Correlation between Soil pH, Heterodera glycines Population Densities, and Soybean Yield
25
Citation
23
Reference
10
Related Paper
Citation Trend
Abstract:
Soybean cyst nematode ( Heterodera glycines Ichinohe) is the most damaging pathogen of soybean [ Glycine max (L.) Merr.] in the United States. Observations in fields suggest that high H. glycines population densities are associated with high soil pH, but H. glycines and soil pH have not been linked to soybean yield. The objective of our study was to assess the relationship between soil pH and H. glycines population densities and subsequent effect on yield. Experiments were conducted in Wisconsin from 1997 to 2000 and in Iowa from 1996 to 1998. Results were consistent among the experiments and showed a positive correlation between soil pH and H. glycines population densities and a negative correlation between yield and both soil pH and H. glycines population densities in both states. In the Wisconsin experiment, yield of both H. glycines –resistant and H. glycines –susceptible cultivars decreased as pH increased, but the decrease was less with H. glycines –resistant cultivars. Overall, results indicate that H. glycines population densities and the impact of nematode population densities on soybean yield are related to soil pH; however, the mechanism of these interactions is unknown.Keywords:
Heterodera
Soybean cyst nematode
Population density
Soybean [ Glycine max (L.) Merr.] cyst nematode ( Heterodera glycines Ichinohe; SCN) causes significant yield loss each year. New cultivars (released since 1997) have superior yield compared with older cultivars (released between 1938 and 1983), but responses to SCN have not been evaluated. Studies were established at three locations in Iowa for 2 yr to measure yield loss of 23 cultivars that differed in year of release and SCN resistance in locations with varying SCN population density and Heterodera glycines Type (HG Type). Initial SCN population densities (Pi) were <1000 eggs 100 cm −3 (HG Type 2.7) at Whiting, between 1000 and 4000 eggs 100 cm −3 (HG Type 1.2.5.7 and 2.5.7) at Nevada, and between 4000 and 12,500 eggs 100 cm −3 (HG Type 0 and 7) at De Witt in 2005 and 2006. Analysis of simple effects from year × location interactions consistently showed that new SCN‐resistant cultivars had lower final SCN population densities (Pf) and reproduction factors (Rf) compared with old and new SCN‐susceptible cultivars. Among all locations, seed yield of new SCN‐resistant cultivars was 14% greater than new SCN‐susceptible cultivars and 32% greater than old SCN‐susceptible cultivars. Yield increase was a result of increased seed production (seeds m −2 ) and not from a change in seed mass. Yield of new SCN‐susceptible cultivars was 18% greater than old SCN‐susceptible cultivars but did not provide greater control of SCN. These data indicate that yield increases with new SCN‐susceptible cultivars are not the result of improved SCN management. Data support the selection of SCN‐resistant cultivars for fields in which SCN has been identified, regardless of Pi or HG Type to increase yield and reduce SCN population densities.
Soybean cyst nematode
Heterodera
Cite
Citations (16)
Heterodera glycines, commonly known as the soybean cyst nematode (SCN), has become a major factor in soybean production in the Midwest United States. The influence of five tillage treatments and two treatments of row spacing on SCN population dynamics and yield of SCN-resistant and -susceptible soybean cultivars was investigated in a corn-soybean rotation system in southern Minnesota from 1993 to 1996. No effects of tillage and row spacing were observed on nematode population density. As expected, the susceptible cultivar Sturdy consistently supported higher nematode densities than did the resistant cultivar Bell in 1993 to 1995 and Freeborn in 1996. Nematode reproduction varied among years. Predicted nematode density at equilibrium was 3,800, 13,000, 12,000, and 27,000 eggs per 100 cm 3 of soil in plots with the susceptible cultivar and 480, 240, 430, and 700 eggs per 100 cm 3 of soil in plots with the resistant cultivars in 1993, 1994, 1995, and 1996, respectively. The effects of tillage and row spacing on soybean yield were inconsistent. The resistant cultivars yielded 653, 195, and 435 kg/ha more (P < 0.05) than the susceptible cultivar in 1994, 1995, and 1996, respectively, but no yield difference between susceptible and resistant cultivars was observed in 1993. Planting resistant cv. Bell increased the yield of the following susceptible cv. Sturdy compared with continual planting of the susceptible cultivar. A sequence with continued resistant cultivar or cultivars, however, produced a higher overall yield and lower nematode density at the end of the 4-year rotation cycle than any sequence in which the susceptible cultivar was included. Yield of resistant and susceptible cultivars was negatively related to the SCN initial population density.
