Changes in kernel characteristics during grain filling in silage-specific and dual-purpose corn hybrids

2012 ◽  
Vol 92 (3) ◽  
pp. 427-439 ◽  
Author(s):  
B. L. Ma ◽  
L. M. Dwyer

Ma, B. L. and Dwyer, L. M. 2012. Changes in kernel characteristics during grain filling in silage-specific and dual-purpose corn hybrids. Can. J. Plant Sci. 92: 427–439. Silage-specific corn (Zea mays L.) hybrids have been gaining in popularity in recent years, but there is a lack of information about the difference in kernel characterization between Leafy silage-specific and dual-purpose hybrids. A field study was conducted for 4 yr to determine the changes in kernel moisture content, kernel dry weight, kernel nitrogen (N) and phosphorus (P) concentrations over the period of grain filling for Leafy silage-specific and dual-purpose hybrids at two plant population densities. In both types of hybrids, kernel dry weight content increased rapidly from approximately 2 wk after silking and reached a maximum at about 50 to 68 d after silking. While some differences among hybrids in kernel maximum dry weight were noted (P<0.05), there was no distinction between hybrid types. The coefficients of kernel moisture change differed greatly between the two types with lower rates of decline of kernel moisture in some of the Leafy silage-specific hybrids (down-hill slope b<0.0136±0.00044 g kg−1d−1) than the dual-purpose or silage hybrids without the Leafy characteristic (b≥0.0164±0.00039 g kg−1d−1). Higher plant population density had a negligible effect on kernel moisture decline and N and P concentrations, but reduced kernel dry weight by up to 7% in one year. Kernel P was linearly positively correlated with N content (r>0.79, P<0.01), and there was a linear relationship between kernel moisture and the whole-plant silage moisture content (R2≥0.70). Our data also showed that one of the Leafy silage-specific hybrids had higher rates of kernel dry weight accumulation and softer kernel hardness (P<0.05) than the dual-purpose or non-Leafy silage hybrids. Our findings on the distinct characteristics of hybrid types are important considerations for corn producers to choose suitable hybrids and make decisions on silage harvest dates.

1977 ◽  
Vol 4 (5) ◽  
pp. 785 ◽  
Author(s):  
I Sofield ◽  
LT Evans ◽  
MG Cook ◽  
IF Wardlaw

Controlled-environment conditions were used to examine the effects of cultivar and of temperature and illuminance after anthesis on grain setting and on the duration and rate of grain growth. After an initial lag period, which did not differ greatly between cultivars, grain dry weight increased linearly under most conditions until final grain weight was approached. Growth rate per grain depended on floret position within the ear, varied between cultivars (those with larger grains at maturity having a faster rate), and increased with rise in temperature. With cultivars in which grain number per ear was markedly affected by illuminance, light had relatively little effect on growth rate per grain. With those in which grain number was less affected by illuminance, growth rate per grain was highly responsive to it, especially in the more distal florets. In both cases there was a close relation between leaf photosynthetic rate as influenced by illuminance, the rate of grain growth per ear, and final grain yield per ear. The duration of linear grain growth, on the other hand, was scarcely influenced by illuminance, but was greatly reduced as temperature rose, with pronounced effects on grain yield per ear. Cultivars differed to some extent in their duration of linear growth, but these differences accounted for less of the difference in final weight per grain than did those in rate of grain growth. Under most conditions the cessation of grain growth did not appear to be due to lack of assimilates.


2002 ◽  
Vol 82 (3) ◽  
pp. 549-550 ◽  
Author(s):  
D. Murray Brown ◽  
Andrew Bootsma

The “desirable” kernel moisture that was used for the original heat unit rating of the “check” corn hybrids in Ontario for 30 yr was replaced with a kernel moisture of 32% in 1993. This level of moisture at physiological maturity was confirmed in a study by Ma and Dwyer (2001) that related the progression if the kernel “milk” line with the decrease in moisture content during grain filling. This communication discusses an interpretation of these results. Key words: Crop heat units, milk line, kernel moisture


1971 ◽  
Vol 77 (3) ◽  
pp. 453-461 ◽  
Author(s):  
R. W. Willey ◽  
R. Holliday

