Competitive ability of cowpea genotypes with different growth habit

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 775-782 ◽  
Author(s):  
Guangyao Wang ◽  
Milton E. McGiffen ◽  
Jeff D. Ehlers ◽  
Edilene C. S. Marchi
Keyword(s):  
Growth Rate ◽  
Competitive Ability ◽  
Growth Habit ◽  
Biomass Accumulation ◽  
Growing Season ◽  
Similar Reduction ◽  
Relative Growth ◽  
Use Efficiency ◽  
Common Purslane ◽  
Prostrate Growth

Growth habit is an important determinant of competitive ability in legume crops. Erect ‘Iron-Clay’ (IC), semi-erect ‘IT89KD-288’ (288), and prostrate ‘UCR 779’ (779) cowpea genotypes were planted with four densities of common sunflower or common purslane to determine which cowpea growth habit is more competitive to these weeds having markedly different statures. Both sunflower and purslane reduced cowpea relative growth rate (RGR) but at different phases of the growing season. Low-growing purslane had an effect in the earlier part of the season, and sunflower decreased cowpea RGR in the middle of growing season. RGR of genotype IC was the least affected and genotype 779 the most reduced by sunflower. Cowpea apparently compensated for early season purslane competition by increasing RGR after purslane flowering, with RGR for the IC genotype increasing the most and 779 increasing the least. All cowpea genotypes caused a similar reduction in sunflower biomass accumulation; but purslane biomass was most reduced by genotype IC and least affected by genotype 288. Erect genotype IC is more competitive due to its taller stature, greater height growth rate, and higher position of maximal leaf area density, despite a lower photosynthetic rate and light use efficiency than the other cowpea genotypes. Our results suggest that erect cowpea growth habit may be generally more competitive with weeds compared to semi-erect or prostrate growth habit.

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

Growth and Development of Organic Arsenical-Susceptible and -Resistant Common Cocklebur (Xanthium strumarium) Biotypes Under Noncompetitive Conditions

1994 ◽  
Vol 8 (1) ◽  
pp. 154-158 ◽  
Author(s):  
William E. Haigler ◽  
Billy J. Gossett ◽  
James R. Harris ◽  
Joe E. Toler
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Plant Height ◽  
Growth And Development ◽  
Reproductive Potential ◽  
Dry Weight ◽  
Growing Season ◽  
Xanthium Strumarium ◽  
Relative Growth ◽  
Growth Development

The growth, development, and reproductive potential of several populations of organic arsenical-susceptible (S) and -resistant (R) common cocklebur biotypes were compared under noncompetitive field conditions. Plant height, leaf area, aboveground dry weights, and relative growth rate (RGR) were measured periodically during the growing season. Days to flowering, bur dry weight, and number of burs per plant were also recorded. Arsenical S- and R-biotypes were similar in all measured parameters of growth, development, and reproductive potential. Populations within each biotype varied occasionally in plant height, leaf area, aboveground dry weights, and reproductive potential.

Interaction of nutrient-loaded black spruce seedlings with neighbouring vegetation in greenhouse environments

1995 ◽  
Vol 25 (6) ◽  
pp. 1017-1023 ◽  
Author(s):  
Vikram Malik ◽  
Victor R. Timmer
Keyword(s):  
Negative Correlation ◽  
Competitive Ability ◽  
Black Spruce ◽  
Biomass Accumulation ◽  
Growing Season ◽  
Significant Negative Correlation ◽  
Biomass Growth ◽  
Naturally Occurring ◽  
Nutrient Reserves ◽  
Accumulation Slope

The interaction of newly planted, nutrient-loaded black spruce (Piceamariana (Mill.) B.S.P.) seedlings with naturally occurring vegetation was investigated for one growing season under greenhouse conditions using bioassays retrieved from a boreal mixedwood site. Nutrient-loaded seedlings were similar in height and biomass to conventionally fertilized seedlings at planting, but contained 43, 76, and 33% more tissue N, P, and K content due to higher nursery fertilization, which induced luxury consumption. Nutrient-loaded seedlings outperformed conventionally fertilized seedlings in respective height and biomass growth by 35 and 28% in herbicide-treated plots, and by 44 and 37% in untreated plots, resulting in a 27% reduction in neighbouring vegetation biomass by the end of the season. The loading treatments stimulated nutrient uptake after planting, although the depletion of preplant nutrient reserves was greater. A significant negative correlation was observed between tree and weed biomass accumulation. Slope differences indicated that loaded trees were less sensitive to neighbouring vegetation than conventionally fertilized trees. The enhanced competitive ability of loaded seedlings against naturally occurring vegetation was probably due to the translocation of more nutrients to actively growing parts from reserves built up during the nursery preconditioning phase.

