GROWTH AND [14C] SUCROSE UPTAKE OF APICAL AND BASAL MAIZE KERNELS

1986 ◽  
Vol 66 (4) ◽  
pp. 863-869
Author(s):  
JONATHAN M. GREENBERG ◽  
TIM LLOYD SETTER
Keyword(s):  
Zea Mays ◽  
Liquid Scintillation ◽  
Zea Mays L ◽  
Dry Weight ◽  
Grain Filling ◽  
Kernel Weight ◽  
Sucrose Uptake ◽  
Sucrose Transport ◽  
The Difference ◽  
Maize Kernels

Kernels located near the apex of the ear of corn (Zea mays L.) are smaller and more likely to abort than basal kernels. Studies were conducted to evaluate the importance of time of pollination and rate of sucrose uptake in determining differences in mature kernel weight between apical and basal kernels. Simultaneous pollination of all florets in an ear did not reduce the difference in mature dry weight between apical and basal kernels or the incidences of sterility and abortion. The ability of developing apical and basal kernels to take up sucrose was evaluated by immersing the bases of detached kernels in 50 mM 14C-sucrose and measuring the incorporated radioactivity by liquid scintillation counting. Sucrose uptake increased during development, especially at the beginning of the linear phase of grain filling. Differences in sucrose uptake rate were insufficient to explain the differences between apical and basal kernels in dry weight.Key words: Carbohydrate, partitioning, corn, sucrose transport, seed development, Zea mays L.

Cross-pollination effects on maize (Zea mays L.) hybrid yields

1992 ◽  
Vol 72 (1) ◽  
pp. 27-33 ◽  
Author(s):  
R. T. Weiland
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Grain Filling ◽  
Maize Yield ◽  
Kernel Weight ◽  
First Year ◽  
Kernel Number ◽  
Cross Pollination ◽  
Grain Filling Period ◽  
N Fertility

Recent studies have shown that pollen from a long-season maize (Zea mays L.) hybrid increased yield of a short-season hybrid by lengthening the effective grain-filling period, while the reciprocal cross did not alter this period or yield. This effect (metaxenia) was evaluated further in the studies reported here with hybrids of more diverse maturity and under both high and low N fertility. In the first year of this study (1989), sib- and cross-pollinations were made among B73Ht × Mo17 (B × 7) and two early-silking hybrids, LH59 × LH146 (L × 6) and Pioneer 3732 (3732) under N-sufficient (275 kg ha−1) and two lower N regimes (17 and 67 kg ha−1). Only a few significant effects were observed and these were noted at high N with one exception. With 3732 pollen, grain yield of B × 7 was decreased at 275 kg N ha−1, and physiological maturity occurred 3 d earlier. Yield of 3732 was increased by L × 6 pollen in comparison with B × 7 pollen. Kernel number and average kernel weight were not altered by pollen source. Pollen type did not affect yields under low N fertility, except for a reduction when B × 7 was pollinated by L × 6 at the 67-kg N ha−1 rate. In 1990, under N-sufficient fertility, B73Ht × LH156 (B × 6), a late-silking hybrid, and LH146 × LH82 (L × 2), an earlier hybrid, were sib- and cross-pollinated with B × 7 and 3732. The only significant effect observed was that L × 2 pollen increased B × 6 yield. Thus with the hybrids used, yields of early-season types were not altered by cross-pollination with long-season types. Previous results showing increased yields when 3732 was pollinated by B × 7 were not duplicated in either year, suggesting metaxenia effects are highly dependent upon environment.Key words: Metaxenia, xenia, cross-pollination, maize, yield, N levels

Some factors influencing electrolyte leakage from maize (Zea mays L.) kernels

1991 ◽  
Vol 1 (1) ◽  
pp. 15-20 ◽  
Author(s):  
H. Bruggink ◽  
H. L. Kraak ◽  
M. H. G. E. Dijkema ◽  
J. Bekendam
Keyword(s):  
Zea Mays ◽  
Moisture Content ◽  
Electrolyte Leakage ◽  
Zea Mays L ◽  
Mechanical Damage ◽  
Kernel Weight ◽  
Conductivity Measurements ◽  
Factors Influencing ◽  
Quality Testing ◽  
Maize Kernels

AbstractEven though the embryo of a maize (Zea mays L.) kernel contributes relatively little to total kernel weight, it is a main source of electrolytes which leach from the kernel during imbibition. Ageing of maize kernels for 18 days at 40°C and a moisture content of about 15% results in an increase of electrolyte leakage which almost exclusively originates from the embryo. The effect of ageing is most apparent after prolonged periods of imbibition. Mechanical damage increases leakage early during imbibition, the effect of damage being considerably larger for aged than for unaged kernels. The large amount of electrolytes measured after the first hour of imbibition of undamaged kernels comes mainly from the pericarp. The electrolyte content of the pericarp is variety dependent and may interfere with quality testing by conductivity measurements.