SUMMARYThree wheat experiments are described in which a range of plant populations were shaded during different periods of development; in two of the experiments plant thinning was also carried out at a number of growth stages. Shading during the period of ear development caused an appreciable decrease in grain yield by decreasing the number of grains per ear. Shading during the grain filling period also reduced grain yield, this being brought about by decreased grain size. Thus in contrast to the barley experiments reported earlier (Willey & Holhday, 1971), these particular results gave no indication of a potential surplus of carbohydrate for grain filling and an associated limited ear capacity. However, when plant thinning was carried out at anthesis to make more carbohydrate available for grain filling in the remaining ears, grain yield per ear did not increase. It is argued, therefore, that grain yield probably was determined at least partly by a limited ear capacity. Plant thinning at earlier stages showed how the development of competition during the ear development period progressively reduced the potential capacity of the ear; the greater competition of higher plant populations accelerated this reduction in ear potential.From an examination of the effects of plant population, it is suggested that the number of grains per ear is the component having greatest influence on the decline in grain yield at above-optimum populations. The possible importance of the number of grains per unit area as an indicator of ear capacity on an area basis, and as a determinant of grain yield per unit area, is emphasized. A close relationship between grain yield per unit area and number of grains per unit area is illustrated for a number of plant-population response curves, and it is suggested that the decrease in grain yield at high populations is probably determined by a decrease in the number of grains per unit area. Evidence is presented to substantiate the idea put forward in the barley paper that this decrease in the number of grains per unit area may be attributable more to a lower production of total dry matter by the high populations during the later stages of ear development, than to an unfavourable partitioning of such dry matter between the ear and the rest of the plant.


1988 ◽  
Vol 28 (6) ◽  
pp. 771 ◽  
Author(s):  
S Fukai ◽  
MA Foale

The effects of row spacing on growth and yield of grain sorghum (Sorghum bicolor (L.) Moench.) were investigated at a constant population density using 5 cultivars of different duration to flowering under dryland conditions in south-eastern Queensland. The row spacings were narrow (0.33 m), standard (1.0 m), and wide-double (1.67 + 0.33 m). Rainfall was plentiful during the tillering and grain filling stages of growth, but a severe water deficit developed at the boot-anthesis stage. The water stress impaired heading and grain set, and grain dry weight was low (40-190 g m-2), with earlier flowering cultivars producing higher yields. There was a cultivar x row spacing interaction for yield; in the earliest flowering cultivar Texas (610SR), which headed before severe stress developed, there was no significant effect of row spacing while in the other cultivars the yield was highest in double row and least in narrow row. There was no detectable difference in soil water available to the plants at any time during growth, but a slightly higher plant water status and faster phenological development in the wider row plants. These responses are related to the fact that the tiller production was least in double row and therefore individual stems had more water available to them.


Author(s):  
Gezahegn Biru Sefera ◽  
Habtamu Ashagre ◽  
Thomas Abraham

Mung bean (Vigna radiata L.) is a pulse crop with multiple uses and it was introduced recently in the study area. However, its productivity is limited by inadequate plant population and NPS fertilizer rate in the study area. Hence, this study was carried out to determine optimum plant population and NPS fertilizer rates for mung bean borda varaity in Bako, Western Ethiopia. The experiment comprised of factorial combinations of four different plant populations (500000, 571429, 666667, and 800000 plants ha-1) and five NPS fertilizer rates (0, 50, 100, 150 and 200 kg ha-1) and it was laid out using Randomised Complete Block Design with three replications. The results indicated that main effect of plant population and NPS fertilizer rates had significant effect on phenology, growth, yield, and yield components of mung bean, except stand count, above-ground biomass, straw and seed yield, which were affected by the main factors and their interactions. Highest nodule dry weight per plant (0.14g), number of pods per plant (4.74g), seeds per pod (10.26g), 100-seed weight (3.61g), and harvest index (31.16%) were observed under minimum plant population (500,000 plants ha-1). Moreover, the highest days for 50% flowering (49.08 days), 90% physiological maturity (64.5 days), effective nodules per plant (2.28),nodule fresh weight (0.33gm), nodule dry weight (0.141g plant-1),plant height (11.10cm), number of leaves per plant (8.80), number of branches per plant (3.11), tap root length (8.99cm), number of pods per plant (4.79), seeds per pod (10.78g), 100-seed weight (3.73) and harvest index (32.98%) were observed under 200 kg ha-1 NPS fertilizer. The highest stand count per hectare (780,667 plants ha−1), above-ground biomass (4,947kg ha-1), seed yield ha-1 (1,371kg ha-1) and straw yield (3,575 kg ha-1) were recorded at higher plant population (800,000 plants ha-1) with 200kg NPS ha-1 fertilizer rate (kg ha-1). However, higher plant population (800,000 plants ha-1) at the rate of 100 kg NPS ha-1fertilizer produced 1,325 kg ha-1seed yield which was the highest net benefit (50,080 ETB) and marginal rate of returns (5,610.8%). Therefore, application of 100 kg NPS ha-1 fertilizer rate with plant population of 800,000 plants ha-1 can be recommended for mung bean production in the study area and similar agro-ecologes. However, the current study was carried out only in one location for one cropping season, hence further studies over many seasons and across several locations are needed to have a conclusive recommendation for wide range of agro ecologies for mung bean production.


