scholarly journals GRAIN YIELD COMPARISON OF PURE STANDS AND EQUAL PROPORTION MIXTURES FOR SEVEN HYBRIDS OF MAIZE

1985 ◽  
Vol 65 (3) ◽  
pp. 471-479 ◽  
Author(s):  
G. J. HOEKSTRA ◽  
L. W. KANNENBERG ◽  
B. R. CHRISTIE
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Moisture Stress ◽  
Pure Stand ◽  
Equal Proportion ◽  
Yielding Ability ◽  
Competitive Effects ◽  
Plant Densities ◽  
The Difference ◽  
The One

The objective of this study was to compare yielding ability and competitive effects in pure stands and equal-proportion mixtures of maize hybrids. Seven maize (Zea mays L.) hybrids were grown for 2 yr in pure stand and in all equal-proportion, two-component mixtures at plant densities of 61 500 and 136 000 plants per hectare. In 1978, a year of severe moisture stress, mixtures yielded 6% more grain on average than expected on the basis of pure stand yields. Half of the mixtures yielded more than the pure stand yield of the high-yielding component; however, one mixture yielded significantly less than predicted based on pure stand yields. In 1979, mixtures yielded as expected based on pure stand yields. The yield difference between 1978 and 1979 for mixtures was less than the difference between pure stands indicating that mixtures were, on average, more consistent in performance across environments than their components. The yield advantage of mixtures in 1978, however, was too low to recommend growing blends as a production practice. Relative yields of individual hybrids were different in pure stands compared to mixtures. Furthermore, the order of hybrids ranked according to their pure-stand yields differed from the order based on yielding ability in mixtures. In general, a direct relationship existed between yielding ability in mixtures and competititve influence. Hybrids with a high average yield across mixtures yielded more in mixtures with low-yielding hybrids than in mixtures with high-yielding hybrids. Conversely, low-yielding hybrids produced less grain when in mixtures with a high-yielding hybrid than in mixtures with a low-yielding hybrid. However, the one hybrid which was consistently the most competitive was not the highest yielding under stress conditions.Key words: Blends, corn, grain yield, hybrid mixtures, population stress, Zea mays

GRAIN YIELD COMPARISON OF PURE STANDS AND MIXTURES OF DIFFERENT PROPORTIONS FOR TWO HYBRIDS OF MAIZE

1985 ◽  
Vol 65 (3) ◽  
pp. 481-485 ◽  
Author(s):  
G. J. HOEKSTRA ◽  
L. W. KANNENBERG ◽  
B. R. CHRISTIE
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Zea Mays L ◽  
Pure Stand ◽  
Higher Plant ◽  
Data Support ◽  
Plant Densities ◽  
The Difference ◽  
Corn Grain ◽  
Corn Grain Yield

The objective of this study was to determine the effects on grain yield of growing cultivars in mixtures of different proportions. Two maize (Zea mays L.) hybrids, Pride 116 and United 106, were grown for 2 yr in pure stand and in seven mixtures of different proportions (7:1, 6:2, 5:3, 4:4, 3:5, 2:6, 1:7) at plant densities of 61 500, 99 400, and 136 000 plants per hectare. The total number of mixture combinations was 42, i.e. 2 years × three densities × seven proportions. All but one mixture yielded as expected based on the yield of component hybrids in pure stand. The higher yielding hybrid (United 106) yielded significantly less grain per plant in mixtures than in pure stand. The lower yielding hybrid (Pride 116) yielded more in mixtures than in pure stand, although the difference was not significant. These data support previous observations that the ability of a hybrid to yield in pure stands is not necessarily related to its ability to yield in mixtures. High plant densities appear to enhance the likelihood of interactions occurring among hybrids. For United 106, the number of proportions yielding less grain per plant than in pure stand was highly significant at the two higher plant densities. For Pride 116, the number of proportions yielding more than in pure stand was highly significant at the highest plant density.Key words: Corn, grain yield, mixtures of different proportions, high plant densities, Zea mays

The effects of soil moisture stress on the growth of barley. I. Vegetative development and grain yield

1964 ◽  
Vol 15 (5) ◽  
pp. 729 ◽  
Author(s):  
D Aspinall ◽  
PB Nicholls ◽  
LH May
Keyword(s):  
Grain Size ◽  
Soil Moisture ◽  
Grain Yield ◽  
Stem Elongation ◽  
Moisture Stress ◽  
The Other ◽  
Vegetative Development ◽  
Soil Moisture Stress ◽  
The One ◽  
Periods Of Stress

