• Authors:
    • Delatorre, C.
    • Federizzi, L.
    • Locatelli, A.
    • Martinelli, J.
    • Graichen, F.
    • Kulcheski, F.
  • Source: Euphytica
  • Volume: 175
  • Issue: 3
  • Year: 2010
  • Summary: Crown rust, which is caused by Puccinia coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats ( Avena sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F 6 genetic map from Pc68/5*Starter * UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in 12 linkage groups. The map covered 409.4 cM of the Avena sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located in the linkage group 4_12 in the Kanota * Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes.
  • Authors:
    • Liu Qian
    • Zhang TingWei
    • Liu ChangZhong
  • Source: Guizhou Agricultural Sciences
  • Issue: 6
  • Year: 2010
  • Summary: The results from studying the effect of inter-cropping of wheat with different crops on occurrence quantity of wheat aphid at flowering and filling stage of wheat showed that the aphid occurrence quantity of inter-cropping of wheat with maize or Helianthus annuus or soybean significantly lower than wheat single cultivation, there was significantly difference in aphid occurrence quantity among three inter-cropping patterns and the aphid occurrence quantity of wheat/maize inter-cropping pattern was the lowest, followed by wheat/ Helianthus annuus inter-cropping pattern.
  • Authors:
    • Rocha, D.
    • Cano, M.
    • Patino, H.
    • Medeiros, F.
    • Gonzalez, F.
  • Source: Ciencia Rural
  • Volume: 40
  • Issue: 1
  • Year: 2010
  • Summary: The impact of energy supplementation on the performance and carcass characteristics of 24 Aberdeen-Angus * Charolais steers grazing an annual ryegrass ( Lolium multiflorum) and oat ( Avena strigosa [ Avena nuda]) pasture managed in order to avoid constrains to animal performance was evaluated. Treatments were levels of supplementation of 0, 0.4, 0.8 and 1.2% BW with a corn and mineral based supplement. Animals were slaughtered after reaching 4.5 mm of fat cover in the rump (P8) evaluated ultrasonography. No differences were observed in fat deposition, measured in live animals with ultrasound at the end of performance period, and in liveweight gain, which showed average values of 3.9 mm and 1.54 kg/day, respectively. Blood serum levels of urea were linearly decreased and cholesterol linearly increased by energy supplementation, with no differences in the serum levels of glucose and triglycerides. Energy supplementation linearly increased the killing-out proportion and carcass weight gain, but no differences were observed on the rib eye area, slaughter weight and hot carcass weight, which averaged 67.85 cm 2, 438.95 kg and 227.75 kg, respectively. Increasing the levels of supplementation resulted in higher killing-out proportion and higher carcass daily gains, without changes in performance and carcass parameters evaluated.
  • Authors:
    • Jing, Q.
    • Dai, T.
    • Wollenweber, B.
    • Jiang, D.
    • Mu, H.
    • Cao, W.
  • Source: Journal of Agronomy and Crop Science
  • Volume: 196
  • Issue: 1
  • Year: 2010
  • Summary: Low radiation reduces wheat grain yield in tree-crop intercropping systems in the major wheat planting area of China. Here, two winter wheat ( Triticum aestivum L) cultivars, Yangmai 158 (shading tolerant) and Yangmai 11 (shading sensitive), were shaded from jointing to maturity to evaluate the impact of low radiation on crop growth, photosynthesis and yield. Grain yield losses and leaf area index (LAI) reduction were less than the reduction in solar radiation under both shading treatment in both cultivars. Compared with the control (S0), grain yield only reduced 6.4% and 9.9% under 22% shading treatment (S1), while 16.2% and 25.8% under 33% shading (S2) in Yangmai 158 and Yangmai 11 respectively. The reduction in LAI was 6.0% and 9.2% (S1), and 18.2% and 22.2% (S2) in Yangmai 158 and Yangmai 11 respectively. However, decline in canopy apparent photosynthetic rate (CAP) was 15.0-22.9% (S1) and 29.5-49.6% (S2), which was consistent with the reduction in radiation. The reduction in LAI was partially compensated by increases in the fraction of the top and bottom leaf area to the total leaf area, which facilitated to intercept more solar radiation by the canopy. The decrease in photosynthetic rate ( Pn) of flag leaf was partially compensated by the increase in Pn of the third leaf from the top. In addition, an inconsistency between the low Pn and the high Chl content in flag leaf was observed at 30 DAA. This could be explained that more excitation energy was dispersed via the non-photochemical approaches in the photosystem II (PSII) of flag leaf after long-term shading.
