scholarly journals A Comprehensive Study of Orchid Seed Production Relative to Pollination Traits, Plant Density and Climate in an Urban Reserve in Western Australia

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 123 ◽  
Author(s):  
Mark C. Brundrett
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Fruit Set ◽  
Plant Density ◽  
Resource Competition ◽  
Higher Plant ◽  
Trade Offs ◽  
Terrestrial Orchids ◽  
Plant Densities ◽  
Disturbance Tolerance

The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0–95% of flowers, floral displays from 90–3300 mm2 and capsules from 15–1300 mm3 per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59—95%), followed by sexually deceptive autumn or winter-flowering (18–39%), visual deception (0–48%) and sexually deceptive spring-flowering (13–16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4× greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

Seed production from three annual species of Trifolium on sandy soils in the wheat belt of Western Australia

1969 ◽  
Vol 9 (36) ◽  
pp. 92 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Soil Moisture ◽  
Seed Production ◽  
Western Australia ◽  
Plant Density ◽  
Subterranean Clover ◽  
Soil Conditions ◽  
Seeding Rate ◽  
Relative Water ◽  
Plant Densities ◽  
Seed Yields

Seed production and persistence of subterranean, cupped, and rose clovers were examined over a period of three years in undefoliated swards, at several plant densities, in the wheat belt of Western Australia. Subterranean clover, although earlier flowering, was outyielded by the other two species in the two driest years. No major differences were found between species in relative water content of leaves during periods of soil moisture deficit. Moreover, species differences in soil moisture exploitation were small. A high proportion of inflorescences failed to set seed in subterranean clover. This reproductive defect, which is associated with restricted inflorescence burial due to dry soil conditions, was thought to be the main reason for the poorer seed yield in this species. Despite low seed yields in the establishment year, plant density after the first year did not seriously limit seed yields, even at the lowest seeding rate, in any of the three species.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Effects of the cropyear and the agronomical factors on agronomical elements of different sweet corn (Zea Mays L. convar. saccharata Koern.) genotypes in long-term experiment

2012 ◽  
pp. 105-110
Author(s):  
Ádám Lente
Keyword(s):  
Plant Density ◽  
Sweet Corn ◽  
Sowing Date ◽  
Higher Plant ◽  
Sowing Time ◽  
Sowing Dates ◽  
Long Term Experiment ◽  
Plant Densities ◽  
Fertilization Level ◽  
The University

In the crop season of 2010 (rainy year), we studied the effect of three agrotechnical factors (sowing time, fertilization, plant density) and four different genotypes on the agronomical characteristics of sweet corn on chernozem soil in the Hajdúság. The experiments were carried out at the Látókép Experimental Farm of the University of Debrecen. In the experiment, two sowing dates (27 April, 26 May), six fertilization levels (control, N30+PK, N60+PK, N90+PK, N120+PK, N150+PK) and four genotypes (Jumbo, Enterprise, Prelude, Box-R) were used at two plant densities (45 thousand plants ha-1, 65 thousand plants ha-1). The amount of precipitation in the season of 2010 was 184 mm higher, while the average temperature was 0.8 oC higher in the studied months than the average of 30 years. Weather was more favourable for sweet maize at the first sowing date, if we consider the yields, however, if we evaluate the agronomical data and yield elements (number of cobs, cob length and diameter, the number of kernel rows, the number of kernels per row) it can be stated that the size of the fertile cobs was greater at the second sowing date due to the lower number of cobs. The largest number of fertile cobs was harvested in the case of the hybrid Enterprise (72367.9 ha-1) in the higher plant density treatment (65 thousand ha-1) at the fertilization level of N120+PK when the first sowing date was applied. The largest cobs were harvested from the hybrid Box-R (cob weight with husks: 516.7 g, number of kernels in one row: 45.7) at the lower plant density (45 thousand plants ha-1) in the second sowing date treatment. Cob diameter and the number of kernel rows were the highest for the hybrid Prelude.

scholarly journals Planting Date and Plant Density Affect Yield of Pungent and Nonpungent Jalapeño Peppers

HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 520-523 ◽  
Author(s):  
V.M. Russo
Keyword(s):  
Capsicum Annuum ◽  
Plant Density ◽  
Planting Date ◽  
Row Spacing ◽  
Higher Plant ◽  
Cultural Methods ◽  
Plant Densities ◽  
The Cost ◽  
Transplant Site

There is little known about how cultural methods affect yields of nonpungent jalapeño peppers (Capsicum annuum L.). Seedlings of the nonpungent jalapeño peppers `Pace 103', `Pace 105', `Pace 108', `Dulce', and `TAM Sweet2', as well as the pungent jalapeño peppers `Delicias' and `TAM Jalapeño1', used for comparison, were grown in a greenhouse with either one or two seedlings per cell in transplant trays. Transplanting to the field was in mid-April and mid-June of 2000 and 2001. In-row spacing was 0.46 m between transplanting sites. Density was varied by placing either one or two seedlings at a transplant site with resultant plant densities of 24,216 or 48,432 plants/ha. Marketable and cull yields, on a per hectare basis, were determined. In both years there were more fruit produced, and higher yields (25+% greater), at the higher plant density, especially for the mid-April planting. The exception for the mid-April planting date was `TAM Jalapeño1', which was not different at the two densities. If the increased income from higher yield can compensate for the cost of producing two seedlings in each transplant tray cell, then this technique should be employed when these types of peppers are used in early plantings.