The effects of soil moisture stress on tillering, stem elongation, and grain yield of barley (cv. Prior) have been studied by subjecting the plants to periods of stress at different stages of development. Soil moisture stress treatments consisted of repeated short cycles of stress, single short cycles (both in large pots), or single long cycles (in large lysimeters). The data collected support the contention that the organ which is growing most rapidly at the time of a stress is the one most affected. Grain numbers per ear were seriously affected by stress occurring prior to anthesis, an effect probably associated with the process of spikelet initiation and, later, with the formation of the gametes. Grain size, on the other hand, was reduced more by stress at anthesis and shortly after. Elongation of the internodes was reduced mostly by stress at or just before earing, and was less seriously affected by earlier or later stress. Tillering, although being suppressed during a drought cycle, was actually stimulated upon rewatering. The effect was greater the earlier the period of stress, and was probably related to nutrient uptake and distribution within the plant.

scholarly journals Competition between triticale (Triticosecale Witt.) and field beans (Vicia faba var. minor L.) in additive intercrops

2011 ◽  
Vol 52 (No. 2) ◽  
pp. 47-54 ◽  
Author(s):  
P. Sobkowicz
Keyword(s):  
Grain Yield ◽  
Vicia Faba ◽  
Pure Stand ◽  
Competitive Balance ◽  
Light Soil ◽  
Plant Densities ◽  
Field Beans ◽  
Balance Index

In a microplot experiment conducted in 1999 and 2000 on light soil triticale and field beans were grown as sole crops and in the intercrop system. Two pure stand plant densities were established: 200 and 400 plants/m<sup>2</sup> for triticale and 50 and 100 plants/m<sup>2</sup> for field beans. Four possible intercropping combinations were obtained by adding densities of both crops. Triticale was a better competitor than field beans in all intercrops resulting in competitive balance index significantly greater than zero. The number of pods per plant of field beans was significantly reduced in all intercropping combinations compared to the pure stands, however quality of grain of the legume was unaffected by competition. Intercrop comprising 200 plants/m<sup>2</sup> of triticale and 50 plants/m<sup>2</sup> of field beans was most productive in the experiment but addition 50 more plants/m<sup>2</sup> of the legume decreased significantly grain yield of intercrop by 16.2%. The results also show that effective triticale-field beans intercrop for light soil may be designed as additive one, based on 400 plants/m<sup>2</sup> of triticale.

Diallel analysis of competition between diploid and tetraploid genotypes of Secale cereale grown at two densities

1972 ◽  
Vol 78 (2) ◽  
pp. 251-256 ◽  
Author(s):  
J. Norrington-Davies ◽  
Janice M. Hutto
Keyword(s):  
Secale Cereale ◽  
Competitive Ability ◽  
Chromosome Doubling ◽  
Diallel Analysis ◽  
Dry Weight ◽  
Inbred Lines ◽  
Pure Stand ◽  
Competitive Effects ◽  
Alpha Effect ◽  
The Difference

SUMMARYTwo inbred diploid lines of Secale cereale L. and their derived tetraploids were grown together with a commercial diploid and tetraploid in all possible pair combinations in a pot experiment. Comparisons between lines and varieties were made in respect to dry weight measured at 30 weeks.The competitive effects within mixtures were not compensatory, the commercial varieties tending to increase in dry weight more than the homozygous inbred lines decreased. This gave rise to mixture means which tended to exceed their mid-constituent values.The analysis of reciprocal differences in dry weight showed that the effects of competition between any one genotype and its associate in mixtures were constant (alpha competition), the sign and magnitude of the alpha effect being related to the pure stand values of the genotype.The mean effect of competition was to increase the difference in dry weight between genotypes by 2·108 g for each gram by which the genotypes differed when grown alone. In each case the values for genotypes with the higher dry weight increased in mixture whereas the values for those with lower dry weights decreased.Not surprisingly, the commercial varieties were found to be better competitors than the inbred lines, but of more interest was the ineffectiveness of chromosome doubling on competitive ability. Under the conditions of density and fertility reported here, the tetraploid inbred lines could not be distinguished from their diploid progenitors either in their competitive ability or in their reaction to increased density when grown in mixtures. The same is true for the tetraploid and diploid commercial varieties.