The contribution of lateral rooting to phosphorus acquisition efficiency in maize (Zea mays) seedlings

2004 ◽  
Vol 31 (10) ◽  
pp. 949 ◽  
Author(s):  
Jinming Zhu ◽  
Jonathan P. Lynch
Keyword(s):  
Growth Rate ◽  
Lateral Root ◽  
Root Respiration ◽  
Lateral Roots ◽  
Biomass Accumulation ◽  
Phosphorus Availability ◽  
Phosphorus Acquisition ◽  
Relative Growth ◽  
Phosphorus Stress ◽  
Low Phosphorus

Low soil phosphorus availability is a primary constraint for plant growth in many terrestrial ecosystems. Lateral root initiation and elongation may play an important role in the uptake of immobile nutrients, such as phosphorus, by increasing soil exploration and phosphorus solubilisation. The overall objective of this study was to assess the value of lateral rooting for phosphorus acquisition through assessment of the ‘benefit’ of lateral rooting for phosphorus uptake and the ‘cost’ of lateral roots in terms of root respiration and phosphorus investment at low and high phosphorus availability. Five recombinant inbred lines (RILs) of maize derived from a cross between B73 and Mo17 with contrasting lateral rooting were grown in sand culture in a controlled environment. Genotypes with enhanced or sustained lateral rooting at low phosphorus availability had greater phosphorus acquisition, biomass accumulation, and relative growth rate (RGR) than genotypes with reduced lateral rooting at low phosphorus availability. The association of lateral root development and plant biomass accumulation under phosphorus stress was not caused by allometry. Genotypes varied in the phosphorus investment required for lateral root elongation, owing to genetic differences in specific root length (SRL, which was correlated with root diameter) and phosphorus concentration of lateral roots. Lateral root extension required less biomass and phosphorus investment than the extension of other root types. Relative growth rate was negatively correlated with specific root respiration, supporting the hypothesis that root carbon costs are an important aspect of adaptation to low phosphorus availability. Two distinct cost–benefit analyses, one with phosphorus acquisition rate as a benefit and root respiration as a cost, the other with plant phosphorus accumulation as a benefit and phosphorus allocation to lateral roots as a cost, both showed that lateral rooting was advantageous under conditions of low phosphorus availability. Our data suggest that enhanced lateral rooting under phosphorus stress may be harnessed as a useful trait for the selection and breeding of more phosphorus-efficient maize genotypes.

Response of red alder (Alnus rubra) seedlings to a woolly alder sawfly (Eriocampa ovata) outbreak

1998 ◽  
Vol 28 (4) ◽  
pp. 591-595 ◽  
Author(s):  
John H Markham ◽  
C P Chanway
Keyword(s):  
Growth Rate ◽  
Positive Relationship ◽  
Negative Relationship ◽  
Growing Season ◽  
High Elevation ◽  
Alnus Rubra ◽  
Herbivore Damage ◽  
Red Alder ◽  
Relative Growth ◽  
High Degree

We monitored the effect of an outbreak of Eriocampa ovata L.on experimental Alnus rubra Bong. seedlings during the year of the outbreak (1993) and the following growing season. Seedlings planted on low-elevation sites had significantly more of their leaves damaged (>50% per tree) than plants on high-elevation sites (<25% per tree), with significant differences between low-elevation sites during the year of the outbreak. There was a positive relationship between the amount of herbivore damage and plant relative growth rate early in the growing season and a negative relationship by August. This suggests that the sawflies attacked the largest and fastest growing plants, reducing their growth by midsummer. Plants with the highest degree of herbivore damage were the largest by the end of the growing season with no effects on plant growth the following year. Leaves from plants that had previously been defoliated were less palatable to E. ovata in 1994, but plants with a high degree of herbivore damage in 1994 were likely plants that had a high degree of damage in 1993.

scholarly journals Biomass accumulation and radiation use efficiency of winter wheat under deficit irrigation regimes

2009 ◽  
Vol 55 (No. 2) ◽  
pp. 85-91 ◽  
Author(s):  
Q. Li ◽  
M. Liu ◽  
J. Zhang ◽  
B. Dong ◽  
Q. Bai
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Deficit Irrigation ◽  
Biomass Accumulation ◽  
Growing Season ◽  
Radiation Use Efficiency ◽  
Area Index ◽  
Irrigation Regimes ◽  
Use Efficiency ◽  
Radiation Use

To better understand the potential for improving biomass accumulation and radiation use efficiency (RUE) of winter wheat under deficit irrigation regimes, in 2006–2007 and 2007–2008, an experiment was conducted at the Luancheng Experimental Station of Chinese Academy of Science to study the effects of deficit irrigation regimes on the photosynthetic active radiation (PAR), biomass accumulation, grain yield, and RUE of winter wheat. In this experiment, field experiment involving winter wheat with 1, 2 and 3 irrigation applications at sowing, jointing, or heading stages was conducted, and total irrigation water was all controlled at 120 mm. The results indicate that irrigation 2 or 3 times could help to increase the PAR capture ratio in the later growing season of winter wheat; this result was mainly due to the changes in the vertical distributions of leaf area index (LAI) and a significant increase of the LAI at 0–20 cm above the ground surface (LSD, <i>P</i> < 0.05). Compared with irrigation only once during the growing season of winter wheat, irrigation 2 times significantly (LSD, <i>P</i> < 0.05) increased aboveground dry matter at maturity; irrigation at sowing and heading or jointing and heading stages significantly (LSD, <i>P</i> < 0.05) improved the grain yield, and irrigation at jointing and heading stages provided the highest RUE (0.56 g/mol). Combining the grain yield and RUE, it can be concluded that irrigation at jointing and heading stages has higher grain yield and RUE, which will offer a sound measurement for developing deficit irrigation regimes in North China.

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