The effect of changes of assimilate supply around flowering on grain sink size and yield of maize (Zea mays L.) cultivars of tropical and temperate adaptation

1988 ◽  
Vol 39 (2) ◽  
pp. 153 ◽  
Author(s):  
GK Aluko ◽  
KS Fischer
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Zea Mays L ◽  
Flag Leaf ◽  
Dry Weight ◽  
Grain Filling ◽  
Plant Parts ◽  
Male Inflorescence ◽  
Female Inflorescence ◽  
Sink Size

Two maize (Zea mays L.) cultivars of temperate and one of tropical adaptation were grown in a subtropical (27�s.) environment under favourable conditions of plant population density, water and nutrient supply. The radiation incident to the plant during the period from flag leaf to 10 days after flowering was varied from the control by either shading or temporarily restraining leaves of neighbouring plants. The effects of these changes in assimilate supply, and of the presence of the male inflorescence, on the immediate dry weight of various plant parts and grain sink size, and consequential on dry matter production and grain yield was investigated. The radiation treatments effected small but significant changes in crop growth rate. Shading reduced the dry weight of the ear, and husk of the female inflorescence and male inflorescence (tassel). There were increases due to enhanced radiation. While removal of tassels also enhanced the dry weight of the female inflorescence, there was no evidence that the male inflorescence was a preferred sink for assimilates during this stage of growth.In the temperate cultivars, grain number m-2 was associated with ear dry weight at 10 days after anthesis (r = 0.95**). However, only in the tropical cultivar did the larger grain sink result in an increase in grain yield. Shading reduced grain yield in all cultivars probably because of a reduction in the supply of labile assimilates for grain filling.

EFFECT OF TEMPERATURE DURING GRAIN FILLING ON WHOLE PLANT AND GRAIN YIELD IN MAIZE (Zea mays L.)

1983 ◽  
Vol 63 (2) ◽  
pp. 357-363 ◽  
Author(s):  
B. BADU-APRAKU ◽  
R. B. HUNTER ◽  
M. TOLLENAAR
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Leaf Senescence ◽  
Zea Mays L ◽  
Growth Yield ◽  
Grain Filling ◽  
Kernel Weight ◽  
Effect Of Temperature ◽  
Plant Parts ◽  
Whole Plant

In a 2-yr study, plants of an adapted, short-season single cross maize (Zea mays L.) hybrid were grown outdoors until 18 days post-silking. At that stage, the plants were transferred to controlled-environment growth cabinets where temperature effects on leaf senescence, grain and whole plant dry matter (DM) production and DM distribution were studied. The day/night temperature regimes were 25/15 °C, 25/25 °C, 35/15 °C and 35/25 °C. Higher temperatures reduced whole plant DM accumulation during grain filling. The reduction in DM accumulation was primarily related to a reduction in the period of time from 18 days post-silking until 100% leaf senescence and, to a limited extent, to a lower rate of whole plant DM production. Grain yield per plant was also lower under higher temperatures. The decreases in grain yield were almost entirely determined by a shorter duration of grain filling, while no temperature effect was observed on kernel growth rates or on kernel number per ear. During rapid grain filling, the increase in kernel DM results from utilization of a combination of assimilates temporarily stored in the vegetative plant parts and assimilates produced through current photosynthesis. Under the highest temperature regime, assimilates remobilized from other plant parts accounted for a greater proportion of kernel weight gain. In addition, there was an indication that higher night temperatures resulted in an increased proportion of gain in kernel weight resulting from remobilization of stored DM.Key words: Corn, temperature, grain-filling period, grain growth, yield components, leaf senescence

scholarly journals Variability and traits association in maize (Zea mays L.) for yield and yield associated characters

2017 ◽  
Vol 15 (2) ◽  
pp. 193-198
Author(s):  
A Ferdoush ◽  
MA Haque ◽  
MM Rashid ◽  
MAA Bari
Keyword(s):  
Zea Mays ◽  
Genetic Variability ◽  
Grain Yield ◽  
Zea Mays L ◽  
Dry Weight ◽  
Kernel Weight ◽  
High Yield ◽  
Phenotypic Traits ◽  
Cereal Crop ◽  
Breeding Programs