Plant density and yield of grain maize in England

1973 ◽  
Vol 81 (3) ◽  
pp. 455-463 ◽  
Author(s):  
E. S. Bunting
Keyword(s):  
Grain Yield ◽  
Water Content ◽  
Field Experiments ◽  
Plant Density ◽  
Unit Area ◽  
Maximum Yield ◽  
Spatial Arrangement ◽  
Practical Significance ◽  
Plant Densities ◽  
The Difference

SUMMARYResults from 10 field experiments are reported. Inra 200, the standard variety in official maize grain trials in Britain, was grown in six of the trials; comparative information was obtained on a range of competitive commercial hybrids and an experimental, early flowering, hybrid. The final plant densities most commonly involved ranged from 5 to 20 plants/m2, with extremes of 2 and 30 plants/m2. The effects of spatial arrangement were also considered in multifactorial or systematic designs; in general, yields increased slightly with more even spacing but no evidence was adduced that spacing, within the limits likely to be encountered in commercial practice, would significantly modify interpretations of density effects.In all varieties tested, a satisfactory model for the response in yield of grain to changes in plant density was 1/y = a + bx + cx2, where y = grain yield/plant and x = density. Estimated parameter values, however, were not the same for all varieties and significant genotype × density interactions were obtained.Grain yield/unit area in Inra 200 was maximal at densities of 8–10 plants/m2, but the response curve did not have a pronounced peak; differences in average yieldat densities ranging from 6 to 14 plants/m2 were less than 6%, and yield at 20 plants/m2 was about 80% of the maximum. Other flint × dent hybrids grown commercially for grain in northern areas (Anjou 210, L.G. 11, Warwick SL 209) reached maximum grain yield/unit area at lower densities (6–8 plants/m2), and the decline in yield with increasing density was much more marked than in Inra 200. In contrast, an earlier flowering, shorter growing, experimental hybrid (ARC 51 A) did not reach maximum yield until density was raised to 14 plants/m2, and was even more tolerant of high plant densities than Inra 200. With increasing plant density the number of ears/plant declined, falling below 1–0 in Inra 200 at densities in excess of 10 plants/m2, and averaging about 0–8 at plants/m2. Over the range 6–20 plants/m2 shelling percentage was reduced by no more than 4%, but water content of the ear (grain plus rachis) increased significantly with density. In the very early hybrid, ARC 51A, the difference in water content of the ear at 6 and 20 plants/m2 was less than 3%, but in Inra 200 it averaged about 8% and in varieties less tolerant of high densities it was often ofthe order of 15%. These results could be related to the delaying effects of increasing density on time of silk emergence. Relatively, time of pollen shed was little affected by density changes. In Inra 200 the difference in time between mid-anthesis and mid-silk was about 7 days more at 20 plants/m2 than at 6 plants/m2 while in Anjou 210 and Kelvedon 59A the comparable increase was 14 days.The practical significance of the findings is discussed in relation to current grain and silage maize production practices, and to future breeding and testing programmes in Northern Europe.

Effects of Nicosulfuron on Quackgrass (Elytrigia repens) Control in Corn (Zea mays)

1992 ◽  
Vol 6 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Prasanta C. Bhowmik ◽  
Betsey M. O'Toole ◽  
John Andaloro
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Field Experiments ◽  
Single Application ◽  
Leaf Stage ◽  
Field Corn ◽  
Elytrigia Repens ◽  
One Year ◽  
The One ◽  
Conventional Field

Four field experiments were conducted during 1988 and 1989 to determine the effects of POST application of nicosulfuron on quackgrass control in conventional field corn. A single application of nicosulfuron at 35 to 70 g ha–1applied to four- to six-leaf quackgrass controlled over 90% of quackgrass five weeks after treatment. Nicosulfuron at 35 g ha–1applied at the one- to three-leaf stage was not as effective as the same rate applied at the four- to six-leaf stage. When nicosulfuron at 35 g ha–1was applied to four- to six-leaf quackgrass, over 80% of the quackgrass regrowth was controlled one year later. Nicosulfuron did not injure ‘Agway 584S’ corn at the highest rate (140 g ha–1) tested and did not reduce silage or grain yield.

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