in the form of urea, 80 kg phosphorus per hectare in the form of single super phosphate and 40 kg potash per hectare in the form of potash muriate. These fertilizers were given as basal doses at the time of sowing in furrow opened 5 cm deep from the seed lines. After fertilizers application, the furrows were covered with soil. Healthy and bold seeds were dibbled with a spacing of 6 m x 2 m to a depth of 5 cm. The crop was given protective irrigations as and when required. The seedlings were thinned out by maintaining one plant per hill after 15 days of sowing. The data were collected for increase percentages of the seed yield, 1000grain weight, biomass and reduction percentages of the plant height, different weeds and number of plants (per m 2). (d) Traits measurement: Plant height (cm): Plant heights were recorded from the ground level to the growing tip of the main shoot. Measurements were taken from five tagged plants in each treatment and the average height was calculated and expressed in centimetres. Seed yield per hectare (kg ha-1): The seeds were separated manually by gently beating the dried plants with a wooden stick. The seeds were cleaned and dried in the shade, the seed yield was recorded for each treatment and then seed yield per hectare was computed and expressed as kg ha-1. 1000-grain weight (g) : Thousand seeds were counted from the sample drawn from seed yield of each net plot and the weight of 1000 seeds was recorded and expressed in grams. Plant number: The number of plants in a plot 0.5cm x 0.5cm was calculated and compared with standard number in control treatments. Plant Biomass (kg ha-1): After harvesting of the lines from the lowest part of the stem in each experimental unit the total above ground parts were weighed and converted to kg ha-1. for enhancing productivity potential in cv. HIL and one such approach is to find out the physiological response to different herbicides and crop weed competition. Keeping these points in view, the present investigation was undertaken for the following objectives: i. To study the physiological effect of the herbicides on soybean‘s weeds. ii. To evaluate the effect of herbicides on morphology traits and seed yield in soybean. MATERIALS AND METHODS (a) Design experiment: The experiment was carried out on the medium of black clay-loam-silt soil at Agricultural Research Station, Lavasanat, Iran; where is situated at 36° 3' North and 35° 46' E longitude with an altitude of 1700 meters above the mean sea level during 2010-2011. The experiment consisted of seven herbicides in thirteen different concentrations in addition, hand weeding were assessed in comparison with control (no weeding) under complete block design with four replications. (b) Treatments: Different treatments were consisted of, (a) Pre-planting soil incorporation: herbicides were sprayed and mixed with soil one day before sowing, uniformly with the help of knapsack sprayer. T1: Trifluralin (Treflan) 1.2 kg a.i ha-1; T2: Ethalfluralin (Sonalan) 1.16 kg a.i ha-1 (b) Pre-emergence: herbicides were sprayed one day before seed germination. T3: Metribuzin (Sencor) 0.35 kg a.i ha-1; T4: Oxyfluorfen (Goal) 0.36 kg a.i ha-1; T5: Oxyfluorfen (Goal) 0.48 kg a.i ha-1; T6: Pendimethalin (Stomp) 0.66 kg a.i ha-1; T7: Pendimethalin (Stomp) 0.82 kg a.i ha-1 . c) Postemergenc: herbicides were sprayed one day after seed germination. T8: Oxyfluorfen (Goal) 0.36 kg a.i ha-1; T9: Oxyfluorfen (Goal) 0.48 kg a.i ha-1; T10: Bentazon (Basagran) 0.96 kg a.i ha-1; T11: Bentazon (Basagran) 1.2 kg a.i ha-1; T12: Oxyfluorfen+ Bentazon (Storm) 0.85 kg a.i ha-1; T13: Oxyfluorfen+ Bentazon (Storm) 1.06 kg a.i ha-1; T14: Hand weeding; T15: Control. (c) Harvesting Operation: After the harvest of the previous year crop, the land was ploughed with a disc plough, Effect of Different Herbicides on Seed Yield and ... 65 Recent Advances in Medicinal Plants and Their Cultivation 64 Table 1. ANOVA of traits at different concentration of herbicides. Seed yield (kg ha-1): Significant differences were due to various treatments with respect to seed yie