Weed Interference Models

2020 ◽  
pp. 117-142
Author(s):  
Manpreet Singh ◽  
Simerjeet Kaur ◽  
Bhagirath S. Chauhan
Keyword(s):  
Weed Interference ◽  
Interference Models

Pedigree Data Analysis With Crossover Interference

Genetics ◽  
2003 ◽  
Vol 164 (4) ◽  
pp. 1561-1566
Author(s):  
Sharon Browning
Keyword(s):  
Data Analysis ◽  
Linkage Analysis ◽  
Importance Sampling ◽  
Genetic Data ◽  
Genotype Data ◽  
Pedigree Data ◽  
Chi Square ◽  
Crossover Interference ◽  
Map Construction ◽  
Interference Models

AbstractWe propose a new method for calculating probabilities for pedigree genetic data that incorporates crossover interference using the chi-square models. Applications include relationship inference, genetic map construction, and linkage analysis. The method is based on importance sampling of unobserved inheritance patterns conditional on the observed genotype data and takes advantage of fast algorithms for no-interference models while using reweighting to allow for interference. We show that the method is effective for arbitrarily many markers with small pedigrees.

scholarly journals Statistical Analysis of Ordered Tetrads

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 459-472 ◽  
Author(s):  
Hongyu Zhao ◽  
Terence P Speed
Keyword(s):  
Statistical Analysis ◽  
Genetic Markers ◽  
Chi Square ◽  
Yield Information ◽  
Data Yield ◽  
Interference Models ◽  
Chiasma Interference

Abstract Ordered tetrad data yield information on chromatid interference, chiasma interference, and centromere locations. In this article, we show that the assumption of no chromatid interference imposes certain constraints on multilocus ordered tetrad probabilities. Assuming no chromatid interference, these constraints can be used to order markers under general chiasma processes. We also derive multilocus tetrad probabilities under a class of chiasma interference models, the chi-square models. Finally, we compare centromere map functions under the chi-square models with map functions proposed in the literature. Results in this article can be applied to order genetic markers and map centromeres using multilocus ordered tetrad data.

scholarly journals Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 608-618 ◽  
Author(s):  
Martina Keller ◽  
Geoffroy Gantoli ◽  
Jens Möhring ◽  
Christoph Gutjahr ◽  
Roland Gerhards ◽  
...  
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Logistic Models ◽  
Crop Growth ◽  
Growth Stages ◽  
Corn Yield ◽  
Leaf Stage ◽  
Weed Interference ◽  
Free Interval ◽  
Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

LAMB’S-QUARTERS INTERFERENCE WITH DIRECT SEEDED BROCCOLI

1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA
Keyword(s):  
Brassica Oleracea ◽  
Field Experiments ◽  
Chenopodium Album ◽  
Total Yield ◽  
Growth And Yield ◽  
Marketable Yield ◽  
Weed Density ◽  
Weed Interference ◽  
Lamb’S Quarters ◽  
Cole Crop

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop

scholarly journals Weed interference periods on potato crop in Botucatu region, Brazil

2013 ◽  
Vol 8 (19) ◽  
pp. 2224-2231 ◽  
Author(s):  
Martins D ◽  
R Marchi S ◽  
V Costa N
Keyword(s):  
Potato Crop ◽  
Weed Interference

scholarly journals Weed Interference Affects Dry Bean Yield and Growth

2012 ◽  
Vol 4 (3) ◽  
pp. 70-75 ◽  
Author(s):  
Hossein GHAMARI ◽  
Goudarz AHMADVAND
Keyword(s):  
Chenopodium Album ◽  
Growing Season ◽  
Amaranthus Retroflexus ◽  
Growth And Yield ◽  
Weed Competition ◽  
Weed Species ◽  
Dry Bean ◽  
Logistic Equations ◽  
Weed Interference ◽  
Minimum Number

Dry bean is one of the most important pulse crops in Iran. Field study was conducted in 2011 to evaluate effects of weed competition from a natural flora on growth and yield of dry bean (Phaseolus vulgaris L.). The treatments consisted of weed infestation and weed removal periods (10, 20, 30, 40 and 50 days) after crop emergence. Control plots kept weed-infested and weed-free throughout growing season. To assess the weed competition effect on crop characteristics, Richards, Gompertz and logistic equations were fitted to the data. The most abundant weed species were Chenopodium album and Amaranthus retroflexus. Increase in duration of weed interference decreased the stem height of dry bean. At the end of the growing season, dry bean was 20 cm taller in season-long weed-free treatment compared to the season-long weed-infested treatment. As the number of days of weed interference increased, a declining trend of LAI and number of pods was observed. The minimum number of pods was obtained in season-long weed-infested treatment (5.01 pods/plant). Weed interference during the whole growing season, caused a 60% reduction in yield. Considering 5% and 10% acceptable yield lost, the critical period of weed competition was determined from 20 to 68 and 23 to 55 days after planting (DAE), respectively.

The Reduction of Plant-Available Nitrogen by Cover Crop Mulches and Subsequent Effects on Soybean Performance and Weed Interference

2013 ◽  
Vol 105 (2) ◽  
pp. 539-545 ◽  
Author(s):  
M. S. Wells ◽  
S. C. Reberg-Horton ◽  
A. N. Smith ◽  
J. M. Grossman
Keyword(s):  
Cover Crop ◽  
Available Nitrogen ◽  
Weed Interference ◽  
Plant Available Nitrogen

scholarly journals Periods of Weed Interference on Orange Tree Crops

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
G.S. GONÇALVES ◽  
J.E.B. CARVALHO ◽  
M.V.B. GARCIA ◽  
L.A. GAMA ◽  
C.L.L.L. AZEVEDO ◽  
...  
Keyword(s):  
Weed Management ◽  
Growing Season ◽  
Control Treatment ◽  
Weed Interference ◽  
Orange Tree ◽  
Cultivation Practices ◽  
Fruit Productivity ◽  
Orange Trees ◽  
Production Problems ◽  
Unripe Fruits

ABSTRACT: Current orange tree cultivation practices in the Brazilian State of Amazonas present several production problems, being the inadequate weed management the most important one, and significantly affecting fruit productivity. However, if weeds are managed properly, their coexistence with orange cultivars does not affect the fruit yield of orange trees. Thus, the objective of this research was to identify the period of longer weed interference in orange production. The treatments were conducted during the 2013 and 2014 harvests as follows: one control treatment with no coexistence of weeds and crop throughout the growing season; and six periods of coexistence (October to January, February to May, June to September, October to May, October to January, June to September, and February to September). The coexistence of weeds from October to May with orange trees increased the fall of unripe fruits and reduced the yield and the number of oranges per plant. Therefore, this period was considered as the most critical one for the control of weeds in orange trees.

Effect of Crop Density on Weed Interference in Maize

1994 ◽  
Vol 86 (4) ◽  
pp. 591-595 ◽  
Author(s):  
M. Tollenaar ◽  
A. A. Dibo ◽  
A. Aguilera ◽  
S. F. Weise ◽  
C. J. Swanton
Keyword(s):  
Weed Interference ◽  
Crop Density
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