Soybean cyst nematode
Heterodera
Population density
Crop Rotation
Cite
Citations (30)
The soybean cyst nematode (SCN), Heterodera glycines, is a major yield limiting pest of soybean (Glycine max). Current SCN management strategies include resistant soybean varieties and rotation with non-host crops. Increased adoption of the early soybean production system (ESPS) combined with a greater incidence of winter weeds from no-tillage practices may increase the population density of SCN during the noncrop period since several winter weeds and cover crops are hosts for SCN. A field experiment with a split-strip design was conducted over three years to evaluate whether SCN reproduced on weeds and cover crops during the noncrop period. Winter weeds and crimson clover roots were examined for females and cysts with eggs. The soil was sampled to determine if an increase in SCN egg population density occurred. We found no indication of SCN reproduction on winter weeds during the noncrop period or on the cover crop crimson clover. Accepted for publication 2 November 2006. Published 26 February 2007.
Soybean cyst nematode
Heterodera
Population density
Crop Rotation
Cite
Citations (6)
Double-cropping is defined as producing more than one crop on the same parcel of land in a single growing season. It is reported to have many benefits when incorporated in cropping systems, including improving soil health. In some double-cropping systems, soybean is planted following winter wheat. The soybean cyst nematode (SCN) ( Heterodera glycines Ichinohe) is a major soybean pathogen, and several reports suggest suppressive effects of wheat on SCN populations. Field trials were conducted from 2017 to 2018 to investigate the effect of wheat on SCN populations in double-cropping soybean. Nine fields with three levels of initial SCN populations (low, moderate, and high) were selected in Illinois. Wheat was planted in strips alternating with strips-maintained weed-free and under fallow over winter and early spring. Soybean was planted in all strips after wheat harvest. SCN egg densities were acquired at four time points: wheat establishment, post-wheat/pre-soybean, mid-soybean (R1 growth stage or beginning of flowering), and post-soybean harvest. Wheat strips reduced SCN egg densities compared with fallow strips at the R1 stage (−31.8%) and after soybean harvest (−32.7%). Double-cropping soybean with wheat has the potential to suppress SCN field populations and is a system with the potential to provide additional farm income. This study is meant to be a first step toward a better understanding of the mechanisms that govern the suppression of SCN by wheat.
Soybean cyst nematode
Heterodera
Cropping system
Population density
Multiple cropping
Growing season
Cite
Citations (13)
Many new cultivars of soybean (Glycine max) are released each year. Knowledge of their relative susceptibility to soybean cyst nematode (Heterodera glycines) is of interest to soybean breeders and those making nematode management recommendations. Two-hundred-eighty-one cultivars and breeding lines of soybean were screened for resistance to isolates of H. glycines races 1, 2, 3, 4, 5, 6, 9, and 14. No cultivar or line (except possibly PI 437654 or cultivars developed from this PI line) had resistance to all of the races tested. Twenty-one cultivars and lines were resistant to race 1, 5 to race 2, 146 to race 3, 2 to race 4, 4 to race 5, 24 to race 6, and 24 to race 14; some had resistance to more than one race. In addition, several cultivars and lines had moderate resistance to each of the race isolates tested.
Soybean cyst nematode
Heterodera
Cite
Citations (7)
The soybean cyst nematode (SCN), Heterodera glycines, is a major soybean yield-limiting factor, and the use of resistant cultivars is one of the most effective means to manage the nematode. During the past decade, a number of resistant cultivars in maturity groups I and II have been developed and made available to growers. A total of 47 resistant cultivars and nine susceptible cultivars were evaluated at 15 SCN-infested field sites and two noninfested sites during 1996 to 1998 in Minnesota. As expected, more nematodes developed on susceptible cultivars than on resistant cultivars. Egg density on susceptible cultivars increased by 1.9- to 10.6-fold during the growing season at 12 sites and did not change at the other three sites. Average egg density decreased over time for resistant cultivars at all sites, except where the initial egg density was low (≤455 eggs per 100 cm3 soil). Nematode reproduction factors (Rf = egg density at harvest/egg density at planting) for individual resistant and susceptible cultivars were highly consistent across the eight sites where initial SCN density was more than 1,000 eggs per 100 cm3 soil. Resistance, however, varied among the cultivars, with the average Rf of individual resistant cultivars across the sites ranging from 0.3 to 1.7. Resistant cultivars produced an average yield of 3,082 kg/ha compared with 2,497 kg/ha by susceptible cultivars at eight of 10 sites where egg density at planting was greater than 700 eggs per 100 cm3 soil. In contrast, no difference in yield was observed between resistant and susceptible cultivars at sites where egg density at planting was lower than 500 eggs per 100 cm3 soil. Yield differences between resistant and susceptible cultivars increased with increasing initial SCN egg density. In six fields infested with initial densities of more than 5,000 eggs per 100 cm3 soil, resistant cultivars produced 28.4% (676 kg/ha) more yield on average than susceptible cultivars. Soybean yield increased when cultivars with increasing resistance to the SCN (lower Rf or females formed on roots) were grown in fields infested with SCN. Average relative yield (yield of a cultivar/average yield of all resistant cultivars at a site) of individual resistant cultivars across all SCN-infested sites ranged from 0.76 to 1.10. Yield consistency of soybean cultivars was low among the different sites, indicating that many other factors affected yield. Our results suggest growing resistant cultivars is an effective method to manage SCN in Minnesota while minimizing yield loss due to SCN.