2021 ◽  
pp. 41-53
Author(s):  
Gezahegn Biru Sefera ◽  
Habtamu Ashagre ◽  
Thomas Abraham

Mung bean (Vigna radiata L.) is a leguminous crop with a tremendous potential in achieving food and nutritional security in Ethiopia in future. In addition, mung bean plays a major role in improving soil nitrogen content through atmospheric nitrogen fixation, thus reducing the dependance on synthetic nitrogenous fertilizers. However, its productivity is limited by inadequate plant population and NPS fertilizer rate in the study area. Hence, this study was carried out to determine the optimum plant population and NPS fertilizer rates for mung bean borda variety in Bako. The experiment comprised of factorial combinations of four different plant populations (500000, 571429, 666667, and 800000 plants ha-1) and five NPS fertilizer rates (0, 50, 100, 150 and 200 kg ha-1) and it was laid out using Randomised Complete Block Design with three replications. Results indicated that main effect of plant population and NPS fertilizer rates had significant effect on phenology, growth, yield, and yield components of mung bean, except stand count, above-ground biomass, straw and seed yield, which were affected by the main factors and their interactions. Highest nodule dry weight per plant (0.14g), number of pods per plant (4.74 g), weight of seeds per pod (10.26 g), 100-seed weight (3.61g), and harvest index (31.16%) were observed under minimum plant population (500,000 plants ha-1). Moreover, effective nodules per plant (2.28), nodule fresh weight (0.33 gm), nodule dry weight (0.141g plant-1), number of pods per plant (4.79), seeds per pod (10.78 g), 100-seed weight (3.73 g) and harvest index (32.98%) were observed under 200 kg ha-1 NPS fertilizer rate. Highest stand count per hectare (780,667 plants ha−1), above-ground biomass (4,947kg ha-1), seed yield ha-1 (1,371kg ha-1) and straw yield (3,575 kg ha-1) were recorded at higher plant population (800,000 plants ha-1) with 200kg NPS ha-1 fertilizer rate. However, higher plant population (800,000 plants ha-1) at the rate of 100 kg NPS ha-1 fertilizer produced1, 325 kg ha-1seed yield which was the highest net benefit (50,080 TB) and marginal rate of returns (5,610.8%). Therefore, application of 100 kg NPS ha-1 fertilizer rate with plant population of 800,000 plants ha-1 can be recommended for mung bean production in the study area and similar agro-ecologies. However, the current study was carried out only in one location for one cropping season, hence further studies over many seasons and across several locations are needed to have a conclusive recommendation for wide range of agro-ecologies for mung bean production.


1986 ◽  
Vol 66 (4) ◽  
pp. 863-869
Author(s):  
JONATHAN M. GREENBERG ◽  
TIM LLOYD SETTER

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.