scholarly journals Manipulation of Plant Density to Enhance Rice Yield for a Bioregenerative Life-support System

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 884G-885
Author(s):  
K.R. Goldman ◽  
C.A. Mitchell
Keyword(s):  
Life Support ◽  
Plant Density ◽  
Biomass Accumulation ◽  
High Yield ◽  
Higher Plant ◽  
Yield Efficiency ◽  
Panicle Number ◽  
Plant Densities ◽  
Controlled Environments ◽  
Bioregenerative Life Support System

Rice (Oryza sativa L.) is a candidate crop for use in Controlled Ecological Life-support Systems (CELSS) proposed for a lunar or Mars outpost. `Ai-Nan-Tsao' is a promising semi-dwarf cultivar because growth volume is limited and HI (percent edible biomass) is high. Yield efficiency rate (YER: g grain/m3 per day [g nonedible biomass]-) combines edible yield rate (EYR: g grain/m3 per day) and HI to quantify edible yield in terms of penalties for growth volume, cropping time, and nonedible biomass production. Greenhouse studies indicate EYR increases with plant density from 70 to 282 plants/m2. YER and shoot HI are stable across this density range because nonedible biomass accumulation keeps pace with edible. Tiller number and panicle size per plant decreased with increasing plant density, but total tiller and panicle number per unit area increased to compensate. Density trials in rigorously controlled environments will determine if higher plant densities will produce even greater YER. This research is supported by NASA grant NAGW-2329.

Comparative Response of Conventional and Quality Protein Maize Hybrids to High Population Densities in the Southern Guinea Savanna of Nigeria

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
O B Bello
Keyword(s):  
Grain Yield ◽  
Plant Density ◽  
Plant Population ◽  
Yield Potential ◽  
High Yield ◽  
Quality Protein Maize ◽  
Population Densities ◽  
Higher Plant ◽  
Guinea Savanna ◽  
Plant Densities

Optimum plant population is very important in enhancing high and stable grain yield especially in quality protein maize (QPM) production. A field trial was therefore conducted to compare the performance of six hybrids (three each of QPM and normal endosperm) at three population densities using a split-plot design at the sub-station of the Lower Niger River Basin Development Authority, Oke-Oyi, in the southern Guinea savanna zone of Nigeria during the 2010 and 2011 cropping seasons. Plant population -1 densities (53,333, 66,666, and 88,888 plants ha ) constituted the main plots and the six hybrids were assigned to the subplots, replicated three times. Our results showed a differential response of maize -1 hybrids to high densities, with plant populations above 53,333 plants ha reduced grain yield, and this is more pronounced in QPM than normal endosperm hybrids. This is contrary to the results observed in many other countries. This might be that the hybrids were selected in low yield potential area at low plant densities, and hence not tolerant to plant density stress. It may also be due to low yield potential of the experimental site, which does not allow yield increases at high plant densities. Though normal endosperm hybrids 0103-11 and 0103-15 as well as QPM Dada-ba were superior for grain yield among -1 the hybrids at 53,333 plants ha , hybrid 0103-11 was most outstanding. Therefore, genetic improvement of QPM and normal endosperm hybrids for superior stress tolerance and high yield could be enhanced by selection at higher plant population densities.

Ecological relationships of wild rice, Zizania spp. 10. Effects of sediment and among-population variations on plant density in Zizania palustris

2002 ◽  
Vol 80 (12) ◽  
pp. 1283-1294 ◽  
Author(s):  
P F Lee
Keyword(s):  
Seed Production ◽  
Wild Rice ◽  
Plant Density ◽  
Reproductive Potential ◽  
Resource Depletion ◽  
Dry Weight ◽  
Asymmetric Competition ◽  
Zizania Palustris ◽  
Nutrient Levels ◽  
Plant Densities

The influence of nutrients and intraspecific variations in growth form were examined for their effect on plant density in stands of northern wild rice, Zizania palustris L. In a field situation, densities of a size-restricted wild rice population increased as nutrient levels in the sediment increased. No self-thinning occurred until the population density exceeded 350 plants/m2. A series of controlled experiments examined whether these wild rice densities were determined by resource depletion and (or) intraspecific competition. As nutrient levels increased under constant plant densities, tillering, dry weight, and seed production increased more for populations with the capacity for higher vegetative and reproductive potential. As plant densities increased under constant nutrient levels, height, weight, and seed production declined but inequality of individual plants increased. When both nutrient levels and population densities were increased simultaneously, seed production per panicle declined at higher densities under unfertilized conditions but was unaffected in the treatment with the highest fertilizer level. It was hypothesized that plant densities under field conditions were the result of an integrated mechanism that was influenced by nutrients and the degree of asymmetric competition characteristic of the population. As nutrient levels increase, plant densities would be expected to decrease for populations with high levels of asymmetric competition and increase for populations with low levels of asymmetric competition.Key words: wild rice, density effects, nutrients, intraspecific variation.