Soybean cyst nematode
Heterodera
Population density
Cite
Citations (70)
Soybean cyst nematode, Heterodera glycines Ichinohe, is one of the major phytopathological problems affecting soybeans, Glycine max (L.) Merr., in the major producing countries and the use of resistant cultivars and crop rotation have been the main methods of control adopted to reduce the nematode population in infested soils. Purpose of this study was to evaluate the effect of resistant (BRSGO Ipameri and BRSGO Chapadões) and susceptible (BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR) soybean cultivars on the development of H. glycines males and females during two successive years (2007 and 2008). In the trial of 2008 the plants were divided in three plots, with the last one having the roots stained to count the juveniles and to evaluate survival rate. Resistant cultivars always maintained a small number of females and males, except for cultivar BRSGO Ipameri that had a high count of males. Only cultivars BRS Favorita RR and BRS Silvânia RR had a sex ratio of 1:1. All other susceptible cultivars had, in general, greater number of males than females. Survival rate was nil on both resistant cultivars, and varied from 6.75 to 35.00% on the susceptible cultivars. Key words: Glycine max, cyst nematode, sex ratio, hydroponics.
Heterodera
Soybean cyst nematode
Cite
Citations (1)
The effect of the rhg1 gene on equilibrium population densities (E) and reproduction factors (Rf) of Heterodera glycines was studied by comparing the nematode population development on two near-isogenic soybean lines (NIL), differing at the rhg1 locus. The NIL were inoculated with a series of initial egg densities (Pi) in the greenhouse. The relationships between final population densities (Pf = females per plant or eggs per plant) or Rf (final egg density/Pi) on both NIL and Pi were adequately described by quadratic models. The rhg1 gene suppressed Pf and Rf at all Pi of a population of H. glycines race 3 (HG Type 0-); E and maximum Rf were higher on the NIL-S line than on the NIL-R line. After two generations of culture of the race 3 population on the NIL-R line, the population selected by the rhg1 gene (R-eggs) had higher Pf and Rf on the NIL-R line than the population cultured on the NIL-S line (S-eggs) at all Pi. Both R-eggs and S-eggs produced similar egg numbers on the NIL-S line, which was higher than the egg number of either population on the NIL-R line at all Pi. The ratio of E in female numbers on the NIL-R line to E on the NIL-S line increased from 29% for the original race 3 population (S-eggs) to 46% for the rhg1-selected population (R-eggs). Regardless of different egg sources, a trend of increase in the number of eggs per female with the rise of Pi was observed on the NIL-S line. In contrast, female fecundity of both populations declined with the increase of Pi on the NIL-R line. At most inoculum densities, the highest number of eggs per female was observed on the NIL-S line inoculated with the R-eggs, whereas the lowest number of eggs per female was detected on the NIL-R line inoculated with the S-eggs. This study demonstrated that the E and maximum Rf determined by the quadratic models are useful measurements of plant resistance to nematodes.
Heterodera
Soybean cyst nematode
Population density
Cite
Citations (2)
국내에서 육성된 75개 콩 장려품종에 대하여 콩 씨스트선충 HG type 2.5에 대한 저항성을 검정하였다. 품종에 따라 콩 씨스트선충의 증식 정도는 104-624 씨스트/화분이었다. 국내 콩 장려 품종 중에서 콩 씨스트선충 HG type 2.5에 대한 저항성 품종은 없었으며, '장엽콩', '새알콩', '밀양콩', '만석콩'은 중간저항성, 33품종은 중간감수성, 나머지 38품종은 감수성으로 판정되었다. 국내에서 저항성 장려품종이 육성되기까지 콩 씨스트선충의 피해가 심한 포장에는 '장엽콩', '새알콩', '밀양콩', '만석콩'을 심도록 추천하는 것이 좋겠다. A total of 75 soybean cultivars developed in Korea was screened against soybean cyst nematode (SCN), Heterodera glycines HG type 2.5. Cysts developed on soybean cultivars ranged from 104 to 624 cysts per pot. There was no resistant cultivar but 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' were moderately resistant; 33 cultivars were moderately susceptible and the other cultivars were susceptible. 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' could be recommended for soybean fields infested with SCN until developing SCN resistant soybean.
Soybean cyst nematode
Heterodera
Cite
Citations (0)
Female indices were measured on six soybean cultivars with resistance to Heterodera glycines derived from PI 88788. Cultivars were inoculated with four isolates of race 6, 3 of race 9, 2 of race 4, and one of race 14. Changes in female index from slightly < or > 10% of the test cultivars compared to 'Lee' resulted in a change of most of the race designations after at least three generations on 'Essex.' Variation due to race was the greatest source of variation in the analysis of the data and was three to nine times the second largest source of variation. In most cases, female indices for the cultivars within a race were not different (P = 0.05). This study suggests that one cultivar can serve as a type cultivar for a common source ofH. glycines resistance. Value of race designations was demonstrated.
Soybean cyst nematode
Heterodera
Cite
Citations (4)