2016 ◽  
Vol 53 (2) ◽  
pp. 210-225 ◽  
Author(s):  
GUILHERME M. TORRES ◽  
ADRIAN KOLLER ◽  
RANDY TAYLOR ◽  
WILLIAM R. RAUN

SUMMARYSeed-oriented planting provides a manner to influence canopy structure. The purpose of this research was to improve maize light interception using seed-oriented planting to manipulate leaf azimuth across the row thereby minimizing leaf overlap. To achieve leaf azimuths oriented preferentially across the row, seeds were planted: (i) upright with caryopsis pointed down, parallel to the row (upright); and (ii) laying flat, embryo up, perpendicular to the row (flat). These treatments were compared to conventionally planted seeds with resulting random leaf azimuth distribution. Seed orientation effects were contrasted with three levels of plant population and two levels of hybrid specific canopy structures. Increased plant population resulted in greater light interception but yield tended to decrease as plant population increased. The planophile hybrid produced consistently greater yields than the erectophile hybrid. The difference between planophile and erectophile hybrids ranged from 283 to 903 kg ha−1. Overall, mean grain yield for upright and flat seed placement increased by 351 and 463 kg ha−1 compared to random seed placement. Greater cumulative intercepted photosynthetically active radiation (CIPAR) was found for oriented seeds rather than random-oriented seeds. At physiological maturity upright, flat and random-oriented seeds intercepted 555, 525 and 521 MJ m−2 of PAR, respectively. Maize yield responded positively to improved light interception and better radiation use efficiency. Under irrigated conditions, precision planting of maize increased yield by 9 to 14% compared to random-oriented seeds.


2007 ◽  
Vol 55 (6) ◽  
pp. 618 ◽  
Author(s):  
Kim N. Hamilton ◽  
Sarah E. Ashmore ◽  
Rod A. Drew ◽  
Hugh W. Pritchard

Combinational traits of seed size and seed-coat hardness in Citrus garrawayi (F.M.Bailey) (syn. of Microcitrus garrowayi) were investigated as markers for estimation of seed morphological and physiological maturity. Seed size (length) and coat hardness correlated well with changes in seed coat and embryo morphological development, dry-weight accumulation, decreases in moisture content and a significant increase in germinability. Seed moisture content decreased from 82 ± 1% in immature seeds to 40 ± 1% at seed maturation. The outer integument of immature seeds consisted of thin-walled epidermal fibres from which outgrowths of emerging protrusions were observed. In comparison, mature seed coats were characterised by the thickening of the cell walls of the epidermal fibres from which arose numerous protrusions covered by an extensive mucilage layer. Immature seeds, with incomplete embryo and seed-coat histodiffereniation, had a low mean germination percentage of 4 ± 4%. Premature seeds, with a differentiated embryonic axis, were capable of much higher levels of germination (51 ± 10%) before the attainment of mass maturity. Mature seeds, with the most well differentiated embryonic axis and maximum mean dry weight, had the significantly highest level of germination (88 ± 3%).


1995 ◽  
Vol 75 (3) ◽  
pp. 557-563 ◽  
Author(s):  
H. Z. Cross

Grain quality, timeliness of harvest, and profitability can be increased by improving field drying characteristics of maize (Zea mays L.) hybrids. To better understand hows genes control ear drying, I compared maize strains developed by divergently selecting three cycles for (1) high HM or low LM moisture content at 45 d post pollination in the field or (2) fast FD vs. slow ear drying SD In laboratory. A field study across five locations compared HM, LM, FD, and SD strains from each of five synthetics for grain yield, ear moisture at harvest, test weight, lodging, and other agronomic traits. I studied ear moisture during grain filling for two subsets of divergently selected strains from one and three synthetics for 2 yr. In a third 2-yr field study, I measured mature kernel weight, lag period duration (LPD), effective grain-filling period (EFPD), and rate of dry matter accumulation (RDMA) for LM and HM strains developed from each of four synthetics. When averaged across the five synthetics, both SD and LM selections produced equivalent yields but lower ear moisture at harvest than the corresponding divergent strains. The LM strains had higher test weights than HM strains. When averaged across three synthetics and 2 yr, the HM strains produced higher moisture than LM strains at 15, 30, 45, and 60 d after silking. However, environments also influenced moisture content of the kernels during grain filling. In three of the four synthetics studied, HM strains had heavier kernels than corresponding LM strains. The heavier kernels seem to be due to increased RDMA. When averaged across four synthetics, LM strains had shorter LPD than HM strains. These correlated selection responses suggest that a genetic association exists among moisture content during grain filling, moisture content at physiological maturity, moisture content at harvest, LPD, and test weight. Breeding for LM or SD should improve field-drying characteristics of maize without increasing stalk breakage or decreasing yields. Key words:Zea mays L., grain filling, dry-down rates, mass selection, breeding methods


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