INFLUENCE OF TIME OF EMERGENCE AND PLANT DENSITY ON GROWTH OF HEMP-NETTLE (Galeopsis tetrahit)

1989 ◽  
Vol 69 (1) ◽  
pp. 171-183 ◽  
Author(s):  
ANNE LÉGÈRE ◽  
JEAN-MARC DESCHÊNES
Keyword(s):  
Plant Density ◽  
Plant Biomass ◽  
Biomass Accumulation ◽  
Quebec City ◽  
Total Biomass ◽  
City Region ◽  
Higher Plant ◽  
Peak Period ◽  
Plant Densities ◽  
Broadleaf Species

The effects of time of emergence and plant density on hemp-nettle growth (Galeopsis tetrahit) were measured in natural field populations from the Québec City region and in a greenhouse experiment. In the field, more than 80% of the plants emerged during a peak period of about 2 wk in early May. Few hemp-nettle plants emerged after this peak period. Late-emerging plants produced relatively little biomass compared to plants that had emerged during the early emergence flush. Total biomass accumulation increased with density on three out of four sites. Stands from the lowest density (80 plants m−2) generally produced less biomass than stands of higher plant densities. Average plant biomass production decreased with increasing density. Plants from low density stands displayed a bushy profile compared to the etiolated, single-stemmed plants from high density stands. Mature hemp-nettle stands did not develop strong hierarchical population structures such as found for other annual broadleaf species. Hemp-nettle plants within a stand were distributed rather evenly over a number of height classes. A large proportion of the total biomass was produced by a relatively considerable number of plants 45–59 cm in height rather than by a few dominating individuals.Key words: Hemp-nettle, Galeopsis tetrahit, weed populations, emergence pattern, population density, population structure

scholarly journals Agronomic and economic viability of intercropping onion and lettuce

2012 ◽  
Vol 30 (2) ◽  
pp. 349-354 ◽  
Author(s):  
Wagner F da Mota ◽  
Rosimeire D Pereira ◽  
Gizeli de S Santos ◽  
Janiele Cássia B Vieira
Keyword(s):  
Economic Performance ◽  
Plant Density ◽  
Economic Viability ◽  
Agronomic Performance ◽  
Higher Plant ◽  
Plant Densities ◽  
Factorial Treatments ◽  
Set Up

The study aimed to evaluate the agronomic and economic performance of intercropping onion and lettuce on four plant densities of each species. The experiment was set up in completely randomized blocks, with four replications and treatments arranged in a 4 x 4 factorial. Treatments resulted from a combination of four (100, 80, 60, and 40% of recommended plant densities in monoculture) plant densities for both lettuce and onion. Intercropping did not affect the agronomic performance of onion or lettuce. Higher plant densities (100% for both vegetables) resulted in higher lettuce and onion yields. The best economic results were observed using (a) onion at 80% of plant density combined with lettuce at 40 and 100% and (b) onion at 100% and lettuce at all densities (40 to 100%).

scholarly journals Times of Trinexapac-ethyl application associated to plant densities in agronomic performance of second-season corn

2021 ◽  
Vol 10 (9) ◽  
pp. e39310914751
Author(s):  
Mariana Alves de Oliveira ◽  
Claudemir Zucareli ◽  
Allan Ricardo Domingues ◽  
Lucas Augusto de Assis Moraes ◽  
Leandro Teodoski Spolaor ◽  
...  
Keyword(s):  
Grain Yield ◽  
Plant Density ◽  
Plant Size ◽  
Kernel Weight ◽  
Agronomic Performance ◽  
State University ◽  
Leaf Architecture ◽  
Higher Plant ◽  
Growing Seasons ◽  
Plant Densities

Plant growth regulators, which can alter the plant size and anatomy, allow the use of cultivars of interest that do not have a modern leaf architecture, making higher plant densities possible. The objective of this study was to evaluate the agronomic performance of second season corn, grown at different plant densities and under Trinexapac-ethyl applications at different stages of crop development. The field study was carried out in two growing seasons (2013 and 2014), at the Fazenda Escola of the State University of Londrina. Fifteen treatments were evaluated in a randomized block, 5 x 3 factorial design, at five plant densities (40,000, 60,000, 80,000, 100,000 and 120,000 plants per hectare), of Trinexapac-ethyl applied in three stages: control (no application), V6 and V9, with four replications. The morphological plant characteristics, the yield components and grain yield were evaluated. Increases in plant density raise the plant height, reduce the number of grains per ear, ear length and 100-kernel weight, and have no influence on grain yield. The application of Trinexapac-ethyl in stage V9 reduces plant and ear insertion height and 100-kernel weight.

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