  • Authors:
    • Gill, R. I. S.
    • Baljit, S.
    • Navneet, K.
  • Source: Indian Journal of Agronomy
  • Volume: 55
  • Issue: 1
  • Year: 2010
  • Summary: Field experiments were done to standardize the agronomic practices of wheat grown in association with poplar ( Populus deltoides Bartr.) plantation at Ludhiana, Punjab. The study was conducted under block plantation of poplar (Clone G-48) grown at a spacing of 5*4 m, (accommodating 500 trees/ha) at the age of 2, 3 and 4 years in 2004, 2005 and 2006, respectively. The soil of the site was low in available N and medium in available P. Three seed rates (100, 125 and 150 kg/ha) and combinations of 3 N (125, 187.5 and 250 kg N/ha) and 2 P levels (27 and 40.5 kg P/ha) were evaluated to find out the optimum fertilizer and seed requirement of wheat (cv. PBW 343) intercropped with poplar. The height and diameter of trees increased from 10.4-15.1 m and 10.4-16.5 cm, respectively in the span of 2 years (2004-06). Wheat yield under poplar reduced with the increase in tree age. However, the crop under poplar responded positively to higher fertilizer and seed rates. The yield of sole wheat was significantly higher when compared with intercropped wheat. Among 3 seed rates, 25% additional seed rate (125 kg/ha) over recommended to sole wheat significantly increased (6%) the grain yield of wheat under poplar plantation. Among different fertilizer levels, grain yield of wheat was significantly higher (3.93 tonne/ha) at 50% additional N than recommended to sole wheat with recommended P i.e. at 187.5 kg N and 27 kg P/ha. N and P uptake by wheat was higher in sole wheat than under poplar. Additional application of seed and nutrients over the recommended levels significantly increased their uptake. The benefit cost ratio in poplar plantation were highest with the application of 150 kg/ha seed and 187.5+27 kg N+P/ha to wheat.
  • Authors:
    • Sakai, R. H.
    • Ambrosano, E. J.
    • Melo, P. C. T. de
    • Negrini, A. C. A.
    • Schammass, E. A.
    • Rossi, F.
  • Source: HORTICULTURA BRASILEIRA
  • Volume: 28
  • Issue: 1
  • Year: 2010
  • Summary: The performance of lettuce in sole and intercropped with green manures was assessed under different establishment times. The lettuce fresh and dry weight, number of leaves per plant, diameter and length of head, and fresh and dry weight of green manure were evaluated. The intercropping design was additive and both cash and cover crops were planted in rows. The experimental design was of randomized complete blocks in split plot scheme, with six replicates. The plots represented the green manure sowing days (0, 20, 40 and 60 before transplanting of lettuce), and the sub-plots were assigned by cropping systems (lettuce in sole crop and intercropped with black oat, cowpea or white lupin). Simultaneous planting in the intercropping did not affect the lettuce performance. However, when the green manures were sown before lettuce, they influenced it in a negative way. Among the green manures, cowpea increased biomass and had a higher negative effect on lettuce performance compared to white lupin, which appeared to produce less competition. The sole crop and the intercropping with simultaneous planting of the green manures resulted in a better lettuce performance.
  • Authors:
    • Meinhardt, C. G.
    • Nelson, K. A.
    • Smoot, R. L.