Maize (Zea mays L.) is world’s third most important cereal crop that has a remarkable productive potential in Bangladesh. In Bangladesh, maize is the second most important cereal crop in terms of production. The selection for high yield with desirable traits depends on the genetic variability in the existing germplasm. Successful breeding programs need adequate genetic variation for selection and improvement based on necessity. The research was conducted in the experimental farm of the Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh during November 2015 to April 2016. The aim of this study was to evaluate the performance of 20 maize genotypes based on their yield and yield contributing characters to determine existing genetic variability. The extrapolated ANOVA for different yield contributing parameters showed a high degree of variation among the genotypes used. Correlation co-efficient analysis revealed that yield plant−1 (g) had positive and significant association with ear girth (cm), 1000-kernel weight (g), yield plot−1 (g), grain yield   (tha−1) with dry weight. The genotypes differed significantly for most of the phenotypic traits. The phenotypic co-efficient of variation (PCV) was higher than genotypic co-efficient of variation (GCV) in all traits studied indicating that those traits were interacted with the environment. The traits under study expressed wide heritability estimates (26.81% to 99.95%). Among the characters, highest heritability was recorded for 1000-kernel weight (g). High heritability along with high genetic advance was noticed for 1000-kernel weight (g), yield plot−1 (g)and grain yield (tha−1). Considering different desirable traits P-12, Popcorn, V90-1, 988 were observed as superior genotypes. The data would be useful for proper identification and selection of appropriate parents in breeding programs to develop new maize varieties.J. Bangladesh Agril. Univ. 15(2): 193-198, December 2017

HERITABILITIES AND RELATIONSHIPS AMONG GRAIN-FILLING PERIOD, SEED WEIGHT AND QUALITY IN FORTY ITALIAN VARIETIES OF CORN (ZEA MAYS L.)

1980 ◽  
Vol 60 (4) ◽  
pp. 1101-1107 ◽  
Author(s):  
M. PERENZIN ◽  
F. FERRARI ◽  
M. MOTTO
Keyword(s):  
Zea Mays ◽  
Seed Weight ◽  
Zea Mays L ◽  
Grain Filling ◽  
Kernel Weight ◽  
Genotypic Differences ◽  
Dry Matter Accumulation ◽  
Grain Moisture ◽  
Wide Range ◽  
Grain Filling Period

Forty Italian open-pollinated varieties of corn (Zea mays L.), selected to represent a wide range of plant maturity and grain weight, were evaluated in 1977 and 1978 to determine genetic variances and heritabilities for length and rate of grain-filling period, kernel weight and three seed-quality traits and to examine relationships among these traits. The results showed highly significant genotypic differences and high heritability estimates for most of the traits studied. Moreover, kernel weight and rate of grain filling were found to be closely associated, although this relationship could not be statistically tested. A relatively high correlation was also detected between kernel weight and length of the grain-filling period. The increase in seed weight obtained through a delay in black-layer formation was associated with a higher grain moisture content and a decreased grain protein percentage. A further noteworthy finding of this study was the identification of two varieties which attained a large seed weight in a relatively short time through a very high rate of dry matter accumulation. The implications of these findings are discussed from a physiological and breeding point of view.

scholarly journals Excision Patterns of Activator (Ac) and Dissociation (Ds) Elements in Zea mays L.: Implications for the Regulation of Transposition

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1851-1869 ◽  
Author(s):  
Manfred Heinlein
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Waxy Gene ◽  
Transposition Frequency ◽  
Cis Acting ◽  
Dosage Effects ◽  
In Trans ◽  
Ds Excision ◽  
Maize Kernels ◽  
Strong Contrast

The pattern of aleurone variegation of maize kernels carrying Ac and bz-m2(DI) as reporter allele for Ac activity depends on the dosage of both Ac and Ds. Alterations of Ac dosage can abolish Ds excision at certain times and allow it to occur at other times. wx-m7 and wx-m9 are different Ac insertions in the Waxy gene which have different dosage effects on Ds excision. Kernels, heterozygous for the two Ac alleles and being either wx-m7/wx-m7/wx-m9 or wx-m9/wx-m9/wx-m7 exhibit characteristic patterns of predominantly late excisions; this is in strong contrast to the pattern of early excisions present on wx-m7/wx-m7/wx-m7 homozygotes. This observation supports the hypothesis that the Ac alleles express different amounts of transposase (TPase) during development and that above a certain level of TPase transposition is inhibited. Furthermore, experimental results suggest that the frequency of Ac-induced events is influenced by the dosage and composition of the transactivated Ds or Ac allele. Thus, transposition frequency seems not to be exclusively determined in trans by the amount of active TPase, but also by specific cis-acting properties of the TPase substrate.

EFFECTS OF TEMPERATURE ON RATE AND DURATION OF KERNEL DRY MATTER ACCUMULATION OF MAIZE

1988 ◽  
Vol 68 (4) ◽  
pp. 935-940 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. W. BRUULSEMA
Keyword(s):  
Growth Rate ◽  
Zea Mays ◽  
Dry Matter ◽  
Zea Mays L ◽  
Dry Weight ◽  
Controlled Environment ◽  
Dry Matter Accumulation ◽  
Linear Kernel ◽  
Effects Of Temperature ◽  
Kernel Growth

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate

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