  • Source: International Journal of Agronomy
  • Volume: 2010
  • Year: 2010
  • Summary: Field research (2003-2005) evaluated the effect of wheat row spacing (19 and 38 cm) and cultivar on double-cropped (DC) soybean response, 38-cm wheat on relay-intercrop (RI) response, and wheat cultivar selection on gross margins of these cropping systems. Narrow-row wheat increased grain yield 460 kg ha -1, light interception (LI) 7%, and leaf area index (LAI) 0.5 compared to wide rows, but did not affect DC soybean yield. High yielding wheat (P25R37) with greater LI and LAI produced lower (330 kg ha -1) soybean yields in an RI system than a low yielding cultivar (Ernie). Gross margins were $267 ha -1 greater when P25R37 was RI with H431 Intellicoat (ITC) soybean compared to Ernie. Gross margins were similar for monocrop H431 non-coated (NC) or ITC soybean, P25R37 in 19- or 38-cm rows with DC H431 NC soybean, and P25R37 in 38-cm rows with RI H431 ITC soybean in the absence of an early fall frost.
  • Authors:
    • Marangon, R.
    • Mondardo, J.
    • Martin, T.
    • Pavinato, P.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Division Symposium 3.2 Nutrient best management practices
  • Year: 2010
  • Summary: The use of phosphate fertilizer has promoted changes in phosphorus fractions and availability in soil, that highlights the requirement of more studies to understand phosphorus dynamics in soil, and to develop cultivation strategies to increase crop grain yield under phosphate fertilization. The work aimed to evaluate changes in soil phosphorus availability in sequential crop seasons, under effects of phosphate fertilizer sources and cover crop plants. The experiment was carried at Technological Federal University of Parana, Dois Vizinhos, PR, Brazil. The soil is a Ferralsol, with high level of available P. Experimental design was a factorial 3*8, in randomized blocks, with three replicates and 5*5 m plots. Treatments were composed of natural phosphate and soluble phosphate, and a control. During winter season, the seven cover crops were: vetch, white lupin, radish, ryegrass, black oat, clover and pigeon pea, and a witness with no cover crop. Brazilian Ferralsol, with high level of available P, does not increase plant grain yield with sources of phosphate fertilization. Available P in soil changes markedly with phosphate fertilization, especially in the surface layer (0-5 cm). Important results are expected in soil P availability after winter cover crops.
  • Authors:
    • Elliott, N.
    • Giles, K.
    • Phoofolo, M.
  • Source: Environmental Entolomology
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Creating conditions that enhance the abundance of resident populations of natural enemies in agroecosystems is considered critical to the efficiency of biological control of insect pests. We conducted a study to determine the potential of relay-intercropping for enhancing the abundance of aphidophagous lady beetles in sorghum. A relay-intercropping system consisting of alfalfa, winter wheat, and cotton as intercrops and sorghum as a main crop was compared with sorghum monoculture plots at two study sites in OK from 2003 to 2006. Lady beetles and aphids were sampled throughout the season using sticky traps and field counts on individual sorghum plants. Results from sticky traps and field counts show that differences in abundance and species composition of lady beetles between intercropped and monoculture sorghum were not statistically different during each year of study. Also, the lady beetle-greenbug ratios in relay-intercropped and monoculture plots were not significantly different. Lack of significant effects of relay-intercropping in our study may have been attributable to the confounding effects of spatial and temporal scale and the low number of aphids and other alternative prey in the intercrops compared with high incidence of corn leaf aphids in sorghum early in the season.
  • Authors:
    • Chai, Q.
    • Qi, W.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 1
  • Year: 2010
  • Summary: A field experiment was conducted in China to investigate the effect of different root partition patterns on wheat/maize competitiveness under intercropping system and how it affects yield. Two root partition patterns (plastic film and nylon mesh partition patterns) were used. Results showed that wheat/maize competitiveness in intercropping system steadily increased from sowing to flowering stage of wheat and then decreased the competitive advantage of wheat over maize under intercropping decreases by root partitioning. Intercropping system without root partition increased the competitive advantage of wheat by 20.5 and 4.9% respectively, compared to those with plastic film and nylon mesh partitions. The land equivalent ratios of intercropping systems without root partition, with plastic film partition and nylon mesh partition were 1.46, 1.20 and 1.39, respectively. Yield for the intercropping system was quadratically correlated with wheat competitiveness to maize. Improving wheat/maize competitiveness in intercropping systems increased yield. The stage of wheat flowering was critical for optimizing wheat competitiveness.